Ch5+-+The+Cardiovascular+System+-+Part+I (1).ppt

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HUMAN BIOLOGY Seventeenth Edition Sylvia S. Mader Chapter 5 Cardiovascular System: Heart and Blood Vessels ©2 0 2 0 M c G ra w -H ilE d u c a tio n.A lrig h ts re s e rve d.A u th o rize d o n ly fo rin stru c to ru s e in th e c la s s ro o m.N o re p ro d u c tio n o rfu rth e rd istrb u tio n p e rm ite d w ith o u th e p rio rw rite n c o n s e n to fM c G ra w -H ilE d u c a tio n.  What is the cardiovascular system? CO2 O2 Includes the heart and blood vessels Heart brings nutrients to cells and helps get rid of wastes Respiratory System tissue cells Exchange of substances occurs food Cardiovascular System thru interstitial fluid kidneys Blood is refreshed in the lung, liver kidneys, intestine and liver Lymphatic system helps this system by collecting excess fluid Digestive System Urinary System surrounding tissues ( lymph) and indigestible metabolic wastes returns it to the blood food residues (feces) (urine) What are the functions of the cardiovascular system? – Transport: oxygen, carbon dioxide, and other waste products, nutrients, and hormones – Protection: cells of the immune system are transported to help protect the body from infection – Regulation: maintains homeostasis of a variety of the body’s conditions, Ex. pH balance, electrolyte levels  What are the two cardiovascular pathways in the body? CO2 jugular vein head and armsO2 (also subclavian carotid artery vein from arms) (also subclavian artery to arms) Pulmonary circuit: the right CO2 O2 side of the heart that brings O2 CO2 blood from the different body parts to the heart that pulmonary lungs pulmonary pumps it to lungs artery superior vein vena cava aorta heart Systemic circuit: the left inferior vena cava side of the heart that sends blood from the heart to the hepatic vein intestinal entire body to deliver liver digestive arteries nutrients and rid it of wastes hepatic portal tract renal vein artery renal vein kidneys iliac vein iliac artery Remark: details in the figure for illustration only CO2 O2 trunk and legs What is the main pathway of oxygen-rich blood in the body? Heart – arteries – arterioles – capillaries - venules – veins – back to the heart… There are three types of blood vessels: - Arteries - Veins - Capillaries  There are three kinds of blood vessels  Arteries carry the blood away from the heart  Capillaries are where the exchange with tissue fluid takes place  Veins return the blood to the heart  Arteries and Arterioles Arteries carry blood away from the heart Their walls have 3 layers: – Inner layer endothelium; thin inner epithelium – Middle layer thick smooth muscle & elastic tissue which allow artery to expand – Outer layer connective tissue Arterioles are small arteries that regulate blood flow & blood pressure Structure of Arteries and Veins  Capillaries tissue lymphatic blood lymphatic venule arteriole cells capillary capillary duct Microscopic vessels between arterioles & venules Made of one layer of endothelium Form beds of vessels where exchange with body cells occurs In tissues, only certain capillaries are open at one time  Capillaries & The Microcirculation artery connective tissue arteriole a. precapillary blood sphincter flow elastic tissue capillary bed endothelium arteriovenous smooth muscle shunt v. valve venule blood flow vein v = vein; a = artery Precapillary sphincters (smooth muscle) control blood flow in the capillary bed (the microcirculatory unit) If sphincter closes, blood moves from arterioles to venules via the Arteriovenous shunt (AV shunt)  Veins and Venules Veins carry blood toward the heart Venules are small veins that receive blood from capillaries Venule and vein walls have the same 3 layers as arteries: – Thin inner epithelium (endothelial layer) – Middle smooth muscle layer, less than arteries – Outer connective tissue, less than arteries Veins carry blood against gravity have valves to keep blood flowing toward the heart Veins have thinner walls than arteries, expand more How do the structures of the blood vessels and heart match their functions? The left ventricle is much more muscular than the right ventricle because it must pump blood to the entire body The arteries are more muscular than veins to withstand the higher pressure exerted on them The veins have thinner walls and wider lumens to store blood  Exchange at the capillary beds is primarily a result of osmotic and blood pressure from heart to heart Arterial end Venous end Blood pressure is higher Tissue fluid Osmotic pressure is higher than osmotic pressure than blood pressure Net pressure out oxygen amino carbon Net pressure in acids glucose dioxide water wastes water salt plasma protein smooth osmotic pressure arteriole muscle fiber blood pressure venule Two forces control movement of fluid through the capillary walls: 1. Osmotic pressure Tends to cause water to move from tissue fluid to the blood 2. Blood pressure Tends to cause water to move from the blood to tissues  Capillary Exchange Movement across capillary walls occurs via various mechanisms depending on the solute characteristics:  Small, lipid-soluble molecules (oxygen, carbon dioxide, & some drugs like some anaesthetic agents diffuse through the lipid bilayer which forms the plasma membrane of the endothelial cells  Small, lipid-insoluble ions and molecules (Na+, K+, Cl-, glucose, amino acids, & many drugs) pass via water –filled channels in-between or through cells  Large, lipid-insoluble molecules (proteins & micronutrients, …etc.) cross capillary walls via vesicles or in bound form to carriers.