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Heart + Blood Vessel
Heart and blood vessel location, size, function
| Question | Answer |
|---|---|
| Arteries | Blood vessels which carry blood away from the heart. |
| Arterioles | Smaller branches off arteries |
| Metaarterioles | Branches between arterioles & Capillaries |
| Capillaries | Thin-walled; connections between the smallest arteries & veins |
| Arteriovenous shunts | Connection between arterial & venous pathways that do not involve the capillary network |
| Capillary arrangement | Depends on metabolic needs of tissues. Increased metabolism equals increased capillaries. |
| Capillary blood flow regulation | Precapillary sphincter (Muscle ring) |
| Capillary exchange | By filtration & passive processes: a Gases, b nutrients, c waste products |
| Veins | Carry blood toward the heart, and contain valves |
| Systolic pressure | Maximum pressure at ventricular contraction |
| Diastolic | Minimum pressure at ventricular diastole |
| Normal blood pressure | 120/80 |
| Blood pressure depends upon | a Heart action, b Blood volume, c Peripheral resistance (caused by plaque buildup) |
| Viscosity | Thickness or thinness of blood |
| Blood pressure regulation via nervous system | Mainly by reflex arcs |
| Vasomotor fibers | Vasodilation (acetylcholine) and vasoconstriction (norepinephrine) |
| Vasomotor center | Neural cluster in medulla which modifies pressure based upon input from sensors |
| Baroreceptors | Detect changes in arterial pressure & relay information to the vasomotor center & the cardiac inhibitory center |
| Chemoreceptors | Detect changes in chemical oxygen concentration |
| Blood pressure regulation via higher brain changes | Cerebral cortex. Hypothalamus. Fight or flight |
| Blood pressure regulation via hormonal factors | Renin in the kidneys when the kidneys detect lower blood pressure. The renin stimulates the formation of protein angiotensin I, which is then converted to angiotensin II by the angiotensin- converting enzyme in the lungs. This effect of constricting bloo |
| Phlebitis | Inflammation of a vein |
| Thrombophlebitis | Phlebitis associated with a blood clot |
| Varicose veins | Vessel wall or valve failure |
| Anastomosis | Where arteries join arteries, veins join veins or arteries join veins. |
| Heart size | 9cm x 14cm, but varies with body size |
| Heart location | Behind sternum, between lungs, protected within thoracic cage |
| Visceral pericardium | Thin, serous inner covering |
| Parietal pericardium | Thick, outer sac |
| Pericardial cavity | Filled with serous fluid |
| Epicardium | Outer, protective layer |
| Myocardium | Muscular layer |
| Endocardium | Continuous with blood vessels |
| Circumflex artery | Supplies blood to left atrium & left ventricle |
| Anterior interventricular artery | Supplies blood to right & left ventricles |
| Posterior interventricular artery | Supplies blood to right & left ventricles |
| Marginal artery | Supplies blood to right atrium & right ventricle |
| Cardiac veins | Drain blood back to the coronary sinus for transport to right atrium |
| Cardiac cycle | Atrial walls relax when ventricle walls contract (and vice versa) atria fill (about 70%) when relaxed. Blood flows through the AV valve then atria contract to force remaining blood into ventricle. This forces AV valve to close. Right AV - tricuspid. Left |
| Lub | Sound of AV valve closing |
| Dub | Sound of semilunar valve closing |
| Split heart sounds or Lub, Dup, Dup | Occurs during inspiration due to pulmonary semilunar valve closing before aortic semilunar valve |
| Functional syncytium | Cardiac muscle cells are mechanically, chemically, and electrically connected to one another, thus, the entire tissue resembles a single, enormous muscle cell |
| Atrial syncytium | Located in atrial walls |
| Ventricular syncytium | Located in ventricular walls |
| Atrioventricular node, or AV node | Stimulated by SA node, located in the floor of the right atrium |
| Sinoatrial node, or SA node | Pacemaker - small mass of specialized muscle tissue that can excite itself. Initiates approx. 70 - 80 impulses per minute. Located in right atrial wall. |
| Cardiac conduction | SA node, AV node, Bundle of His, Purkinje fibers, ventricular contraction |
| Murmurs | Sound resulting from incomplete valve closure. Blood leaks back into atria |
| Cardiac cycle regulation | Nerve control from medulla oblongata |
| Accelerator nerves | Cause an increase in rate & force |
| Cardioinhibitor reflex center | Arresting or slowing the rate of ventricular contractions |
| Cardioaccelerator reflex center | Increasing or speeding-up the rate of ventricular contractions. |
| How temperature regulates cardiac cycle | Heat increases HR by enhancing metabolic rate of heart cells. Also, cold slows metabolic rate of heart cells thus decreasing HR |
| How ion concentration regulates cardiac cycle | Physiological relationships between intracellular and extracellular ions must be maintained for normal heart function: Hypocalcemia depress heart. Hyperkalemia may lead to heart block or arrest. Hypokalemia causes heart to beat feeby and arrhythmically. |
Created by:
hajet
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