Week_2_Cardiology

Week_2_Cardiology - Lec. 7 Intro to the cardiovascular...

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Unformatted text preview: Lec. 7 Intro to the cardiovascular system Purpose of the heart A system of transport and exchange Delivery of hormones, nutrients, and components against pathogens Removal of waste Types of blood vessels Made from endothelial cells, smooth muscle and connective tissue Arteries o Thick walled - 3cm to 1mm in size o Atherosclerosis is common disease of arteries Arterioles o Primary regulators of resistance o Control rate of blood flow to different tissues o Tone regulated by nerves, hormones, and vasoactive substances o Abnormal regulation can cause high blood pressure Capillaries o 5-7 m in diameter - just large enough for a single blood cell o Location for diffusion of nutrients and wastes o Large cross sectional area because of large number and small size o Slow velocity of blood flow allows diffusion of oxygen and metabolic nutrients o 4% of total blood volume Venules o Large compared to capillaries o Contain smooth muscle cells that are innervated o Control capillary pressure and venous capacitance Veins o Drain directly into heart via inferior and superior vena cava o Relatively thin walled compared to arteries o Distensible with large capacitance Pulmonary vs Systemic Circulation Systemic circulation o Carries oxygenated from heart to organs. Returns to heart with waste such as CO 2 o Relatively high pressure (70-100mm Hg average pressure) o Contains most of the blood in the body Pulmonary circulation o Carries deoxygenated blood from right side to lungs to get oxygen and remove CO 2 then back to left side o High Capacitance allows for maintenance of relatively low pressure (15-20mm Hg) o Has about 10% of blood in body Ohms law and circulation V=IR or in the circulatory system P=QR (pressure =flow*resistance) Also Q= P/R (if constant pressure and resistance increases flow decreases Velocity and flow o Velocity is speed, flow is amount o V=Q/A (velocity =flow/area) (as area, velocity) Capacitance C=V/P (capacitance = volume/pressure Capacitance is proportional to compliance or stretch-ability Cardiac Myocytes Different in ventricles vs artia o Atria 5-10 mm wide 20 mm long o Ventricle: 10-20 mm wide 50-150 mm long 5-10 mm thick Myocytes are connected with intercalated disks Ventricular Wall Fibers Heart has three layers of wall fibers Each layer points in a different direction - Outside is up mid is right and inside is down Cardiac interstitum Myocytes are only 1/3 of the heart Rest is fibroblasts and connective tissue Fibroblasts regulate collagen, the main ECM component in the heart which acts as a scaffold, tethers fibers, and coordinates transduction of forces Lec. 8 Pericardium and Anatomy of the heart Pericardium Parietal (outer) and visceral (inner) are both thin and stretchy Fibrous pericardium (outermost layer) is thick and won't stretch Paricardial sac filled with serous fluid to act as lubricant Inner pericardium also called epicardium and parietal+fibrous incorrectly called fibrous...
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This note was uploaded on 09/14/2011 for the course PHARM cs taught by Professor Staff during the Spring '11 term at UCSD.

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Week_2_Cardiology - Lec. 7 Intro to the cardiovascular...

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