Blood and Circulatory System Review

by PCourtemanche
Last updated 9 years ago

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Blood and Circulatory System Review

Circulatory System Review

3 Types of Blood Vessels: 1. Arteries - carry blood away from heart and branch into arterioles. Walls thick with smooth muscle. Pulse is felt in arteries. 2. Capillaries - microscopic vessels only a single layer of cells, the endothelium. All diffusion takes place here. 3. Veins - carry blood back to heart. They have valves to prevent backflow.

1. Red Blood Cells (RBS) - Erythrocytes - transport oxygen via hemoglobin2. White Blood Cells (WBC) - Leukocytes - immune system3. Platelets - cell fragments, clotting

RBC: biconcave disks, each hemoglobin binds 4 oxygens, lacks nuclei, lack mitochondria so oxygen is not consumed, contain fibrinogen (clots when converted to active form of fibrin).

Heart Rate = rate of contraction per minuteStroke Volume = volume pumped by left ventricle during contractionHR influenced by nervous system, hormones, and temperature.

Blood Pressure-measured with sphygmomanometer-ave. 120 (systolic - contraction)/70 (diastolic - relaxed)- heart contracts pushing blood through arteries, encounters peripheral resistance = highest in arteries, lowest (almost zero) in veins-contraction of skeletal muscles forces blood back to heart in veins, overcomes valves-exercise, walls of arterioles dilate, would drop BP but HR increases (output) maintaining BP-gravity must be overcome, longer distance=higher BP-hypertension (high BP) increases risk of heart attack and stroke-atherosclerosis (plaques in vessels) raises BP by narrowing vessels and reducing elasticity



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