BIO 392 Cardiovascular And Respiratory | 59 Questions
And Answers | Latest Updates
How would alpha blockers (drugs that block alpha- and beta-adrenergic receptors) affect blood pressure? ANS
- Decrease TPR
- Decrease stroke volume
- Decrease heart rate
Contractile cardiac myocyte action potentials start with a sodium spike, a rapid depolarization caused by the
regenerative opening of V-gated Na channels. As in the axon, these channels rapidly inactive and at about the
same time, V-gated K channels activate, beginning a rapid depolarization. However, very quickly other (and
vastly more) K channels _________ and ___________
channels open, with the net effect that the membrane potential enters a plateau phase of depolarization.
Some of the _______ (cation) entering during this plateau depolarization will bind to troponin. Some will
cause more of the same ion to be released from the __________ by activating ____________.
Eventually the K channels (in first blank open or close), the channels from (second blank) close and the
contractile myocyte repolarizes. Just like skeletal muscle, contraction is slowed and stopped when intracellular
levels of ion (in third blank) are ANS First blank: Close
Second blank: L-Type Ca Channels
Third blank: Calcium
Fourth blank: Sarcoplasmic Reticulum (SR)
Fifth blank: Ryanodine Receptors
Sixth blank: Active transport of Ca into the SR.
What is the role of valves in the heart? ANS Preventing backflow
Zeke has a resting heart rate of 68 bpm. During exercise, Zeke's heart rate rises to 176 bpm. At rest, his left
ventricle has an end diastolic volume of 120 mL and ejects 72 mL of blood with each systolic contraction.
During exercise, his left ventricle has an end-diastolic volume of 150 mL and ejects 115 mL with each systolic
contraction. What is Zeke's ejection fraction during exercise? ANS Ejection fraction = 76.67%
EF (exercise) = SV/EDV * 100
EF (exercise) = 115 mL/150 mL * 100
- Stroke volume (exercise) = end-diastolic volume (exercise) - end-systolic volume (exercise)
SV (exercise) = 150 mL - 35 mL = 115 mL
, A drug like atropine would block muscarinic acetylcholine receptors on the SA node pacemaker cells. As a
result, cAMP levels in the pacemakers would (increase or decrease) ________. The ability of V-gated Ca
channels to conduct Ca would (increase or decrease) ________, and the heart rate would (increase or decrease)
_______. ANS First blank: increase
Second blank: increase
Third blank: increase
Zeke has a resting heart rate of 68 bpm. During exercise, Zeke's heart rate rises to 176 bpm. At rest, his left
ventricle has an end diastolic volume of 120 mL and ejects 72 mL of blood with each systolic contraction.
During exercise, his left ventricle has an end-diastolic volume of 150 mL and ejects 115 mL with each systolic
contraction. What is Zeke's resting cardiac output? Calculate and input your answers in mL/min. ANS CO
(rest) = 4896 mL/min
CO = heart rate (HR) * stroke volume (SV)
End-systolic volume (rest) = end-diastolic volume (rest) - stroke volume (rest)
End-systolic volume (rest) = 120 mL - 72 mL = 48 mL
CO (rest) = 68 bpm * 72 mL
You know that during systole the ventricles eject blood in the arteries. To do so they have to overcome the
pressure in the arteries, starting with the diastolic pressure remaining at the end of diastole. How would
increased diastolic pressure potentially affect Cardiac Output? ANS - The heart would have to work harder
(contract more forcefully) to achieve the same ejection observed with lower diastolic pressure.
- Stroke volume may decrease (if the heart cannot sufficiently compensate).
What is the main reasons that physiologists consider the long plateau depolarization and long refractory period
of the ventricular myocytes important? ANS It helps prevent summation/tetanic summation of ventricular
contraction.
You have a chainsaw accident and start bleeding profusely. Before you can tie a tourniquet you lose 20% of
your blood. While you are hemorrhaging....
a) Your heart rate will _________
b) Your venous tone will ________
c) Your ventricular contractility will _________.
d) Parasympathetic input to the heart will ________.
e) Sympathetic input to the heart will ______
f) TPR will _______ due to net ___(g)____ of arterioles throughout the body. ANS a) increase
And Answers | Latest Updates
How would alpha blockers (drugs that block alpha- and beta-adrenergic receptors) affect blood pressure? ANS
- Decrease TPR
- Decrease stroke volume
- Decrease heart rate
Contractile cardiac myocyte action potentials start with a sodium spike, a rapid depolarization caused by the
regenerative opening of V-gated Na channels. As in the axon, these channels rapidly inactive and at about the
same time, V-gated K channels activate, beginning a rapid depolarization. However, very quickly other (and
vastly more) K channels _________ and ___________
channels open, with the net effect that the membrane potential enters a plateau phase of depolarization.
Some of the _______ (cation) entering during this plateau depolarization will bind to troponin. Some will
cause more of the same ion to be released from the __________ by activating ____________.
Eventually the K channels (in first blank open or close), the channels from (second blank) close and the
contractile myocyte repolarizes. Just like skeletal muscle, contraction is slowed and stopped when intracellular
levels of ion (in third blank) are ANS First blank: Close
Second blank: L-Type Ca Channels
Third blank: Calcium
Fourth blank: Sarcoplasmic Reticulum (SR)
Fifth blank: Ryanodine Receptors
Sixth blank: Active transport of Ca into the SR.
What is the role of valves in the heart? ANS Preventing backflow
Zeke has a resting heart rate of 68 bpm. During exercise, Zeke's heart rate rises to 176 bpm. At rest, his left
ventricle has an end diastolic volume of 120 mL and ejects 72 mL of blood with each systolic contraction.
During exercise, his left ventricle has an end-diastolic volume of 150 mL and ejects 115 mL with each systolic
contraction. What is Zeke's ejection fraction during exercise? ANS Ejection fraction = 76.67%
EF (exercise) = SV/EDV * 100
EF (exercise) = 115 mL/150 mL * 100
- Stroke volume (exercise) = end-diastolic volume (exercise) - end-systolic volume (exercise)
SV (exercise) = 150 mL - 35 mL = 115 mL
, A drug like atropine would block muscarinic acetylcholine receptors on the SA node pacemaker cells. As a
result, cAMP levels in the pacemakers would (increase or decrease) ________. The ability of V-gated Ca
channels to conduct Ca would (increase or decrease) ________, and the heart rate would (increase or decrease)
_______. ANS First blank: increase
Second blank: increase
Third blank: increase
Zeke has a resting heart rate of 68 bpm. During exercise, Zeke's heart rate rises to 176 bpm. At rest, his left
ventricle has an end diastolic volume of 120 mL and ejects 72 mL of blood with each systolic contraction.
During exercise, his left ventricle has an end-diastolic volume of 150 mL and ejects 115 mL with each systolic
contraction. What is Zeke's resting cardiac output? Calculate and input your answers in mL/min. ANS CO
(rest) = 4896 mL/min
CO = heart rate (HR) * stroke volume (SV)
End-systolic volume (rest) = end-diastolic volume (rest) - stroke volume (rest)
End-systolic volume (rest) = 120 mL - 72 mL = 48 mL
CO (rest) = 68 bpm * 72 mL
You know that during systole the ventricles eject blood in the arteries. To do so they have to overcome the
pressure in the arteries, starting with the diastolic pressure remaining at the end of diastole. How would
increased diastolic pressure potentially affect Cardiac Output? ANS - The heart would have to work harder
(contract more forcefully) to achieve the same ejection observed with lower diastolic pressure.
- Stroke volume may decrease (if the heart cannot sufficiently compensate).
What is the main reasons that physiologists consider the long plateau depolarization and long refractory period
of the ventricular myocytes important? ANS It helps prevent summation/tetanic summation of ventricular
contraction.
You have a chainsaw accident and start bleeding profusely. Before you can tie a tourniquet you lose 20% of
your blood. While you are hemorrhaging....
a) Your heart rate will _________
b) Your venous tone will ________
c) Your ventricular contractility will _________.
d) Parasympathetic input to the heart will ________.
e) Sympathetic input to the heart will ______
f) TPR will _______ due to net ___(g)____ of arterioles throughout the body. ANS a) increase
