80 likes | 139 Views
Chapter 12: The Cardiovascular System—The Heart. Function of the heart. Cells depend on interstitial fluid for survival The circulatory system balances the contents of the interstitial fluid (gas exchange, nutrients, waste, etc…)
E N D
Function of the heart • Cells depend on interstitial fluid for survival • The circulatory system balances the contents of the interstitial fluid (gas exchange, nutrients, waste, etc…) • The heart provides the mechanical “pumping” necessary for blood to circulate • Two circuits: • Pulmonary (b/t heart & lungs) • Systemic (b/t heart & body)
Anatomy of the heart • Size: 5” x 3.5” (~fist) • Shape: blunt cone • Apex: pointed end • Base: uppermost part • Location: center of thorax, behind the sternum (mediastinum) • 4 Chambers • Right atrium • Right ventricle • Left atrium • Left ventricle
Pericardial cavity (Fig. 12-2) • Pericardium encloses the heart (fist in balloon) and has 2 layers • Visceral (epicardium): inner layer closest to the surface of the heart • Parietal: outer layer • Pericardial fluid fills the cavity (lubricant)
Surface Anatomy of the heart (Fig. 12-3) • Auricle: outer flap of deflated atrium • Coronary Sulcus: groove between atria and ventricles • Anterior/Posterior Interventricular Sulci: boundary b/t lft. and rt. ventricles
The heart wall (Fig. 12-4) • Three layers • Epicardium: outermost layer (serous) • Myocardium: cardiac muscular layer; concentric wrapping • Endocardium: innermost layer, continuous with vessel linings
Internal anatomy of the heart • Interatrial Septum: separates left/right atria • Interventricular septum: separates left/right ventricles • Left/Right Atrioventricular (AV) valve • Bicuspid: left AV has 2 cusps, aka mitral valve • Tricuspid right AV has 3 cusps • Superior Vena Cava: blood from head, neck, upper limbs, and chest • Inferior Vena Cava: blood from rest of the trunk, viscera, and lower limbs • Coronary Sinus: opens into right atrium, receives blood from coronary veins
Internal anatomy of the heart • Chordae Tendineae: connects cusps to papillary muscles • Pulmonary semilunar valve: b/t right ventricle and pulmonary arteries • Aortic semilunar valve: b/t left ventricle and aorta • Aorta: start of systemic circuit • Pulmonary trunk: start of pulmonary circuit • Left/Right Pulmonary veins: receives deoxygenated blood from lungs