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Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Coronary Circulation Blood in the heart chambers does not nourish the myocardium (heart muscle) The heart has its own nourishing circulatory system consisting of Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood Cardiac veins—drain the myocardium of blood Coronary sinus—a large vein where all of the cardiac veins come together on the posterior of the heart, receives blood from cardiac veins
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Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Heart Continued
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Review Blood Flow
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Coronary Circulation Blood in the heart chambers does not nourish the
myocardium (heart muscle) The heart has its own nourishing circulatory system
consisting of Coronary arteries—branch from the aorta to supply the
heart muscle with oxygenated blood Cardiac veins—drain the myocardium of blood Coronary sinus—a large vein where all of the cardiac
veins come together on the posterior of the heart, receives blood from cardiac veins
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Coronary Circulation Blood empties into the right
atrium via the coronary sinusBlood from the heart enters the coronary arteries through a branch at the base of the aorta.
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Coronary Circulation Angina pectoris:
-Chest pain due to inadequate supply of oxygen to the muscle
-Indication some degree of coronary vessels blockage
Myocardial infarction:
- Medical term for heart attack
-Heart cells die from lack of blood supply
-Usually caused by blockage of one of the coronary arteries
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Heart: Conduction System Intrinsic conduction system (nodal system)
Heart muscle cells contract, without nerve impulses, they use nodes
http://www.dailymotion.com/video/xhp35u_argosy-medical-animation-sectioned-heart_tech
Heart beat sounds: “lub dub”
Sounds are made by the closing of the valves
Lub is the AV valves closing
Dub is the SA valves closing
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Heart: Conduction System Special tissue:
Sinoatrial node = SA node (“pacemaker”), in right atrium
Atrioventricular node = AV node, at junction of the right atrium near the interatrial septum
Atrioventricular bundle = AV bundle in the interventricular septum
Bundle branches in the interventricular septum
Purkinje fibers spread within the ventricle wall muscles
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
SA node (sino-atrial node) acts as the heart’s
“pacemaker” cells whose primary
function is electrical conduction, not contractility
the action potential produced by its depolarization spreads across the atria
(remember that action potential is the movement of molecules across the membranes of cells to create electrical current)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Heart Contractions Impulse spreads to
the AV node Then the atria
contract impulse passes
through the AV bundle, bundle branches, and Purkinje fibers
the ventricles contract
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Heart Contraction http://highered.mcgraw-hill.com/sites/0072495855/
student_view0/chapter22/animation__conducting_system_of_the_heart.html
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Heart Contractions
Figure 11.6
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Heart: Cardiac Cycle
The cardiac cycle refers to 1 complete heart beat
Normally .8 sec for 1 cardiac cycle
Cardiac cycle includes: Systole = contraction Diastole = relaxation
Relates to the ventricles, unless otherwise stated
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Heart ContractionsNormal Heart Rate: 75 beats/min Tachycardia—rapid heart rate over 100 beats per
minute (tachy= fast) Bradycardia—slow heart rate less than 60 beats
per minutes (brady= slow)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Heart: Cardiac Cycle Cardiac cycle—events of one complete heart beat
Mid-to-late diastole—blood flows from atria into ventricles
Ventricular systole—blood pressure builds before ventricle contracts, pushing out blood
Early diastole—atria finish refilling, ventricular pressure is low
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter22/animation__the_cardiac_cycle__quiz_1_.html
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