18 HUMAN ANATOMY Power Point Lecture Slides prepared

18 HUMAN ANATOMY Power. Point® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham PART 2 The Heart fifth edition MARIEB | MALLATT | WILHELM Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

The Heart § A muscular double pump § Pulmonary circuit – takes blood to and from the lungs § Systemic circuit – vessels transport blood to and from body tissues § Atria – receive blood from the pulmonary and systemic circuits § Ventricles – the pumping chambers of the heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

The Pulmonary and Systemic Circuits Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 1

Location and Orientation within the Thorax § § Heart – typically weighs 250– 350 grams (healthy heart) Largest organ of the mediastinum § Located between the lungs § Apex lies to the left of the midline § Base is the broad posterior surface Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Location and Orientation within the Thorax Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 2

Four “Corners” of the Heart § Superior right § At costal cartilage of third rib and sternum § Inferior right § At costal cartilage of sixth rib lateral to the sternum § Superior left § At costal cartilage of second rib lateral to the sternum § Inferior left § Lies in the fifth intercostal space at the midclavicular line Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Location and Orientation within the Thorax Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 2

Structure of the Heart – Coverings § Pericardium – two primary layers § Fibrous pericardium § Strong layer of dense connective tissue § Serous pericardium § Formed from two layers § Parietal pericardium § Visceral pericardium Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Structure of the Heart – Coverings Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 3

Structure of the Heart – Layers of the Heart Wall § Epicardium § Visceral layer of the serous pericardium § Myocardium § Consists of cardiac muscle § Muscle arranged in circular and spiral patterns § Endocardium § Endothelium resting on a layer of connective tissue § Lines the internal walls of the heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Structure of the Heart – Layers of the Heart Wall Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 4

Heart Chambers § § PLAY Right and left atria § Superior chambers Right and left ventricles § Inferior chambers Internal divisions § § Interventricular septa Interatrial septa External markings § § § Coronary sulcus Anterior interventricular sulcus posterior interventricular sulcus Rotatable Heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Heart Chambers Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 5 b

Right Atrium § § § Forms right border of heart Receives blood from systemic circuit Pectinate muscles § Ridges inside anterior of right atrium § Crista terminalis § Landmark used to locate veins entering right atrium § Fossa ovalis § Depression in interatrial septum § Remnant of foramen ovale Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Right Ventricle § § Receives blood from right atrium through the tricuspid valve Pumps blood into pulmonary circuit via § Pulmonary trunk § Internal walls of right ventricle § Trabeculae carneae § Papillary muscles § Chordae tendineae Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Left Atrium § § § Makes up heart’s posterior surface Receives oxygen-rich blood from lungs Opens into the left ventricle through § Mitral valve (left atrioventricular valve) Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Left Ventricle § § Forms apex of the heart Internal walls of left ventricle § Trabeculae carneae § Papillary muscles § Chordae tendineae § Pumps blood through systemic circuit via § Aortic semilunar valve (aortic valve) PLAY Rotatable Heart Section Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Heart Chambers Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 5 e

Inferior View of the Heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 5 d

Pathway of Blood Through the Heart § Beginning with oxygen-poor blood in the superior and inferior venae cavae § Go through pulmonary and systemic circuits § A blood drop passes through all structures sequentially § Atria contract together § Ventricles contract together Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Blood Flow Through the Heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 6

Pathway of Blood Through the Heart Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 6 b

Heartbeat § 70 – 80 beats per minute at rest § Systole – contraction of a heart chamber § Diastole – expansion of a heart chamber § Systole and diastole also refer to § Stage of heartbeat when ventricles contract and expand Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Structure of Heart Wall § Walls differ in thickness § Atria – thin walls § Ventricles – thick walls § Systemic circuit § Longer than pulmonary circuit § Offers greater resistance to blood flow Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Structure of Heart Wall § Left ventricle – three times thicker than right § Exerts more pumping force § Flattens right ventricle into a crescent shape Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 18. 7