Human blood is represented by 2 components: a liquid base or plasma and cellular elements. What is plasma and what is its composition? What is the functional purpose of plasma? Let's look at everything in order.
All about plasma
Plasma is a liquid formed by water and dry substances. It makes up the bulk of the blood - about 60%. Thanks to plasma, blood has a liquid state. Although according to physical indicators (density) plasma is heavier than water.
Macroscopically, plasma is a transparent (sometimes cloudy) homogeneous liquid of light yellow color. It collects in the upper part of the vessels when the formed elements settle. Histological analysis shows that plasma is the intercellular substance of the liquid part of the blood.
Plasma becomes cloudy after a person consumes fatty foods.
What does plasma consist of?
Plasma composition is presented:
- Water;
- Salts and organic substances.
- Proteins;
- Amino acids;
- Glucose;
- Hormones;
- Enzyme substances;
- Minerals (Na, Cl ions).
What percentage of plasma volume is protein?
This is the most numerous component of plasma, it occupies 8% of all plasma. Plasma contains protein of various fractions.
The main ones:
- Albumin (5%);
- Globulins (3%);
- Fibrinogen (belongs to globulins, 0.4%).
Composition and objectives of non-protein compounds in plasma
Plasma contains:
- Organic compounds based on nitrogen. Representatives: uric acid, bilirubin, creatine. An increase in the amount of nitrogen signals the development of azotomy. This condition occurs due to problems with the excretion of metabolic products in the urine or due to the active destruction of protein and the entry of large amounts of nitrogenous substances into the body. The latter case is typical for diabetes, fasting, and burns.
- Organic compounds that do not contain nitrogen. This includes cholesterol, glucose, lactic acid. Lipids also keep them company. All these components must be monitored, as they are necessary to maintain full functioning.
- Inorganic substances (Ca, Mg). Na and Cl ions are responsible for maintaining a constant pH of the blood. They also monitor osmotic pressure. Ca ions take part in muscle contraction and stimulate the sensitivity of nerve cells.
Blood plasma composition Albumen
Albumin in plasma blood is the main component (more than 50%). It has a small molecular weight. The place of formation of this protein is the liver.
Purpose of albumin:
- Transports fatty acids, bilirubin, drugs, hormones.
- Takes part in metabolism and protein formation.
- Reserves amino acids.
- Forms oncotic pressure.
Doctors judge the condition of the liver by the amount of albumin. If the albumin content in plasma is reduced, this indicates the development of pathology. Low levels of this plasma protein in children increase the risk of developing jaundice.
Globulins
Globulins are represented by large molecular compounds. They are produced by the liver, spleen, and thymus.
There are several types of globulins:
- α – globulins. They interact with thyroxine and bilirubin, binding them. Catalyze the formation of proteins. Responsible for transporting hormones, vitamins, lipids.
- β – globulins. These proteins bind vitamins, Fe, and cholesterol. They transport Fe and Zn cations, steroid hormones, sterols, and phospholipids.
- γ – globulins. Antibodies or immunoglobulins bind histamine and take part in protective immune reactions. They are produced by the liver, lymph tissue, bone marrow and spleen.
There are 5 classes of γ-globulins:
- IgG(about 80% of all antibodies). It is characterized by high avidity (antibody to antigen ratio). Can penetrate the placental barrier.
- IgM- the first immunoglobulin that is formed in the unborn baby. The protein has high avidity. It is the first to be detected in the blood after vaccination.
- IgA.
- IgD.
- IgE.
Fibrinogen is a soluble plasma protein. It is synthesized by the liver. Under the influence of thrombin, the protein is converted into fibrin, an insoluble form of fibrinogen. Thanks to fibrin, a blood clot forms in places where the integrity of the vessels has been compromised.
Other proteins and functions
Minor fractions of plasma proteins after globulins and albumins:
- Prothrombin;
- Transferrin;
- Immune proteins;
- C-reactive protein;
- Thyroxine-binding globulin;
- Haptoglobin.
The tasks of these and other plasma proteins boil down to:
- Maintaining homeostasis and the state of aggregation of the blood;
- Control of immune reactions;
- Transport of nutrients;
- Activation of the blood clotting process.
Functions and tasks of plasma
Why does the human body need plasma?
Its functions are varied, but basically they come down to 3 main ones:
- Transporting blood cells and nutrients.
- Establishing communication between all body fluids that are located outside the circulatory system. This function is possible due to the ability of plasma to penetrate the vascular walls.
- Ensuring hemostasis. This involves controlling the fluid that stops bleeding and removing the resulting blood clot.
The use of plasma in donation
Today, whole blood is not transfused: plasma and formed components are isolated separately for therapeutic purposes. At blood donation points, people most often donate blood specifically for plasma.
Blood plasma system How to get plasma?
Plasma is obtained from the blood using centrifugation. The method allows you to separate plasma from cellular elements using a special apparatus without damaging them. The blood cells are returned to the donor.
The plasma donation procedure has a number of advantages over simple blood donation:
- The volume of blood loss is less, which means less harm is caused to health.
- Blood can be donated for plasma again after 2 weeks.
There are restrictions on plasma donation. Thus, a donor can donate plasma no more than 12 times per year.
Plasma donation takes no more than 40 minutes.
Plasma is the source of such important material as blood serum. Serum is the same plasma, but without fibrinogen, but with the same set of antibodies. They are the ones who fight pathogens of various diseases. Immunoglobulins contribute to the rapid development of passive immunity.
To obtain blood serum, sterile blood is placed in an incubator for 1 hour. Next, the resulting blood clot is peeled off the walls of the test tube and placed in the refrigerator for 24 hours. The resulting liquid is added to a sterile vessel using a Pasteur pipette.
Blood pathologies affecting the nature of plasma
In medicine, there are several diseases that can affect the composition of plasma. All of them pose a threat to human health and life.
The main ones are:
- Hemophilia. This is a hereditary pathology when there is a lack of protein, which is responsible for coagulation.
- Blood poisoning or sepsis. A phenomenon that occurs due to infection entering directly into the bloodstream.
- DIC syndrome. A pathological condition caused by shock, sepsis, severe injuries. It is characterized by blood clotting disorders, which simultaneously lead to bleeding and the formation of blood clots in small vessels.
- Deep venous thrombosis. With the disease, the formation of blood clots in the deep veins (mainly in the lower extremities) is observed.
- Hypercoagulation. Patients are diagnosed with excessive blood clotting. The viscosity of the latter increases.
Plasma test or Wasserman reaction is a study that detects the presence of antibodies in plasma to Treponema pallidum. Based on this reaction, syphilis is calculated, as well as the effectiveness of its treatment.
Plasma is a liquid with a complex composition that plays an important role in human life. It is responsible for immunity, blood clotting, homeostasis.
Video - health guide (Blood plasma)
Blood plasma is a viscous, homogeneous liquid of light yellow color. It makes up about 55-60% of the total blood volume. It contains blood cells in the form of a suspension. Plasma is usually clear, but may be slightly cloudy after eating a fatty meal. Consists of water and mineral and organic elements dissolved in it.
Plasma composition and functions of its elements
Most of the plasma is water, its amount is approximately 92% of the total volume. In addition to water, it includes the following substances:
- proteins;
- glucose;
- amino acids;
- fat and fat-like substances;
- hormones;
- enzymes;
- minerals (chlorine, sodium ions).
About 8% of the volume is proteins, which are the main part of plasma. It contains several types of proteins, the main ones being:
- albumins – 4-5%;
- globulins – about 3%;
- fibrinogen (belongs to globulins) – about 0.4%.
Albumen
Albumin is the main plasma protein. It has a low molecular weight. Content in plasma is more than 50% of all proteins. Albumin is formed in the liver.
Protein functions:
- perform a transport function - transport fatty acids, hormones, ions, bilirubin, medications;
- take part in metabolism;
- regulate oncotic pressure;
- participate in protein synthesis;
- reserve amino acids;
- deliver medications.
A change in the level of this protein in plasma is an additional diagnostic sign. The condition of the liver is determined by the concentration of albumin, since many chronic diseases of this organ are characterized by its decrease.
Globulins
The remaining plasma proteins are classified as globulins, which are large in molecular weight. They are produced in the liver and in the organs of the immune system. Main types:
- alpha globulins,
- beta globulins,
- gamma globulins.
Alpha globulins bind bilirubin and thyroxine, activate the production of proteins, transport hormones, lipids, vitamins, and microelements.
Beta globulins bind cholesterol, iron, vitamins, transport steroid hormones, phospholipids, sterols, zinc and iron cations.
Gamma globulins bind histamine and participate in immunological reactions, which is why they are called antibodies, or immunoglobulins. There are five classes of immunoglobulins: IgG, IgM, IgA, IgD, IgE. Produced in the spleen, liver, lymph nodes, and bone marrow. They differ from each other in biological properties and structure. They have different abilities to bind antigens, activate immune proteins, have different avidity (rate of binding to antigen and strength) and ability to pass through the placenta. Approximately 80% of all immunoglobulins are IgG, which have high avidity and are the only ones that can cross the placenta. IgM is synthesized first in the fetus. They are also the first to appear in the blood serum after most vaccinations. They have high avidity.
Fibrinogen is a soluble protein that is produced in the liver. Under the influence of thrombin, it is converted into insoluble fibrin, due to which a blood clot is formed at the site of vessel damage.
Other proteins
In addition to the above, plasma also contains other proteins:
- complement (immune proteins);
- transferrin;
- thyroxine-binding globulin;
- prothrombin;
- C-reactive protein;
- haptoglobin.
Non-protein components
In addition, blood plasma includes non-protein substances:
- organic nitrogen-containing: amino acid nitrogen, urea nitrogen, low molecular weight peptides, creatine, creatinine, indican. Bilirubin;
- organic nitrogen-free: carbohydrates, lipids, glucose, lactate, cholesterol, ketones, pyruvic acid, minerals;
- inorganic: sodium, calcium, magnesium, potassium cations, chlorine anions, iodine.
The ions in the plasma regulate the pH balance and maintain the normal state of cells.
Functions of proteins
Proteins have several purposes:
- homeostasis;
- ensuring the stability of the immune system;
- maintaining the aggregate state of the blood;
- nutrient transfer;
- participation in the process of blood clotting.
Plasma functions
Blood plasma performs many functions, including:
- transportation of blood cells, nutrients, metabolic products;
- binding of liquid media located outside the circulatory system;
- making contact with body tissues through extravascular fluids, thereby achieving hemostasis.
Donor plasma saves many lives
Use of donor plasma
In our time, transfusions often require not whole blood, but its components and plasma. Therefore, blood transfusion centers often donate blood for plasma. It is obtained from whole blood by centrifugation, that is, the liquid part is separated from the formed elements using a machine, after which the blood cells are returned to the donor. The procedure lasts about 40 minutes. The difference from donating whole blood is that blood loss is much less, and you can donate plasma again after two weeks, but no more than 12 times during the year.
Blood serum is obtained from plasma, which is used for medicinal purposes. It differs from plasma in that it does not contain fibrinogen, but contains all the antibodies that can resist pathogens. To obtain it, place sterile blood in a thermostat for an hour. Then the resulting clot is peeled off from the wall of the test tube and kept in the refrigerator for a day. After this, using a Pasteur pipette, the settled whey is poured into a sterile container.
Conclusion
Blood plasma is its liquid component, which has a very complex composition. Plasma performs important functions in the body. In addition, donor plasma is used for transfusion and preparation of therapeutic serum, which is used for the prevention and treatment of infections, as well as for diagnostic purposes to identify microorganisms obtained during analysis. It is considered more effective than vaccines. Immunoglobulins contained in serum immediately neutralize harmful microorganisms and their metabolic products, and passive immunity is formed faster.
The state of plasma is almost unanimously recognized by the scientific community as the fourth state of matter. Around this state, a separate science has even been formed that studies this phenomenon - plasma physics. The state of plasma or ionized gas is represented as a set of charged particles, the total charge of which in any volume of the system is zero - a quasineutral gas.
There is also gas-discharge plasma, which occurs during a gas discharge. When an electric current passes through a gas, the first ionizes the gas, the ionized particles of which carry the current. This is how plasma is obtained in laboratory conditions, the degree of ionization of which can be controlled by changing the current parameters. However, unlike high-temperature plasma, gas-discharge plasma is heated by current, and therefore quickly cools when interacting with uncharged particles of the surrounding gas.
Electric arc - ionized quasi-neutral gas