MT #1 Cardiovascular + Physiology of the Heart Flashcards
(254 cards)
What determines the contractility?
a. isotonic tension
b. isometric tension
c. maximum isometric tension, maximum contraction speed
d. contraction speed
c. maximum isometric tension, maximum contraction speed
What influences the efficiency of the working fibers in the heart?
a. parasympathetic stimulation
b. sympathetic inhibition
c. direct electrical stimulation
d. sympathetic stimulation
d. sympathetic stimulation
How does the cardiac output change during the direct stimulation of the heart?
a. the C.O. doesn`t change
b. the C.O. decreases slightly
c. the C.O. increases significantly
d. the C.O. decreases significantly
a. the C.O. doesn`t change
How does the cardiac output change if we stimulate the heart through its sympathetic nerve?
a. the C.O. decreases continously
b. the C.O. increases continously
c. the C.O. doesn`t change
d. the C.O. increases slightly
b. the C.O. increases continously
How does the systole/diastole rate change with direct stimulation of the heart?
a. systole and diastole decrease
b. systole increases, dyastole decreases
c. systole doesn`t change, dyastole decreases
d. systole decreases, dyastole increases
c. systole doesn`t change, dyastole decreases
How does the systole/diastole ratio change if we stimulate the heart through its sympathetic nerve?
a. it increases
b. it decreases
c. it increases the muscle force only
d. the ratio doesn`t change too much
d. the ratio doesn`t change too much
How can we measure the cardiac output?
a. on the basis of the Ficks-principle
b. on the basis of the Van`t Hoff law
c. on the basis of the Laplace law
d. on the basis of Henderson-Hasselbalch equation
a. on the basis of the Ficks-principle
What formula can be used to calculate the cardiac output?
a. C.O.=QtO2x(CaO2-CvO2)
b. C.O.=QtO2/(CaO2-CvO2)
c. C.O.=QtO2/(CvO2-CaO2)
d. C.O.=QtO2/(CaO2xCvO2)
b. C.O.=QtO2/(CaO2-CvO2)
Can we apply the Stewart-principle for the determination of the cardiac output?
a. yes, because we measure the volume
b. yes, when we inject tritiated water
c. yes, but modified, instead of volume we measure volume flow
d. no
c. yes, but modified, instead of volume we measure volume flow
What efficiency does the heart have?
a. 80%
b. 30-40%
c. 4%
d. 10-20%
d. 10-20%
What is the external work of the heart?
a. The product of systolic volume and the mean arterial pressure
b. The quotient of pulse pressure and the circulatory mid-pressure
c. The product of cardiac output and the arterial mid-pressure
d. the difference of the pressure-work and the kinetic-work
a. The product of systolic volume and the mean arterial pressure
What can we show with the help of the Rushmer-diagram?
a. the ratio of external and internal work
b. the ratio of the active and passive component of the external work of the heart
c. the difference between the external and internal work of the heart
d. the efficiency of the work of the heart
b. the ratio of the active and passive component of the external work of the heart
What does the passive work of the heart derive from?
a. from the tension during the isovolumetric contraction
b. from the isovolumetric relaxation
c. from the energy stored in the elastic components
d. from the tension of the aortic wall
c. from the energy stored in the elastic components
How do the pressure and volume of the left ventricle change during the fast ejection phase of systole?
a. the pressure does not change, the volume decreases significantly
b. the pressure drops, the volume decreases
c. the pressure increases, the volume does not change
d. the pressure increases, the volume decreases
d. the pressure increases, the volume decreases
How does the efficiency of the heart change with increasing ventricular volume?
a. It decreases
b. It increases
c. It does not change
d. It decreases, since the oxygen consumption is less
a. It decreases
What happens when we stimulate the heart muscle to the threshold potential?
a. Cl and Ca influx
b. K outflow, Na inflow
c. Na influx
d. Ca and Na influx
c. Na influx
What happens at a potential of +25 mV?
a. Na inflow stops, K inflow, Cl outflow
b. Ca inflow, Na outflow
c. Na inflow continues, K outflow stops
d. Na inflow stops; Cl inflow begins
d. Na inflow stops; Cl inflow begins
What influx happens during the plateau-phase of the heart muscle’s AP?
a. slow Ca inflow, slow K outflow
b. quick Ca inflow, slow K outflow
c. slow Ca outflow, quick K inflow
d. quick Na inflow, slow Ca inflow
a. slow Ca inflow, slow K outflow
What is going on in the phase leading to the total repolarization of the heart muscle?
a. slow Ca inflow, slow K outflow
b. rapid K outflow, Ca inflow stops
c. Ca inflow, slow K outflow
d. Na inflow, slow Ca inflow
b. rapid K outflow, Ca inflow stops
How does the potassium conductance change during phase 3 of the AP of the working fibers of the heart?
a. it decreases
b. it does not change
c. it increases
d. its change is parallel to the sodium conductance
c. it increases
Which ion flux causes the plateau phase in the AP of the heart muscle?
a. potassium
b. chloride
c. sodium
d. mainly calcium
d. mainly calcium
How does the sodium conductance change in phase 1 of the AP of the working fibers of the heart?
a. it ceases suddenly
b. it increases
c. it decreases continously
d. it does not change
a. it ceases suddenly
What is the most important difference between the action potential of the heart muscle and that of the skeletal muscle?
a. the AP of the heart muscle is shorter
b. the AP of the skeletal muscle has no plateau phase
c. the contraction of the heart muscle starts after the AP
d. the AP of the skeletal muscle overlaps its mechanogram
b. the AP of the skeletal muscle has no plateau phase
What answer is produced when the stimulus is given during the absolute refractory phase?
a. a new AP is generated
b. a new AP is produced when the stimulus is strong enough
c. no AP can be produced
d. AP is generated about 300 msecs later
c. no AP can be produced