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181 Cards in this Set
- Front
- Back
The _____ side of the heart receives oxygen-rich blood from body tissues and then pumps the blood to the ____ to pickup ___ and dispel ____ |
1) Right 2) Lungs 3) Oxygen 4) Carbon Dioxide |
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The blood vessels that carry blood to and from the lungs form the _____ |
Pulmonary Circuit |
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The ____ side of the heart receives oxygenated blood returning from the _____ and pumps this blood throughout the body to supply ____ and ____ to the body tissues. |
1) Left 2) Lungs 3) Oxygen 4) Nutrients |
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The blood vessels that carry blood to and from all body tissues form the ____ |
Systemic Circuit |
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The heart has two receiving chambers called the right and left _____ |
atrium |
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The heart has two main pumping chambers the right and left _____ that pump blood around the two circuits. |
Ventricle |
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The heart is about the size of a ____ |
fist |
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The heart is _____ shaped |
Cone |
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Define Mediastinum |
The medial cavity of the thorax where the heart is enclosed. |
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Approx. 2/3 of the heart's mass lies to the left of the _____. |
Midsternal line |
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The ____ points toward the left hip |
apex |
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Define Apical Impluse |
Heart beat that can be felt through the chest wall |
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Define Pericardium |
The double-layered sac enclosing the heart and forming its superficial layer |
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The pericardium has ____ and ___ layers |
fibrous and serous layers |
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Define Fibrous Pericardium |
The loosely fitting superficial part of the pericardium |
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3 jobs of the Fibrous Pericardium |
1) Protects the heart 2) Anchors it to surrounding structures 3) Prevent overfilling of the heart with blood |
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Define Serous Pericardium |
A thin, slippery, two-layered serous membrane that forms a closed sac around the heart. |
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Serous Pericardium is made of two layers the ____ and the ___ |
1) Parietal 2) Visceral |
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Parietal Layer |
Lines the internal surface of the fibrous pericardium |
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____ attaches to the large arteries exiting the heart and then turns _____ and continues over the external heart surface as the ______ |
1) Parital Layer 2) Inferiorly 3) Visceral Layer/Epicardium |
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Define Pericardial Cavity |
A slit-like cavity between the parietal and visceral layers that contains a film of serous fluid. |
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The serous membranes of the pericardial cavity allow |
Allow the two serous membranes to glide smoothly past one another, allowing the heart to work relatively friction-free |
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Pericarditis |
Inflammation of the pericardium, roughens the serous membrane surfaces. |
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Three layers of the heart wall |
1) Epicardium 2) Myocardium 3) Endocardium |
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Myocardium is composed mainly of ___ and forms the ____ of the heart |
1) Cardiac msucle 2) Bulk |
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The myocardium branching cardiac muscle cells are tethered to one another by connective tissues fibers called ___ that ____ all parts of the heart. |
1) Circular bundles 2) Link |
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Define Cardiac Skeleton |
The dense connective tissue fibers that reinforce the myocardium internally and anchors the cardiac muscle fibers. |
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Importance of the cardiac skeleton |
1) Without the support the vessels and valves might eventually stretch because of the continuous stress 2) Limits spread of action potentials to specific pathways in the heart because they are not electrically excitable |
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Define Endocardium |
Glistening white sheet of endothelium resting on a thin connective tissue layer |
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_____ is located on the inner myocardial surface and lines the heart chambers and covers the fibrous skeleton of the valves. |
Endocardium |
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_____ is continuous with the endothelial linings of the bod vessels leaving and entering the heart. |
Endocardium |
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The heart has four chambers. Two superior ____ and two inferior ____ |
1) Atria 2) Ventricles |
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Define Interatrial Septum |
The internal partition that divides the heart longitudinally where it separates the atria |
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Define Interventricular Septum |
The internal partition that divides the heart longitudinally where it separates the ventricles. |
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Define Pectinate muscles |
Parallel ridges in the walls of the atria of the heart that are shaped like teeth of a comb |
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Right atrium is made of two parts |
1) Pectinate Muscles - anterior portion 2) Smooth-walled posterior part |
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Left atrium is mostly _____. The _____ muscles are found only in the auricles |
1) Smooth 2) Pectinate |
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The atria are relatively small, thin-walled chambers because |
they need to contract only minimally to push blood "down" to the ventricles |
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Blood enters the right atrium through these 3 veins |
1) Superior Vena Cava 2) Inferior Vena Cava 3) Coronary Sinus |
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Function of Superior Vena Cava |
Returns blood from body regions superior to the diaphragm |
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Function of the Inferior Vena Cava |
returns blood from body area below the diaphragm |
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Function of Coronary Sinus |
collects blood draining from myocardium |
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Four _____ veins enter the left atrium which transport blood from the ____ back to the heart. |
1) Pulmonary Veins 2) Lungs |
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The _____ makes up most of the heart's anterior surface. |
Right ventricle |
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Papillary Muscles |
play a role in valve function and project into the ventricular cavity |
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The ventricles are the ___ of the heart |
pumps |
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When the ventricles contract they |
propel blood out of the heart into the circulatory system. |
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Pulmonary Trunk |
Vessel leaving the right ventricle that routes the blood to the lungs where gas exchange occurs |
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Aorta |
Vessel leaving the left ventricle and is the largest artery in the body |
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Blood flows in one direction |
from atria to ventricles and out the great arteries leaving the superior aspect of the heart |
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4 valves that enforce blood flow direction |
1) Atrioventricular Valves (AV) - tricuspid valve and mitral valve(or bicuspid) 2) Semilunar Valves (SV) - aortic and pulmonary |
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Define chordae tendineae |
Tiny white collagen cords attached to each of the AV valve flaps which anchor the cusps to the papillary muscles protruding from the ventricular walls. |
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When the heart is relaxed the AV valves _____ into the _____ below and blood flows into atria, through ____ and into ventricles |
1) Hang limply 2) Ventricle chambers 3) AV valves |
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When the ventricles contract the flap edges ____ and ____ the AV valve |
1) Meet 2) Close |
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The ____ and ___ serve to anchor the AV valve flaps in their closed position |
1) Chordae Tendineae 2) Papillary muscles |
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The ___ and ____ guard the bases of the large arteries issuing from the ventricles (the aorta and pulmonary trunk) and prevent ____ into the associated ventricles. |
1) Aortic valve 2) Pulmonary valve (Semilunar,SL) |
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The ____ circuit , ____served by the ____ ventricle, is a short, low-pressure circulation. |
1) Pulmonary 2) Right |
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The ____ circuit, served by the ____ ventricle, takes a long pathway through the entire body and encounters ____. |
1) Systemic 2) Left 3) Resistance to blood flow |
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The anatomy of left ventricle that shows the difference in workload |
Left ventricle walls are three times thicker than those of the right ventricle and its cavity is nearly circular. |
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The anatomy of right ventricle that shows the difference in workload |
The cavity is flattened into a crescent shape that partially encloses the left ventricle |
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The wrapping of the right ventricle around the left ventricle allows the left ventricle to ____ |
produce more pressure and be a more powerful pump. |
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____ volumes of blood are pumped through the pulmonary and systemic circuits |
Equal |
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The heart is two _______ |
side-by-side pumps |
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Define Coronary Circulation |
The functional blood supply of the heart and shortest circulation in the body |
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Both the left and right coronary arteries arise from the base of the ____ and _____ the heart in the _____ |
1) Aorta 2) encircle the heart 3) Coronary sulcus |
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The ____ coronary artery runs toward the left side of the heart and then divides into two major brnaches |
Left |
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The Left coronary artery divides into these two major branches |
1) Anterior interventricular artery 2) Circumflex artery |
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Anterior interventricular artery supplies blood to _____ and ____ |
1) interventricular septum 2) anterior walls of both ventricles |
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Circumflex artery supplies ____ and ___ with blood |
1) Left atrium 2) Posterior walls of left ventricle |
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Right coronary artery two branches |
1) Right marginal artery 2) Posterior interventricular artery |
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The branches of the ___ coronary artery supply the ___ and nearly all of the ____ |
1) Right 2) Right atrium 3) right ventricle |
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Coronary arterial supply ____ and there are many _____ among the coronary arterial branches |
1) varies 2) anastomoses (junctions) |
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These fusing networks provide _____ for blood delivery to the heart muscle |
additional routes |
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Angina pectoris |
Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium May result from stress-induced spasms of the coronary arteries or from increased physical demands on the heart The myocardial cells are weakened by temp lack of oxygen but do not die |
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Myocardial infarction |
Commonly called heart attack Cells do die Caused by prolonged coronary blockage Area of cell death is repaired with noncontractile scar tissue |
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Physical attributes of cardiac cells |
striated, short, fat, branched, and interconnected. |
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The intracellular spaces of cardiac muscle are filled with ____ that connects to the ____ which gives cardiac muscle ____ |
1) loose connective matrix (endomysium) 2) fibrous skeleton 3) something to exert force against |
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Intercalated discs |
junctions between cells that anchor cardiac cells to one another |
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Intercalated discs contain ___ and ___ |
1) desmosomes 2) gap junctions |
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Function of desmosomes |
prevent adjacent cells from separating during contraction |
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Function of gap junctions |
allow ions to pas and electrically couple adjacent cells - transmitting current across the entire heart |
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Because ____ electrically couple cardiac cells, the ____ behaves as a _____, a single coordinated unit |
1) Gap junctions 2) myocardium 3) functional synctium |
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____ account for 25 - 35% of the volume of cardiac cells. This makes cardiac cels high resistant to ___ |
1) Mitochondria 2) Fatigue |
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_____ are wider and fewer in cardiac muscle cells than in skeletal |
T tubles |
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____ is simpler in cardiac muscle cells than skeletal |
Sarcoplasmic reticulum |
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Define intercalated discs |
Junctions where plasma membranes of adjacent cardiac cells interlock |
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Intercalated discs contain ___ and ___ |
1) Desmosomes 2) Gap Junctions |
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Desmosomes prevent ______ |
adjacent cells from separating during contraction |
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Gap Junctions allow ____ |
ions to pass from cell to cell, transmitting current across entire heart |
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Define Functional Syncytium |
When cells act as a single unit, such as when the myocardium of the heart works all together |
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The ability to ___ and ___ is intrinsic |
1) Depolarize 2) Contract |
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Define Intrinsic Cardiac Conduction System |
A network of non-contractile (autorhythmic) cells that initiate and distribute impulses to coordinate the depolarization and contraction of the heart |
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Autorhythmic cells nickname |
Pacemaker cells |
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____ cells have unstable resting potentials due to ____. |
1) Autorhythmic 2) Open slow Na channels |
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Define pacemaker potentials |
Spontaneously changing membrane potentials |
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Pacemaker potentials initiate the ____ |
action potentials that spread throughout the heart to trigger its contractions |
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3 parts of action potential in pacemaker cells |
1) Pacemaker potential 2) Depolarization 3) Repolarization |
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Steps of action potential in pacemaker cells |
1) At threshold Ca channels open 2) Explosive Ca entry produces rising phase of action potential 3) Repolarization results from inactivation of Ca channels and opening of K channels |
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Autorhythmic cells are found in these 5 places |
1) Sinoatrial (SA) node 2) Atrioventricular (AV) node 3) Atrioventricular Bundle 4) Right and Left bundle branches 5) Subendocardial Conducting Network |
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Define Sinoatrial (SA) node |
Crecent-shaped node located in the right atrial wall, just inferior to the superior vena cava |
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SA node generates impulses ___ times per minute |
75 |
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The ___ node sets the pace for the heart as a whole because ___ |
1) SA node 2) no other region of the conduction system has a faster depolarization rate |
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The ____ is the heart's pacemaker |
SA node |
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Define Sinus rhythm |
Normal rhythm of the heart determined by SA node impulses |
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Define Atrioventricular (AV) node |
Located inferior portion of the interatrial septum above the tricuspid valve |
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From the SA node the depolarization spreads via ____ throughout the ____ to the _____ |
1) gap junctions 2) atria 3) Atrioventricular (AV) node |
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The AV node delays impulse approx. ___ |
.1 sec |
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The delay of the AV node allows ___________ |
the atria to respond and complete their contraction before the ventricles contract |
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The AV node has ____ and ____ that cause the delay |
1) smaller diameter fibers 2) fewer gap junctions |
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Define Atrioventricular Bundle (Bundle of His) |
Located in the superior part of the interventricular septum |
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Though the atria and ventricles abut they are ____ |
not connected by gap junctions |
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The AV bundle is the only ____ |
electrical connection between atria and ventricle |
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The AV bundle splits into ___ and ___, which course toward _____ |
1) Left Bundle Branch 2) Right Bundle Branch 3) Apex of heart |
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Define Subendocardial Conducting Network |
Long strands of barrel-shaped cells, also called Purkinje fibers, that complete the pathway to the apex |
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Without SA input the AV node would depolarize about ____ |
50 times per minute |
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Without AV node input the AV bundle and Purkinje fibers only depolarize about |
30 times per minute |
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Defects in the intrinsic conduction system may result in (3) |
1) Arrhythmia - irregular heart beat 2) Uncoordinated atrial and ventricular contractions 3) Fibrillation - rapid, irregular contractions that make pumps useless |
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Defective SA node may result in (2) |
1) Ectopic Focus - abnormal pacemaker takes over 2) If AV node takes over there will be a junctional rhythm (40 - 60 bpm) |
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Defective AV node may result in |
1) Partial or total heartblock 2) Few or no impulses from SA node reach the ventricles |
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Heartblock |
Total heart block is when no impulses get through to the ventricles and they beat at their intrinsic rhythm which is too slow for circulation |
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Heartbeat is modified by the ____ |
Autonomic Nervous System |
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The _____ increases the rate and force of heartbeat |
Sympathetic Nervous System |
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The _____ slows the heart |
Parasympathetic Nervous System |
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The cardiac centers are located in the ____ |
medulla oblongata |
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The cardioacceleratory center innervates the _____, _______, _____, and _____ through ______ |
1) SA node 2) AV node 3) Heart muscle 4) Coronary arteries 5) sympathetic neurons |
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Cardioinhibitary center inhibits ____ and ___ through _____ in the _____ |
1) SA node 2) AV node 3) Parasympathetic fibers 4) Vagus Nerves |
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Define electrocardiogram |
a composite of all the action potentials generated by nodal and contractile cells at a given time |
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An EKG does not _____ |
provide information on valve function |
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Name 3 types of waves |
1) P wave - depolarization of SA node 2) QRS complex - Ventricular depolarization 3) T wave - ventricular repolarization |
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Order of sequence of excitement |
1) SA node generates impulse 2) Impulse delays at AV node 3) AV bundle connects atria and ventricles 4) Bundle branches impulses through interventricular septum toward apex 5) Subendocardial Conducting Network (Purkinje fibers) depolarizes the contractile cells of both ventricles |
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Name for the two sounds associated with closing of heart valves |
Lub-Dub |
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First sounds of heart occurs when |
AV valves close and signifies the beginning of systole |
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Second heart sounds occurs when |
SL valves close at the beginning of ventricular diastole |
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Define heart murmur |
abnormal heart sounds most often indicative of valve problems |
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3 phases of cardiac cycle |
1) Ventricular Filling 2) Ventricular Systole 3) Isovolumetric relaxtion |
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Define systole |
periods of contraction |
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Define diastole |
periods of relaxation |
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Define cardiac cycle |
includes all events associated with blood flow through the heart during one complete heartbeat - atrial systole and diastole followed by ventricular systole and diastole |
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Describe events of Ventricular filling |
1) Atria is in mid-to-late diastole 2) AV valves are open and blood is filling ventricles 3) AV flaps begin to float to closed position 4) Atria contracts following P wave 5) Ventricles are in last part of diastole and have EDV |
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____% of blood passively flows into the ventricles, the other ___ % comes from ____ |
1) 80% 2) 20% 3) Atrial systole |
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Define End Diastolic Volume (EDV) |
When ventricle has maximum amount of blood volume it will contain |
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Describe events of Ventricular Systole |
1) Atria relax and ventricles beging to contract 2) Ventricle pressure rises closing AV valves 3) Ventricular pressure continues to rise opening SL valves 4) Blood rushes into aorta and pulmonary trunk |
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Define Isovolumetric Contraction Phase |
The split-second period hen the ventricles are completely closed chambers and the blood volume remains constant as ventricle contract |
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Describe events of Isovolumetric relaxation |
1)Ventricles relax 2) Backflow of blood in aorta and pulmonary trunk closes SL valves and causes dicrotic notch |
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Isovolumetric relaxation occurs during |
early ventricle diastole |
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Define dicrotic notch |
rise in aortic pressure |
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Define End systolic volume (ESV) |
volume of blood remaining in each ventricle after contraction and ejection |
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Cardiac Output (CO) = |
Heart Rate (HR) + Stroke Volume (SV) |
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Define Cardiac Output (CO) |
The volume of blood pumped by each ventricle in one minute |
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Heart Rate (HR) = |
number of beats per minute |
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Define Stroke Volume (SV) |
volume of blood pumped out by a ventricle with each beat |
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Stroke Volume (SV) = |
EDV (amount of blood collected in a ventricle during diastole) - ESV (the volume of blood remaining in a ventricle after it has contracted) |
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Three main factors affecting Stroke Volume (SV) |
1) Preload 2) Contractility 3) Afterload |
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Define preload |
Degree of stretch of cardiac muscle cells before they contract |
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In a normal heart the higher the preload the ____ the stroke volume |
higher |
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Define Frank- Starling law of heart |
The higher the preload the higher the stroke volume |
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Cardiac muscle exhibits a _____ relationship |
length-tension |
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At rest, cardiac muscle cells are ___ than optimal length |
shorter |
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Slow heartbeat and exercise increase ____ |
venous return |
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Define venous return |
The amount of blood returning to the heart and distending its ventricles |
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Define contractility |
Contractile strength at a given muscle length |
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Contractility is independent of |
muscle stretch and EDV |
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Define Positive inotropic agents |
Factors that increase heart rate |
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Define Negative inotropic agents |
Factors that decrease heart rate |
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Examples of positive inotropic agents affecting contractility |
1) Increased CA influx due to sympathetic nervous system 2) Hormones (thyroxine, glucagon, and epinephrine) |
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Examples of negative inotropic agents contractility |
1) Acidosis 2) Increased extracellular K 3) Calcium channel blockers |
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Define afterload |
Pressure that must be overcome for ventricles to eject blood |
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_____ increases afterload, resulting in increased ___ and reduced ____ |
1) Hypertension 2) ESV 3) SV |
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Define Positive chronotropic factors |
Factors that increase heart rate |
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Define negative chronotropic factors |
Factors that decrease heart rate |
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The ____ exerts the most important extrinsic controls affecting heart rate |
ANS |
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_____ is activated by emotional or physical stressors which causes release of ___, which causes ____ |
1) Sympathetic Nervous System 2) Norepinephrine 3) increase heart rate |
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___ opposes effects of sympathetic nervous system and effectively ___ |
1) Parasympathetic nervous system 2) reduces heart rate |
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The heart at rest exhibits ___ because ___ |
1) vagal tone 2) dominant influence is inhibitory |
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Define Atrial (bainbridge) reflex |
An autonomic reflex initiated by increased venous return and increased atrial filling |
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Stretching the ___ increases heart rate stimulating the _____ and ____, which activates the ____ |
1) Atrial walls 2) SA node 3) Atrial stretch receptors 4) sympathetic relexes |
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Hormones that affect heart rate |
1) Epinephrine - enhances heart rate and contractility 2) Thyroxine increases heart rate and effects of norepinephrine and epinephrine |
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___ must be maintained for normal heart function |
Intra and extracellular ion concentrations |
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Define Tachycardia |
Abnormally fast heart rate >100 bpm |
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Define Bradycardia and affects |
1) Heart rate slower than 60 bpm 2) Inadequate blood circulation 3) Desired for endurance training |
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Define Congestive Heart failure |
Progressive condition where the CO is so low that blood circulation is inadequate to meet tissue needs |