Blood

1) Describe the process of coagulation including all the necessary enzymes and factors.

Initiation of coagulation can begin in two pathways, the extrinsic pathway and the intrinsic pathway. The extrinsic pathway begins with the damaged blood vessel and perivascular tissues releasing a lipoprotein mixture called tissue thromboplastin (factor III). Factor III combines with factor VII to form a complex, which in the presence of Ca2+, activates factor X. The intrinsic pathway begins when platelets degranulate. They release factor XII. This leads to activated factors XI, IX, VIII, in that order. Each serving as the enzyme catalyzing the next step to factor X, which also require Ca2+ and Fe3+. Once factor X is activated steps are identical on the intrinsic and extrinsic pathways called the common pathway. Factor X combines with factors III and V in the presence of Ca2+ and PF3 to producw prothrombin activator. This enzyme acts on prothromboin (factor II) and converts it to the ezyme thrombin. Thrombin chops fibrinogen into strands of fibrin. Factor XIII cross links these shorter fibrin strands to create fibrin polymer, which forms the structural framework of the blood clot.

2) Characterize and describe all the formed elements of blood.

Thrombocytes вЂ" Platelets

- smallest formed element (2-4 micrometers)

- second most abundant formed element (after erythrocytes)

- phagocytize bacteria

- secrete clotting factors which promote blood clotting

Erythrocytes вЂ" Red Blood Cells

- transport O2 and CO2

- 8 micrometers in diameter and 2 micrometers thick, discoid cell shape with a sunken center and thick rim

- made of globin and heme

- anucleated

- life span of 120 days

Leukocytes вЂ" White Blood Cells

Granulated

Neutrophils

- make up 60-70 % of WBCs

- 9-12 micrometers in diameter

- 3-7 lobes nucleus

- phagocytize bacteria

- release antimicrobial chemicals

Eosinophils

- make up 2-4% of WBCs

- 10-12 micrometer in diameter

- figure 8 lobe nucleus

- phagocytize antigen - antibody complexes, allergens, and inflammatory chemicals

- release enzymes that weaken or destroy parasites

Basophils

- make up <.5-1% of WBCs

- 8-10