Nikolay Alexandrovich Agadzhanyan
Normal physiology
Abbreviations in the text
BP - blood pressure
ADH – antidiuretic hormone
ADP – adenosine diphosphoric acid
ACTH – adrenocorticotropic hormone
APUD – system – Amine Precursors Uptake and Decarboxylating system
ATP – adenosine triphosphoric acid
GDP – secondary evoked potential
VIP – vasoactive intestinal peptide
ANS – autonomic nervous system
EP – evoked potential
EPSP – excitatory postsypaptic potential
GABA – gamma-aminobutyric acid
HDF – guaposindiphosphagus
GIP – gastrointestinal pep tide
GHB – gamma-hydroxybutyric acid
GTP – guaposine triphosphate
BBB - blood-ecephalic barrier
DK – respiratory coefficient
DNA – deoxyribonucleic acid
DO – tidal volume
VC – vital capacity of the lungs
GIP – gastric inhibitory peptide
IL – interleukins
IHD – coronary heart disease
CFU-E – colopia-forming unit of erythrocytes
COMT – catechol methyltransferase
AOS – acid-base state
CSF-G – grapulocyte colopiestimulating factor
CSF-M – blood cell colopiestimulating factor
LH – luteinizing hormone
MAO – mopoamine oxidase
MVL - maximum ventilation
DMD - slow diastolic depolarization
MOC – minute blood volume
MP – membrane potential
MOC - maximum oxygen consumption
HNO., – oxyhomoglobip
RLC - residual lung capacity
OO - basic exchange
BCC – volume of circulating blood
PAG – para-amipohippuric acid
AP – action potential
Software – primary answer
PP – pancreatic peptide
P"GG - narthyroid-stimulating hormone
PACK – reflation of the state of aggregation of blood
RNA – ribonucleic acid
RF – reticular formation
PWV – pulse wave propagation speed
STH – somatotropic hormone
IPSGT – inhibitory postsynaptic potential
TSH – thyroid stimulating hormone
TNF – tumor necrosis factor
FRC – functional residual capacity
FSH – follicle stimulating hormone
cAMP – cyclic adenosine monophosphate
CVP – central venous pressure
CSF - cerebrospinal fluid
cGMP – cyclic 3,5-guanosine monophosphate
CNS - central nervous system
HR – number of heartbeats
ECoG – electrocorticogram
EEG – electroencephalogram
ECG – electrocardiogram
YUGA – juxtaglomerular apparatus
Chapter 1. History of physiology. Methods of physiological research
Physiology is an important area of human knowledge, the science of the life activity of the whole organism, physiological systems, organs, cells and individual cellular structures. As the most important synthetic branch of knowledge, physiology strives to reveal the mechanisms of regulation and patterns of vital activity of the organism and its interaction with the environment. Physiology is the basis, the theoretical basis - the philosophy of medicine, combining disparate knowledge and facts into one whole. The doctor assesses a person’s condition and the level of his capacity according to the degree of functional impairment, i.e., according to the nature and magnitude of deviations from the norm of the most important physiological functions. In order to return these deviations to normal, it is necessary to take into account the individual age and ethnic characteristics of the organism, as well as the environmental and social conditions of the environment.
When pharmacologically correcting body functions impaired in inadequate conditions, one should pay attention not only to the peculiarities of the influence of natural, climatic and industrial conditions of the environment, but also to the nature of anthropogenic pollution - the quantity and quality of harmful highly toxic substances in the atmosphere, water, and food.
Structure and function are closely related and interdependent. For an integrative assessment of the vital activity of an entire organism, physiology synthesizes specific comprehensive information obtained from such sciences as anatomy, cytology, histology, molecular biology, biochemistry, ecology, biophysics and related ones. To assess the entire variety of complex physiological processes that occur in the body during adaptation, a systematic approach and deep philosophical understanding and generalization are required. Physiological knowledge was obtained as a result of original experimental materials accumulated by scientists from different countries.
The main object of medical research is humans, but the main physiological patterns, for a known reason, were established in experiments on various species of animals, both in laboratory and natural conditions. The higher the organization of the animal, the closer the object being studied comes to the person, the more valuable the results obtained. However, the results of experimental studies on animals in the field of comparative and ecological physiology can be transferred to humans only after careful analysis and mandatory critical comparison of the obtained materials with clinical data.
If signs of functional disorders occur in a subject, for example, during adaptation to inadequate conditions, extreme exposures, or when taking pharmacological drugs, the physiologist must comprehend, explain what determines these disorders, and give an ecological and physiological justification. One of the main vital properties is the body’s ability to compensate, that is, to equalize deviations from the norm, to restore the impaired function in one way or another.
Physiology studies a new quality of living things - its function or manifestations of the vital activity of the organism and its parts, aimed at achieving a useful result and having adaptive properties. The basis of the vital activity of any function is the metabolism, energy and information.
The conditions of human existence are determined by the specific physical and chemical characteristics of the internal and external environment, natural and climatic factors, as well as socio-cultural traditions and the quality of life of the population. The phenogenotypic characteristics of each individual must be taken into account when using pharmacological drugs.
The formation of the complex physiological system of each organism is based on an individual time scale. The methodological principles of biorhythmology - chronophysiology, chronopharmacology are currently confidently penetrating into research at all levels of the organization of living things - from the molecular to the whole organism. Rhythm as one of the fundamental features of the functioning of the body is directly related to the mechanisms of feedback, self-regulation and adaptation. When conducting chronophysiological and chronopharmacological studies, it is necessary to take into account data on the season of the year, time of day, age, typological and constitutional characteristics of the body and environmental conditions of the habitat.
The main essence of life is manifested in the implementation of two fundamentally important processes - birth and survival. The need to preserve human life was present at all stages of its development, and already in ancient times, elementary ideas about the activities of the human body were formed.
The father of medicine, Hippocrates (460 – 377 BC), laid the foundation for understanding the role of individual systems and functions of the body as a whole. Another famous doctor of antiquity, the Roman anatomist Galen (201 - 131 BC), held similar views. Humoral hypotheses and theories remained dominant for thousands of years among doctors in ancient China, India, the Middle East and Europe.
The importance of temporary factors and cyclical changes in the environment was first pointed out by Aristotle (384 - 322 BC). He wrote: “The duration of all these phenomena: pregnancy, development, and life - is completely natural to measure in periods. I call periods day and night, month, year, and the times measured by them; in addition, lunar periods...” All these original ideas were forgotten for some time. Their thorough study began on the basis of scientific observation and experience only in the Renaissance. The greatest physician of this era, T. Paracelsus (1493 - 1541), emphasized in his writings that a doctor’s theory is experience; no one can become a doctor without science and experience.
Name: Normal human physiology.
The second edition of the textbook “Normal Human Physiology” includes 22 chapters, divided into 4 sections: the basic principles of human physiology, regulatory and control systems, functions of the body’s life support systems, and integrative functions of humans. The material of the chapters is presented in accordance with the State educational standard on normal physiology for medical universities in Russia, and is presented at the systemic, organ and tissue levels. Particular attention is paid to the molecular mechanisms of physiological processes.
The textbook is intended for undergraduates, graduate students and teachers, and may also be in demand by clinical residents and biomedical researchers.
The life activity of a multicellular organism completely depends on the environment, its gas, water, salt composition, nutrients, the temperature of the environment in which it evolved and lives, etc. It was the external environment that, in the course of evolution, shaped the specific characteristics of metabolism between the human body, animals and the external environment: nutritional (exchange of nutrients and products of their metabolism), gas, water-salt, etc. This exchange between the body and the external environment does not have a direct effect on the cells of the body’s tissues, since the liquid in the intercellular spaces is that intermediate medium , through which oxygen, energy and plastic resources enter the cells from the external environment, and, on the contrary, products of protein, fat, carbohydrate, salt metabolism, etc., enter it from the cells. From the fluid of the intercellular spaces, the latter, with blood and lymph during the blood circulation and lymph circulation, move to the organs that ensure the removal of these substances from the body (gastrointestinal tract, kidneys, lungs, skin, etc.). Thus, for the cells of the human and animal body, the “external environment” of habitat is the extracellular fluid, which Claude Bernard called the “internal environment of the body” and considered its existence as a necessary condition for the life of the cells of the body, independent of changes in the external environment.
CONTENT
Introduction. Physiology as a subject and concepts characterizing it
I. BASIC FUNDAMENTALS OF HUMAN PHYSIOLOGY
Chapter 1. Body fluids
1.1. Internal environment of the body
1.2. Biological properties of fluids that make up the internal environment of the body
1.2.1. Water as a component of body fluids
1.2.2. Histohematic barriers
1.2.3. Intracellular fluid
1.2.4. Interstitial or tissue fluid
1.3. Blood plasma as the internal environment of the body
1.3.1. Electrolyte composition of blood plasma
1.3.2. Osmotic and oncotic pressure of blood plasma
1.3.3. Exchange of water between blood plasma and interstitial fluid
1.3.4. Products of protein metabolism, carbohydrates and lipids of blood plasma
1.3.5. Blood plasma proteins
1.4. Factors ensuring the liquid state of blood
1.5. Lymph as the internal environment of the body
1.6. Mechanism of lymph formation
1.7. Transcellular body fluids
1.8. Exchange of fluids between water sectors in the human body
Chapter 2. Physiology of excitable tissues
2.1. Structure and physiological functions of the membrane of excitable tissue cells
2.1.1. Transport of substances across the cell membrane
2.1.1.1. Movement of water across cell membranes
2.1.1.2. Osmosis
2.1.1.3. Diffusion
2.1.1.4. Primary active transport
2.1.1.5. Secondary active transport
2.1.1.6. Endocytosis and exocytosis
2.1.1.7. Intracellular transport of molecules
2.2. Excitability as the main property of nervous and muscle tissue
2.2.1. The concept of irritation and irritants
2.2.2. Dependence of the occurrence of excitation on the duration and strength of stimulation
2.2.3. Excitability and excitation during the action of direct current on nerve and muscle tissue
2.2.3.1. Physiological electroton
2.2.3.2. Law of polarity of irritation of nerve and muscle tissue
2.2.3.3. Electrodiagnostic law
2.2.4. The concept of functional mobility of excitable tissues
2.3. Electrical phenomena in excitable cells
2.3.1. Resting membrane potential
2.3.2. Action potential of excitable cells
2.2.1. Refractory period in excitable cells
2.3.1. Local membrane response of excitable cells
2.4. Conduction of impulses along nerve fibers
2.4.1. Unmyelinated fibers
2.4.2. Myelinated fibers
2.4.3. Laws for the conduction of excitation along nerve fibers
2.5. Conduction of excitation through the synapse
2.5.1. Conduction of excitation through the neuromuscular junction
2.5.1.1. Presynaptic mechanism
2.5.1.2. Diffusion of acetylcholine across the synaptic cleft of the neuromuscular junction
2.5.1.3. Postsyaptic mechanism
2.5.1.4. Restorative processes of the membrane structure and function of the neuromuscular synapse after the transfer of excitation
2.5.2. Conduction of excitation through the axosomatic synapse
2.5.2.1. Function of the presynaptic terminal of neurons
2.5.2.2. Presynaptic mechanism of excitation
2.5.2.3. Presynaptic regulation of mediator exocytosis
2.5.2.4. Postsynaptic mechanism of excitation conduction
2.5.2.5. Functions of metabotropic receptors of the postsynaptic membrane of the axosomatic synapse
2.5.3. Conducting excitation in the main types of synapses of the central nervous system
2.5.3.1. Cholinergic synapse
2.5.3.2. Adrenergic synapse
2.5.3.3. Dopaminergic synapse
2.5.3.4. Serotonergic synapse
2.5.3.5. Glutamatergic synapse
2.5.3.6. GABAergic synapse
2.5.3.7. Glycinergic synapse
2.6. Functions of muscle tissue
2.6.1. Skeletal muscle
2.6.1.1. Functions of myofilaments
2.6.1.2. Mechanism of skeletal muscle contraction
2.6.1.3. Activation of muscle contraction
2.6.1.4. Skeletal muscle relaxation
2.6.1.5. Types of muscle contractions
2.6.1.6. Types of skeletal muscle fibers
2.6.1.7. Physiological indicators of skeletal muscle contraction
2.6.2. Skeletal muscle fatigue
2.7. Smooth muscle
2.7.1. Types of smooth muscles
2.7.2. Electrical activity of smooth muscle cells
2.7.3. Neuromuscular smooth muscle junction
2.7.4. Molecular mechanism of smooth muscle contraction
2.7.5. Molecular mechanism of smooth muscle relaxation
2.7.6. Physiological parameters of smooth muscle contraction
2.8. Functions of cardiac muscle cells
2.8.1. Electrical activity of cardiac muscle cells
2.8.1.1. Resting potential
2.8.1.2. Molecular mechanism of the action potential in typical cardiac muscle cells
2.8.1.3. The mechanism of occurrence of pacemaker activity in the cells of the sinoatrial node
2.8.2. Molecular mechanism of cardiomyocyte contraction
2.8.3. Molecular mechanism of cardiomyocyte relaxation
2.8.4. Mediator control of cardiomyocyte contraction
II. REGULATING AND CONTROL SYSTEMS
Chapter 3. General principles and mechanisms of regulation of physiological functions
3.1. General principles of organization of the regulatory system
3.1.1. Levels of organization of the regulatory system
3.1.2. Types and mechanisms of regulation
3.1.3. Reactivity and effect of regulation
3.1.4. Mechanisms of regulation of life activity
3.2. Reflex regulation of body functions
3.2.1. Sensory receptors
3.2.2. Afferent and efferent nerve conductors
3.2.3. Excitation and inhibition in the reflex arc
3.2.4. Mechanisms of communication between the links of the reflex arc
3.2.5. Nerve centers and their properties
3.2.6. Interaction of various reflexes. Principles of coordination of reflex activity
3.2.7. Reflex regulation of visceral functions
3.3. Voluntary (volitional) regulation of physiological functions
3.4. Hormonal regulation of body functions
3.4.1. General characteristics of the components of the hormonal regulatory system
3.4.2. Types and routes of action of hormones
3.5. Local humoral regulation of cell functions
3.6. Systemic principle of organizing mechanisms for regulating physiological functions
Chapter 4. Functions of the central nervous system
4.1. Fundamentals of neuronal and glial function
4.1.1. General characteristics of neurons
4.1.2. Functional model of a neuron
4.1.2.1. Input signals
4.1.2.2. Combined signal - action potential
4.1.2.3. Conducted signal
4.1.2.4. Output signal
4.1.3. Functional characteristics of neuroglia
4.1.3.1. Astrocytes
4.1.3.2. Oligodendrocytes
4.1.3.3. Ependymal glia
4.1.3.4. Microglia
4.2. General principles of functional association of neurons
4.2.1. General principles of organization of functional brain systems
4.2.1.1. Existence of several levels of information processing
4.2.1.2. Topographic ordering of pathways
4.2.1.3. Presence of parallel pathways
4.2.2. Types of Neural Networks
4.2.3. Neurochemical classes of neurons
4.2.3.1. Glutamatergic system
4.2.3.2. Cholinergic system
4.2.3.3. Neuronal systems using biogenic amines
4.2.3.4. GABAergic system
4.2.3.5. Peptidergic neurons
4.3. Functions of the spinal cord
4.3.1. Functional organization of the spinal cord
4.3.2. Spinal cord reflexes
4.3.2.1. Tendon reflexes
4.3.2.2. Muscle stretch reflex
4.3.2.3. Reflex regulation of muscle tension
4.3.2.4. Flexion and extension reflexes
4.3.2.5. Rhythmic reflexes
4.3.2.6. Involvement of the spinal cord in locomotion
4.3.2.7. Spinal autonomic reflexes
4.3.3. Functional organization of the spinal cord pathways
4.4. Brain stem functions
4.4.1. Functional organization of the brainstem
4.4.1.1. Cranial nerves
4.4.1.2. Functional specialization of stem nuclei
4.4.2. Reflex function of the brain stem
4.4.2.1. Static and statokinetic reflexes
4.4.2.2. Descending motor pathways of the brainstem
4.4.2.3. Oculomotor centers of the brainstem
4.5. Functions of the reticular formation
4.5.1. Features of the neural organization of the reticular formation
4.5.2. Descending and ascending influences of the reticular formation
4.6. Functions of the cerebellum
4.6.1. Functional organization of the cerebellum
4.6.2. Interaction between cortical neurons and cerebellar nuclei
4.6.3. Efferent connections of the cerebellum with motor structures of the brain
4.7. Functions of the diencephalon
4.7.1. Functions of the thalamus
4.7.2. Functions of the hypothalamus
4.7.2.1. The role of the hypothalamus in the regulation of autonomic functions
4.7.2.2. The role of the hypothalamus in the regulation of endocrine functions
4.8. Functions of the limbic system of the brain
4.8.1. Functions of the tonsils
4.8.2. Functions of the hippocampus
4.9. Functions of the basal ganglia (striopallidal system)
4.9.1. Interaction of the basal ganglia with other brain structures
4.9.2. Modulation of neural switching in the basal ganglia
4.10. Functions of the cerebral cortex
4.10.1. Functional distribution of neurons in the cortex
4.10.2. Modular organization of the cortex
4.10.3. Electrical activity of the cortex
4.10.4. Functions of sensory areas of the cortex
4.10.4.1. Function of the somatosensory cortex
4.10.4.2. Function of the visual cortex
4.10.4.3. Function of the auditory cortex
4.10.5. Functions of association areas of the cortex
4.10.5.1. Functions of the parieto-temporo-occipital cortex
4.10.5.2. Functions of the prefrontal association cortex
4.10.5.3. Functions of the limbic cortex
4.10.6. Functions of motor cortex areas
4.10.6.1. Function of the primary motor cortex
4.10.6.2. Function of the secondary motor cortex
4.11. Movement regulation
4.11.1. Hierarchical organization of motor systems
4.11.2. Descending tracts of the motor cortex
4.11.3. Control of movements performed
4.12. Interhemispheric functional asymmetry
4.12.1. Functional capabilities of isolated hemispheres
4.12.2. Identification of the functions of undivided hemispheres
4.12.3. Functional specialization of the cerebral hemispheres
Chapter 5. Autonomic nervous system
5.1. Structure of the autonomic nervous system
5.2. Functions of the autonomic nervous system
5.3. Functions of the peripheral parts of the autonomic nervous system
5.3.1. Sympathetic and parasympathetic divisions
5.3.2. Enteric nervous system
5.4. Reflexes of the autonomic nervous system
5.5. Higher centers of autonomic regulation
Chapter 6. Endocrine nervous system - regulator of functions and processes in the body
6.1. Chemical nature and general mechanisms of action of hormones
6.1.1. Mechanisms of action of peptide, protein hormones and catecholamines
6.1.1.1. Main systems of secondary intermediaries
6.1.1.2. Secondary intermediary relationships
6.1.2. Mechanism of action of steroid hormones
6.1.2.1. Genomic mechanism of action
6.1.2.2. Non-genomic mechanism of action
6.1.3. Self-regulation of effector sensitivity to hormonal signals
6.2. Regulatory functions of pituitary hormones
6.2.1. Hormones of the adenohypophysis and their effects in the body
6.2.1.1. Regulation of secretion and physiological effects of corticotropin
6.2.1.2. Regulation of secretion and physiological effects of gonadotropins
6.2.1.3. Regulation of secretion and physiological effects of thyrotropin
6.2.1.4. Regulation of secretion and physiological effects of somatotropin
6.2.1.5. Regulation of secretion and physiological effects of prolactin
6.2.2. Neurohypophysis hormones and their effects in the body
6.2.2.1. Regulation of secretion and physiological effects of vasopressin
6.2.2.2. Regulation of secretion and physiological effects of oxytocin
6.2.3. Hormones of the intermediate lobe
6.2.4. Endogenous opiates
6.3. Regulatory functions of adrenal hormones
6.3.1. Hormones of the adrenal cortex and their effects in the body
6.3.1.1. Regulation of secretion and physiological effects of mineralocorticoids
6.3.1.2. Regulation of secretion and physiological effects of glucocorticoids
6.3.1.3. Regulation of secretion and physiological effects of sex steroids in the adrenal cortex
6.3.2. Adrenal medulla hormones and their effects in the body
6.4. Regulatory functions of thyroid hormones
6.4.1. Regulation of secretion and physiological effects of iodine-containing thyroid hormones
6.4.2. Regulation of secretion and physiological effects of calcitonin
6.5. Regulatory functions of parathyroid hormone
6.6. Regulatory functions of pineal gland hormones
6.7. Regulatory functions of endocrine tissue hormones in organs with non-endocrine functions
6.7.1. Regulatory functions of pancreatic hormones
6.7.1.1. Physiological effects of insulin
6.7.1.2. Physiological effects of glucagon
6.7.2. Regulatory functions of gonadal hormones
6.7.2.1. Testicular hormones and their effects in the body
6.7.2.2. Ovarian hormones and their effects in the body
6.8. Regulatory functions of hormones in cells combining hormone production and non-endocrine functions
6.8.1. Regulatory functions of placental hormones
6.8.2. Regulatory functions of thymus hormones
6.8.3. Regulatory functions of kidney hormones
6.8.3.1. Synthesis, secretion and physiological effects of calcitriol
6.8.3.2. Renin formation and the main functions of the renin-angiotensin-aldosterone system
6.8.4. Regulatory effects of cardiac hormones
6.8.5. Regulatory function of vascular endothelial hormones
6.8.6. Regulatory function of gastrointestinal hormones
6.9. The role of the endocrine system in nonspecific adaptive reactions
6.9.1. Hormonal support of general adaptation syndrome, or stress
6.9.2. Hormonal regulation of local compensatory reactions
III. FUNCTIONS OF LIFE SUPPORT SYSTEMS
Chapter 7. Functions of blood cells. Hemostasis. Regulation of hematopoiesis. Basics of transfusnology
7.1. Functions of red blood cells
7.1.1. Functions and properties of red blood cells
7.1.2. Hemoglobin
7.1.3. Aging and destruction of red blood cells in the body
7.1.4. The role of iron ions in erythropoiesis
7.1.5. Erythropoiesis
7.1.6. Regulation of erythropoiesis
7.2. Leukocytes
7.2.1. Functions of neutrophil granulocytes
7.2.2. Functions of basophilic granulocytes
7.2.3. Functions of eosinophilic leukocytes
7.2.4. Functions of monocyte-macrophages
7.2.5. Regulation of granulo- and monocytopoiesis
7.3. Platelet functions
7.3.1. Structure and function of platelets
7.3.2. Thrombocytopoiesis and its regulation
7.4. Mechanisms of blood clotting (hemostasis)
7.4.1. Platelet hemostasis
7.4.2. Blood coagulation system
7.4.3. Anticoagulant mechanisms of blood
7.4.4. Fibrinolysis
7.5. General patterns of hematopoiesis
7.5.1. Hematopoietic progenitor cells
7.5.2. Regulation of proliferation and differentiation of COCs
7.5.3. The role of the stroma of hematopoietic organs in the regulation of hematopoiesis
7.5.4. Regulation of the release of blood cells from the bone marrow into the bloodstream
7.5.5. Features of hematopoietic tissue metabolism
7.6. The role of vitamins and microelements in hematopoiesis
7.7. Basics of transfusiology
7.7.1. Blood groups
7.7.2. The influence of transfused blood and its components on the human body
Chapter 8. Immune system
8.1. Origin and functions of immune system cells
8.1.1. T lymphocytes
8.1.1.1. Characteristics of T lymphocytes
8.1.1.2. Subpopulations of T lymphocytes
8.1.1.3. Functions of T lymphocytes
8.1.2. B lymphocytes
8.1.2.1. Characteristics of B lymphocytes
8.1.2.2. Functions of B lymphocytes
8.1.3. Antigen presenting cells
8.2. Structure and functions of the immune system organs
8.2.1. Bone marrow
8.2.2. Thymus (thymus gland)
8.2.3. Spleen
8.2.4. The lymph nodes
8.2.5. Mucosal-associated lymphoid tissue (mucosal-associated lymphoid tissue)
8.3. Stages and forms of the immune response
8.3.1. Early protective inflammatory response
8.3.2. Antigen presentation and recognition
8.3.3. Activation of T and B lymphocytes in the immune response
8.3.4. Cellular immune response
8.3.5. Humoral immune response
8.3.6. Immunological memory as a form of specific immune response
8.3.7. Immunological tolerance
8.4. Mechanisms that control the immune system
8.4.1. Hormonal control
8.4.3. Cytokine control
Chapter 9. Functions of the circulatory and lymphatic systems
9.1. Circulatory system
9.1.1. Functional classifications of the circulatory system
9.1.2. General characteristics of blood movement through vessels
9.1.3. Systemic hemodynamics
9.1.3.1. Systemic blood pressure
9.1.3.2. Total peripheral vascular resistance
9.1.3.3. Cardiac output
9.1.3.4. Heart rate (pulse)
9.1.3.5. Work of the heart
9.1.3.6. Contractility
9.1.3.6.1. Automaticity and conductivity of the myocardium
9.1.3.6.2. Membrane nature of heart automation
9.1.3.6.3. Excitability of the heart muscle
9.1.3.6.4. Coupling of excitation and contraction of the myocardium
9.1.3.6.5. Cardiac cycle and its phase structure
9.1.3.6.6. Mechanical, electrical and physical manifestations of cardiac activity
9.1.3.6.7. General principles of cardiac output regulation
9.1.3.6.8. Neurogenic regulation of heart activity
9.1.3.6.9. Mechanisms of adrenergic and cholinergic regulation of cardiac activity
9.1.3.6.10. Humoral influences on the heart
9.1.3.7. Venous return of blood to the heart
9.1.3.8. Central venous pressure
9.1.3.9. Circulating blood volume
9.1.3.10. Correlation of the main parameters of systemic hemodynamics
9.1.4. General patterns of organ circulation
9.1.4.1. Functioning of organ vessels
9.1.4.2. Nervous and humoral influences on organ vessels
9.1.4.3. The role of vascular endothelium in the regulation of their lumen
9.1.5. Features of blood supply to organs and tissues
9.1.5.1. Brain
9.1.5.2. Myocardium
9.1.5.3. Lungs
9.1.5.4. Gastrointestinal tract (GIT)
9.1.5.5. Main digestive glands
9.1.5.6. Liver
9.1.5.7. Leather
9.1.5.8. Bud
9.1.5.9. Skeletal muscles
9.1.5.10. Related vascular functions
9.1.6. Microcirculation (microhemodynamics)
9.1.7. Central regulation of blood circulation
9.1.7.1. Reflex regulation of blood circulation
9.1.7.2. Spinal level of regulation
9.1.7.3. Boulevard level of regulation
9.1.7.4. Hypothalamic influences
9.1.7.5. Involvement of limbic structures
9.1.7.6. Cortical influences
9.1.7.7. General scheme of central regulation
9.2. Lymph circulation
9.2.1. Lymphatic vessels
9.2.2. The lymph nodes
9.2.3. Lymphotok
9.2.4. Nervous and humoral influences
Chapter 10. Functions of the respiratory system
10.1. External breathing
10.1.1. Biomechanics of breathing
10.1.1.1. Biomechanics of inspiration
10.1.1.2. Biomechanism of exhalation
10.1.2. Change in lung volume during inhalation and exhalation
10.1.2.1. Intrapleural pressure function
10.1.2.2. Lung air volumes during phases of the respiratory cycle
10.1.3. Factors influencing pulmonary volume during the inspiratory phase
10.1.3.1. Compliance of lung tissue
10.1.3.2. Surface tension of the fluid layer in the alveoli
10.1.3.3. Airway resistance
10.1.3.4. Flow-volume relationship in the lungs
10.1.4. The work of the respiratory muscles during the respiratory cycle
10.2. Ventilation and blood perfusion of the lungs
10.2.1. Ventilation
10.2.2. Perfusion of the lungs with blood
10.2.3. Effect of gravity on ventilation and blood perfusion of the lungs
10.2.3. Ventilation-perfusion ratio in the lungs
10.3. Gas exchange in the lungs
10.3.1. Composition of alveolar air
10.3.2. Gas tension in the blood of the capillaries of the lungs
10.3.3. Diffusion rate of 02 and CO2 in the lungs
10.4. Transport of gases by blood
10.4.1. Oxygen transport
10.4.1.1. Change in the affinity of hemoglobin for oxygen
10.4.2. Carbon dioxide transport
10.4.2.1. The role of red blood cells in CO2 transport
10.5. Breathing regulation
10.5.1. Respiratory center
10.5.1.1. Origin of the respiratory rhythm
10.5.2. The influence of the nerve centers of the pons on the respiratory rhythm
10.5.3. Function of spinal respiratory motor neurons
10.5.4. Reflex regulation of breathing
10.5.4.1. Chemoreceptor control of breathing
10.5.4.2. Mechanoreceptive control of breathing
10.6. Breathing during exercise
10.7. Human breathing at changed barometric air pressure
10.7.1. Human breathing at low air pressure
10.7.2. Human breathing at elevated air pressure
Chapter 11. Functions of the digestive system
11.1. State of hunger and satiety
11.2. General characteristics of the functions of the digestive system and the mechanisms of its regulation
11.2.1. Secretory function
11.2.2. Motor function
11.2.3. Suction function
11.2.4. General characteristics of the mechanisms regulating the functions of the digestive system
11.3. Periodic activity of the digestive system
11.4. Oral digestion and swallowing function
11.4.1. Oral cavity
11.4.2. Salivation
11.4.3. Chewing
11.4.4. Swallowing
11.5. Digestion in the stomach
11.5.1. Secretory function of the stomach
11.5.2. Regulation of gastric juice secretion
11.5.2.1. Phases of gastric secretion
11.5.3. Contractile activity of the stomach muscles
11.5.3.1. Regulation of contractile activity of the stomach
11.5.3.2. Evacuation of stomach contents into the duodenum
11.6. Digestion in the duodenum
11.6.1. Digestive functions of the pancreas
11.6.1.1. Composition and properties of pancreatic juice
11.6.1.2. Nervous and humoral regulation of pancreatic secretory function
11.6.2. Digestive functions of the liver
11.6.2.1. Mechanism of bile formation
11.6.2.2. Composition and properties of bile
11.6.2.3. Regulation of bile formation and bile excretion
11.6.3. Non-digestive liver functions
11.7. Digestion in the small intestine
11.7.1. Secretory function of the small intestine
11.7.1.1. Regulation of secretory function of the small intestine
11.7.2. Motor function of the small intestine
11.7.2.1. Regulation of small intestinal motility
11.7.3. Small intestine absorption function
11.8. Digestion in the large intestine
11.8.1. Movement of chyme from the jejunum to the cecum
11.8.2. Juice secretion in the large intestine
11.8.3. Motor activity of the large intestine
11.8.4. The role of colon microflora in the process of digestion and the formation of the body’s immunological reactivity
11.8.5. The act of defecation
11.8.6. Immune system of the digestive tract
11.8.7. Nausea and vomiting
Chapter 12. Metabolism and energy. Nutrition
12.1. The role of proteins, fats, carbohydrates, minerals and vitamins in metabolism
12.1.1. Proteins and their role in the body
12.1.2. Lipids and their role in the body
12.1.2.1. Cellular lipids
12.1.2.2. Brown fat
12.1.2.3. Blood plasma lipids
12.1.3. Carbohydrates and their role in the body
12.1.4. Minerals and their role in the body
12.1.5. Water and its role in the body - see section 14.3. Water-salt metabolism
12.1.6. Vitamins and their role in the body
12.2. The role of metabolism in meeting the body's energy needs
12.2.1. Methods for assessing the body's energy expenditure
12.3. Metabolism and energy at different levels of functional activity of the body
12.3.1. BX
12.3.2. Energy expenditure of the body under conditions of physical activity
12.4. Regulation of metabolism and energy
12.5. Nutrition
12.5.1. Rational nutrition as a factor in maintaining and promoting health
Chapter 13. Body temperature and its regulation
13.1. Normal body temperature
13.2. Heat production and heat transfer
13.2.1. Heat production
13.2.2. Heat dissipation
13.2.3. Behavioral thermoregulation
13.3. Body temperature regulation
13.3.1. The body's perception of temperature influences (thermoreception)
13.3.2. The central link of the thermoregulation system
13.3.3. Effector (executive) link of the thermoregulation system
13.4. Hyperthermia and hypothermia
13.5. Interaction of the thermoregulation system with other physiological systems of the body
13.5.1. Cardiovascular system and thermoregulation
13.5.2. Water-salt balance and thermoregulation
13.5.3. Breathing and thermoregulation
Chapter 14. Selection. Kidney functions. Water-salt metabolism
14.1. Organs and processes of excretion
14.1.1. Excretory function of the skin
14.1.2. Excretory function of the liver and digestive tract
14.1.3. Excretory function of the lungs and upper respiratory tract
14.2. Kidney functions
14.2.1. Mechanisms of urine formation
14.2.1.1. Glomerular ultrafiltration and its regulation
14.2.1.2. Tubular reabsorption and its regulation
14.2.1.3. Tubular secretion and its regulation
14.2.1.4. Composition and properties of final urine
14.2.1.5. Mechanisms of urine excretion and urination
14.2.2. Excretory function of the kidneys
14.2.3. Metabolic kidney function
14.2.4. The role of the kidneys in regulating blood pressure
14.3. Water-salt metabolism
14.3.1. External water balance of the body
14.3.2. Internal water balance of the body
14.3.3. Electrolyte, or salt, balance of the body
14.3.4. General principles of regulation of water-salt metabolism
14.4. Integrative mechanisms of regulation of water-salt metabolism and homeostatic kidney function
14.4.1. Homeostatic mechanisms during hyperosmotic dehydration
14.4.2. Homeostatic mechanisms during isosmotic dehydration
14.4.3. Homeostatic mechanisms during hypoosmotic dehydration
14.4.4. Homeostatic mechanisms during hypoosmotic hyperhydration
14.4.5. Homeostatic mechanisms during isosmotic hyperhydration
14.4.6. Homeostatic mechanisms during hyperosmotic overhydration
14.4.7. Electrolyte imbalances
Chapter 15. Acid-base state
15.1. Acids and bases of the internal environment
15.2. Physicochemical homeostatic mechanisms
15.2.1. Buffer systems of the internal environment of the body
15.2.2. Tissue homeostatic metabolic processes
15.3. Physiological homeostatic mechanisms
15.3.1. Lungs and acid-base status
15.3.2. Kidneys and acid-base status
15.3.3. Gastrointestinal tract, liver, bone tissue and acid-base status
15.4. Basic physiological indicators of acid-base status
15.5. Basic changes in acid-base status and their compensation
15.5.1. Functional significance of acidosis and alkalosis
15.5.2. Respiratory acidosis
15.5.3. Non-respiratory acidosis
15.5.4. Respiratory alkalosis
15.5.5. Non-respiratory alkalosis
15.5.6. General patterns of compensation for acid-base imbalances
Chapter 16. Human reproductive function
16.1. Human sexual differentiation
16.1.1. Genetic sex
16.1.2. Gonadal sex
16.1.3. Phenotypic sex
16.2. Reproductive function of the male body
16.2.1. Functions of the testes
16.2.2. Spermatogenesis
16.2.3. Hormonal regulation of spermatogenesis
16.2.4. Male sexual intercourse
16.2.4.1. Stages of male sexual intercourse
16.2.4.2. Regulation of ejaculation
16.2.4.3. Orgasm
16.3. Reproductive function of the female body
16.3.1. Ovarian cycle and oogenesis
16.3.1.1. Follicular phase
16.3.1.2. Ovulatory phase
16.3.1.3. Luteal phase
16.3.1.4. Luteolysis of the corpus luteum
16.3.2. Menstrual cycle (uterine cycle)
16.3.2.1. Menstrual phase
16.3.2.2. Proliferative phase
16.3.2.3. Secretory phase
16.3.3. Female sexual intercourse
16.4. Fertilization (fertilization)
16.5. Implantation of a fertilized egg
16.6. Pregnancy
16.6.1. Functions of the placenta
16.6.2. Placental hormones
16.7. Childbirth and lactation
16.7.1. Childbirth
16.7.2. Lactation
Chapter 17. Sensory systems
17.1. General physiology of sensory systems
17.1.1. Receptor classifications
17.1.2. Conversion of stimulus energy in receptors
17.1.3. Receptive fields
17.1.4. Information processing in switching nuclei and pathways of the sensory system
17.1.5. Subjective sensory perception
17.2. Somatovisceral sensory system
17.2.1. Tactile sensitivity
17.2.2. Proprioceptive sensitivity
17.2.3. Temperature sensitivity
17.2.4. Pain sensitivity
17.2.5. Visceral sensitivity
17.3. Visual sensory system
17.3.1. Projecting light rays onto the retina of the eye
17.3.1.1. Accommodation
17.3.1.2. Refractive errors
17.3.3.3. Adjustment of light intensity
17.3.1.4. Projection of the visual field onto the retina
17.3.1.5. Eye movements
17.3.2. Conversion of light energy in the retina
17.3.2.1. Scotopic and photopic retinal systems
17.3.2.2. Receptor potential of rods and cones
17.3.2.3. Adaptation of photoreceptors to changes in illumination
17.3.3. Receptive fields of retinal cells
17.3.3.1. Receptive fields with on-centers and off-centers
17.3.3.2. Receptive fields of color perception
17.3.3.3. M- and P-types of retinal ganglion cells
17.3.4. Conducting pathways and switching centers of the visual system
17.3.4.1. Functional organization of the lateral geniculate body
17.3.5. Processing of visual sensory information in the cortex
17.3.5.1. Visual perception
17.4. Auditory sensory system
17.4.1. Psychophysical characteristics of sound signals
17.4.1.1. Frequency perception range
17.4.1.2. Sound volume
17.4.2. Peripheral part of the auditory system
17.4.2.1. External ear function
17.4.2.2. Middle ear function
17.4.2.3. Inner ear
17.4.2.4. Function of the inner ear
17.4.2.5. Bioelectric processes in the organ of Corti
17.4.2.6. Frequency coding
17.4.2.7. Coding of sensory information in auditory nerve endings
17.4.3. Pathways and switching nuclei of the auditory system
17.4.4. Processing of sensory information in the auditory cortex
17.5. Vestibular sensory system
17.5.1. Vestibular apparatus
17.5.1.1. Properties of receptor cells of the vestibular apparatus
17.5.1.2. Adequate stimuli to the receptors of the otolith organs
17.5.1.3. Adequate stimuli to the receptors of the semicircular canals
17.5.2. Central part of the vestibular system
17.6. Taste sensory system
17.6.1. Taste reception
17.6.1.1. Receptor potentials of taste cells
17.6.1.2. Taste sensitivity
17.6.2. Central part of the taste system
17.6.3. Taste perception
17.7. Olfactory sensory system
17.7.1. Classification of odors
17.7.2. Peripheral section of the olfactory system
17.7.2.1. Mechanism of excitation of olfactory cells
17.7.3. Central division of the olfactory system
17.7.4. Physiological role of smell in humans
17.7.4.1. Physiological reactions to odors
17.7.4.2. The ability to perceive pheromones in humans
IV INTEGRATIVE FUNCTIONS OF THE ORGANISM
Chapter 18. Higher nervous activity (according to I. P. Pavlov)
18.1. Classical conditioned reflexes
18.1.1. Conditions influencing associative learning
18.1.2. Reflex arc of classical conditioned reflex
18.1.3. Stages of formation of a conditioned reflex
18.1.4. Conditioned reflexes of higher order
18.1.5. Types of classical conditioned reflexes
18.2. Inhibition of conditioned reflexes
18.2.1. External braking
18.2.2. Internal inhibition
18.2.2.1. Extinction inhibition
18.2.2.2. Delayed braking
18.2.2.3. Differential braking
18.2.2.4. Conditioned inhibition
18.3. Operant conditioning
18.4. Analytical and synthetic activity of the cerebral cortex
18.5. Dynamic stereotype
18.6. Phase phenomena in the cerebral cortex
18.7. Typology of higher nervous activity
Chapter 19. Motivations and emotions
19.1. Motivations
19.1.1. The concept of primary and secondary motivations
19.1.2. Concept of attraction and avoidance motivations
19.1.3. Human food motivation
19.1.3.1. Homeostatic mechanisms of regulation of food motivation in humans
19.1.3.2. The role of medulla oblongata structures in the regulation of food motivation
19.1.3.3. The role of the lateral hypothalamus in the emergence of food motivation
19.1.3.4. The role of the melanocortin system of the hypothalamus in the termination of food motivation
19.1.3.5. The role of the limbic system in the regulation of food motivation in humans
19.1.4. Human sexual motivation
19.1.4.1. Genetic, social and psychological factors in the emergence of sexual motivation in humans
19.1.4.2. The role of sex hormones in the modulation of human sexual motivation
19.1.4.3. Stages of sexual arousal in humans with sexual motivation
19.1.4.4. Neural regulation of sexual motivation in humans
19.2. Emotions
19.2.1. Types of emotions
19.2.2. The role of emotions in human behavior
19.2.3. Neurophysiological mechanisms of emotion expression
19.2.3.1. The hypothalamus as a center for regulating the body’s autonomic and endocrine reactions during emotions
19.2.3.2. The role of the amygdala in basic emotions
19.2.3.3. Regulation of positive emotions in humans
19.2.3.4. Regulation of negative emotions in humans
Chapter 20. Physiological foundations of human cognitive activity
20.1. Attention
20.1.1. Forms of attention
20.1.2. Neurophysiological mechanisms of attention
20.1.2.1. Functions of the midbrain and pons in the control of attention
20.1.2.2. Functions of cortical centers of attention
20.1.3. Attention in different modalities
20.2. Perception
20.2.1. Visual perception
20.2.1.1. Functions of the striate cortex in visual perception
20.2.1.2. Visual perception with the participation of parts of the extrastriate cortex
20.2.1.3. Features of visual perception of individual faces and objects
20.2.2. Auditory perception
20.2.3. Somatosensory perception
20.3. Consciousness
20.3.1. Neurophysiological correlates of consciousness
20.3.1.1. Electrical activity of the human brain
20.3.1.2. Activation of the human brain as a neurophysiological basis for the manifestation of states of consciousness
20.3.1.3. Awareness of visual perception (visual awareness)
20.3.1.4. Attention and consciousness
20.4. Memory and learning
20.4.1. Forms of memory and learning
20.4.2. Neural mechanisms of implicit memory
20.4.2.1. Habituation and sensitization
20.4.2.2. Associative learning (conditioned reflexes)
20.4.3. The mechanism of explicit memory formation
20.5. Speech
20.5.1. Language properties
20.5.2. Speech apparatus
20.5.3. Speech structures of the brain
20.5.3.1. Speech disorders in focal brain damage
20.5.3.2. Wernicke-Geschwind model of speech activity
20.5.3.3. Modern model of human speech activity
20.5.3.4. Lateralization of speech
20.6. Thinking
20.6.1. Neurophysiological foundations of human mental activity
20.6.1.1. Neurophysiological foundations of abstract thinking (human reasoning)
20.6.1.2. Neurophysiological basis of mental arithmetic operations
20.6.1.3. Neurophysiological basis of thinking when reading
20.6.2. Functions of the left and right hemispheres of the human brain during thinking
Chapter 21. Sleep and wakefulness
21.1. Physiological significance of sleep
21.1.1. Restorative sleep theory
21.1.2. Circadian theory of sleep
21.2. Frequency of physiological processes during sleep
21.2.1. Stages of sleep
21.2.2. Sleep structure
21.2.3. Slow-wave sleep phase
21.2.4. Paradoxical sleep phase
21.3. Neurophysiological mechanisms of sleep
21.3.1. Participation of brain stem centers in the regulation of the sleep-wake cycle
21.3.2. Circadian rhythm regulation
21.3.3. Involvement of the cortex and limbic system in the regulation of the sleep-wake cycle
21.3.4. Humoral inducers and sleep regulators
21.4. Dreams and the physiological role of REM sleep
21.5. Sleep duration and consequences of sleep deprivation
21.6. Wakefulness and consciousness
21.7. Different levels of wakefulness
Chapter 22. Physiological foundations of labor
22.1. Energy formation in skeletal muscles during physical work
22.1.1. Anaerobic pathway for ATP resynthesis
22.1.2. Aerobic glycolysis
22.1.3. “Oxygen cascade” and the efficiency of oxygen transport to working muscles
22.1.4. Oxygen consumption, oxygen deficiency, oxygen debt and oxygen demand during muscular work
22.2. Physiological basis of motor skill training
22.2.1. Development of muscle strength qualities
22.2.2. Physiological mechanisms of formation of labor skills
22.2.3. Performance
22.3. Functions of physiological systems of the human body during physical work
22.3.1. Circulation
22.3.2. Blood
22.3.3. Breath
22.3.4. Endocrine system
22.4. Physiological functions during mental work
22.5. Working under conditions of eye strain
22.6. Fatigue at work
22.6.1. Fatigue of a person during physical work
22.6.1.1. Human fatigue during static physical work
22.6.1.2. Human fatigue during dynamic muscular work
Chapter 23. Human adaptation to environmental conditions
23.1. General principles and mechanisms of adaptation
23.1.1. Adaptation
23.1.2. Nonspecific adaptive reactions of the body
23.1.3. Sympathoadrenal reaction
23.1.4. Stress reaction
23.1.5. Training response and activation response
23.1.6. Urgent and long-term adaptation
23.1.7. Norm of adaptive reaction and disadaptation
23.1.8. Genotypic and phenotypic adaptation. Covering adaptations
23.1.9. Reversibility of adaptation processes
23.2. Human adaptation to climatic factors
23.2.1. Bioclimatic factors of hot climates
23.2.2. Adaptive reactions of the human body to a hot environment
23.2.3. Features of human adaptation to work in a hot environment
23.2.4. Prevention of heat damage to the body
Subject index
2nd ed., revised. and additional - M.: 2003. - 656 p.
The second edition of the textbook (the first was published in 1997 and was printed three times in 1998, 2000 and 2001) has been revised in accordance with the latest scientific achievements. New facts and concepts are presented. The authors of the textbook are highly qualified specialists in relevant areas of physiology. Particular attention is paid to the description of methods for quantitative assessment of the functional state of the most important systems of the human body. The textbook corresponds to the program approved by the Ministry of Health of Russia.
For students of medical universities and faculties.
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VOLUME 1.
PREFACE
Chapter 1. PHYSIOLOGY. SUBJECT AND METHODS. IMPORTANCE FOR MEDICINE. SHORT STORY. - G. I. Kositsky, V. M. Pokrovsky, G. F. Korotko. . .
1.1. Physiology, its subject and role in the medical education system
1.2. Methods of physiological research
1.3. Physiology of the whole organism
1.4. Organism and external environment. Adaptation
1.5. A Brief History of Physiology
Chapter 2. EXCITABLE TISSUE
2.1. Physiology of excitable tissues. - V.I. Kobrin
2.1.1. Structure and basic properties of cell membranes and ion channels
2.1.2. Methods for studying excitable cells
2.1.3. Resting potential
2.1.4. Action potential
2.1.5. The effect of electric current on excitable tissues 48
2.2. Physiology of nervous tissue. - G. A. Kuraev
2.2.1. Structure and morphofunctional classification of neurons
2.2.2. Receptors. Receptor and generator potentials
2.2.3. Afferent neurons, their functions
2.2.4. Interneurons, their role in the formation of neural networks
2.2.5. Efferent neurons
2.2.6. Neuroglia
2.2.7. Conducting stimulation along nerves
2.3. Physiology of synapses. - G. A. Kuraev
2.4. Physiology of muscle tissue
2.4.1. Skeletal muscles. - V.I. Kobrin
2.4.1.1. Classification of skeletal muscle fibers
2.4.1.2. Functions and properties of skeletal muscles
2.4.1.3. Mechanism of muscle contraction
2.4.1.4. Modes of muscle contraction
2.4.1.5. Muscle work and power
2.4.1.6. Energy of muscle contraction
2.4.1.7. Heat generation during muscle contraction
2.4.1.8. Musculoskeletal interaction
2.4.1.9. Assessment of the functional state of the human muscular system
2.4.2. Smooth muscles. - R. S. Orlov
2.4.2.1. Classification of smooth muscles
2.4.2.2. The structure of smooth muscles
2.4.2.3. Innervation of smooth muscles
2.4.2.4. Functions and properties of smooth muscles
2.5.1. Secretion
2.5.2. Multifunctionality of secretion
2.5.3. Secretory cycle
2.5.4. Biopotentials of glandulocytes
2.5.5. Regulation of glandulocyte secretion
Chapter 3. PRINCIPLES OF ORGANIZATION OF FUNCTION MANAGEMENT. - V. P. Degtyarev
3.1. Control in living organisms
3.2. Self-regulation of physiological functions
3.3. System organization of management. Functional systems and their interaction
Chapter 4. NERVOUS REGULATION OF PHYSIOLOGICAL FUNCTIONS
4.1. Mechanisms of activity of the central nervous system. - O. G. Chorayan
4.1.1. Methods for studying the functions of the central nervous system
4.1.2. Reflex principle of regulation of functions
4.1.3. Inhibition in the central nervous system
4.1.4. Properties of nerve centers
4.1.5. Principles of integration and coordination in the activity of the central nervous system
4.1.6. Neuronal complexes and their role in the activity of the central nervous system
4.1.7. Blood-brain barrier and its functions
4.1.8. Cerebrospinal fluid
4.1.9. Elements of cybernetics of the nervous system
4.2. Physiology of the central nervous system. - G. A. Kuraev 134
4.2.1. Spinal cord
4.2.1.1. Morphofunctional organization of the spinal cord
4.2.1.2. Features of the neural organization of the spinal cord
4.2.1.3. Spinal cord pathways
4.2.1.4. Reflex functions of the spinal cord
4.2.2. Brain stem
4.2.2.1. Medulla
4.2.2.2. Bridge
4.2.2.3. Midbrain
4.2.2.4. Reticular formation of the brainstem
4.2.2.5. Diencephalon
4.2.2.5.1. Thalamus
4.2.2.6. Cerebellum
4.2.3. Limbic system
4.2.3.1. Hippocampus
4.2.3.2. Amygdala
4.2.3.3. Hypothalamus
4.2.4. Basal ganglia
4.2.4.1. Caudate nucleus. Shell
4.2.4.2. Pale ball
4.2.4.3. Fence
4.2.5. Cerebral cortex
4.2.5.1. Morphofunctional organization
4.2.5.2. Sensory areas
4.2.5.3. Motor areas
4.2.5.4. Associative areas
4.2.5.5. Electrical manifestations of cortical activity
4.2.5.6. Interhemispheric relationships
4.2.6. Coordination of movements. - V. S. Gurfinkel, Yu. S. Levik
4.3. Physiology of the autonomic (vegetative) nervous system. - A. D. Nozdrachev
4.3.1- Functional structure of the autonomic nervous system
4.3.1.1. The sympathetic part
4.3.1.2. Parasympathetic part
4.3.1.3. Metasympathetic part
4.3.2. Features of the design of the autonomic nervous system
4.3.3. Autonomic (vegetative) tone
4.3.4. Synaptic transmission of excitation in the autonomic nervous system
4.3.5- Influence of the autonomic nervous system on the functions of tissues and organs
Chapter 5. HORMONAL REGULATION OF PHYSIOLOGICAL FUNCTIONS. - V. A. Tachuk, O. E. Osadchiy
5.1. Principles of hormonal regulation
5.2. Endocrine glands
5.2.1. Research methods
5.2.2. Pituitary
5.2.3. Thyroid
5.2.4. Parathyroid glands
5.2.5. Adrenal glands
5.2.6. Pancreas
5.2.7. Sex glands
5.3. Education, secretion and mechanisms of action of hormones 264
5.3.1. Regulation of hormone biosynthesis
5.3.2. Secretion and transport of hormones
5.3.3. Mechanisms of action of hormones on cells
Chapter 6. BLOOD. - B.I. Kuzink
6.1. Concept of the blood system
6.1.1. Basic functions of blood
6.1.2. Amount of blood in the body
6.1.3. Blood plasma composition
6.1.4. Physicochemical properties of blood
6.2. Formed elements of blood
6.2.1. Red blood cells
6.2.1.1. Hemoglobin and its compounds
6.2.1.2. Color index
6.2.1.3. Hemolysis
6.2.1.4. Functions of red blood cells
6.2.1.5. Erythron. Regulation of erythropoiesis
6.2.2. Leukocytes
6.2.2.1. Physiological leukocytosis. Leukopenia 292
6.2.2.2. Leukocyte formula
6.2.2.3. Characteristics of individual types of leukocytes
6.2.2.4. Regulation of leukopoiesis
6.2.2.5. Nonspecific resistance and immunity
6.2.3. Platelets
6.3. Blood groups
6.3.1. AVO system
6.3.2. Rhesus system (Rh-hr) and others
6.3.3. Blood groups and morbidity. Hemostasis system
6.4.1. Vascular-platelet hemostasis
6.4.2. Blood clotting process
6.4.2.1. Plasma and cellular coagulation factors
6.4.2.2. Blood clotting mechanism
6.4.3. Natural anticoagulants
6.4.4. Fibrniolysis
6.4.5. Regulation of blood coagulation and fibrinolysis
Chapter 7. BLOOD AND LYMPH CIRCULATION. - E. B. Babsky, G. I. Kositsky, V. M. Pokrovsky
7.1. Heart activity
7.1.1. Electrical phenomena in the heart, conduction of excitation
7.1.1.1. Electrical activity of myocardial cells
7.1.1.2. Functions of the conduction system of the heart. . .
7.1.1.3. Refractory phase of the myocardium and extrasystole
7.1.1.4. Electrocardiogram
7.1.2. Pumping function of the heart
7.1.2.1. Phases of the cardiac cycle
7.1.2.2. Cardiac output
7.1.2.3. Mechanical and abnormal manifestations of cardiac activity
7.1.3. Regulation of heart activity
7.1.3.1. Intracardiac regulatory mechanisms
7.1.3.2. Extracardiac regulatory mechanisms. .
7.1.3.3. Interaction of intracardiac and extracardiac nervous regulatory mechanisms
7.1.3.4. Reflex regulation of heart activity
7.1.3.5. Conditioned reflex regulation of heart activity
7.1.3.6. Humoral regulation of heart activity
7.1.4. Endocrine function of the heart
7.2. Functions of the vascular system
7.2.1. Basic principles of hemodynamics. Classification of vessels
7.2.2. Movement of blood through vessels
7.2.2.1. Blood pressure
7.2.2.2. Arterial pulse
7.2.2.3. Volumetric blood flow velocity
7-2.2.4. Movement of blood in capillaries. Microcirculation
7.2.2.5. Movement of blood in veins
7.2.2.6. Blood circulation time
7.2.3. Regulation of blood movement through vessels
7.2.3.1. Innervation of blood vessels
7.2.3.2. Vasomotor center
7.2.3.3. Reflex regulation of vascular tone
7.2.3.4. Humoral influences on blood vessels
7.2.3.5. Local mechanisms of blood circulation regulation
7.2.3.6. Regulation of circulating blood volume.
7.2.3.7. Blood depots
7.2.4. Regional blood circulation. - Y. A. Khananashvili 390
7.2.4.1. Cerebral circulation
7.2.4.2. Coronary circulation
7.2.4.3. Pulmonary circulation
7.3. Lymph circulation. - R. S. Orlov
7.3.1. Structure of the lymphatic system
7.3.2. Lymph formation
7.3.3. Composition of lymph
7.3.4. Lymph movement
7.3.5. Functions of the lymphatic system
Chapter 8. BREATHING. - V. CD. Pyatin
8.1. The essence and stages of breathing
8.2. External breathing
8.2.1. Biomechanics of respiratory movements
8.3. Pulmonary ventilation
8.3.1. Lung volumes and capacities
8.3.2. Alveolar ventilation
8.4. Mechanics of breathing
8.4.1. Lung compliance
8.4.2. Airway resistance
8.4.3. Work of breathing
8.5. Gas exchange and gas transport
8.5.1. Diffusion of gases through the airborne barrier. . 415
8.5.2. Content of gases in alveolar air
8.5.3. Gas exchange and O2 transport
8.5.4. Gas exchange and CO2 transport
8.6. Regulation of external respiration
8.6.1. Respiratory center
8.6.2. Reflex regulation of breathing
8.6.3. Coordination of breathing with other body functions
8.7. Peculiarities of breathing during physical exertion and with altered partial pressure of O2
8.7.1. Breathing during physical exertion
8.7.2. Breathing when climbing to altitude
8.7.3. Breathing at high pressure
8.7.4. Breathing pure O2
8.8. Dyspnea and pathological types of breathing
8.9. Non-respiratory functions of the lungs. - E. A. Maligonov,
A. G. Pokhotko
8.9.1. Protective functions of the respiratory system
8.9.2. Metabolism of biologically active substances in the lungs
VOLUME 2.
Chapter 9. DIGESTION. G. F. Korotko
9.1. Physiological basis of hunger and satiety
9.2. The essence of digestion. Conveyor principle of organizing digestion
9.2.1. Digestion and its importance
9.2.2. Types of digestion
9.2.3. Conveyor principle of organizing digestion
9.3. Digestive functions of the digestive tract
9.3.1. Secretion of the digestive glands
9.3.2. Motor function of the digestive tract
9.3.3. Suction
9.3.4. Methods for studying digestive functions
9.3.4.1. Experimental methods
9.3.4.2. Study of digestive functions in humans?
9.3.5. Regulation of digestive functions
9.3.5.1. Systemic mechanisms for controlling digestive activity. Reflex mechanisms
9.3.5.2. The role of regulatory peptides in the activity of the digestive tract
9.3.5.3. Blood supply and functional activity of the digestive tract
9.3.5.4. Periodic activity of the digestive organs
9.4. Oral digestion and swallowing
9.4.1. Eating
9.4.2. Chewing
9.4.3. Salivation
9.4.4. Swallowing
9.5. Digestion in the stomach
9.5.1. Secretory function of the stomach
9.5.2. Motor function of the stomach
9.5.3. Evacuation of stomach contents into the duodenum
9.5.4. Vomit
9.6. Digestion in the small intestine
9.6.1. Pancreatic secretion
9.6.2. Bile secretion and bile secretion
9.6.3. Intestinal secretion
9.6.4. Cavity and parietal digestion in the small intestine
9.6.5. Motor function of the small intestine
9.6.6. Absorption of various substances in the small intestine
9.7. Functions of the colon
9.7.1. Entry of intestinal chyme into the large intestine
9.7.2. The role of the colon in digestion
9.7.3. Motor function of the colon
9.7.4. Defecation
9.8. Microflora of the digestive tract
9.9. Liver functions
9.10. Non-digestive functions of the digestive tract 87
9.10.1. Excretory activity of the digestive tract
9.10.2. Participation of the digestive tract in water-salt metabolism
9.10.3. Endocrine function of the digestive tract and the release of biologically active substances in secretions
9.10.4. Increment (endosecretion) of enzymes by the digestive glands
9.10.5. Immune system of the digestive tract
Chapter 10. METABOLISM AND ENERGY. NUTRITION. E. B. Babsky V. M. Pokrovsky
10.1. Metabolism
10.1.1. Protein metabolism
10.1.2. Lipid metabolism
10.1.3. Carbohydrate metabolism
10.1.4. Exchange of mineral salts and water
10.1.5. Vitamins
10.2. Energy conversion and general metabolism
10.2.1. Methods for studying energy exchange
10.2.1.1. Direct calorimetry
10.2.1.2. Indirect calorimetry
10.2.1.3. Gross Exchange Study
10.2.3. BX
10.2.4. Surface rule
10.2.5. Energy exchange during physical labor
10.2.6. Energy exchange during mental work
10.2.7. Specific dynamic action of food
10.2.8. Regulation of energy metabolism
10.3. Nutrition. G. F. Korotko
10.3.1. Nutrients
10.3.2. Theoretical foundations of nutrition
10.3.3. Nutrition standards
Chapter 11. THERMOREGULATION. E. B. Babsky, V. M. Pokrovsky
11.1. Body temperature and isothermia
11.2. Chemical thermoregulation
11.3. Physical thermoregulation
11.4. Isotherm regulation
11.5. Hypothermia and hyperthermia
Chapter 12. ALLOCATION. KIDNEY PHYSIOLOGY. Yu. V. Natochin.
12.1. Selection
12.2. Kidneys and their functions
12.2.1. Methods for studying kidney function
12.2.2. Nephron and its blood supply
12.2.3. The process of urine formation
12.2.3.1. Glomerular filtration
12.2.3.2. Kayalceous reabsorption
12.2.3.3. Kayal secretion
12.2.4. Determination of the magnitude of renal plasma and blood flow
12.2.5. Synthesis of substances in the kidneys
12.2.6. Osmotic dilution and concentration of urine
12.2.7. Homeostatic functions of the kidneys
12.2.8. Excretory function of the kidneys
12.2.9. Endocrine function of the kidneys
12.2.10. Metabolic kidney function
12.2.11. Principles of regulation of reabsorption and secretion of substances in renal tubular cells
12.2.12. Regulation of kidney activity
12.2.13. Quantity, composition and properties of urine
12.2.14. Urination
12.2.15. Consequences of kidney removal and artificial kidney
12.2.16. Age-related features of the structure and function of the kidneys
Chapter 13. SEXUAL BEHAVIOR. REPRODUCTIVE FUNCTION. LACTATION. Yu. I. Savchenkov, V. I. Kobrin
13.1. Sexual development
13.2. Puberty
13.3. Sexual behavior
13.4. Physiology of sexual intercourse
13.5. Pregnancy and maternal relations
13.6. Childbirth
13.7. Major changes in the body of a newborn
13.8. Lactation
Chapter 14. SENSORY SYSTEMS. M. A. Ostrovsky, I. A. Shevelev
14.1. General physiology of sensory systems
14.1.1. Methods for studying sensory systems
4.2. General principles of the structure of sensory systems
14.1.3. Basic functions of the sensor system
14.1.4. Mechanisms of information processing in the sensory system
14.1.5. Adaptation of the sensory system
14.1.6. Interaction of sensory systems
14.2. Particular physiology of sensory systems
14.2.1. Visual system
14.2.2. Auditory system
14.2.3. Vestibular system
14.2.4. Somatosensory system
14.2.5. Olfactory system
14.2.6. Taste system
14.2.7. Visceral system
Chapter 15. INTEGRATIVE ACTIVITY OF THE HUMAN BRAIN. O. G. Chorayan
15.1. Conditioned reflex basis of higher nervous activity
15.1.1. Conditioned reflex. Education mechanism
15.1.2. Methods for studying conditioned reflexes
15.1.3. Stages of formation of a conditioned reflex
15.1.4. Types of conditioned reflexes
15.1.5. Inhibition of conditioned reflexes
15.1.6. Dynamics of basic nervous processes
15.1.7. Types of higher nervous activity
15.2. Physiological mechanisms of memory
15.3. Emotions
15.4. Sleep and hypnosis. V. I. Kobrin
15.4.1. Dream
15.4.2. Hypnosis
15.5. Basics of psychophysiology
15.5.1. Neurophysiological foundations of mental activity
15.5.2. Psychophysiology of the decision-making process. . 292
15.5.3. Consciousness
15.5.4. Thinking
15.6. Second signaling system
15.7. The principle of probability and “fuzziness” in the higher integrative functions of the brain
15.8. Interhemispheric asymmetry
15.9. The influence of physical activity on the functional state of a person. E. K. Aganyats
15.9.1. General physiological mechanisms of the influence of physical activity on metabolism
15.9.2. Autonomic support of motor activity 314
15.9.3. The influence of physical activity on the regulatory mechanisms of the central nervous system and hormonal link
15.9.4. The influence of physical activity on the functions of the neuromuscular system
15.9.5. Physiological significance of fitness
15.10. Fundamentals of the physiology of mental and physical labor. E. K. Aganyants
15.10.1. Physiological characteristics of mental work
15.10.2. Physiological characteristics of physical labor
15.10.3. The relationship between mental and physical labor
15.11. Fundamentals of chronophysiology. G. F. Korotko, N. A. Agad-zhanyan
15.11.1. Classification of biological rhythms
15.11.2. Circadian rhythms in humans
15.11.3. Ultradian rhythms in humans
11/15/4. Infradian rhythms in humans
15.11.5. The biological clock
11/15/6. Pacemakers of mammalian biological rhythms
Basic quantitative physiological indicators of the body
List of recommended literature
The general goal of the course is to obtain basic knowledge about the molecular cellular processes that underlie the activity of organs, as well as the principles of their regulation, which makes it possible to combine the functions of individual organs into a single set of processes necessary for human life.
The course is designed for 10 weeks, each of which contains four lessons of two hours. Thus, the weekly load is 8 hours. This time is necessary to become familiar with basic terminology, watch presentations, listen to video lectures, and work on assessment tests.
Format
The course is built on the principle of transferring the pedagogical experience of St. Petersburg State University teachers through the use of modern innovative technologies, which include video lectures accompanied by texts, explanations, links, assignments, tests, as well as receiving feedback from the course authors. At the end of the course, the student should master basic terminology, an understanding of the basic functions of cells that underlie the functioning of organs, and the basic principles of managing organ functions.
Informational resources
Textbooks:
- Nozdrachev and others. The beginnings of physiology. St. Petersburg
- Human physiology. In 2 volumes / Ed. V.M. Pokrovsky.-M.
- Human physiology. In 4 volumes. Per. from English Ed. R. Schmidt and G. Tevs.- M.
Requirements
Entry requirements for the course are basic knowledge of biology, that is, completion of the undergraduate curriculum in the direction of “Biology” for 1-2 semesters.
Course program
Week 1. Physiology as a science. Internal environment of the body. Ionic asymmetry. Transport of ions, organic substances and water across the plasma membrane of cells. Transport of ions, organic substances and water through the epithelium. Signal transmission in the cell. Signaling.
Week 2. Physiology of excitable tissues. Membrane potential, its origin. Membrane ion channels. Local response. Critical level of depolarization. Action potential, its phases, their origin. Refractoriness and its causes. Electrotonic changes in membrane potential. Generator potential. Receptor potential. Synapse. The mechanism of excitation transmission in chemical synapses. Excitatory and inhibitory postsynaptic potential. The mechanism of nerve impulse transmission along unmyelinated and myelinated nerve fibers.
Week 3. Nervous regulation of functions in the body. Neuron as a structural and functional unit of the nervous system. Interaction between excitation and inhibition processes as the basis for signal integration. Mechanisms of signal integration in the nervous system. Occlusion and relief. Monosynaptic reflex. Polysynaptic reflex.
Week 4. Physiology of neuromuscular transmission. Nerve trunk and types of nerve fibers. Types of muscle tissue: skeletal, cardiac and smooth muscles. Features of structure and physiological properties. Phasic and tonic fibers. Myosin heavy chain isoforms: fast and slow fiber types. Motor neuron and motor units. Proprioception. Structural and functional organization of the neuromuscular synapse in vertebrates. Types of mediator secretion: evoked and spontaneous quantum secretion, non-quantum secretion. Quantum composition. Molecular basis of the secretion of mediator quanta. Nicotinic cholinergic receptor. End plate potential. Guarantee factor of neuromuscular transmission. The role of Na, K-ATPase.
Week 5. Physiology of muscle contraction. Dihydropyridine receptors, ryanodine receptors. The role of Ca2+ ions. Sarcomere structure. The main proteins of myofibrils. The mechanism of muscle contraction. Isometric and isotonic contraction. Serrated and smooth tetanus, pessimum.
Week 6. Autonomic nervous system. Structural and functional features of the somatic and autonomic nervous system. Sympathetic, parasympathetic and metasympathetic divisions of the autonomic nervous system. Principles of organization of the afferent and efferent links of autonomic reflexes. The influence of the sympathetic, parasympathetic and metasympathetic divisions of the autonomic nervous system on the innervated organs. Participation of the autonomic nervous system in the integration of functions in the formation of integral behavioral acts. Vegetative components of behavior.
Week 7. Hypothalamic-pituitary system and pineal gland. Hypothalamic-pituitary system (structures). Hormones of the hypothalamic-neurohypophyseal system. Family of Prolactin and somatotropin. Thyrotropin and gonadotropin family. Proopiomelanotropin family. Pineal gland and its hormones.
Week 8. Hormones of peripheral endocrine glands. Hormones of the thyroid and parathyroid glands. Pancreatic hormones. Adrenal hormones. Hypothalamic-pituitary-adrenal system. Glucocorticosteroids and stress. Gonadal hormones.
Week 9. General problems of the physiology of sensory systems. Characteristics of general auxiliary structures of sensory systems. Definition and classification of sensory receptors. Transformation of the energy of an irritating stimulus into the electrical activity of sensory receptors - receptor potential, as well as the mechanisms of its generation and transformation into impulse activity (analog-to-digital conversion). Conduction of electrical signals arising in sensory receptors under the action of the energy of an adequate stimulus. Mechanisms for enhancing the resolution and sensitivity of sensory systems, as well as mechanisms for processing sensory information and the representation of various sensory systems in the cerebral cortex.
Week 10. Psychophysiological aspects of the functioning of sensory systems. The relationship between the energy parameters of the irritating stimulus and the characteristics of the sensation arising in the sensory systems: psychophysical laws of Weber-Fechner, Stevens' law. Physiology of the central nervous system. Electrical signals of the central nervous system. The role of subcortical structures in the regulation of body functions. Cerebral cortex. Columns. Mirror neurons. Biology of behavior.
Learning outcomes
At the end of the course, the student should master basic terminology, an understanding of the basic functions of cells that underlie the functioning of organs, and the basic principles of managing organ functions. To receive a certificate, you must complete all tasks and pass the final test.
Formed competencies
After completing the Introduction to Physiology course, students will be required to:
- Know the molecular and cellular basis of cell and organ functions.
- Know the names of scientists who formulated the principles of the body’s activity and discovered new mechanisms of its functioning.
- Understand the systemic mechanisms of regulation of organ activity and the interaction of various organ systems in the body.
Surrounding objects and phenomena do not always appear to us as such,
what they really are. We don't always see and hear what
what's really happening.
P. Lindsay, D. Norman
One of the physiological functions of the body is the perception of the surrounding reality. Receiving and processing information about the surrounding world is a necessary condition for maintaining the homeostatic constants of the body and shaping behavior. Among the stimuli acting on the body, only those for which there are specialized formations are captured and perceived. Such stimuli are called sensory stimuli, and complex structures intended for their processing are sensory systems. Sensory signals differ in modality, i.e. the form of energy that is characteristic of each of them.
Objective and subjective side of perception
When a sensory stimulus is applied, electrical potentials arise in the receptor cells, which are conducted to the central nervous system, where they are processed, which is based on the integrative activity of the neuron. The ordered sequence of physical and chemical processes occurring in the body under the action of a sensory stimulus represents the objective side of the functioning of sensory systems, which can be studied by methods of physics, chemistry, and physiology.
Physicochemical processes developing in the central nervous system lead to the emergence of a subjective sensation. For example, electromagnetic waves with a wavelength of 400 nm cause the sensation “I see the color blue.” The sensation is usually interpreted based on previous experience, resulting in the perception “I see the sky.” The emergence of sensation and perception reflects the subjective side of the work of sensory systems. The principles and patterns of the emergence of subjective sensations and perceptions are studied using the methods of psychology, psychophysics, and psychophysiology.
Perception is not a simple photographic representation of the environment by sensory systems. A good illustration of this fact is ambiguous pictures - the same image can be perceived in different ways (Fig. 1A). The objective side of perception is fundamentally similar for different people. The subjective side is always individual and determined by the personality characteristics of the subject, his experience, motivations, etc. Hardly any of the readers perceive the world around them in the same way as Pablo Picasso perceived it (Fig. 1B).
Specificity of sensory systems
Any sensory signal, regardless of its modality, is converted in the receptor into a certain sequence (pattern) of action potentials. The body distinguishes between types of stimuli only due to the fact that sensory systems have the property of specificity, i.e. react only to a certain type of stimulus.
According to the law of “specific sensory energies” by Johannes Müller, the nature of the sensation is determined not by the stimulus, but by the irritated sensory organ. For example, mechanical stimulation of the photoreceptors of the eye will produce a sensation of light, but not pressure.
The specificity of sensory systems is not absolute, however, for each sensory system there is a certain type of stimulus (adequate stimuli), the sensitivity to which is many times higher than to other sensory stimuli (inadequate stimuli). The more the thresholds of excitation of the sensory system for adequate and inadequate stimuli differ, the higher its specificity.
The adequacy of the stimulus is determined, firstly, by the properties of the receptor cells, and secondly, by the macrostructure of the sensory organ. For example, the photoreceptor membrane is designed to sense light signals because it has a special protein called rhodopsin, which breaks down when exposed to light. On the other hand, the adequate stimulus for the receptors of the vestibular apparatus and the organ of hearing is the same - the flow of endolymph, which deflects the cilia of the hair cells. However, the structure of the inner ear is such that the endolymph moves when exposed to sound vibrations, and in the vestibular apparatus the endolymph shifts when the position of the head changes.
The structure of the sensory system
The sensory system includes the following elements (Fig. 2):
auxiliary device
touch receptor
sensory pathways
projection zone of the cerebral cortex.
The auxiliary apparatus is a formation whose function is the primary transformation of the energy of the current stimulus. For example, the auxiliary apparatus of the vestibular system converts angular accelerations of the body into mechanical displacement of the kinocils of hair cells. The auxiliary apparatus is not typical for all sensory systems.
The sensory receptor converts the energy of the current stimulus into specific energy of the nervous system, i.e. into an ordered sequence of nerve impulses. In the primary receptor, this transformation occurs in the endings of the sensory neuron; in the secondary receptor, it occurs in the receiving cell. The axon of a sensory neuron (primary afferent) conducts nerve impulses to the central nervous system.
In the central nervous system, excitation is transmitted along a chain of neurons (the so-called sensory pathway) to the cerebral cortex. The axon of a sensory neuron forms synaptic contacts with several secondary sensory neurons. The axons of the latter follow to neurons located in the nuclei of higher levels. Along the sensory pathways, information is processed, which is based on the integrative activity of the neuron. The final processing of sensory information occurs in the cerebral cortex.
Principles of organization of sensory pathways
The principle of multi-channel information flow. Each sensory pathway neuron forms contacts with several neurons at higher levels (divergence). Therefore, nerve impulses from one receptor are conducted to the cortex through several chains of neurons (parallel channels) (Fig. 3). Parallel multichannel transmission of information ensures high reliability of sensory systems even in conditions of loss of individual neurons (as a result of disease or injury), as well as high speed of information processing in the central nervous system.
The principle of duality of projections. Nerve impulses from each sensory system are transmitted to the cortex along two fundamentally different pathways - specific (monomodal) and nonspecific (multimodal).
Specific pathways conduct nerve impulses from receptors of only one sensory system, because on each neuron of such a pathway, neurons of only one sensory modality converge (monomodal convergence). Accordingly, each sensory system has its own specific pathway. All specific sensory pathways pass through the nuclei of the thalamus and form local projections in the cerebral cortex, ending in the primary projection zones of the cortex. Specific sensory pathways provide the initial processing of sensory information and conduct it to the cerebral cortex.
On neurons of the nonspecific pathway, neurons of different sensory modalities converge (multimodal convergence). Therefore, in the nonspecific sensory pathway, information from all sensory systems of the body is integrated. The nonspecific pathway for information transmission occurs as part of the reticular formation and forms extensive diffuse projections in the projection and association zones of the cortex.
Nonspecific pathways provide multibiological processing of sensory information and ensure the maintenance of an optimal level of arousal in the cerebral cortex.
The principle of somatotopic organization characterizes only specific sensory pathways. According to this principle, excitation from neighboring receptors enters nearby areas of the subcortical nuclei and cortex. Those. the perceptive surface of any sensitive organ (retina, skin) is, as it were, projected onto the cerebral cortex.
The principle of top-down control. Excitation in the sensory pathways is carried out in one direction - from receptors in the cerebral cortex. However, the neurons that make up the sensory pathways are under descending control of the overlying parts of the central nervous system. Such connections make it possible, in particular, to block the transmission of signals in sensory systems. It is assumed that this mechanism may underlie the phenomenon of selective attention.
Basic characteristics of sensations
The subjective sensation resulting from the action of a sensory stimulus has a number of characteristics, i.e. allows you to determine a number of parameters of the current stimulus:
quality (modality),
intensity,
temporal characteristics (the moment of the beginning and end of the action of the stimulus, the dynamics of the strength of the stimulus),
spatial localization.
Quality coding stimulus in the central nervous system is based on the principle of specificity of sensory systems and the principle of somatotopic projection. Any sequence of nerve impulses generated in the pathways and cortical projection areas of the visual sensory system will cause visual sensations.
Intensity coding – see the section of the lecture course “Elementary physiological processes”, lecture 5.
Timing Coding cannot be separated from intensity coding. When the strength of the current stimulus changes over time, the frequency of action potentials generated in the receptor will also change. With prolonged exposure to a stimulus of constant strength, the frequency of action potentials gradually decreases (for more details, see the section of the lecture course “Elementary Physiological Processes”, Lecture 5), so the generation of nerve impulses can stop even before the cessation of the stimulus.
Spatial localization coding. The body can quite accurately determine the localization of many stimuli in space. The mechanism for determining the spatial localization of stimuli is based on the principle of somatotopic organization of sensory pathways.
Dependence of sensation intensity on the strength of the stimulus (psychophysics)
The absolute threshold is the least intense stimulus that can cause a certain sensation. The magnitude of the absolute threshold depends on
characteristics of the current stimulus (for example, the absolute threshold for sounds of different frequencies will be different);
conditions in which the measurement is carried out;
functional state of the body: focus of attention, degree of fatigue, etc.
Differential threshold is the minimum amount by which one stimulus must differ from another for this difference to be felt by a person.
Weber's law
In 1834, Weber showed that to distinguish the weight of 2 objects, their difference must be greater if both objects are heavy and less if both objects are light. According to Weber's law, differential threshold value ( Dj) is directly proportional to the strength of the current stimulus ( j) .
Where Dj - the minimum increase in stimulus strength required to cause an increase in sensation (differential threshold) , j - the strength of the current stimulus.
Graphically this pattern is presented in Fig. 4A. Weber's law is valid for medium and high stimulus intensities; at low stimulus intensities it is necessary to introduce a correction constant into the formula A.
 |
Rice. 4. Graphic representation of Weber’s law (A) and Fechner’s law (B). |
Fechner's law
Fechner's law establishes a quantitative relationship between the strength of the current stimulus and the intensity of sensation. According to Fechner's law, the strength of sensation is proportional to the logarithm of the strength of the current stimulus.
where Y is the intensity of sensation, k– proportionality coefficient, j- the strength of the current stimulus, j 0 – stimulus strength corresponding to the absolute threshold
Fechner's law was derived from Weber's law. The unit of sensation intensity was taken to be “barely noticeable sensation.” When a stimulus is applied, the magnitude of which is equal to the absolute threshold of sensation, a minimal sensation occurs. In order to experience a subtle increase in sensation, the strength of the stimulus must be increased by a certain amount. In order to experience a further subtle increase in sensation, the increase in stimulus strength must be large (according to Weber's law). When graphically depicting this process, a logarithmic curve is obtained (Fig. 4B).
Stevens Law
Fechner's law is based on the assumption that the strength of the sensation caused by a threshold increase in a weak and strong stimulus is equal, which is not entirely true. Therefore, the dependence of the intensity of sensation on the strength of the stimulus is more correctly described by the formula proposed by Stevens. Stevens' formula was proposed based on experiments in which the subject was asked to subjectively rate the intensity of the sensation caused by stimuli of varying strength. According to Stevens' law, the intensity of a sensation is described by an exponential function.
,
Where a– empirical exponent, which can be either greater or less than 1, the rest of the notations are as in the previous formula.