Exam 2 Flashcards
What is Digoxin?
drug used to treat heart failure by increasing the ability of contraction
What channel/pump does Digoxin inhibit and whats the result?
Na/K ATPase resulting in an increase in intracellular Na+
What channel/pump does Digoxin increase activity of and what’s the result?
NCX channel (Na/Ca channel) resulting in an increase in intracellular Ca2+
Digoxin increases intracellular Ca+ and Na+, what is the affect of this?
increased muscles tension/contractivity
Digoxin is a _________ inotropic
positive
What is a positive inotropic?
increases the ability of cardiac muscles to lengthen to increase contractility
When PLN is bound the SERCA2, does it inactive or active the pump?
inactivate
When PLN becomes phosphorylated/dephosphorylated by PKA it stops blocking SERCA2 activity
phosphorylated
What phosphorylates PLN so it stops inhibiting SERCA2?
PKA
What 2 ways can you calculate MAP?
MAP = DP + PP/3
MAP = CO x TPR
How can you calculate TPR?
TPR = MAP/CO
What does the PV loop look like when preload is increased?
right side expands (increased EDV)
What does a PV loop look like when afterload is increased?
gets taller (increased pressure) and ESV increases
What does a PV loop look like when contractility is increased?
increased pressure and decreased ESV
If a baroreceptors senses stretch it will __________ the membrane potential at the receptors
depolarize
If a baroreceptor senses stretch it will increase/decrease firing of nerves
increase
What is the goal of the baroreceptors if it senses stretch?
decrease CO to decrease pressure
When baroreceptors in the carotid/aortic artery sense stretch, what is the affect on sympathetic and parasympathetic output?
sympathetic DECREASES
parasympathetic INCREASES
When baroreceptors in the carotid/aortic artery sense stretch, is epinephrine released of acetyl choline?
acetyl choline (increased parasympathetic response)
When baroreceptors in the carotid/aortic artery sense stretch, will vessels vasodialte or vasocontrict?
vasodilate
When baroreceptors in the carotid/aortic artery sense stretch, is peripheral resistance going to be increased or decreased?
decreased
When baroreceptors in the carotid/aortic artery sense stretch, is the force of contraction going to increase or decrease?
decrease
When baroreceptors in the carotid/aortic artery sense stretch, will heart rate increase or decrease?
decrease
When baroreceptors in the carotid/aortic artery sense stretch, will cardiac output increase or decrease?
decrease
When baroreceptors in the carotid/aortic artery sense low pressure, what is the affect on sympathetic and parasympathetic output?
sympathetic INCREASE
parasympathetic DECREASE
When baroreceptors in the carotid/aortic artery sense low pressure, will heart rate increase or decrease?
increase
When baroreceptors in the carotid/aortic artery sense low pressure, will contractility increase or decrease?
increase
When baroreceptors in the carotid/aortic artery sense low pressure, will cardiac output increase or decrease?
increase
When baroreceptors in the carotid/aortic artery sense low pressure, will vessels vasoconstrict or vasodilate?
vasoconstriction
When baroreceptors in the carotid/aortic artery sense low pressure, will total peripheral resistance increase or decrease?
increase
When baroreceptors in the right atrium artery sense low pressure, will more or less aldosterone be released?
more
When baroreceptors in the right atrium artery sense low pressure, will Na+ reabsorption increase or decrease?
increase
When baroreceptors in the right atrium artery sense low pressure, will fluid absorption in capillaries increase or decrease?
increase
Why does the SA node action potential have an unable resting membrane potential?
HCN channels allow slow influx of Na+ causing a gradual increase in depolarization
HCN channels are sensitive to what 2 things?
- cAMP
- hyperpolarization
What are the steps of the SA node action potential?
- HCN funny current (slow influx of Na+)
- threshold is reached and Ca2+ enters cell
- Ca2+ channels close at peak and K+ channels open
- K+ leaves cell
- K+ channel closes and HCN channels begin to open again
Does cAMP increase or decrease HR?
increase
Does acetyl choline increase or decrease HR?
decrease
What are the steps to atrial/ventricle action potential?
- Na+ channels open (Na+ enters)
- at peak Na+ channels close and K+ channels opens
- K+ flows in briefly
- Ca2+ channels open “plateau phase”
- Ca2+ channels close and K+ channels dominate again
- K+ channels close
_________ have smooth muscle and elastic tissue
arteries
_________ have smooth muscles but NO elastic tissue
arterioles
What node in the heart is the slowest and why?
AV node
allows ventricles to fill
Depolarization = contraction/relaxation
contraction
How do you calculate flow rate?
FR = velocity x area
If you were to increase the [K+] outside the cell what would happen to the membrane potential?
more positive membrane potential (increasing membrane potential)