Heart Anatomy & Function PDF

Ch 17: The Heart Cardiovascular System Ch 11 Please read pg 351 to 385  The Cardiovascular System This is a closed Cardio = Heart system composed of: 1. Heart  pumps blood 2. Blood Vessels Vascular = Blood v...

Ch 17: The Heart Cardiovascular System Ch 11 Please read pg 351 to 385  The Cardiovascular System This is a closed Cardio = Heart system composed of: 1. Heart  pumps blood 2. Blood Vessels Vascular = Blood vessels  allow blood to circulate to all parts of body  The Cardiovascular System (The Heart) Functions: 1. Deliver oxygen and nutrients 2. Remove carbon dioxide and other waste products Size  About the size of your fist Location  Thoracic cavity  Medial to the lungs  Superior to the diaphragm  Posterior to the sternum  Pointed apex directed toward left hip, base pointed to right shoulder  mediastinum  The Heart: Coverings There are two coverings around heart: 1. Fibrous Pericardium  Outside covering; loose and superficial 2. Serous Pericardium  Inside covering; deep to the fibrous pericardium  a serous membrane a) P________ pericardium - outside layer; lining the inner surface of the fibrous pericardium b) V________ pericardium – physically attached to the heart; also called e_____________  Serous fluid fills the cavity in between  The Heart: Heart Wall There are three layers in the heart wall: 1. E_____________  Outside layer  This layer IS the visceral pericardium 2. M_____________  Middle layer  Mostly cardiac muscle 3. E_____________  Inner layer  Simple squamous epithelium  Also called endothelium  The Heart Anatomy Has four hollow chambers  Two Atria that receive blood 1. Right Atrium 2. Left Atrium  In diagrams… Two Ventricles that Blood vessels that carry discharge blood oxygen-poor blood will be blue and are 3. Right Ventricle generally veins 4. Left Ventricle Blood vessels that carry oxygen-rich blood will be red and are generally arteries Veins  Carry blood Please TOWARDS the heart comment on the muscular Arteries anatomy of  Carry blood AWAY the heart from the heart  The Heart: Path of blood Right and left side act as separate pumps  Right atrium and ventricle  Pump oxygen-poor blood  Left atrium and ventricle  Pump oxygen-rich blood  The Heart Anatomy Heart Anatomy Ten large blood vessels are attached to the heart 1. Superior vena cava 2. Inferior vena cava 3. Pulmonary trunk 4. Right pulmonary artery 5. Left pulmonary artery Right Left 6. Two Right pulmonary side side veins 7. Two Left pulmonary veins 8. Aorta Apex Blood Circulation 1. Pulmonary Circuit  HeartLungs Heart  Includes pulmonary arteries and veins 2. Systemic Circuit  HeartBodyHeart  Includes Venae Cavae and Aorta  The purpose of the pulmonary circuit is to oxygenate blood  The purpose of the systemic circuit is to supply cells with oxygenated blood  The Heart: Path of blood 1. Oxygen-poor blood flows through the inferior and superior venae cavae into the right atrium 2. Flows through a valve into the right ventricle 3. Right ventricle forcefully pumps blood through a valve to pulmonary trunk (which divides into right and left pulmonary arteries) to lungs 4. At the lungs, blood picks up oxygen and unloads carbon dioxide 5. Oxygen-rich blood from lungs flows through the 4 pulmonary veins into the left atrium 6. Flows though a valve into the left ventricle 7. Left ventricle forcefully pumps blood through a valve to aorta to all tissues in the body 8. Tissues use up oxygen from blood and cycle begins again The Heart: Valves Valves Two Atrioventricular valves  (AV) Allow blood to flow in only one direction  between atria and  ventricles Valves open as blood is pumped through 1. B_____ valve (left)  Close to prevent backflow 2. T______ valve  (right) Held in place by chordae tendineae Two Semilunar valves “heart strings” 1. P_______ semilunar  valve (right ventricle Total of 4 valves in your and pulmonary heart artery) 2. A_______ semilunar valve (left ventricle and aorta) The Heart  Operation of AV Valves  Blood entering atria  Ventricles contract puts pressure on AV forcing blood against valves AV valve flaps  Valves forced open  AV valves close  Ventricles fill  Chordae tendineae  Atria contract forcing tighten rest of blood into  prevents valve flaps ventricles from everting into atria Ventricles relax Pressure rises Pressure falls Blood is pushed against Blood flows back from arteries semilunar valves a little Forced open Push against the flaps Closes semilunar valve Heart Sounds  Using a stethoscope, you can hear TWO sounds during each cardiac cycle Lub Dup Closing of the Closing of the AV valves semilunar valves  Lub-dup, pause, lub-dup, pause  Cardiac Cycle Cardiac cycle  events of one complete heart beat 1. Atria contract simultaneously 2. Atria relax, then ventricles contract Contraction = Systole Relaxation = Diastole Cardiac Cycle Figure 11.6  The Heart: Conduction System  Heart beats are controlled by an intrinsic… “conduction system”  Allows heart muscle cells to contract, without nerve impulses  Special tissue found no where else in body  The Heart: Conduction System Consists of: 1. Sinoatrial node (SA node)  Pacemaker (sends signal) 2. Atrioventricular node  causes atria to contract 3. Atrioventricular bundle 4. Bundle branches 5. Purkinje fibers  causes ventricles to contract Heart Contractions Figure