Anatomy PhysioEx Exercise 6,
Cardiovascular Physiology
What is an extrasystole? When can an extrasystole happen? - ANSAn extrasystole is an extra
ventricular contraction. It occurs during relaxation of the heart
When you increased the frequency of electrical stimulation, what happened to the amplitude of
the frog heart? - ANSThe amplitude remained the same despite the increase in frequency.
What is the difference between skeletal and cardiac refractory periods? - ANSSkeletal muscle
has a shorter absolute refractory period than cardiac muscle. (This is why cardiac muscle is
incapable of wave summation)
What is the period of time between the beginning of the cardiac action potential and
repolarization called? - ANSAbsolute refractory period
About how long does the total refractory period of cardiac muscle last? - ANS200-250
milliseconds
Vagus nerve - ANS10th cranial nerve; carries signals to the heart that decreases heart rate;
activated by the parasympathetic nervous system
What is vagal escape? - ANSVagal escape is when the ventricles begin to beat again after the
heart has stopped beating due to the excessive vagus nerve stimulation
What happens when the vagus nerve is stimulated? - ANSthe heart rate slows down and the
heart can eventually stop beating
What cluster of autorhythmic cardiac cells has the fastest rate of spontaneous depolarization
and is also called the heart's "pacemaker"? - ANSSA (sinoatrial) node
What was the importance of using Rhiger's solution on the frog heart? - ANSRhiger's solution
consists of essential electrolytes and is necessary for keeping the isolated frog's heart viable for
the experiment
What effect did decreasing the temperature of the Rhiger's solution have on the frog's heart? -
ANSDecreasing the temperature decreased the frog's heart rate
What effect did increasing the temperature of the Rhiger's solution have on the frog heart? -
ANSIncreasing the temperature increased the heart rate
Cardiovascular Physiology
What is an extrasystole? When can an extrasystole happen? - ANSAn extrasystole is an extra
ventricular contraction. It occurs during relaxation of the heart
When you increased the frequency of electrical stimulation, what happened to the amplitude of
the frog heart? - ANSThe amplitude remained the same despite the increase in frequency.
What is the difference between skeletal and cardiac refractory periods? - ANSSkeletal muscle
has a shorter absolute refractory period than cardiac muscle. (This is why cardiac muscle is
incapable of wave summation)
What is the period of time between the beginning of the cardiac action potential and
repolarization called? - ANSAbsolute refractory period
About how long does the total refractory period of cardiac muscle last? - ANS200-250
milliseconds
Vagus nerve - ANS10th cranial nerve; carries signals to the heart that decreases heart rate;
activated by the parasympathetic nervous system
What is vagal escape? - ANSVagal escape is when the ventricles begin to beat again after the
heart has stopped beating due to the excessive vagus nerve stimulation
What happens when the vagus nerve is stimulated? - ANSthe heart rate slows down and the
heart can eventually stop beating
What cluster of autorhythmic cardiac cells has the fastest rate of spontaneous depolarization
and is also called the heart's "pacemaker"? - ANSSA (sinoatrial) node
What was the importance of using Rhiger's solution on the frog heart? - ANSRhiger's solution
consists of essential electrolytes and is necessary for keeping the isolated frog's heart viable for
the experiment
What effect did decreasing the temperature of the Rhiger's solution have on the frog's heart? -
ANSDecreasing the temperature decreased the frog's heart rate
What effect did increasing the temperature of the Rhiger's solution have on the frog heart? -
ANSIncreasing the temperature increased the heart rate
