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105 Cards in this Set
- Front
- Back
how much does the heart pump per year?
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over 1 million gallons
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how many miles of blood vessels are there?
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over 60,000
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where is the heart located?
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mediastinum
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mediastinum
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area from the sternum to the vertebral column and between the lungs
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apex
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directed anteriorly, inferiorly and to the left
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base
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directed posteriorly, superiorly and to the right
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anterior surface
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deep to the sternum and ribs
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inferior surface
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rests on the diaphragm
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right border
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faces right lung
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left border
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(pulmonary border)
faces left lung |
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what is located under the diagphragm?
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stomach and esophagus
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what are the hearts surfaces and borders?
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surfaces anterior/inferior
borders right/left |
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fibrous pericardium
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dense irregular ct
protects and anchors the heart prevents overstretching |
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serous pericardium
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thin delicate membrane
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what does the serous pericardium contain?
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parietal layer-outer layer
pericardial cavity with pericardial fluid visceral layer (epicardium) |
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epicardium
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visceral layer of serous pericardium
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myocardium
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cardiac muscle layer is the bulk of the heart
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endocardium
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chamber lining and valves
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muscle bundels of the myocardium
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cardiac muscle fibers swirl diagonally around the heart in interlacing bundles
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what are the chambers of the heart?
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2 upper atria
2 lower ventricles |
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sulci of the heart
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grooves on the surface of the heart containing coronary blood vessels and fat
coronary sulcus anterior interventricular sulcus posterior interventricular sulcus |
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coronary sulcus (sinus)
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most important
encircles heart and marks the boundary between the atria and ventricles |
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anterior interventricular sulcus
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marks the boundary between the ventricules anteriorly
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posterior interventricular sulcus
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(artery)
marks the boundary between the ventricles posteriorly |
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pulminary arteries have what type of blood?
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deoxygenated
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pulminary arteries are the only artery that is
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deoxygenated
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right atrium
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receives blood from 3 sources
interatrial septum partitions the atria fossa ovalis tricuspid valve |
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fossa ovalis
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a reminant of the fetal foramen ovale
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right atrium tricuspid valve
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blood flows through into right ventricle
has 3 cusps composed of dense ct covered by endocardium (epithelial tissue) |
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the right ventricle forms most of
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anterior surface of the heart
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right ventricle
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papillary muscles
chordae tendineae interventricular septum pulmonary semilunar valve |
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papilary muscles
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are coned shaped trabeculae carneae ( raised bundles of cardiac muscles)
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chordae tendineae
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chords between valve cusps and papillary muscles
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interventricular septum
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partitions ventricles ( stops tricuspid valve from opening up)
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pulmonary semilunar valve
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blood flows into pulmonary trunk
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left atrium forms most of
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the base of the heart
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left atrium
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receive blood from lungs
bicuspid (mitrol) valve |
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left atrium receives blood from lungs
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4 pulmonary veins (2 right and 2 left)
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bicuspid valve
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(mitral valve)
blood passes through into left ventricle has 2 cusps left atrioventricular, mitral, or bicuspid valve (lamb) |
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left ventricle forms
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the apex of the heart
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left ventricle
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chordae tendinae anchor bicuspid valve to papillary muscles (also has trabeculae carneae like right ventricle)
-aortic semilunar valve |
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aortic semilunar valve
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-blood passes through valve into the ascending aorta
-just above the valve are the openings to the coronary arteries |
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myocardial thickness and function
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thickness of myocardium varies according to the function of the chamber
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atria are
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thin walled, deliver blood to adjacent ventricles
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ventricle walls
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are much thicker and stronger than the atria walls
-right ventricle supplies blood to the lungs (little flow resistance) -left ventricle wall is the thickest to supply systemic circulation |
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what wall is the thickess of the cardiac walls?
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myocardium of left ventricle is much thicker than the right
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fibrous skeleton of heart
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dense ct rings surround the valves of the heart, fuse and merge with the interventricular septum
-support structure for heart valves -insertion point for cardiac muscle bundles -electrical insulator between atria and ventricles |
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electrical insulator between atria and ventricles
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prevents direct propagation of ap's (action potentials) to ventricles
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atrioventricular valves open
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a-v valves open and allow blood to flow from atria into ventricles when ventricular pressure is lower than atrial pressure
-occurs when ventricles are relaxed, chordae tendineae are slack and papillary muscles are relaxed |
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atrioventricular valves close
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a-v valves close preventing backflow of blood ino atria
-occurs when ventricles contract, pushing valve cusps closed, chordae tendinae are pulled taunt and papillary muscles contract to pull cords and prevent cusps from everting |
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semilunar valves
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-sl valves open with ventricular contraction
-sl valves close with ventricular relaxation |
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sl valves open with ventricular contraction
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allow blood to flow into pulmonary trunk and aorta
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sl valves close with ventricular relaxation
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prevents blood from returning to ventricles, blood fills valve cusps, tightly closing the sl valves
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function of atria
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atria contract, blood fills ventricles through a-v valves
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function of ventricles
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ventricles contract, blood pumped into aorta and pulmonary trunk through sl valves
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blood circulation
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2 closed circuits, the systemic and pulmonic(systemic circulation and pulmonary circulation)
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systemic circulation
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-left side of heart pumps blood through body
-left ventricle pumps oxygenated blood into aorta -aorta branches into many arteries that travel to organs -arteries branch into many arterioles in tissue -arterioles branch into thin walled capillaries for exchange of gases and nutrients -deoxygenated blood begins its return in venules -venules merge into veins and return to right atrium |
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pulmonary circulation
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-right side of heart pumps deoxygenated blood to lungs
-right ventricle pumps blood to pulmonary trunk -pulmonary trunk branches into pulmonary arteries -pulmonary arteries carry blood to lungs for exchange of gases -oxygenated blood returns to heart in pulmonary veins |
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blood flow colors
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blue-deoxygenated
red-oxygenated |
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coronary circulation
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blood supply to the heart
-heart as a very active muscle needs lots of o2 -when the heart relaxes high pressure of blood in aorta pushes blood into coronary vessels -many anastomoses |
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anastomoses
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connections between arteries supplying blood to the same region, provide alternate routes if one artery becomes occluded
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coronary arteries
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branches off aorta above aortic semilunar valve
-left coronary artery -right coronary artery |
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coronary veins
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-collect wastes from cardiac muscle
-drains into a large sinus on posterior surface of heart (coronary sinus) -coronary sinus empties into right atrium |
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where does the coronary sinus empty into?
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right atrium
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cardiac muscle histology
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branching intercalated discs with gap junctions, involuntary, striated, single central nucleus per cell
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conduction system of heart
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coordinates contraction of heart muscle
-autorhythmic cells -sa node -av node -av bundle of His |
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autorythmic cells
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cells fire spontaneously, act as a pacemaker and form conduction system for the heart
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sa node
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-cluster of cells in wall of rt. atria
-begins heart activity that spreads to both atria -exicitation spreads to av node |
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av node
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in atrial septum, transmits signal to bundle of His
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av bundle of His
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the conection between atria and ventricles
divides into bundles branches and purkinje fibers, large diameter fibers that conduct signals quickly |
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rythm of conduction system
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-sa node fires spontaneously 90-100 times per minute
-av node fires at 40-50 times per minute -if both nodes are suppresed fibers in ventricles by themselves fire 20-40 times per minute |
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rythm of cs
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-artificial pacemaker is needed if pace is to slow
-extra beats are forming at other sites are called ectopic pacemakers(increased by cafeine and nicotine) |
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depolarization
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-cardiac cell resting membrane potential is-90mv
-excitation spreads through gap junctions -fast na channels open for rapid depolarization |
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plateau phase
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-250 msec (only 1msec in neuron)
-slow ca2 channels open, let ca2 enter from outside cell and from storage in sarcoplasmic reticulum, while k channels close -ca2 binds to troponin to allow for actin-myosin cross-bridge formation and tension development |
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repolorization
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-ca2 channels close and k channels open and -90mv is restored as potassium leaves the cell
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refratory period
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very long so heart can fill
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systole
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contraction
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diastole
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relaxation
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one cardiac cycle
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what happens to the heart in one beat at 75 beats/min, one cycle requires 0.8 sec.
-end diastolic volume (edv) -end systolic volume (esv) -stroke volume (sv) |
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at 75 beats/min, one cycle requires 0.8 sec.
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systole and diastole of both atria, plus the systole and diastole of both ventricles
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edv
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volume in ventricle at end of diastole, about 130ml
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esv
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volume in ventricle at end of systole, about 60ml
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sv
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-the volume ejected per beat from each ventricle, about 70ml
-sv=edv-esv |
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isovolumetric relaxation
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all relaxing at the same time(closed)
atriums filing up(coronary sinus) |
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ventricular filing
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- rapid ventricular filing as blood flows from full atria
-diastasis:as blood flows from atria in smaller volume -atrial systole pushes final 20-25 ml blood into ventricle atrial ventricular valves open |
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ventricular systole
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-isovolumetric contraction: brief period, av valves close before sl valves open
-ventricular ejection:as sl valves open and blood is ejected to ventricule |
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bp in aorta
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120mm hg
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bp in pulmonary trunk
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30mm hg
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differences in ventricle wall thickness allows
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heart to push the same amount of blood with more force from the left ventricle
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the volume of blood ejected from each ventricle is
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70ml (stroke volume)
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sound of the heart beat are from
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turbulence in blood flow caused by valve closure
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what are the 2 sounds of the heart?
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lubb/dupp
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lubb
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is created with the closing of the atrioventricular valves
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dupp
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is created with the closing of semilunar valves
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cardiac output
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amount of blood pushed into aorta or pulmonary trunk by ventricle
determined by stroke volume and heart rate |
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cardiac reserve
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maximum output/output at rest
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influences on stroke volume
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preload (affect of stretching)
contractility afterload |
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preload
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frank-starling law of heart
-more muscle is stretched, greater force of contraction -more blood more force of contraction results |
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contractility
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autonomic nerves, hormones, ca+2 or k+ levels
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afterload
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-amount of pressure the heart has to overcome
-high blood pressure creates high afterload |
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regulation of heart rate
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-nervous control from the cardiovascular center in the medulla
-heart rate is also affected by hormones |
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nervous control from the cardiovascular center in the medulla
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-sympathetic impulses increase heart rate and force of contraction
-parasympathetic impulses decrease heart rate baroceptors (pressure receptors) detect change in bp and send info to the cardiovascular center(located in the arch of the aorta and carotid arteries) |
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what hormones affect heart rate?
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-epinephrine, norepinephrine, thyroid hormones
-ions (na+, k+, ca2+) -age, gender, phsical fitness, and temp. |
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factors in heart disease
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diabetes mellitus
genetic predisposition male gender high blood levels of fibrinogen left ventricular hypertrophy |
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what should the total cholesterol be for an adult?
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under 200 mg/dl
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