BLOOD

A - BODY FLUIDS

B - BLOOD

I- Function

II- Composition

III- Hemostasis

IV- Blood group

BLOOD

A - BODY FLUIDS

B - BLOOD

I- Function

II- Composition

III- Hemostasis

IV- Blood group

Body fluid

- 40% solid matter

- 60% of fluid:

- 2\3 intracellular

- 1\3 extracellular

- 80% interstitial

- 20% circulation

BLOOD

A - BODY FLUIDS

B - BLOOD

I- Function

II- Composition

III- Hemostasis

IV- Blood group

Blood: Functions:

• 1. transport nutrients to cells and remove wastes.

• 2. regulation of temperature, pH, osmotic pressure, glucose, calcium...

• 3. protection = fight infection (white blood cells)

BLOOD

A - BODY FLUIDS

B - BLOOD

I- Function

II- Composition

III- Hemostasis

IV- Blood group

Hematocrit

Hematocrit

BLOOD

A - BODY FLUIDSB - BLOODI- FunctionII- Composition

a- Plasmab- Formed elements:

b1- Erythrocyteb2- Leukocyteb3- Thrombocyte

III- Hemostasis

IV- Blood group

Plasma compositionplasma - yellowish clear liquid, composed of water, proteins and other

solutes.Water = 90%Proteins = (all synthesized by the liver) (almost 10%):

Albumin = 54%, regulates osmotic pressureGlobulins = 38%, alpha and beta globulins in transport,

gamma globulins in defense (antibodies)Fibrinogen = 7%, coagulation

Other solutes (less than 1%) :Electrolytes - Na+, K+, Ca++, Mg++Nutrients - glucose, amino acids, fatty acids,

monoglycerides ...Gases - O2, N2, CO2Regulatory substance - hormones, enzymesVitaminsWastes

 

BLOOD

A - BODY FLUIDSB - BLOODI- FunctionII- Composition

a- Plasmab- Formed elements: (hematopoiesis)

b1- Erythrocyteb2- Leukocyteb3- Thrombocyte

III- Hemostasis

IV- Blood group

Hematopoiesis

Blood cells – Formed Elements

Erythrocytes

- 99% of formed elements- bag" filled with hemoglobin (15g/100ml of

blood)- about 4 to 5 millions RBC per mm3 blood- Carry oxygen

   

Erythropoiesis

• In red bone marrow (all hematopoiesis)• Hemocytoblast Reticulocyte (nucleated)• Last stage = erythrocytes (lost nucleus)

BLOOD

A - BODY FLUIDSB - BLOODI- FunctionII- Composition

a- Plasmab- Formed elements:

b1- Erythrocyteb2- Leukocyteb3- Thrombocyte

III- Hemostasis

IV- Blood group

Hemoglobin

• Globin + Heme

Globin = 2 alpha + 2 beta chains

Heme = porphyrin ring + Fe• Carry oxygen to tissues

Life cycle of a RBC

Factors influencing RBC synthesis- Presence of nutrients:

- Proteins globin- Iron- vitamin B-12 (found in food)

• Intrinsic factor: secreted in stomachpromotes absorption of Vit B-12 in the duodenum deficit pernicious anemia

• erythropoietin hormone synthesized by kidneydecreased blood O2 stimulates secretion of

erythropoietin by the kidney.stimulates the bone marrow to produce more RBCs

Applications: altitude sickness - athlete training - blood doping

BLOOD

• A - BODY FLUIDS• B - BLOOD• I- Function• II- Composition• a- Plasma• b- Formed elements:• b1- Erythrocyte• b2- Leukocyte• b3- Thrombocyte• III- Hemostasis• - Vasospasm• b- Platelet plug formation• c- Coagulation• d- Clot retraction and fibrinolysis• IV- Blood group• a- ABO blood group• b- Rhesus blood group

Leukopoiesis

Leukocytes

granular leukocytes- neutrophils - 70% - phagocytosis of bacteria, debris;

work within the blood vessels- Eosinophils - 3% - destroy parasites- Basophils - allergic reactions (mast cells in tissues)

• agranular leukocytes- lymphocytes - 20%, form antibodies

B-lymph (bone marrow) T-lymph (bone => thymus)

- monocytes - phagocytosis of bacteria and debris (macrophages in tissues)

 

BLOOD

• A - BODY FLUIDS• B - BLOOD• I- Function• II- Composition• a- Plasma• b- Formed elements:• b1- Erythrocyte• b2- Leukocyte• b3- Thrombocyte• III- Hemostasis• - Vasospasm• b- Platelet plug formation• c- Coagulation• d- Clot retraction and fibrinolysis• IV- Blood group• a- ABO blood group• b- Rhesus blood group

Thrombocytes - Platelets

• Derived from megakaryoblasts

• Bits of cytoplasm

• Full of chemical

• 200 000 mm3

• Role: Platelet plug formation

BLOOD

• A - BODY FLUIDS• B - BLOOD• I- Function• II- Composition• a- Plasma• b- Formed elements:• b1- Erythrocyte• b2- Leukocyte• b3- Thrombocyte• III- Hemostasis• a- Vasospasm• b- Platelet plug formation• c- Coagulation• d- Clot retraction and fibrinolysis• IV- Blood group• a- ABO blood group• b- Rhesus blood group

Hemostasis

• Definition: Ability of the body to stop bleeding.

• Four phases:

1- Vasospasm

2- Platelet plug formation

3- Coagulation

4- Clot Retraction

Step 1: Vasospasm

• Local effect• Reflex• Due to smooth

vessels in blood vessels

• Goal: to decrease amount of bleeding

Step 2: Platelet plug

• Platelets:

- change shape

- become sticky

- release chemicals

- among them: serotonin

Step 3: Coagulation

• Transform fibrinogen into strand of fibrin

• Two pathways– Extrinsic pathway– Intrinsic pathway

Extrinsic and Intrinsic coagulation pathways

BLOOD

A - BODY FLUIDS

B - BLOOD

I- Function

II- Composition

III- Hemostasis

IV- Blood groups

Blood Types

• Many blood types

• Due to proteins present on the surface on the RBC

• In some case, presence of antibodies in the plasma

• Examples: ABO, Rh, MN …

Rh blood type

Rh +: -Rh protein present on

the RBCs- no antibody ever

present in the plasma

Rh -: no protein on the RBCs, no antibody anti-Rh in the blood BUT the person can manufacture them if they are exposed to them

RH+: more common (85%)

Readings

• Chp 15

• Entire chp + blood groups (seen in class)