Cardiovascular System: Blood Comparative Anatomy Tony Serino, Ph.D. Biology Department Misericordia Univ.

Blood Liquid connective tissue Arises from hemopoietic tissue: 1. myeloid tissues (Red bone marrow) 2.lymphoid tissues (thymus, spleen, lymph nodes, tonsils, etc. In fetus, liver and yolk sac are hemopoietic

Properties of the Blood Volume 4-6L (5-6L men, 4-5L women) based on body size (8% of total body weight) pH 7.4 + 0.1 5X the viscosity of water Hematocrit = 45

Blood Composition

Plasma Composition 90% water 10% suspended or dissolved constituents Plasma Constituents (10%) 0.9% NaCl + other electrolytes Nutrients Plasma proteins: albumin, globulins, fibrinogen Dissolved gases: O2, CO2, N2

Functions of the Blood Transportation media Osmoregulation Acid-Base balance Protection

Hemopoiesis (RBC development) Rate controlled by erythropoietin secretion Availability of Fe++, folic acid, vitamin B12 and amino acid precursors for hemoglobin production

Formed Elements

RBC (erythrocyte) Lives 120 days Non-nucleated biconcave disc 4.5-5.5 million/mm3 1/3 of cytoplasm is hemoglobin

RBCs

Hemoglobin

Point Mutation in Sickle Cell

Sickle Cell Anemia

ABO Blood Group Summary

WBC Development

WBC Development

WBC Development

Distribution of WBC

Neutrophil Most abundant circulating WBC (55-65% of WBCs), highly phagocytic, 1st to arrive at site of infection

Eosinophil 2-4% of WBC, combat irritants that trigger inflammation, phagocytic for Ag-Ab complexes, destroy worm infections, limit inflammation

Basophil Least abundant WBC (0.5% of WBC), trigger inflammation, contain vesicles with vasoactive compounds

Monocyte 3-8% of WBC, highly phagocytic and chemotaxic, arrive second to neutrophils at site of infection but in more massive numbers, can undergo diapedesis; some take up permanent residence in some tissues (often has a C-shaped nucleus)

Lymphocyte Second most abundant WBC (20-30% of WBC), function in specific immunity, two types: T and B cells

Platelet Development

Platelets 150-400 thousand/mm3 2-4 mcm in diameter Function in clotting and vessel repair

Platelet Plug and Clotting Platelet aggregation is increased by the stuck platelets releasing Thromboxane which stimulates vasoconstriction and attracts more platelets to area. Prostacyclin inhibits this and is released by non-damaged endothelial cells The common clotting pathway

Fibrin Clot

Comparative Aspects of Blood highly conserved structures through evolution –hemoglobin with only slight modifications to amino acid sequence between vertebrates RBCs of most vertebrates are oval nucleated cells Increase volume of blood in terrestrial vertebrates probably necessary due to air having less percent oxygen than water