NPB Study Guide Midterm 2

Pacemaker cells and conductive pathways the

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Unformatted text preview: heart;7 indicative of normal functioning III. Blood Vessels 1. Blood Vessels Transport Blood Throughout the Body ( like PVC pipes) A. Different Types - three main types: arteries, capillaries, and veins;7 all have subgroups B. Structure - three layers within their walls;7 outer layer of strong connective tissue → a middle layer of smooth muscle → an internal layer of epithelium * arteries = away from heart;7 veins = back to heart * 2. The Vessels Perform Specific Functions A. Arteries;7 “Pressure Vessels” - heart ejects blood into arteries → arteries stretch as they fill → arteries then recoil, pushing the blood out - mean arterial pressure (blood pressure)average = ⅓ (SP) + ⅔ (DP)= 1000 mmH g - systolic BP: ventricles are contracting = 120 mmHg - diastolic BP: ventricles relaxing = 70 mmHg - think of manually pumping a bike tire, when pressure increases its harder to pump - High BP, 140 and higher for SP;7 90 and higher for DP B. Arterioles;7 “Resistance Vessels” - resistance causes the blood pressure to drop and slows the flow of blood - arterioles have a perpensity to constrict;7 that increases the resistance such that blood will not flow through constricted vessels → allows os to move blood to regions that need it ~ smaller diameter/radius increases resistance C. Capillaries;7 “Exchange Vessels” - thin epithelial walls - allows molecules to move between blood stream and tissues;7 gases (O CO ), fuels like glucose (fats), wastes, signal molecules like hormones (drugs) - doesn’t require a lot of ATP (generall) because they diffuse down the concentration gradient - 14 mmHg;7 blood moves at slow velocity D. Venules and Veins;7 “Capacitance Vessels” - primary jobs are to receive blood from capillaries and temporarily store blood before it returns to the heart - low pressure ( - 0.7 mmHg;7 vaccuum) → adaptations to facilitate transportation processes III. Schematic of the Blood Flow Problem: veins have low blood pressure 1. Venus valves - no backwards flow 2. Skeletal muscle pump - pumps because the muscles squeeze veins 3. Locking out legs/ knees - fainting → strict muscle to help 1. Blood flows according to pressure gradients/differences - Ventricles “beat” (contracting) → eject blood into arteries - Arteriolar recoil drives the blood ( it creates more arteriolar pressure) 2. Valves prevent backwards f...
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