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IE 553 Engineering of Human Work Dr. Andris Freivalds Class #21. Circulatory Systems ( Å&R, Ch.4). Homeostasis – constant environment Bulk flow vs. Diffusion Functions: Transportation of Supplies: food, O 2 , Wastes: metabolites, CO 2 Hormones Regulation of heat flow
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IE 553 Engineering of Human Work Dr. Andris Freivalds Class #21 IE 553
Circulatory Systems (Å&R, Ch.4) • Homeostasis – constant environment • Bulk flow vs. Diffusion • Functions: • Transportation of • Supplies: food, O2, • Wastes: metabolites, CO2 • Hormones • Regulation of heat flow • pH buffer (acid-base balance) IE 553
Circulatory System IE 553
Body Water and Blood • Body = 60% water • Blood = 5l • Composed: plasma + cells • Red blood cells (%hematocrit) • White blood cells • Platelets (+ fibrinogen → clotting) IE 553
Heart IE 553
Contraction Process 1) 2) 3) 4) • Sinoatrial node (pacemaker) – spontaneous depolarization • Atrioventricular node – delays conduction • Purkinje fibers –polarization spreads • 4) Ventricles contract IE 553
Pressure Regulation IE 553
Terminology -1 • Heart rate (HR) = #QRS/min • Cardiac output (CO) = volume of blood ejected by ventricle • Stroke volume (SV) = volume of blood ejected by each ventricular beat • Oxygen uptake (VO2) = volume of oxygen extracted from inspired air • Atrio-ventricular difference (AVO2) IE 553
Terminology - 2 • Systolic pressure (SP) = max pressure during ventricular ejection • Diastolic pressure (DP) = min pressure before ventricular ejection • Mean arterial pressure (MAP) = ‘average’ pressure • Total peripheral resistance (TPR) = resistance to blood flow, R = kl/r4 IE 553