all things heart
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| 658108423 | Pericardium | Protects and Anchors the Heart. A double-walled sac around the heart composed of a fibrous pericardium(outside layer) and a serous pericardium(inside two-layered layer). Allows heart to work in relatively friction-free environment. | |
| 658108424 | Serous Pericardium | 2 layered inside layer/sac around the heart. internal surface(lines fibrous pericardium) and the visceral layer(lines the surface of the heart). Both these layers are separated by fluid-filled pericardial cavity. | |
| 658108425 | Epicardium | visceral layer of the serous pericardium | |
| 658108426 | Myocardium | cardiac muscle layer forming the bulk of the heart | |
| 658108427 | Endocardium | inner layer of myocardial surface (blood touches when atria/ventricles are filled) | |
| 658108428 | Atria(s) | receiving chambers of the heart | |
| 658108429 | Right Atria | blood enters from superior/inferior vena cava & coronary sinus to here. passes to Right Ventricle then lungs to be filled with oxygen. | |
| 658108430 | Left Atria | blood enters from pulmonary veins, sent to Left Ventricle then to rest of systemic circuit. | |
| 658108431 | Ventricles | discharging chambers of the heart | |
| 658108432 | Right Ventricle | pumps blood into the pulmonary trunk, to lungs to become oxygenated | |
| 658108433 | Left Ventricle | pumps blood into aorta, which leads to rest of body being fed oxygen | |
| 658108434 | Pathway of Blood | R. Atrium - Tricuspid Valve - R. Ventricle - Pulmonary Semi-lunar Valve - Pulmonary Arteries - Lungs - Pulmonary Veins - L. Atrium - Bicuspid Valve - L. Ventricle - Aortic Semi-lunar Valve - Aorta - Systemic Circulation | |
| 658108435 | Coronary Circulation | Left Ventricle - Aorta - back to left ventricle - major vessels of the heart | |
| 658108436 | Valves | ensure one directional blood flow through the heart (no backflow) | |
| 658108437 | Atrioventricular Valve | (AV valves) lie between the atria and ventricles. prevent back-flow of blood into atria when ventricles contract. 2 of them: Right = tricuspid Left = Bicuspid. | |
| 658108438 | Chordae Tendinae | Anchor AV valves to papillary muscles of the heart. | |
| 658108439 | Semilunar Valves | prevent back-flow of blood into ventricles when contracted by ventricles | |
| 658108440 | Aortic Semilunar Valve | lies between Left Ventricle and the Aorta | |
| 658108441 | Pulmonary Semilunar Valve | lies between Right Ventricle and Pulmonary Trunk | |
| 658108442 | Cardiac Muscle | Stimulated by nerves and is self-excitable. Striated with intercalated discs that anchor cells together(also allows free passage of ions). Long contractions (250ms vs. 1-2ms of skeletal muscle). | |
| 658108443 | Autorhythmic Cells | Make up 1% of heart cells. These cells make up the AV & SA nodes. | |
| 658108444 | resting heart rate | 70 beats per minute | |
| 658108445 | Sinoatrial Node | SA Node. Generates impulses about 75times/minutes. | |
| 658108446 | Atrioventricular Node | AV Node. delays impulse approximately 0.1 second | |
| 658108447 | Bundle of His | impulse pass from atria to ventricles via AV bundle (also known as Atrioventricular Bundle). Bundle splits into two pathways which carry impulse toward Apex of heart. | |
| 658108448 | Purkinje Fibers | Carry heart impulses to the Apex and Ventricullar Walls | |
| 658108449 | Extrinsic Innervation | heart is stimulated by the sympathetic cardioacceleratory center in the Medulla. Innervates the SA and AV Nodes. | |
| 658108450 | P Wave | Corresponds to depolarization of the Atria | |
| 658108451 | QRS Wave | Corresponds to depolarization of the Ventricles | |
| 658108452 | T Wave | corresponds to repolarization of the Ventricles | |
| 658108453 | Atrial Repolarization | masked by the larger QRS wave of the ventricles | |
| 658108454 | Systole | Contraction of the heart muscle (also closing of AV valves) | |
| 658108455 | Diastole | relaxation of the heart muscle (also filling of the ventricles with blood) | |
| 658108456 | Cardiac Output | the amount of blood pumped by each ventricle in one minute. CO = HR x SV | |
| 658108457 | Heart Rate | the number of heart beats per minute | |
| 658108458 | Stroke Volume | the amount of blood pumped out by a ventricle with each beat (average 70ml/s) | |
| 658108459 | Blood Pressure | BP = CO x PR | |
| 658108460 | Peripheral Resistance | force against blood flow | |
| 658108461 | factors affecting stroke volume | 1. preload 2. contractility 3. afterload | |
| 658108462 | frank starling law | The greater the stretch the longer the contraction (up to a point) | |
| 658108463 | Increased Contractility | increased sympathetic stimuli, certain hormones, Ca+2 and some drugs | |
| 658108464 | Decreased Contractility | acidosis, increased K+, calcium channel blockers and drugs |
