Karius

Question 1

what are the two roles of prostacycline (aka PGI2) play in hemostasis

Answer 1

vasodilation

inhibition of platelets

Question 2

what two chemicals promote vasoconstriction and hemostasis

Answer 2

thromboxane A2 and serotonin

which comes from the vesicles inside the platelets

Question 3

what enzyme is required for production of thromboxane A2

Answer 3

COX1

Question 4

a patient is suffering from a bleeding disoder in which they bleed excessively because their platelets are unable to bind collagen, what factor is likely missing

Answer 4

vonwillebrond

provides the initial link between collagen and platelets

Question 5

what is required to activate protein C

Answer 5

thrombin binding thrombomodulin found on endothelial cell

Question 6

what would a person missing protein C have problems with

Answer 6

problem with breaking down clots because protein C inactivates factors VII and V

Question 7

what causes the dicrotic notch in the aortic pressure wave

Answer 7

aortic valve closure at the start of isovolumetric ventricular relaxation

Question 8

what occurs at the same time as isovolumetric contraction

Answer 8

mitral valve closure and first heart sound

Question 9

what event coincides with the second heart sound

Answer 9

aortic valve closure

Question 10

a left ventricle that is not very compliant will result in what heart sound

Answer 10

third or fourth

Question 11

a patient has an arterial blood pressure of 139/92

at what pressure does the aortic valve open

Answer 11

92 - has to exceed the diastolic

Question 12

why does atrial pressure increase during ventricular contraction

Answer 12

because both AV valve are closed but blood is returning from veins

Question 13

what causes the c wave in the venous pressure curve

Answer 13

isovolumetric contraction because the QRS complex occurs before (excitation precedes contraction)

Question 14

a cardiac muscle cell located in the septum of the heart where its phase 0 occurred at the very start of the QRS complex. where in the T wave does this cell repolarize

Answer 14

at the very end of the T wave

the first to depolarize is the last to repolarize

Question 15

why is it important that the first to depolarize is the last to repolarize

Answer 15

by keeping the first to depolarize refractory to the very end, we are less likely to experience a circus rhythm
which is a flutter or fibrillation

Question 16

what is the difference between AP of the first to depolarize vs the last to depolarize

Answer 16

the plataeu phase of the first to depolarize will be longer

a cell that depolarizes early will have along plateau while a cell that depolarizes late will have a short p

Question 17

under what conditions is hearing S3 normal?

Answer 17

kids, pregnant women (maybe) athletes with a thin body wall