BLOOD Functions of Blood 1 Transportation Blood transports

BLOOD

Functions of Blood: 1. Transportation – Blood transports oxygen from lungs to cells throughout body and CO 2 from cells to lungs; carries nutrients from GI tract to body cells, hormones from endocrine glands 2. Regulation – Blood regulates p. H of body fluids; body temperature; 3. Protection – Blood clots in response to injury; WBC protect against disease

Blood Components 8% of total body weight Men = 5 -6 liters / Women = 4 -5 liters 1. Plasma 2. Protein 3. Cells

Plasma 91. 5% water 7% proteins 1. 5% other solutes

Proteins Albumin (54% of all blood proteins) – maintain proper osmotic pressure Globulins (38%) – antibodies and immunoglobulins; defensive proteins produced during certain immune responses Fibrinogen (7%) – key protein in formation of blood clots;

Cellular components (formed elements) I. Red Blood Cells II. White Blood Cells A. Granular leukocytes �Neutrophils �Eosinophils �Basophils B. Agranular leukocytes �T and B lymphocytes and natural killer cells �Monocytes III. Platelets

Red Blood Cells (Erythrocytes) 5, 000/ microliter 260, 000/ drop travels 700 miles in 120 days 3, 000 new RBCs per second Mature RBC are enucleated (eject the nucleus) giving the cell its biconcave shape Hemoglobin (Hb)= protein of RBC heme- carries oxygen globin – carries carbon dioxide

RBC Outnumber WBC 1000 to 1 Percentage of RBC in total blood volume = hematocrit Only live 120 days because of wear and tear on plasma membrane as they squeeze through capillaries. Worn out RBC are removed from circulation

Erythropoiesis Figure 4. The life cycle of a red blood cell. a) Kidneys respond to a lower than normal oxygen concentration in the blood by releasing the hormone erythropoietin. (EPO) b) Erythropoietin travels to the red bone marrow and stimulates an increase in the production of red blood cells (RBCs). c) The red bone marrow manufactures RBCs from stem cells that live inside the marrow. d) RBCs squeeze through blood vessel membranes to enter the circulation. e) The heart and lungs work to supply continuous movement and oxygenation of RBCs. f) Damaged or old RBCs are destroyed primarily by the spleen

White Blood Cells (WBC) Leukocytes Have nuclei and do not contain hemoglobin Classified as either granular or agranular Functions - combat pathogens and illness by phagocytosis or production of antibodies.

Granulocytes Leukocytes that contain granules and lobbed nuclei 1. Neutrophils – most abundant; cytoplasm stains pink; 3 -7 lobed nucleus; function in active phagocytosis; numbers increase rapidly during acute infections

2. Eosinophils – red coarse granules; bi-lobed figure 8 nucleus; functions in killing parasitic worms; numbers increase during allergy attacks

3. Basophils – (mast cells); few large bluish granules; U 0 r S- shaped nucleus; contain histamine which is discharged at sites of inflammation

Agranulocytes Lack visible cytoplasmic granules Nuclei are spherical, oval, or kidney-shaped. 1. Lymphocytes – one large spherical nucleus; stains dark blue; part of immune system a) B lymphocytes - produce antibodies b) T lymphocytes – activate B cells; fight tumors and viruses

2. Monocytes – one horse-shoe shaped nucleus; stains blue; largest of WBC; become macrophages; function in fighting chronic infections such as TB

Platlets Cell fragments needed for clotting process

Hemostasis 1. Vascular spam – smooth muscle in the blood vessel contracts. 2. Platelet plug formation – platelets cling to parts of the damaged blood vessel and release chemicals that make them sticky -> forming a thrombus (platelet plug). 3. Coagulation – series of chemical reactions that culminates in the formation of fibrin threads. (this traps RBCs and forms the clot)

Abnormal Clotting Thrombus – occurs in an unbroken vessel; may prevent blood flow if large Hemorrhage – excessive bleeding; can result if blood takes too long to clot. Embolus – occurs when clot or debris move within the blood stream. Pulmonary Embolism – occurs when embolus travels to lungs; can be fatal

Hemophilia

Blood Groups and Types The surface of RBC contain a genetically determined assortment of glycoproteins called antigens. Two major blood groups: ABO and Rh

ABO Blood Group

Rh Blood Group