Term
| 2 circuits of the blood vessels |
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Definition
-Pulmonary circuit
-carries blood to and from the exchange surfaces of the lungs
-Systemic circuit
-transports blood to and from the rest of the body
-Each circuit begins and ends at the heart. |
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Term
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Definition
-Efferent vessels
-carry blood away from the heart
-highly muscular |
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Definition
-Afferent vessels
-return blood to the heart |
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Term
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Definition
-small thin walled vessels between the smallest arteries and the smallest veins.
-thin wall allows for exchange of nutrients, dissolved gases, and waste products between the blood and surrounding tissue. |
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Term
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Definition
-Heart has 4 chambers
-Right Atrium
-receives blood from the systemic circuit
-Right Ventricle
-discharges blood into the pulmonary circuit
-Left Atrium
-collects blood from the pulmonary circuit
-Left Ventricle
-ejects blood into the systemic circuit. |
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Term
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Definition
-lining of the pericardial cavity
-serous membrane
-visceral pericardium covers the outer surface of the heart (epicardium)
-parietal pericardium lines the inner surface of the pericardial sac.
-Normally contains small amount of pericardial fluid secreted by pericardial membrane that acts as lubricant |
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Term
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Definition
| -deep groove usually filled with fat, marks the border between the atrial and ventricles. |
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Term
| Anterior interventricular sulcus and posterior interventricular sulcus |
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Definition
| -smaller fat filled grooves that mark the boundary between the left and right ventricles |
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Term
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Definition
-3 distinct layers
-Epicardium
-covers the outer surface of the heart
-serous membrane attached to the myocardium
-Myocardium
-muscular wall of the heart
-contains cardiac muscle tissue, blood vessels and nerves
-concentric layers wrap around atria and spiral into the walls of the ventricles, this causes the squeezing/twisting contractions of the heart.
-Endocardium
-simple squamous epithelium, inside layer |
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Term
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Definition
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Term
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Definition
| -separates the two ventricles |
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Term
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Definition
-where each atrium opens into the ventricle on the same side.
-comprised of fibrous tissue to ensure one way blood flow from atria to ventricle. |
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Term
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Definition
| -delivers blood to the right atrium from the head, neck, upper limbs and chest. |
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Term
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Definition
| -delivers blood to the right atrium from the trunk, viscera and the lower limbs. |
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Definition
-opens into the right atrium slightly below the connection with the inferior vena cava.
-returns venous blood from the cardiac veins |
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Term
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Definition
-allowed blood to flow from the right atrium to the left atrium while the lungs were developing
-closes after 48 hours after birth. |
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Term
| Right atrioventricular valve |
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Definition
-fibrous tissue vavle allowing for one way flow from the right atrium into the right ventricle.
-3 flaps called cusps
-known as the tricuspid valve |
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Term
| Chordae tendineae and papillary muscles |
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Definition
-CT are fibers that connect to PM (cone shaped projections on the inner surface of the ventricles) to form the AV's.
-Prevent backflow |
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Term
| Pulmonary trunk, pulmonary semilunar valve, left & right pulmonary arteries and left & right pulmonary veins |
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Definition
-start of the pulmonary circuit
-blood flows from the right ventricle past the PSV into the PT and into the left and right pulmonary arteries that branch repeatedly in the lungs down to capillaries where gases are exchanged.
-From the respiratory capillaries the blood flows into the left and right pulmonary veins, which deliver it to the left atrium. |
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Term
| Left atrioventricular valve |
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Definition
-bicuspid valve
-same as RAV, allows for flow of blood from the left atrium to the left ventricle and prevents backflow.
-"Mitral" valve. |
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Term
| Aorta and aortic semilunar valve |
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Definition
| -Blood leaves the left ventricle and passes through the aortic semilunar valve and into the aorta, which is the start of the systemic system. |
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Term
| Difference between left and right ventricles |
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Definition
-RV does not need to push as hard to create blood flow since lungs are close to heart and veins are short and wide.
-RV wall is relatively thin.
-Contraction of the RV is efficient but develops low pressure
-Systemic circuit requires 6-7 times more force than pulmonary circuit.
-LV has extremely thick muscular wall
-2 things happen when LV contracts
-distance between base and apex decreases
-diameter of the ventricular chamber decreases
-LV bulges into RV when it contracts, also helps blood leave RV. |
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Term
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Definition
-sac-like expansions of the base of the ascending aorta next to the cusp of the aortic semilunar valve that prevent cusps from sticking to the wall of the aorta when the valve opens.
-Right and left coronary arteries originate at the aortic sinuses. |
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Term
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Definition
| -supplies blood to the muscle tissue |
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Term
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Definition
-originate at the aortic sinuses
-BP here is the highest in the systemic circuit.
-Ensures continuous blood flow to cardiac muscle. |
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Definition
| -supplies blood to the right atrium and portions of both ventricles. |
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Term
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Definition
| -supplies blood to the left ventricle, left atrium and interventricular septum |
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Term
| Marginal and posterior interventricular (descending) branches |
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Definition
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Term
| Circumflex and anterior interventricular (descending) branches |
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Definition
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Term
| Great and middle cardiac veins |
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Definition
| -carry blood away from the coronary capillaries |
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Term
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Definition
-where the great and middle coronary veins drain into
-large thin walled posterior portion of the coronary sulcus.
-opens into the right atrium near the base of the inferior vena cava. |
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Term
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Definition
| -an area of dead tissue caused by an interruption in blood flow |
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Term
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Definition
-MI (heart attack)
-coronary circulation becomes blocked and cardiac muscle cells die from a lack of oxygen.
-most often a result of severe coronary artery disease
-buildup of fatty deposits in the walls of the coronary arteries. |
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Term
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Definition
-created by contractions of individual cardiac muscle cells in the atria and ventricles.
-2 types of cells: contractile and cells of the conducting system
-contractile cells produce powerful contractions that propel blood
-cells of the conducting system are non-contractile and control and coordinate the activities of the contractile cells. |
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Term
| Automaticity (autorhythmicity) |
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Definition
| -Cardiac muscle tissue contracts on its own in the absence of neural and hormonal stimulation |
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Term
| Heart contraction sequence |
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Definition
| -Atria contract first, followed by the ventricles |
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Term
| Heart's conducting system |
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Definition
-specialized cardiac muscle cells initiate and distribute electrical impulses.
-2 types of cells that do not contract: nodal and conducting cells
-Action potential created in the nodal cells and sweeps through conducting system, reaching all of the cardiac muscle tissue and causing a coordinated contraction. |
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Term
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Definition
-nodal cells: establish rate of cardiac contraction, located at the SA (sinoatrial) and AV (atrioventricular) nodes
-depolarize spontaneously and generate action potentials at regular intervals |
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Term
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Definition
-Sinoatrial node
-posterior wall of the right atrium near the entrance of the superior vena cava.
-depolarizes rapidly and spontaneously
-70-80 beats per minute |
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Term
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Definition
-Atrioventricular node
-located in the floor of the right atrium near the coronary sinus
-cells of the SA node electrically connected to the AV node by conducting cells in the atrial walls
-Also depolarizes spontaneously 40-60 beats per minute.
-AV node usually only fires after action potential from SA node, but if it does not receive that AP it fires on its own.
-slows the impulse down before reaching the AV bundle to allow for the atria to contract and fill the ventricles before the ventricles fire. |
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Term
| AV bundle and bundle branches |
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Definition
-aka bundle of His
-bundle of collecting cells that receives AP from AV node, extends along the interventricular septum then divides into the left and right bundle branches which radiate across the inner surfaces of the left and right ventricles. |
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Term
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Definition
| -convey impulses to the contractile cells of the ventricular myocardium |
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Term
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Definition
| -heart rate slower than 60bpm |
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Term
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Definition
| -heart rate faster than 100bpm |
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Term
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Definition
| -cases in which abnormal conducting cells or ventricular muscle cells generate APs so rapidly that they override the SA or AV nodes, thus bypassing the regular system and disrupting the timing of ventricular contractions. |
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Term
| Electrocardiogram (ECG/EKG) |
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Definition
| -recoding device of electrical events of the body |
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Term
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Definition
-accompanies the depolarization of the atria on EKG.
-atria begin contracting 100msec after start of P wave |
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Term
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Definition
-appears as the ventricles depolarize.
-electrical activity relatively strong due to the mass of the ventricular muscle being larger than that of the atria. |
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Term
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Definition
-fuck it.
-indicates ventricular repolarization |
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Term
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Definition
-abnormal patterns of cardiac activity
-clinical problems arise when the arrythmias reduce the heart's pumping efficiency
-serious arrythmias can be indicative of damage to the myocardium, injuries to the pacemaker or conduction pathways, exposure to drugs, or variations in the electrolyte composition of the extracellular fluid. |
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Term
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Definition
-period between the start of one heartbeat and the start of the next
-fluids move from an area of high pressure to low pressure.
-during CC, pressure in each chamber rises during systole and falls during diastole. Increased pressure in one chamber causes blood to flow to another chamber (or vessel) of lower pressure |
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Term
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Definition
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Term
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Definition
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Term
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Definition
-"Lubb"
-produced as the AV valves close and the semilunar valves open.
-marks the start of ventricular systole
-"Dubb"
-occurs at the beginning of ventricular diastole, when the semilunar valves close.
-Third and fourth heart sounds may be audible as well but are very faint |
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Term
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Definition
-SV
-amount of blood ejected by a ventricle during a single heartbeat |
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Term
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Definition
CO = SV x HR
-the amount of blood pumped by each ventricle in one minute.
-provides an indication of the blood flow through peripheral tissues |
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Term
| Factors that control cardiac output |
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Definition
-Primary
-blood volume reflexes
-autonomic innervation
-hormones
-Secondary
-concentration of ions in the extracellular fluid |
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Term
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Definition
-affects the heart rate
-adjusts the heart rate in response to the venous return of blood to the right atrium.
-entry of blood flow stimulates stretch receptors in the right atrial walls and triggers a reflexive increase in the HR through increased sympathetic activity, as a result SA node depolarize faster |
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Term
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Definition
-duration of ventricular diastole when blood can flow into the ventricles
-depends on HR; faster the HR, slower the filling time and the opposite |
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Term
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Definition
-"more in = more out" rule
-the myocardium stretches farther, the ventricles produce greater force upon contraction and stroke volume increases |
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Term
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Definition
-both sympathetic and parasympathetic systems innervate the heart
-primarily reflect the responses of the SA node to acetylcholine and norepinephrine. |
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Term
| Acetylcholine effects on heart and stroke volume |
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Definition
-released by the parasympathetic motor neurons results in a lowering of the HR.
-results in decreased force of cardiac contractions, greatest reduction is in the atria due to limited parasympathetic innervation of the ventricles |
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Term
| Epinephrine and norepinephrine innervations of the heart |
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Definition
-NE increases the heart rate, released by the sympathetic nervous system.
-a more sustained increase in HR results from release of E and NE by the adrenal medullae during sympathetic activation
-stimulate cardiac muscle cell metabolism and increases force and degree of contraction, resulting in increased SV. |
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Term
| Cardioacceleratory and cardioinhibitory centers |
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Definition
-located in the medulla oblongata
-cardioacceleratory center activates sympathetic motor neurons
-cardioinhibitory center controls parasympathetic motor neurons
-respond to changes in BP and atrial concentrations of dissolved oxygen and CO2.
-monitored by baroreceptors and chemoreceptors |
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