Transcript CV System
The Cardiovascular System Chapter 13 By the end of today, you should be able to: •Describe the 3 major elements of the cardiovascular system. •Contrast the 2 “circuits” or “routes” that blood takes throughout the cardiovascular system. •Relate the effects of activity/exercise to the cardiovascular system The Closed Circulatory System •Humans have a closed circulatory system (blood confined to vessels). •The heart pumps blood into large vessels that branch into smaller ones leading into the organs. (arteriesarteriolescapillaries) •Materials are exchanged by diffusion b/w blood and the fluid bathing the cells (interstitial fluid) The Cardiovascular System •Three Major Elements – Heart, Blood Vessels, & Blood •1. The Heart • cardiac muscle tissue • highly interconnected cells –4 chambers •Right atrium •Right ventricle •Left atrium •Left ventricle •Pulmonary circuit –Sends oxygen-depleted (deoxygenated) blood to lungs to pick up oxygen & unload CO2 •Systemic circuit –Sends oxygen-rich (oxygenated) blood & nutrients to all body cells and remove wastes Circuits The Cardiovascular System • 2. Blood Vessels -A network of tubes – • • • • • • All blood vessels in body, joined end to end, would stretch 62,000 miles (2.5 times around the Earth) Arteriesarterioles Move blood away from the heart Elastic Fibers 3 layers (endothelial tissue, smooth muscle, connective tissue) Carries blood under relatively high pressure from heart to arterioles Largest artery = aorta (diameter of garden hose) Blood Vessels • Capillaries • where gas exchange takes place • Materials diffuse thru slits (openings) in capillary walls • Single layer of epithelial tissue • Connect arterioles to venules • Serve the Respiratory System FYI--(There is always 1/5 of our blood supply in the lungs) Blood V essels • VeinsVenules • Move blood towards the heart • 3 layers (similar to arteries except middle layer poorly developed) • Carries blood under low pressure • Many have valves that prevent backflow of blood • Largest vein = inferior vena cava • heart anatomy video model The Cardiovascular System 3. The Blood • RBCs (erythrocytes) • WBCs (leukocytes) • Platelets (thrombocytes) • Plasma Exercise • CV System adapts to exercise • Increase in heart pumping efficiency, blood volume, blood hemoglobin concentration, # of mitochondria in muscle fibers • All of these improve oxygen delivery to and utilization by muscle tissue • Good=Slow, steady buildup of exercise frequency & intensity • Bad=suddenly shoveling snow, running 3 miles when body isn’t used to it Inside the Human body video – 48 min Anatomy of the human body 1 Plastination, Heidelberg, Germany