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Chap. 12, Heart
heart and cardiovascular function
46
Biology
Undergraduate 3
06/02/2013

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Term
myocardium
Definition
muscular wall of the heart consisting primarily of cardiac muscle cells
Term
pericardium
Definition
the serous membrane that forms the outer wall of the pericardial cavity
Term
visceral pericardium
Definition
same as the epicardium
Term
endocardium
Definition
covers the inner surfaces of the heart, consists of endothelium and areolar tissue
Term
epicardium
Definition
covers the outer surface of the heart, also called the visceral pericardium
Term
atria
Definition
superior chambers of the heart, receiving area for blood returning to the heart, push blood into ventricles
Term
ventricle
Definition
inferiors chambers of the heart, RV blood to lungs for gas exchange, LV blood to body
Term
mitral
Definition
left AV valve, same as bicuspid valve, 2 flaps
Term
bicuspid
Definition
left AV valve, same as mitral valve, 2 flaps
Term
tricuspid
Definition
right AV valve, 3 flaps
Term
semilunar valve
Definition
in aorta and pulmonary artery prevent backflow into ventricles, 3 crescent moon shaped cusps
Term
stroke volume
Definition
amount of blood pumped out of a ventricle per beat, equal to EDV-ESV
Term
cardiac output
Definition
amount of blood pumped out by each ventricle per minute, equal to heart rate times stroke volume
Term
end diastolic volume
Definition
determined by length of diastole and venous pressure, volume of blood in the ventricle pre-ventricular ejection, determines the myocardial preload,
Term
isovolumetric relaxation
Definition
blood flows into the relaxed atria, AV valves are closed
Term
isovolumetric contraction
Definition
ventricular contraction pushes the AV vales closed but does not create enough pressure to open the semilunar valves, volume of blood in the ventricle cannot change until the semilunar valves open
Term
angina pectoris
Definition
thoracic pain caused by decreased blood delivery to the myocardium, weakens, but does not kills, the cardiac cells
Term
fibrillation
Definition
causes cardiac arrest, ventricles quiver and stop pumping blood, rapid irregular, out of phase contraction, heart is like squirming bag of worms, loss of ventricular pumping, leads to brain death
Term
intercalated disk
Definition
junction between two cardiac cells, consist of desmosomes to prevent separation during contraction and gap junctions to helps transmit contraction signal between cells
Term
interventricular septum
Definition
wall of muscle separating left and right ventricles
Term
coronary sinus
Definition
carries blood from the myocardium to the right atrium, where the coronary veins join together
Term
coronary arteries
Definition
carry blood to the myocardium, originate at the base of the ascending aorta
Term
pulmonary trunk
Definition
pulmonary artery, leaves the right ventricle and carries blood to the lungs for gas exchange
Term
vasoconstriction
Definition
reduction in diameter of arterioles doe to constriction of smooth muscles in tunica media, increases after load
Term
vasodialation
Definition
increase in diameter of arterioles due to relaxation of smooth muscles in the tunica media, decreases after load
Term
in what ventral body cavity is the heart located?
Definition
thoracic cavity
Term
what is the function of the pericardium
Definition
forms the pericardial sac, filled with serous fluid which prevents friction during movement/contractions
Term
2 types of cell-cell connecting proteins that are found in intercalating disks? what characteristics does each contribute to cardiac muscle?
Definition
myosin and actin, myosin is the thin and tick filaments snad actin is just the thin filaments
Term
path of blood flow beginning with the right atria? left atria?
Definition
RA>tricuspid valve> RV> pulmonary semilunar valve> pulmonary artery/trunk> lungs> pulmonary veins> LA>bucuspid/mitral valve>LV>aortic semilunar valve>aorta>body> vena cava>RA
Term
parts of the heart involved in pulmonary circulation? systemic circulation?
Definition
RA, RV, pulmonary trunk
LA, LV, aorta
Term
what is the main role of the coronary arteries
Definition
to supply myocardium with blood
Term
what is an auricle, function?
Definition
protruding appendages of the atria, increase atrial volume
Term
what is the purpose of the LV having a thicker muscle wall? what else is different about the two ventricles? what is the same?
Definition
LV has a thicker muscle wall b/c requires more force to drive the blood all the way through the body out of the aorta,
the shape of the LV is circular and the RV is crescent shaped, less muscle is required to drive the blood to the lungs b/c shorter distance
Term
what causes heart sounds?
Definition
lub- AV valves closing
dup- SL valves closing
pause after a lub dub is the heart in relaxation,
murmur is valve abnormalities
Term
during the cardiac cycle, when are the AV valves closed? the SL valves?
Definition
1. ventricular filling (AV valve open, SL valves closed
2. atrial depolarization (Av valve open, SL closed)
3. ventricular systole (AV valves close, SL valves open during the ventricular ejection phase)
4. isovolumetric relaxation (SV valves close)
Term
what causes the different types of valves to close
Definition
pressure differenciations between the chambers of the heart, SL valves it is the slight backflow that catches the cusps forcing them closed, AV valves it is hydrostatic pressure pushing them closed
Term
what is the functional purpose of the chordae tendinae?
Definition
to keep valves from being blown out in the other direction
Term
how does blood flow (in terms of pressure)? what is the role of the heart?
Definition
controlled by changes in pressure, flows along the pressure gradient from higher to lower pressure if openings are available, pressure is dofferent between R and L,
Term
what is the purpose of the isovolumetric contraction and isovolumetric relaxation in the cardiac cycle?
Definition
iso relax, to get pressure in vent lower than in the atrium so that the ventricle fills
iso contr, beginning of getting the pressure greater in the ventricle than in the aorta, once pressure in ventricle exceeds than in the aorta SL opens
Term
name the parts of the cardiac conduction system in order of activation and know their location
Definition
SA node (embedded in wall of RA), internodal pathways (in the atria), AV node (junction btw atria and ventricles), AV bundle (Interventricular septum), Purkinje fibers (inferior side of the ventricles)
Term
where is the pacemaker in the heart
Definition
SA Node, embedded in the RA
Term
names and locations of different valves of the heart
Definition
AV valves tricuspid (right) and bicuspid/mitral (left)
SL valves pulmonary between RV and pulmonary artery, aortic between LV and aorta
Term
what would happen to the heart if the external sympathetic intervention was cut? parasympathetic innervation? Vagus nerve?
Definition
sympathetic ns speeds up HR, so oxygen debt would be created,
parasympathetic ns slows down the heart rate, so would not be able to recover after exercise
vagus HR would increase
Term
what is the difference between EDV and ESV?
Definition
EDV is max ventricle volume pre-ventricular contraction
ESV is leftovers after ventricular contraction
Term
what are typical values for HR, SV and CO? How are CO and SV calculated? what kind of physiological changes could change CO?
Definition
CO=HR x SV,
HR 75bpm, SV 70 ml/beat, CO 5.25 L/min
incr/decr HR, incr/decr blood volume, change BP
Term
what are preload, contractility, and after load? How do they alter SV? Give examples to support your answer or be ready to explain a situation Dr D gives.
Definition
preload- degree of stretch of heart muscle cells just before they contract
contractility- increase in contractile strength at cellular level, independent of muscle stretch and EDV)
afterload- pressure that must be overcome for the ventricles to eject blood from the heart, creating back pressure on SL valves
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