chapter 21 physiology, muscle blood flow and cardiac output during exercise; coronary circulation and ischemic heart disease Flashcards Preview

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Flashcards in chapter 21 physiology, muscle blood flow and cardiac output during exercise; coronary circulation and ischemic heart disease Deck (45)
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31

common causes of death after acute coronary occlusion

decreaed cardiac output, dammin of blood in pulmonary blood vessels and then death resulting from pulmonary edema, fibrillation of the heart, rupture of heart

32

what is systolic stretch

when normal portions of ventricular muscle contract, the ischemic portion of the muscle is forced outward which dissipates much of the pumping force

33

whats happening to the heart during coronary shock/cardiac shock

heat becomes incapable of contracting with sufficient force to pump enough blood into the peripheral arterial tree

34

what is low cardiac output failure

more than 40% of left ventricle is infacted

35

name 1 factor that leads the heart to fibrillate in regards to blood supply

loss of blood supply to the cardiac muscle causes rapid depletion of potassium from ischemic musculature. This increases the potassium level of the extracellular fluid which causes fibrillation

36

name 1 factor that leads the heart to fibrillate in regards to polarization

ischemic musculature often cannot completely replarize its membranes after a heartbeat

37

name 1 factor that leads the heart to fibrillate in regards to sympathetic stimulation

powerful sympathetic reflexes often develop after massive infarction

38

name 1 factor that leads the heart to fibrillate in regards to the conduction pathway

cardiac muscled that is infected dilates and causes the condution pathway to increase which predisposes the deveopment of circus movements and fibrillation

39

cardiac tamponade

compression of the heart from the outside of by blood collecting in the pericardial cavity

40

replacement of dead muscle by scar tissue

fibrous tissue develops among the dead fibers because ischemia stimulates fibroblasts. Then the normal areas of the heart gradually hypertrophy to try and compensate for the tissue loss

41

coronary steal syndrome

with an excessively active heart the vessels dilate which allows most of the blood in the coronary vessels to flow through the normal muscle tissue. This leaves little blood in the coronary vessels to flow through the small anastomotic channels into the ischemic area so the ischemic condition worsens

42

angina pectoris

pain associated with contriction of coronary arteries. Usually below upper sternum over the heart, left arm and left shoulder, neck, side of face

43

what else is associated with angina?

cold temperatures, full stomach, increase of workload of heart

44

common drugs for vasodilation

nitroglycerin, nitrate

45

what do beta blockers do?

block sympathetic beta-adregenic receptors which prevent sympathetic enhancement of heart rate and cardiac metabolism during exercise or emotional episodes