Bai giang ve mau (Blood)

Blood - Functions of the blood - Components of the blood - Erythrocyte/red blood cell and its structure and - Erythropoiesis and Eryptosis - Leucocyte/white blood cell types and functi

Blood

Blood

- Functions of the blood

- Components of the blood

- Erythrocyte/red blood cell and its structure and

- Erythropoiesis and Eryptosis

- Leucocyte/white blood cell types and functions

- Hemostasis and blood clotting, the role of Ca2+, vitamin K and liver in hemostasis

- ABO and Rh blood group systems

Blood volume in animals

• Blood is a fluid connective tissue

Components of the blood

Leucocyte, plateletes Plasma (55%)

Erythrocyte (45%)

•Plasma ( Huyết tương) : the

remaining fluid in the blood after

removing all blood cells

•Formed elements:

─ erythrocyte (red bllod cell)

─ leucocyte (white blood cell)

─ Platelet

Hematocrit (hct)= 100 x (erythrocyte volume/ total blood volume)

Functions of the blood

• Transport : nutrients, respiratory gases,

metabolic wastes, hormones

• Maintaining homeostasis for : pH, temperature, electrolyte balance

• Protection: blood clotting, immune response

Osmotic pressure and pH of the blood

• Osmotic pressure - P = 7,6 - 8,1 atm (human)

• Created by salts ( NaCl) + dissolved proteins

• pH = 7,35 - 7,45, is maintained by different

buffering systems

Red blood cells and changes in plasma osmotic

pressure

Dd ưu trương Dd đẳng trương Dd nhược trương

Components of plasma

Formed elements (Các yếu tố hữu hình)

molecules /1 erythrocyte)

7,5µm

2 µm

The life span of red blood cell

• 1 second: 2.5 million are destroyed/degraded 2.5

million are produced

• Erythropoiesis (sự tạo hồng cầu):

– Life span: 120 days (male), 110 days (female)

– Site of erythropoiesis: liver, spleen (during

embryogenesis), bone marrow (aldult)

– 4 days to form a new red blood cell

Factors regulate erythropoiesis

Anemia and blood doping

Anemia: decrease in the oxygen carrying capacity of blood:

- Decrease in number and size of erythrocytes -> low hematocrit

- Decrease in Hb level in each erythrocyte

• Nutritional anemia (iron, folic acid, B12 deficiency)

• Pernicious anemia (lack of intrinsic factor needed for B12 absorption)

• Aplastic anemia (bone marrow deffect)

• Renal anemia (lack EPO)

• Hemorrhagic anemia

• Hemolytic anemia (malaria, sickle cell anemia)

Blood doping: injection of erythrocytes or EPO to increase the

oxygen carrying capacity of blood

Eryptosis (sự phân hủy hồng cầu)

New protein synthesis

Most of old erythrocytes are phagozied by macrophages

in the spleen and to a lesser extent, in the livers

Jaundice

Leucocytes/white blood cells

• Have larger size than RBC: 5 – 25 µm

(adult), 20.000/mm3 (infant)

• Irregular cell shape, nucleated and mobile cells

• Specific and nonspecific immune response

-10-15 µm

- nonphagocytic , producing toxic molecules against larger parasites;

Dennis Kunkel, 2004

Platelets and Hemostasis

platelets/ thrombocytes ( Tiểu cầu)

– Are cell fragments generated by breaking off of

SEM (scanning electron microscope) images of megakaryocyte and platelet

Magnification:* x5,335 Magnification:* x1,600

A mature platelet

a large megakaryocyte is

forming 2 small platelets

He mostasis

Collagen exposing Platelet plug Fibrin clots

1 Vascular spasm

2 Formation of Platelet plug

3 Formation of Blood clot (thrombus):

platelets + fibrin + blood cells

Vascular spasm ( Sự co thắt mạch) starts

the process of hemostasis

• intrinsic mechanisms and increased

sympathetic neural activities cause

damaged blood vessels -> reducing blood loss

Formation of platelet plug

• Megakaryocytes, platelets, endothelial cells producing Von Wilibrand factor (vWf)

• Platelet adhesion: vWf binds to the collagen fibers in the

subendothelium->platelets bind to vWf -> activated platelets which are “sticky” and be able to produce clotting substances:

– Serotonin and epinerphrine cause vasoconstriction reducing blood loss

– ADP causes platelet aggregation by inducing morphological

changes in the platelets so that they adhere to one another

– Aggregated platelets secret more ADP -> more platelet

aggregation (positive feed back loop increases the rate of plug

formation)

– Aggregated platelets also stimulates thromboxane A2 (TXA2)

production which support further platelet aggregation

• Prostacyclin ( prostaglandin I2) and NO produced by healthy

endothelial cells to inhibit platelet plug formation

mang trong

Magnification*: x1,600

Formation of a blood clot

The formation of fibrin clot

•The conversion of soluble plasma protein fibrinogen into a gel of

insoluble fibrin meshwork by the coagulation cascade carried out by

vessels -> prevent blood loss

Coagulation factors

Coagulation factors

I Fibrinogen (produced by the livers ))

II Prothrombin (produced by the livers ) – vit K)

III Thromboplastin (mô thương tổn sx)

V Proaccelerin (produced by the livers )

VII Proconvertin (produced by the livers -vitK)

VIII Antihemophilic factor A

IX Antihemophilic factor B / Christmas factor (produced by the livers -vitK)

X Stuart factor (-produced by the livers , vitK)

XI plasma thromboplastin antecedent, produced by the livers

XII Hageman factor

XIII Fibrin-stabilizing factor

Fibrinolysis

• Clot retraction

actin, myosin in platelets contract to increase the

“tightness” of the plug

plasminogen can enzymatically break down fibrin

thereby dissolves the fibrin clots

plasminogen activators (tissue plasminogen activator-TPA produced by endothelial cells)

• Plasminogen -> plasmin

Factors regulate clot formation

• Anticoagulants in the plasma and produced by endothelial cells

• Inorganic salts : oxalate, citrate salts, EDTA

• Aspirin: at low dose inhibits the formation of TXA2

therefore decreases platelet aggregation

Clot formation disorders

• Liver failure

• Vitamin K deficiency, damaged gut flora

• Hemophilia: genetic disorder caused by mutation of the gene coding for factor VIII

• VIII (85%), IX (15%)

• Thrombocytopenia (Bệnh thiếu hụt tiểu cầu )

(50.000 TC/mm3 )

• Von Willebrand’s disease: genetic bleeding

disorder caused by reduced level of vWf

Blood groups and blood transfusion

of the ABO system

• Gradual lost of ¾ of red blood cells: still can

be recovered

• Quick lost of 1/3 – 1/2 volume of body blood -> dead

• Early blood transfusion between individuals:

- Success in some cases

- Failure in most of the cases

?

Agglutination (clumping) of red blood cells

www.bio-pro.de/ /magazin/01323/index.html

Red blood cell

agglutination is caused

by the intolerance of

the blood grouping

antigens and antibodies

between donors and

recipients

Recipient plasma can agglutinate

donor red blood cells and vice versa

Antigens and antibodies of ABO blood

group

• Antigens and antibodies of ABO blood group :

– Antigen A, antigen B on the membrane of red blood

cells

– Anti-A, anti B antibodies in the plasma

• Agglutination of red blood cells occurs when:

– Anti-A binds Antigen A

– Anti-B binds antigen B

Human Physiology, 12th, S.Fox, 2011

A (antiB)

B (antiA)

AB (-)

O (anti-A, anti -B)

Donor red blood cell

+ : agglutinated , - : not agglutinated

Diagram for blood transfusion in ABO group

Rh factor

•Rh factor(named for the rhesus monkey, in which these

antigens were first discovered)

•Most significant antigen: Rho(D) If this Rh antigen

•is present on a person’s red blood cells, the person is Rh

positive; if it is absent, the person is Rh negative

with a frequence of 85% in the Caucasian population, for example)

Rh factor and hemolytic disease of the