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MindMap Gallery Chapter 3 Blood
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Chapter 3 Blood
Chapter 3 is a mind map of blood, which includes physiological hemostasis, blood types and blood transfusion principles, blood cell physiology, and an overview of blood physiology. Let’s learn together.
Edited at 2023-04-08 16:03:25
- cáncer de pulmón
El cáncer de pulmón es un tumor maligno que se origina en la mucosa bronquial o las glándulas de los pulmones. Es uno de los tumores malignos con mayor morbilidad y mortalidad y mayor amenaza para la salud y la vida humana.
- diabetes
La diabetes es una enfermedad crónica con hiperglucemia como signo principal. Es causada principalmente por una disminución en la secreción de insulina causada por una disfunción de las células de los islotes pancreáticos, o porque el cuerpo es insensible a la acción de la insulina (es decir, resistencia a la insulina), o ambas cosas. la glucosa en la sangre es ineficaz para ser utilizada y almacenada.
- sistema digestivo
El sistema digestivo es uno de los nueve sistemas principales del cuerpo humano y es el principal responsable de la ingesta, digestión, absorción y excreción de los alimentos. Consta de dos partes principales: el tracto digestivo y las glándulas digestivas.
Chapter 3 Blood
- cáncer de pulmón
El cáncer de pulmón es un tumor maligno que se origina en la mucosa bronquial o las glándulas de los pulmones. Es uno de los tumores malignos con mayor morbilidad y mortalidad y mayor amenaza para la salud y la vida humana.
- diabetes
La diabetes es una enfermedad crónica con hiperglucemia como signo principal. Es causada principalmente por una disminución en la secreción de insulina causada por una disfunción de las células de los islotes pancreáticos, o porque el cuerpo es insensible a la acción de la insulina (es decir, resistencia a la insulina), o ambas cosas. la glucosa en la sangre es ineficaz para ser utilizada y almacenada.
- sistema digestivo
El sistema digestivo es uno de los nueve sistemas principales del cuerpo humano y es el principal responsable de la ingesta, digestión, absorción y excreción de los alimentos. Consta de dos partes principales: el tracto digestivo y las glándulas digestivas.
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- Outline
blood
Physiological hemostasis
Overview
Physiological hemostasis: Under normal circumstances, bleeding caused by damage to small blood vessels will stop on its own within a few minutes.
Bleeding time: Normally less than nine minutes (template method). Clinically, a small needle is commonly used to pierce the earlobe or fingertip skin to allow blood to flow out, and then the duration of bleeding is measured. This period is called the bleeding time.
The length of bleeding time can reflect the status of physiological hemostasis
Basic process of physiological hemostasis
vasoconstriction
Injurious stimulation causes vasoconstriction through nerve reflexes
Damage to the blood vessel wall causes local vascular smooth muscle contraction
Platelets adhered to the injured area release vasoconstrictor substances such as 5-HT and TXA2, causing vasoconstriction.
Formation of platelet hemostatic thrombus
Adhesion: identify the injured area and correctly position the hemostatic plug
Release: ADP, TXA2, causing irreversible aggregation of platelets
Aggregation: Formation of platelet hemostatic thrombus, primary hemostasis
blood clotting
Damaged blood vessels can also activate the coagulation system, causing local blood coagulation. The soluble fibrinogen in the plasma is converted into insoluble fibrin and intertwined into a network to strengthen the hemostatic thrombus and achieve secondary hemostasis.
Schematic diagram
blood clotting
Blood coagulation: refers to the process in which blood changes from a flowing liquid state to a non-flowing gel state. Normal person 4-12 minutes
Essence: The soluble fibrinogen in the plasma is converted into insoluble fibrin, which attracts blood cells and other blood components to form a blood clot.
Coagulation factors: substances in plasma and tissues that are directly involved in blood coagulation
Hemophilia A is deficient in FVII, hemophilia B is deficient in FII, and hemophilia C is deficient in FXXI.
Features
Except for factor IV, they are all proteins, most of which exist in the form of zymogens and need to be activated to become active.
The role of factors Ⅲ, Ⅳ, Ⅴ, Ⅷ and high molecular kinin pro-cofactors
Except factor III, all are present in fresh plasma
Most are synthesized in the liver, and vitamin K is required for the synthesis of factors II, VII, IX, and X. So vitamin K deficiency or liver damage → bleeding tendency
coagulation process
Formation of prothrombin complex
Intrinsic coagulation pathway: means that all the factors involved in coagulation come from blood, and are usually initiated by contact between blood and negatively charged foreign surfaces (such as glass, white clay, sulfate, collagen, etc.)
Extrinsic coagulation pathway: The coagulation process initiated when tissue factor (TF) derived from outside the blood is exposed to the blood, also known as the tissue factor pathway
Activation of prothrombin and fibrin production
Characteristics of the coagulation process
cascade amplification reaction
One FⅩⅠα can produce hundreds of millions of molecules of fibrin
Cofactors speed up reactions
FⅧα increases the potency of FⅠⅩα activation by 200,000 times
Tissue factor increases the potency of FⅦα to activate FⅩ by 1000-fold
FⅤα increases the speed of prothrombin activation by FⅩα by 10,000 times.
Positive feedback
FⅩⅡα⇌kallikrein
FⅦα⇌FⅩα
FⅦα⇌FⅠⅩα
FⅤα, FⅧα, FⅩⅠα⇌FⅡα
The internal and external coagulation pathways are interconnected and promote each other
FⅦα⇌FⅠⅩα
Blood coagulation time: The time required from blood collection to blood coagulation. 4-12 minutes
Ways to speed up coagulation
Add calcium
Calcium ions not only play a catalytic role in the blood coagulation process, but also participate in the formation of complexes that catalyze and activate coagulation.
Increase blood contact with rough surfaces
Use rough surface to activate factor XII and promote platelet release of platelet factors
Apply coagulant
Vitamin K, which can promote the liver to synthesize coagulation factors Ⅱ, Ⅶ, ⅠⅩ, Ⅹ
Suitable local heating
The coagulation process is an enzymatic reaction, and increasing temperature can increase enzyme activity.
Ways to slow blood clotting
Calcium remover
Such as sodium citrate, ammonium oxalate or potassium oxalate
lower blood temperature
Apply anticoagulants
Such as heparin, VitK antagonist (warfarin)
Keep blood contact surfaces smooth
Serum: 1-2 hours after blood coagulation, due to the activation of platelets in the blood clot, the blood clot retracts and releases a light yellow liquid
Difference from plasma
The serum is deficient in fibrinogen and some clotting factors (clotting no longer occurs)
Serum increases platelet release of substances
Physiological coagulation mechanism in vivo
The coagulation process is an enzymatic chain amplification reaction (positive feedback)
During the physiological coagulation process in the body
The extrinsic coagulation pathway plays a key role in stimulating the coagulation process, and tissue factor is the initiator (anchor) of the coagulation reaction.
The intrinsic coagulation pathway plays a very important role in amplifying and maintaining the coagulation reaction after it has begun.
Negative regulation of blood coagulation
Anticoagulant effect of vascular endothelium
barrier effect
Inhibit platelet aggregation (synthesis and release of PGI2 and NO)
Anticoagulant, promote fibrinolysis (synthesis, secretion of heparan sulfate proteoglycan, antithrombin, tissue factor pathway inhibitor, thrombin regulatory protein, tissue plasminogen activator)
Fibrin adsorption, blood flow dilution and monocyte macrophage phagocytosis
Fibrin can adsorb 85%-90% of thrombin, thus accelerating local coagulation and avoiding spreading to the surroundings.
Activated coagulation factors entering the circulation can be diluted by the blood flow
and phagocytosed by monocyte macrophages
Physiological anticoagulant substances
serine protease inhibitor
Antithrombin (inactivated thrombin), heparin cofactor II, C1 inhibitor, α1 antitrypsin, etc.
inactivated thrombin
Synthesis by liver and vascular endothelial cells
Binds to the serine in the active center of molecules such as thrombin, factor XIα, Xα, IXα, XIIα, etc., and inhibits their activity
The effect is enhanced 2000 times when combined with heparin
Protein C system
Protein C (inactivated cofactors Vα, VIIIα), protein S, thrombin regulatory protein, protein C inhibitor
Tissue factor pathway inhibitor (TFPI)
Specific inhibitor of the extrinsic pathway
Form tissue factor-FⅦα-TFP-FⅩα tetramer, thereby inactivating the FⅦα-tissue factor complex and inhibiting the extrinsic coagulation pathway
The main physiological anticoagulant substance in plasma
heparin
Mainly exerts indirect anticoagulant effect by enhancing the activity of antithrombin (Ⅲ)
Stimulates vascular endothelial cells to release tissue factor pathway inhibitor (TFPI)
Dissolution of fibrin
The process of fibrin being broken down and liquefied is called fibrinolysis, or fibrinolysis for short.
fibrinolytic process
activation of plasminogen
Degradation of fibrinolytic proteins
Blood types and blood transfusion principles
Blood type and red blood cell agglutination
Blood type: usually refers to the type of specific antigen on the red blood cell membrane
ABO blood group system
ABO blood group classification
According to the presence of A antigen and B antigen on the red blood cell membrane, blood can be divided into four types: A, B, O, and AB.
People with different blood types contain different antibodies in their serum
anti-A antibody
anti-B antibodies
Antigen specificity is determined by the sugar chains on the glycoproteins or glycolipids on the red blood cell membrane
ABO blood group system antibodies
Natural antibodies: mostly IgM, have large molecular weight and cannot pass through the placenta
Immune antibodies: belong to IgG, have small molecular weight and can pass through the placenta. When the body is stimulated by red blood cell antigens that it does not possess, it produces immune blood group antibodies.
ABO blood type inheritance
Controlled by three alleles, A, B and O, the A and B genes are dominant genes, and the O gene is a recessive gene
When forensic hospitals judge paternity based on blood type, they can only make a negative judgment, not a positive one.
Identification of ABO blood type
Red blood cell agglutination: If the blood of two people with incompatible blood types is dropped on a glass slide and mixed, the red blood cells can agglutinate into clusters. This phenomenon is called red blood cell agglutination. Under the action of complement, agglutinated red blood cells rupture and hemolysis
The nature of red blood cell agglutination: antigen-antibody reaction
RH blood group system
Antigens and typing of RH blood group system
Antigens: D, E, C, c, e, with D antigen having the strongest antigenicity
Types
Rh positive: D antigen present (most)
Rh negative: no D antigen
Characteristics and clinical significance (there are no natural antibodies against Rh in serum)
Features
When the RBCs of an Rh-positive person enter the body of a negative person, they produce anti-Rh immune antibodies through humoral immunity.
Anti-Rh antibodies in serum peak 2-4 months after blood transfusion
Immune antibodies are mainly IgG, which have small molecular weight and can pass through the placenta.
clinical significance
Blood transfusion: Generally, it is not necessary to consider the Rh blood type for the first blood transfusion, but it is necessary to consider whether the Rh blood types are the same for the second blood transfusion.
Pregnancy: Rh- mother
If the pregnant woman has received blood transfusion and her baby is Rh-positive, the pregnant woman’s anti-Rh antibodies can Crosses the placenta causing fetal hemolysis.
If the first pregnancy is positive, the fetal RBCs enter the mother's body for some reason (such as the placental villi falling off), or the blood squeezes into the mother's body during placental stripping during delivery, and the pregnant woman produces anti-Rh antibodies. During the second pregnancy, the anti-Rh antibodies in the pregnant woman cross the placenta and cause hemolysis of the fetus.
Blood transfusion principle
Blood type must be identified before blood transfusion, and blood transfusion of the same type must be carried out
Generally, it is ensured that the ABO blood type of the blood donor and the recipient are consistent. Women of childbearing age and patients who require repeated blood transfusions must also have consistent Rh blood types.
A cross-match test is required
There is no agglutination reaction on both sides, and blood transfusion is possible
If there is agglutination reaction on the main side, blood transfusion is absolutely not allowed.
There is agglutination reaction on the secondary side, so blood transfusion is generally not suitable
blood cell physiology
Parts and general processes of blood cell production
Hematopoietic stem cells (HSC) (bone marrow, peripheral blood, umbilical cord blood)
All types of adult blood cells originate from bone marrow hematopoietic stem cells
Features
Self-replication: symmetric versus asymmetric mitosis
multidirectional differentiation
Reestablish long-term hematopoiesis
Maintains the stability of its own cell number through self-replication and self-sustainment
90%-99.5% of hematopoietic stem cells are in G0 phase (relatively quiescent)
hematopoietic microenvironment
The place where hematopoietic stem cells settle, survive, proliferate, differentiate and mature, including stromal cells in hematopoietic organs, extracellular matrix secreted by stromal cells and various hematopoietic regulatory factors, as well as nerves and blood vessels entering hematopoietic organs. In the whole process of blood cell production play the role of regulation, induction and support in
Red Blood Cell Physiology (RBC)
Number and shape of red blood cells
quantity
adult male
Number of red blood cells: 4.0-5.5 (x10*12/L)
Hemoglobin amount: 120-160 (g/L)
adult women
Number of red blood cells: 3.5-5.0 (x10*12/L)
Hemoglobin amount: 110-150 (g/L)
newborn
Number of red blood cells: 6.0-7.0 (x10*12/L)
Hemoglobin amount: 170-200 (g/L)
There are certain differences depending on age, gender, physical condition, and living environment.
Anemia: The number of red blood cells and hemoglobin concentration in the blood are lower than normal
Morphological characteristics
No core, double concave disc shape
Diameter 7-8μm, thickness: 2.5μm (thickest), 1μm (thinnest)
No mitochondria, energy obtained through glycolysis
Physiological characteristics and functions of red blood cells
Physiological characteristics of red blood cells
Plastic deformability
Normal cells have the ability to degenerate under the influence of external forces. After the external force is removed, it can return to its normal double-concave disc shape.
Denaturing capacity depends on the geometry of the red blood cells, the viscosity within the red blood cells and the elasticity of the red blood cell membrane. Of these, the normal biconcave disk-shaped geometry of red blood cells is the most important
suspension stability
The red blood cells in the blood settle slowly and can be relatively stably dispersed and suspended in the plasma.
Why red blood cells are stable in suspension
Biconcave disc shape → Large surface area to volume ratio (140μm*2/90μm*3) → Large friction between red blood cells and plasma
The red blood cell membrane is negatively charged (N-acetylneuraminic acid) → red blood cells repel each other
ESR
The erythrocyte sedimentation tube containing anticoagulated blood is placed vertically, and the sedimentation rate of the red blood cells is expressed by the distance that the red blood cells sink at the end of the first hour, which is called the erythrocyte sedimentation rate (ESR).
normal value
Male: 0-15mm/h
Female: 0-20mm/h
Red blood cell stacking: In certain diseases (tuberculosis, rheumatism), red blood cells can quickly stick to each other with concave surfaces, forming red blood cell stacking.
Red blood cell stacking (the ratio of total surface area to total volume decreases) → suspension stability ↓ → accelerated erythrocyte sedimentation rate
The speed of red blood cell stacking does not depend on the red blood cells themselves, but is related to changes in the composition of the plasma
Globulin, fibrinogen and cholesterol↑→red blood cell stack↑→erythrocyte sedimentation rate↑
Albumin, lecithin↑→red blood cell stack↓→erythrocyte sedimentation rate↓
Permeable brittle type
The characteristic of red blood cells swelling and rupturing in hypotonic saline solution
Reflects the ability of red blood cells to resist hypotonic solutions
High brittleness = low resistance to hypotonic fluids = easy to break Low brittleness = high resistance to hypotonic fluids = not easy to break
Red blood cells have a certain resistance to hypotonic solutions, and red blood cells of the same individual have different resistances to hypotonic saline solutions.
Aged red blood cells are extremely fragile
The fragility of newly mature red blood cells is significantly reduced
function of red blood cells
Transport oxygen and carbon dioxide
Oxygen in the blood is mainly combined with hemoglobin and exists in the form of oxyhemoglobin
Carbon dioxide exists primarily in the form of bicarbonate and carbamoyl hemoglobin. Red blood cells are rich in carbonic anhydrase. Therefore, with the participation of red blood cells, the blood's ability to transport carbon dioxide is also greatly improved.
Buffer acid-base substances in the blood
There are multiple buffer pairs within red blood cells (hemoglobin potassium salt/hemoglobin, oxygen and hemoglobin potassium salt/oxygen and hemoglobin, etc.)
Immune Function
Promote the phagocytosis of antigen-antibody-complement immune complexes by macrophages
Regulation of erythropoiesis
Site of birth: liver, spleen and bone marrow during embryonic period; mainly in bone marrow after birth (2×10*11/day) (clinically, the rise and fall of bone marrow hematopoietic function is often understood through peripheral blood reticulocyte count)
Substances required for the production of red blood cells
Protein and iron are important raw materials for the synthesis of hemoglobin
Iron: essential substance for Hb synthesis
Iron deficiency anemia (morphologically manifested as microcytic hypochromic anemia)
Enhanced hematopoietic function and insufficient iron supply (infants, pregnant women, and lactating mothers)
Iron absorption and utilization disorders (gastric acid, vitamin C deficiency)
Excessive iron loss (chronic blood loss)
Folic acid and vitamin B12 are essential substances for the maturation of red blood cells and are important coenzymes required for the synthesis of DNA (deficiency of either will lead to megaloblastic anemia)
Lack of folic acid or vitamin B12 → Reduced DNA synthesis → Slowed division and proliferation of red blood cells → Megaloblastic anemia (folic acid and vitamin B12 are stored in large amounts in the body, and anemia will occur after 3-4 months and 3-5 years respectively in case of deficiency) )
The absorption of vitamin B12 requires the participation of intrinsic factor. The body lacks intrinsic factor or the body produces anti-intrinsic factor antibodies → vitamin B12 malabsorption → megaloblastic anemia
Regulation of erythropoiesis
Erythroid progenitor cells can be divided into two subpopulations
Early erythroid progenitor cells (BFU-E): stimulated by stem cell factor, interleukin-3 and granulocyte-macrophage colony-stimulating factor, proliferate and develop into late erythroid progenitor cells (CFU-E)
Late erythroid progenitor cells (CFU-E): mainly regulated by erythropoietin (EPO)
Influencing factors
Erythropoietin (EPO)
Mechanism
EPO levels are inversely related to blood hemoglobin concentration
EPO promotes red blood cell production
In a complete lack of EPO, there is little red blood cell production in the bone marrow
When there is a large amount of EPO, as long as sufficient hematopoietic raw materials are provided, the production of red blood cells can be increased 10 times compared with normal levels.
CFU-E is the target cell of EPO
As a survival factor, inhibits the apoptosis of CFU-E
Activates the expression of erythroid-specific genes such as hemoglobin, promotes the transformation of erythroid progenitor cells into proerythroblasts, and promotes the development of immature erythrocytes and hemoglobin synthesis.
Promote the maturation and release of reticulocytes
Source of EPO
EPO is mainly synthesized by interstitial cells around the renal cortex and tubules (fibroblasts, endothelial cells)
Tissue hypoxia is a physiological stimulus that promotes EPO secretion
Other humoral factors
Promote red blood cell production: androgens, thyroid hormones, adrenocortical hormones, growth hormone
Inhibits erythropoiesis: estrogen, transforming growth factor beta, interferon gamma, and tumor necrosis factor
destruction of red blood cells
Average lifespan is about 120
90% of senescent red blood cells are destroyed by macrophages (extravascular destruction) in the spleen and bone marrow. The iron and amino acids released after phagocytosis are reused, while apoferric heme is converted into bile pigment and excreted in the feces or urine.
10% of senescent red blood cells are destroyed in blood vessels, combined with plasma haptoglobin, and taken up by the liver
White blood cell physiology
White blood cell classification and normal values
Total number: (4-10)×10*9/L
Classification
Granulocytes
Neutrophils (50%-70%)
The first line of defense against pathogenic microorganisms
Through deformation, migration, exudation, and chemotaxis, it reaches the lesion to phagocytose, hydrolyze bacteria and necrotic cells, and participate in the inflammatory response.
When infection occurs, neutrophils are the first effector cells to arrive at the inflammatory site, and the number of local neutrophils reaches a peak within 6 hours.
Features
Strong phagocytic activity (bacteria, senescent RBCs, necrotic cells, etc.)
Strong deformation wandering ability and the fastest speed (30μm/min)
clinical
Bacterial infection (products of inflammation) → neutrophils ↑
Neutrophils↓(1×10*9/L)→Body resistance↓
Eosinophils (0.5%-5%)
Eosinophils have slow phagocytosis, basically no bactericidal effect, and do not play a major role in fighting bacterial infections.
Main function (basically no bactericidal effect)
Limits allergic reactions caused by mast cells and basophils
Inhibits the release of active substances from basophils by producing prostaglandin E
Phagocytosis of biologically active substances such as granules and enzymes released by basophils and mast cells
Participate in the immune response to worms: damage the worm body by releasing basic proteins, cationic proteins, peroxides, etc. contained in the particles
Clinical: allergic reaction or helminth infection → eosinophils↑
Basophils (0%-1%)
The granules in basophils contain a variety of biologically active substances (mainly involved in allergic reactions)
Heparin: has anticoagulant effect
Histamine and anaphylaxis: involved in allergic reactions
Chemokines: Attract and recruit eosinophils
No granulocytes
Lymphocytes (20%-40%)
T lymphocytes are mainly related to cellular immunity; B lymphocytes are mainly related to humoral immunity. NK cells participate in innate immunity
Monocytes (3%-8%)
Monocytes enter the tissue and transform into macrophages (the number of lysosomes and mitochondria increases). Their phagocytic power is enhanced and they can engulf larger particles, but their chemotactic migration speed is slow. (It takes days or weeks to become the main phagocytes in the inflammation area and can only be seen in the late stage)
Features
Mononuclear-macrophages phagocytose more bacteria, larger bacteria and particles (5 times more than neutrophils)
Contains esterase: digests bacterial lipid membrane (Mycobacterium tuberculosis)
Synthesizes and releases a variety of factors (interleukin, tumor necrosis factor, interferon, etc.) to participate in the regulation of other cells
Kill tumor cells and virus-infected cells
Plays a key role in processing and presenting antigens, induction and regulation of specific immune responses
Physiological properties and functions of white blood cells
White blood cells have the characteristics of exudation, migration, chemotaxis, phagocytosis and secretion.
Extravasation: Except for lymphocytes, all white blood cells can extend pseudopods and perform deformation movements. With this movement, white blood cells can pass through the capillary wall.
Chemotaxis: The property of white blood cells to move toward certain chemicals.
Chemokines: chemicals that attract white blood cells to move in a directed manner
Phagocytosis (selective): phagocytosis, digestion and killing of bacteria
Secrete cytokines: interleukins, interferons, tumor necrosis factor, colony-stimulating factor, involved in inflammation and immune response
Production and regulation of white blood cells
Destruction of white blood cells: Because white blood cells often travel to tissues to perform their functions, it is difficult to accurately determine their lifespan. Blood simply transports white blood cells from the bone marrow and lymphoid tissues to where they are needed in the body
Neutrophils: 8 hours in blood - 4-5 days in tissue aging and death
Monocytes: blood 2-3 days – tissue macrophages 3 months
Eosinophils and basophils: tissue senescence and death in 8-12 and 12-15 days
Platelet Physiology
Platelet number and function
Platelets are small in size, have no nuclei, are slightly convex on both sides, are disc-shaped, are small in size, and have a diameter of 2-3 μm. They are cells with metabolic capabilities formed by shedding the cytoplasm of bone marrow megakaryocytes.
There are many glycoproteins (GP) on the platelet membrane, which have the function of receptors
Normal value: (100-300)×10*9/L
Platelet function: maintains the integrity of vascular endothelium and participates in physiological hemostasis
Direct endothelial repair: adhere and fuse into vascular endothelial cells
Releases vascular endothelial cell growth factor and platelet-derived growth factor: promotes the proliferation of vascular endothelial cells, smooth muscle cells and fibroblasts, and is beneficial to the repair of damaged blood vessels
Physiological properties of platelets
Adhesion (adhesion of platelets to non-platelet surfaces)
Vascular injury → Subendothelial components (collagen fibers) → Plasma vWF factor (vWF allosteric) Platelet glycoprotein complex (GPIb/IX/Ⅴ)
freed
The process by which platelets excrete substances stored in dense bodies, α-granules or lysosomes after being stimulated is also called platelet release.
α granules: β-platelet granules, PF4, vWF, fibrinogen, FV, thrombospondin, PDGF
Dense bodies: ADP, ATP, 5-HT, calcium ions
It can also instantly synthesize and release thromboxane A2 (TXA2), which has strong platelet aggregation and vasoconstrictive effects.
gather
Platelet-to-platelet adhesion
Requires the participation of fibrinogen, calcium ions and GPIIb-IIIα on the platelet membrane
Polymerizer
Physiological: ADP, epinephrine, 5-hydroxytryptamine, histamine, collagen, thrombin, TXA2 (not stored in platelets, but temporarily synthesized and released after stimulation)
Pathological: bacteria, viruses, immune complexes, drugs
Prostaglandin metabolism in platelets and endothelial cells
Aspirin can inhibit cyclooxygenase, reduce the production of TXA2, increase cAMP↑ in platelets, and inhibit platelet aggregation.
shrink
After platelet activation, intracytoplasmic calcium ions increase, causing platelet contraction reaction. Related to the contractile protein contained in platelets
Adsorption
The surface of platelets can adsorb many coagulation factors in plasma (such as coagulation factors Ⅰ, Ⅴ, ⅩⅠ, ⅩⅢ5)
Platelet production and regulation
Destruction of platelets: The average life span is 7-14 days, but it only has physiological functions in the first two days. Aged platelets are engulfed and destroyed in the spleen, liver and lung tissues. In addition, platelets can also be consumed while performing their physiological functions
Physiological overview of blood
Blood is a fluid tissue composed of plasma and blood cells suspended in it. It circulates within the cardiovascular system and plays a role in transporting substances.
Physiological functions of blood
Material transport (nutrients, metabolites, hormones)
Buffered acids and bases (buffered pairs)
Regulates body temperature (high specific heat of water)
Defense and protection (white blood cells, antibodies, complement)
Physiological hemostasis (platelets, coagulation factors)
Plays an important role in maintaining homeostasis of the internal environment
blood composition
Plasma (55%)
crystalline substance solution
Includes water (91-92%), electrolytes, small organic compounds (nutrients, metabolites and hormones) and some gases
The electrolyte content is basically the same as that of tissue fluid
Plasma proteins (the main difference between plasma and tissue fluid)
Albumin: has the smallest molecular weight but the largest content
Globulin: four types of globulin: α1, α2, β, and γ (γ is almost all antibodies and comes from plasma cells)
Fibrinogen: has the largest molecular weight and the smallest content
Normal value: The total amount of normal adult plasma protein is about 65~85g/L
Albumin (A): about 40-48g/L
Globulin (G): about 15-30g/L
Fibrinogen: about 2-4g/L
A/G: 1, 5~2.5: 1
Liver disease: A/G↓
Main functions of plasma proteins
Form plasma colloid osmotic pressure and regulate the distribution of water inside and outside blood vessels
Binds to hormones to prevent excretion from the kidneys
Carriers for transporting substances (ions, lipids, vitamins, drugs, etc.)
Participate in physiological processes such as coagulation, anticoagulation, and fibrinolysis
Resist the invasion of pathogenic microorganisms
nutritional function
blood cells
White blood cells and platelets (<1%)
Red blood cells (45%)
Hematocrit: The percentage of blood cells occupied by the volume of blood
normal value
Male: 40%-50%
Female: 37%-48%
Meaning: reflects the relative concentration of red blood cells in the blood
clinical
Hematocrit↓→red blood cells↓→anemia
Hematocrit↑→red blood cells↑→polycythemia
Hematocrit↑→Plasma volume↓→Diarrhea or burns
Blood viscosity increases, blood flow resistance increases, and the burden on the heart increases. Blood clots, strokes and heart attacks.
Physical and chemical properties of blood
specific gravity of blood
Whole blood specific gravity: 1.050-1.060
Plasma specific gravity: 1.025-1.030
Specific gravity of red blood cells: 1.090-1.092
application
Separation of red blood cells and plasma
Determination of hematocrit and erythrocyte sedimentation rate
blood viscosity
Cause: caused by friction between molecules or particles inside the liquid
Value: The relative viscosity of whole blood is 4-5, and the relative viscosity of plasma is 1.6-2.4 (taking the viscosity of water as 1)
determining factors
The viscosity of whole blood is mainly determined by the level of hematocrit
Plasma viscosity mainly depends on the content of plasma proteins
Significance: The viscosity of blood is one of the important factors in forming blood flow resistance. When blood flow slows down, red blood cells overlap and aggregate, blood viscosity increases, and blood flow resistance increases.
plasma osmolarity
Osmosis: The process in which solvent molecules (water molecules) cross a semipermeable membrane from the low-concentration side of a solution into the high-concentration side of the solution (the force that promotes the penetration of water molecules can be measured by the pressure difference in the liquid column after equilibrium)
Osmotic pressure: refers to the energy of a solution to attract and retain water molecules, which is the driving force for the occurrence of osmosis.
The osmotic pressure of a solution is proportional to the number of solute particles contained in the solution and has nothing to do with the type and size of the solute particles.
numerical value
Normal value: 300mOsm/(kg·H2O) (770KPa, 5790mmHg)
Colloidal osmotic pressure 1.3mOsm/(kg·H2O)
Crystal osmotic pressure 298.7mOsm/(kg·H2O)
composition
crystal osmotic pressure
Composition: inorganic salts, sugar and other crystalline substances (80% NaCl)
Pressure: high, 298.7mOsm/(kg·H2O)
Significance: Maintain the balance of water inside and outside cells to maintain the normal shape of blood cells
colloid osmotic pressure
Composition: plasma proteins and other colloidal substances (75%-80% is albumin)
Pressure: small, 1.3mOsm/(kg·H2O)
Significance: Regulate the balance of water inside and outside capillaries to maintain blood volume
isotonic solution
Isotonic solution (0.9% NaCl solution or 5% glucose solution is isotonic solution): a solution with an osmotic pressure equal to the plasma osmotic pressure
Hypertonic solution: A solution with an osmotic pressure higher than the osmotic pressure of plasma
Hypotonic solution: a solution whose osmotic pressure is equal to the osmotic pressure of plasma
Isotonic solution: A solution that maintains the normal shape and size of red blood cells suspended in it
Isotonic solution = solute that cannot pass through the cell membrane Isotonic solution
0.9% NaCl solution or 5% glucose solution is both isotonic and isotonic solution
1.9% urea solution is isotonic solution, but not isotonic solution
pH of plasma
Normal value: 7.35-7.45
When pH <7.35, it is acidosis.
When pH>7.45, it is alkalosis
If the plasma is below 6.9 or above 7.8, it will be life-threatening
maintain relatively stable factors
Effects of various buffer pairs in plasma and red blood cells (NaHCO3/H2CO3, protein sodium salt/protein, NaHPO4/NaH2PO4, and intraerythrocyte buffer pairs)
Excretory functions of the lungs and kidneys