The Circulatory System

(Coronary - Heart) • supplies the heart itself with oxygenated blood

(Pulmonary - Lungs) • carried deoxygenated blood to the lungs for gas exchange

• carries oxygenated blood to all parts of the body

• plasma (55%), white blood cells and platelets (<1%), and red blood cells (45%)

• fluid in which blood cells are suspended • mostly water (over 90%) • plasma with fibrinogen and other clotting factors removed is called serum

• glucose, amino acids, fats, vitamins, ions, metabolic waste products, gases (O2, CO2), hormones, proteins: albumin (regulated osmotic pressure); globulins (e.g., antibodies); fibrinogen (clotting factors)

• plasma also carries dissolved ions (e.g., Na+, K+, Ca2+, Cl-, HCO3- (bicarbonate) • increase [Na+] in plasma= increase water in blood stream= increase blood volume= increase pressure • high salt diets can lead to high blood pressure (hypertension)

• general function: body defense and immunity • types: Granulocytes: neutrophil, basophil, eosinphils - particles/grains Agranular: lymphocytes, monocytes

• a type of white blood cell that has small granules (grains/particles) in cytoplasm (Neutrophil, Eosinophil, Basophil) • functions: (immediate) immune responses, act quickly in response to infections, especially bacterial and fungal, by releasing their granule to destroy pathogens or signal other immune responses

Function: • ”first responders” in immune defense • primary role in identifying and destroying bacteria and fungi • release enzymes to attack and digest pathogens • first to arrive - at injury or infection sites to clear pathogens

Function: • ”immune surveillance” ability to help detect and destroy some early cancer cells • release the histamine in their granules during an allergic reaction or asthma attack • release enzymes to improve blood flow and prevent clots

Function: • specialized defense against parasites • release toxic proteins and reactive oxygen species to break down parasites and infected cells

Function: • primarily involved in adaptive (long-term) immune responses • help the body remember and react more effectively to specific pathogens • monocytes also play a role in innate (immediate) immunity by phagocytizing pathogens and presenting antigens to activate other immune cells

• large, irregular nucleus • function as phagocytes • macrophages are monocytes that migrated from bloodstream into body tissue • many leucocytes use phagocytosis to destroy bacteria or harmful substances • phagocytosis: engulf harmful substance, enzymes released to destroy substance and leucocytes, remnants (white blood cell and cellular debris) as pus, may be seen at site of cut or pimple

• two types: B-lymphocytes and T-lymphocytes • these cells react to exposure to antigens by producing proteins • B-cells produce and secrete their proteins as antibodies • T-cells produce and “wear” their proteins in their membrane. Memory Cells of past Infections • in both cases, they neutralize the specific antigens for which they were made

• erythroblasts in marrow undergo mitosis • one new cell becomes another erythroblast, the other becomes a red blood cell • as it matures, it produces large amounts of hemoglobin until the nucleus is squeezed out of the cell • life span is 120 days, when they eventually break apart and are removed by the liver and spleen • function: gas exchange

• cells and cell parts • produced in bone marrow • all blood cells lose their ability to reproduce when they differentiate • when they die, they are replaced by more blood cells that are produced in bone marrow

• small, disc-shaped cell fragments • function: blood clotting

• plasma contains numerous chemical clotting factors, and two clotti proteins: prothrombin and fibrinogen • when a vessel wall is damaged, the clotting factors are activated • these clotting factors cause prothrombin to combine with Ca2+ to form thrombin • thrombin causes fibrinogen (normally soluble and globular) to change into fibrin (insoluble and threadlike)

• meanwhile, collagen changes the platelets’ surface to become sticky • platelets clump together, stick to the damaged vessel wall and plug the wound • fibrin threads join the plug to form a web-like network to form the clot

• carry blood away from the heart • aorta is the largest blood vessel in the body • aorta-arteries-arterioles (smallest artery with smooth muscle wall) • signals from nerve can regulate diameters of arterioles and control blood flow to certain parts of the body

• can withstand high blood pressure; thick, muscular, elastic walls • when blood is pumped, arteries expand slightly in diameter to accommodate increased pressure • outer lateral of arteries has elastin fibres to give elasticity • after contraction, arteries return to normal • inner layer endothelium: a single layer of smooth cells reduce friction with moving blood • arteries are located deep within the body

an increase in the diameter (dilation) of arterioles that increases the blood flow to tissues

a decrease in diameter (contraction) that decreases blood flow