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)
What is not affected by the inactivation of Na+ channels and why?
resting membrane potential because it mainly relies on K+ potential
What is mean arterial pressure?
driving pressure for blood flow
What causes vasovagal syncope?
sudden drop in BP
When you undergo vasovagal syncope, do blood vessels dilate/contract?
dilate (parasympathetic response)
When you undergo vasovagal syncope, does HR increase or decrease?
decrease (parasympathetic response)
What is tachycardia?
increased HR resulting in less time for ventricles to fill resulting in decreased CO (can cause fainting)
How do you calculate ejection fraction?
Stroke volume / EDV
What does a large pulse pressure mean?
heart is working hard
If contractility is increased what is the affect on EDV?
increase
If contractility is increased what is the affect on venous return?
increase
If contractility is increased what is the affect on stroke volume?
increase
If preload is increased what is the affect on blood ejection?
increase
If preload is increased what is the affect on stroke volume?
increase
If preload is increased what is the affect on venous return?
increase
If preload is increased what is the affect on EDV?
increase
If afterload is increased what is the affect on vlood pressure?
increase
If afterload is increased what is the affect on stroke volume?
decrease
If afterload is increased what is the affect on blood ejection?
decrease
If afterload is increased what is the affect on ESV?
increase
How do you calculate resistance?
1/radius^4
According to Frank-Starling mechanisms, venous return should = _______
cardiac output
In heart failure venous return does not equal ______
cardiac output
When blood pressure is high do baroreceptors fire more or less?
more
When blood pressure is high do baroreceptors increase or decrease sympathetic output?
decrease sympathetic
When blood pressure is high do baroreceptors increase or decrease HR?
decrease
When BP is low do baroreceptors increase or decrease sympathetic output?
increase
When blood pressure is low do baroreceptors increase or decrease HR?
increase
Why does cAMP increase HR?
promotes opening of more HCN channels = more Ca2+ influx = quicker depolarization = increased HR
When blood pressure is high at low pressure baroreceptors, is heart rate increased or decreased?
HR increased to increase CO = increased renal profusion = H2O and Na+ excretion = lower blood volume
How does aldosterone increase the blood pressure?
promotes creation of more Na+ channels to increase Na+ and water reabsorption = increased blood volume
What is used to treat an over active RAS system?
ACE inhibitor
Why is Ca2+ pumped in SR?
when next AP comes there is a storage on Ca2= to be release for a better contraction
When blood pressure decreases does vasoconstriction or dilation occur?
constriction (increased sympathetic)
If blood pressure is low for multiple days what sets in?
RAS
What is the purpose of ADH?
to reabsorb H2O and urinate less
Does ADH increase when you are dehydrated or hydrated?
dehydrated (uptakes water)
Low O2 levels causes increased or decreased sympathetic output?
increased sympathetic
Why does arteriole pressure = TPR?
arterioles are the main resistance vessel
What are proprioreceptors?
sense movement in muscles to increase HR
Does increased lactic acid cause vasodilation or constriction?
vasodilation
What are 2 examples of local regulation/autoregulation?
active hyperemia
reactive hyperemia
Why do arteries have more elastic recoil than veins?
veins are low pressure while arteries are high pressure
Does increased CO2 cause vasodilation on constriction?
dilation
does increased K+ cause vasodilation or constriction?
dilation
Does Digoxin increase or decrease the intracellular Ca2+ levels?
increase (stronger contractions)
Does Digoxin increase or decrease the intracellular Na+ levels?
increase to stop influx and increase Ca+ influx
Decreased CO2 in blood causes increased or decrease cerebral BF?
decreased (hyperventilation)
Decreased pH causes increased or decreased cerebral BF?
increased
Low baroreceptors sense stretching where?
right atrium
If a fluid is not moving, the pressure that it exerts is called ____________ pressure.
hydrostatic
Each of the following changes will result in increased blood flow to a tissue EXCEPT one. Identify the exception.
A) increased blood volume
B) decreased vessel diameter
C) increased blood pressure
D) decreased peripheral resistance
E) relaxation of precapillary sphincters
B) decreased vessel diameter
increased size = decreased flow (less pressure)
Which parameters are associated with increased resistance?
A) reduced flow
B) reduced friction
C) increased blood vessel diameter
D) decreased viscosity
E) decreased length
A) reduced flow
When a quantity is expressed as “4 cm/sec,” what is being described is the
A) flow rate.
B) velocity of flow.
C) pressure.
D) pressure gradient.
E) volume.
B) velocity of flow.
At an intercalated disc,
A) the cell membranes of two cardiac muscle fibers are completely separated by a synapse.
B) the myofibrils are loosely attached to the membrane of the disc.
C) two cardiac muscle cells are connected by gap junctions.
D) t-tubules unite the membranes of the adjoining cells.
C) two cardiac muscle cells are connected by gap junctions.
The term myogenic indicates that the heart muscle is the source of
A) the contractile force for pumping.
B) a hormone that indirectly regulates blood volume.
C) the electrical signal that triggers heart contraction.
D) receptors that trigger blood pressure reflexes.
E) stem cells that repair damaged heart tissue.
A) the contractile force for pumping.
The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of ________ K+ permeability and ________ Ca2+ permeability.
A) increasing, increasing
B) decreasing, decreasing
C) increasing, decreasing
D) decreasing, increasing
A) increasing, increasing
Myocardial cells can generate action potentials spontaneously because they have
A) unstable ion channels.
B) permanently open channels for Na+ and K+.
C) a net influx of Na+.
D) L-type Ca2+ channels.
E) prolonged Ca2+ influx.
A) unstable ion channels.
The medical term for heart attack is
A) heart failure.
B) myocardial infarction.
C) heart murmur.
D) fibrillation.
E) heart block.
B) myocardial infarction.
In order for blood to enter the heart,
A) the atria must be in diastole.
B) the pressure in the atria must be lower than in the veins.
C) the AV valves must be open.
D) the atria must not only be at rest but the atrial pressure must be lower than the veins.
D) the atria must not only be at rest but the atrial pressure must be lower than the veins.
Which of the following events result in the first heart sound?
A) The AV valves open.
B) The AV valves close.
C) The semilunar valves close.
D) The semilunar valves open.
E) The atria contract.
B) The AV valves close.
During the cardiac cycle,
A) the P wave of the ECG occurs between the first and second heart sounds.
B) the QRS complex of the ECG precedes the increase in ventricular pressure.
C) the third heart sound occurs during atrial systole.
D) the second heart sound coincides with the QRS complex of the ECG.
E) the greatest increase in ventricular pressure occurs during the ejection phase.
B) the QRS complex of the ECG precedes the increase in ventricular pressure.
What side is the mitral valve on?
left
What side is the tricuspid valve on?
right
What wave/complex is immediately followed by ventricular contraction?
QRS complex
What wave/segment represents atrial contraction?
P wave
What is the amount of blood pumped out of the heart during one contraction called?
cardiac output
Which statement is NOT true regarding cardiac muscle?
A) Cardiac muscle cells must obey the all-or-none law of contraction.
B) Cardiac muscle cells rely on a sarcoplasmic reticulum for storage of Ca2+ ions.
C) Calcium-induced calcium release is the process by which extracellular Ca2+ triggers the release of stored Ca2+ from the sarcoplasmic reticulum.
D) Intercalated disks contain both desmosomes for firm attachment and gap junctions to allow communication.
E) The oxygen demand of cardiac muscle cells is high because they have many mitochondria.
E) The oxygen demand of cardiac muscle cells is high because they have many mitochondria.
If the membranes of the cardiac muscle cells in the SA node become more permeable to potassium ions,
A) the heart rate will increase.
B) the heart rate will decrease.
C) the membrane will depolarize.
D) the stroke volume will increase.
E) the intracellular concentration of calcium ion will increase.
B) the heart rate will decrease.
- hyperpolarizing the membrane and slowing the rate of spontaneous depolarizations
