CARDIOVASCULAR SYSTEM I (BLOOD)

• Transportation

• Regulation

• Protection

Functions of Blood

• pH = 7.35-7.45

• temperature is always higher than body temperature, 38 degrees celcius

• color of blood: oxygen-rich (scarlet), oxygen-poor (dark red)

characteristics of blood

• plasma (55% of whole blood)

• buffy coat: leukocytes and platelets (<1% of whole blood)

• erythrocytes (45% of whole blood)

components of blood

• red blood cells (erythrocytes)

• white blood cells (leukocytes)

• platelets (thrombocytes)

formed elements of blood

• Wateer

• Ion

• Plasma proteins

• Others - nutrients, waste products, respiratory gases, hormones

Components of Blood Plasma

• biconcave

• anuecleate

• lacks mitochondrion

• hemoglobin

characteristics of erythrocytes

• bodies defense against disease

• able to move in an out of cells (diapedesis)

leukocytes

granulocytes

• neutrophils (50-70%

• eosinophils (2-4%)

• basophils (0.5-1%)

Neutrophils (50-70%)

• phagocytize bacteria

• most numerous WBCs

eosinophils (2-4%)

• blue-red nucleus that resembles earmuffs

• kill parasitic worms

• inactivate some inflammatory chemicals of allergy

basophils (0.5-1%)

*release histamine

*contain heparin (an anti-coagulant)

***initiate inflamation

• lymphocytes (25-45%)

• monocytes (3-8%)

agranulocytes

lymphocytes (25-45%)

immune response by direct cell attack or antibodies

monocytes (3-8%)

• largest of the white blood cells

• develop into macrophages

• important in fighting chronic infection

4,000 to 11,000 cells/ml

normal levels of leukocytes in blood

leukocytosis

(abnormal leukocyte level)

above 11,000 leukocytes

generally indicates an infection

leukopenia

• abnormally low leukocyte level

• commonly caused by certain drugs

hemostasis

• sequence of responses that stops bleeding

• mechanisms: (1) vascular spasm, (2) platelet plug formation, (3) blood clotting (coagulation)

Vascular Spasm

• anchored platelets release serotonin

• contraction of smooth muscles

• reduce bloo loss for several hours

platelet plug formation

blood thickens and forms a gel

gel - clot; liquid - serum (plasma minus the clotting proteins)

Alpha granules

clotting factors; platelet- derived growth factors

Dense granules

serotonin, fibrin stabilizing factor ( helps strengthen a blood clot)

Coagulation

A series of chemical reactions that culminates in the formation of fibrin threads

Intrinsic Pathway

- more complex, occurs more slowly
- activators are either in direct contact with blood or contained within (intrinsic to) blood
- trauma to endothelial cells

Extrinsic pathway

• occurs rapidly, few steps/stages

• tissue factor (TF) —— leaks into the blood and initiates formation of prothrombinase

Vitamin K (required in the synthesis of clotting factors VII, IX, X)

Clotting factors

Blood usually clots within 3 to 6 minutes

The clot rmains as endothelium regenerates

The clot is broken down after tissue repair

Blood Clotting

Fibrinolysis

removes unneeded clots when healing has occurred

Thrombus

clot in an unbroken blood vessel

Embolus

a thrombus that breaks away and floats freely in the blood stream

Erythrocytes

contain genetically determined glycoproteins and glycolipid that act as antigens

Antigens

a substance that is recognized foreign by the immune system

isoantigens or agglutinogens

occur in characteristic combinations

Blood Groups

based on the presence and absence of isoantigens

ABO Blood group

based on two glycolipid isoantigens called A and B

Type A - antigen A

Type B - antigen B

Type AB - both antigen A and B

Typ O - neither antigen A or B

ABO Blood Groups

Blood Typing

use antibodies that would react (agglutinate) with other proteins

Rh Blood group

-antigen discovered in Rhesus monkeys

- people whose RBCs contain Rh antigens are Rh+; lack antigens Rh

-- Caucasians

Hemolysis

rupture of RBCs in the donated blood