Apr 8 Lecture 4 Cardiac Anatomy Chapter 18 The Heart Today s objectives 1 Identify and describe the functional anatomy of the 2 Describe the path of blood through the cardiovascular heart system Cardiovascular Circuits Pulmonary Circulation Systemic Circulation Pulmonary circulation circuit exchanges gases only with air in lungs Systemic circulation circuit exchanges fluids nutrients gases removes wastes with body tissues Germann 2nd ed fig 14 2 Schematic of heart A Double Pump In pipes veins low pressure Out pipes arteries high pressure Heart has 4 chambers 2 atria 2 ventricles Veins In In Atria Heart chambers Ventricles Out Arteries Out Heart Anatomy Overview Heart R Lung L Lung Base Located in Mediastinum Apex Base Great vessels Anterior Fig 18 2 Marieb 6th ed Diaphragm Apex of Heart Silverthorn 4th ed fig 14 7 Heart surrounded by Pericardium Serous membranes around heart pericardium Part against body wall parietal pericardium Part against outside of heart visceral pericardium Fluid between layers pericardial fluid Fibrous Pericardium Parietal pericardium Visceral pericardium epicardium Myocardium Endocardium Adam Marieb 7th ed Fig 18 2 Tortora Fig 20 2 720 Heart Layers Epicardium thin outer layer visceral pericardium Myocardium thick middle layer muscle Endocardium thin inner layer continuous w endothelial linings of blood vessels Fig 20 2 719 Martini Fig 20 4a p 673 Heart Coverings Layers Myocardial fibers arranged so that wringing motion produced when ventricles contract Fibrous skeleton of heart CT rings surrounding valves separate atria from ventricles electrical insulation bind muscles support protect Fig 20 11 Seeley 6th ed Silverthorn 4th ed fig 14 7 see fig 20 4 723 Internal Heart Chambers 2 Atria receiving chambers Divided by interatrial septum Thin walled just need to push blood to Auricles appendages Blood enters right atrium RA via 3 veins Superior inferior vena cava coronary sinus Blood enters left atrium LA via 4 pulmonary veins Silverthorn 4th ed fig 14 7 see fig 20 4 723 Internal Heart Chambers 2 Ventricles discharging pumping chambers Divided by interventricular septum Thick walls L thicker than right why Right ventricle RV pumps blood to the lungs via the pulmonary trunk PT to pulmonary arteries Left ventricle LV pumps blood to the body via the aorta Internal Heart Anatomy AV valves Silverthorn 4th ed fig 14 7 see fig 20 4 723 Atrioventricular AV valves Right AV Valve Tricuspid Valve Left AV Valve Bicuspid or Mitral valve See fig 18 8 Heart AV Valves cont Chordae tendinae heart strings Anchor valve flaps to papillary muscles protruding from ventricle walls Martini Figure 20 6 p 676 Tortora Fig 20 6 726 Internal Heart Anatomy Semilunar valves Silverthorn 4th ed fig 14 7 see fig 20 6 723 Valve formed from 3 pocket like cusps SL Valves at bases of large arteries Pulmonary Semilunar Valve Aortic Semilunar Valve Fig 20 6a p 676 d e d r 3 i n d a a S l 9 1 h C Tortora Fig 20 6 727 Blood Flow Through the Pulmonary Circuit Pulmonary circulation blood flow R Atrium R ventricle PULMONARY TRUNK pulmonary arteries pulmonary capillaries pulmonary veins then L Atrium http academic kellogg cc mi us herbrandsonc bio201 McKinley f22 1 cardiovascular sy c jpg Blood Flow through the Systemic Circuit Systemic circulation blood flow L Atrium L ventricle AORTA systemic arteries systemic capillaries systemic veins Superior or Inferior Vena Cavae then R Atrium http academic kellogg cc mi us herbrandsonc bio201 McKinley f22 1 cardiovascular sy c jpg Martini Fig 20 7 p 678 Heart Chambers LV 3x thicker than RV Needs to pump blood to Right ventricle crescent shaped wraps around L ventricle Only needs to pump next door to Superficial cardiac anatomy Coronary sulcus contains coronary sinus Interventricular sulcus Figs from Martini Posterior Anterior A Special Branch of the Systemic Circulation Coronary Circulation Functional blood supply to heart Coronary arteries cardiac veins CAD Angina Myocardial infarction heart attack Fig 18 7 Marieb 6th Lecture 4 Take Home Messages The heart has 4 separate muscular chambers 2 for pulmonary circuit right atrium and right ventricle 2 for systemic circuit left atrium and left ventricle Left ventricle has a greater workload is much more massive than right ventricle receives more nutrients via coronary circulation but the two chambers pump equal amounts of blood at the same time AV valves prevent backflow from ventricles into atria Semilunar valves prevent backflow from aorta and pulmonary trunk into ventricles Lecture 4 Take Home Messages Flow of blood through circulation is one way flow no backflow allowed The heart has its own branch of the systemic circulation coronary circulation that provides oxygen nutrients and removes wastes heart has high O2 demand The right and left coronary arteries branch off aorta just after SL valve and anastomose so that heart muscle receives redundant blood supply Coronary veins drain to the coronary sinus that then drains directly into the right atrium Loss of blood flow to heart muscle creates heart attack myocardial infarction MI Path of blood through body a study guide for you Saladin 4th ed fig 19 9 Widmaier 10th ed fig 12 8 Pathway of Blood Flow Through the Heart a study guide for you Saladin 4th ed fig 19 9 Path of blood through body a study guide for you Fig 20 10 Seeley 6th Study Slide for you Cardio vascular System Overview Silverthorn 4th ed fig 14 1 Study Slide for you Cardiovascular System Overview Shier 11th ed fig 15 1 Study Slide for you Heart surrounded by Serous Membranes called Pericardium Serous membranes thin double layered membranes that cover outer surface of individual organs and inner surface of body cavity walls Simple squamous epithelium mesothelium Connective tissue areolar tissue Figure 4 16 p130 Fig 20 2c part 2 p 671