Anatomy and Physiology
- Anatomy
- Layers
- pericardium: fibrous
- epicardium: covers surface of heart
- myocardium: muscular portion of the heart
- endocardium: lines cardiac chambers and covers surface of heart valves
- Chambers of heart
- right atrium: collecting chamber for incoming systemic venous system
- right ventricle: propels blood into pulmonary system
- left atrium: collects blood from pulmonary venous system
- left ventricle: thick-walled, high-pressure pump that propels blood into system
- Heart valves: membranous openings that allow one way blood flow
- atrioventricular valves: prevent backflow from ventricles to atria during systole
- tricuspid - right heart valve
- mitral - left heart valve
- semilunar valves prevent backflow from aorta and pulmonary arteries into ventricles during diastole
- pulmonic
- aortic
- Blood supply to heart
- arteries
- right coronary artery supplies right ventricle and part of left ventricle
- left coronary artery supplies mostly left ventricle
- veins
- coronary sinus veins
- thebesian veins
- Conduction system
- SA (sinoatrial) node
- junctional tissue
- bundle branch Purkinje system
- Physiology
- Function of the heart is the transport of oxygen, carbon dioxide, nutrients and waste products
- Cardiac cycle consists of:
- systole - the phase of contraction during which the chambers eject blood
- diastole - the phase of relaxation during which the chambers fill with blood. When heart pumps, myocardial layer contracts and relaxes.
- Blood flow:
- deoxygenated blood enters the right atrium through the superior and inferior vena cava
- enters the right ventricle via the tricuspid valve
- travels through the pulmonic valve to pulmonary arteries and lungs
- oxygenated blood returns from lungs through the pulmonary veins into left atrium and enters the left ventricle via bicuspid (mitral) valve.
- from the left ventricle, through the aortic valve through the aorta to the systemic circulation
- The heart itself is supplied with blood by the left and right coronary arteries
- The vascular system is a continuous network of blood vessels.
- the arterial system consists of arteries, arterioles and capillaries and delivers oxygenated blood to tissues
- oxygen, nutrients and metabolic waste are exchanged at the microscopic level
- the venous system, veins and venules, returns the blood to the heart
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