BPK 105 EXAM QUESTIONS
AND VERIFIED CORRECT
ANSWERS GRADED A+
LATEST 100% GUARANTEED
PASS
Skeletal muscles are voluntary muscles attached to bones via tendons
Cardiac muscles are involuntary muscles found along the heart wall.
cardiac muscle fiber action potential lasts longer bc of slow diffusion of Ca2+ into the cell
Cardiac muscle has a Depolarization phase followed by a period of slow repolarization called the
plateau phase. At the end of the plateau phase, a rapid repolarization phase
Similarities:
Actin and myosin myofilaments form sarcomeres, which are joined to form myofibrils,
responsible for muscle contraction and organization
striated (banded) appearance relies on Ca2+ and ATP for contraction
Use same ions, K Ca, Na opening and closing of membrane channels is responsible for the
changes in the permeability of the cell membrane that produce action potentials
,What are the major differences between the cardiac action potential and the skeletal muscle
action potential? What causes these differences, why is it important for how the heart
functions? - CORRECT ANSWER-DEPOLARIZATION:
Skeletal:
the only ions involved are Na+ and K+.
Cardiac:
Thee initial diffusing on Na+ in stimulates volatage-gated Ca2+ channels to open, and Ca2+
diffuses into the membrane, contributing to the overall depolarization
PLATEAU PHASE:
Skeletal muscle
No plateau phase
In cardaic muscle
Na channels close, some K+ channels open, starting a slow repolarization. However, because the
Ca2+ channels remain open, they function to slow the repolarization even further. This is what
makes the cardiac action potential so much longer than the skeletal muscle action potential
(500ms vs 2ms)
REPOLARIZATION
In skeletal muscle repolarization the Na+ channels close while K+ channels remain open until
repolarization is complete and membrane potential has returned to rest. cardiac repolarization
is similar, however since the Na+ channels have already closed, instead the Ca2+ channels close
and many more K+ channels open allowing the potassium to diffuse out (similar to skeletal)
until resting membrane potential is restored.
What is the role of the Sinoatrial (SA) node in the heart? Describe the conduction system of the
heart. How does this conduction system facilitate the smooth coordinated contraction of the
heart that is important for it to function as a pump? - CORRECT ANSWER-The sinoatrial node in
the upper wall of the right atrium functions as the heart's pacemaker, controlling the timing of
the muscle contractions using action potentials.
, It does this by sending action potentials across the atrial walls causing atrial contraction, and to
another area called the atrioventricular (AV) node.
The AV node then transfers the action potentials down the atrioventricular bundle; specialized
cardiac muscle that extends through the fibrous skeleton of the atrium and down through the
interventricular septum of the heart. When the AV bundle reaches the bottom of the septum it
is divided into two left and right bundle branches the carry the action potentials to the apex of
the left and right ventricles.
Finally, at the ends of the AV bundle branches, small bundles form by the conducting tissue
called Purkinje fibers, which carry the action potentials to the muscle of the ventricular walls
causing ventricular contraction. The ventricles rely heavily on the conduction system to be able
to produce coordinated contractions. One way it allows the heart to function as a pump is that
the SA node will not send a new action potential until the ventricles have completely relaxed
from the last one. This coordinated succession of action potentials ensures that the muscles
does not get overworked, and that nothing interferes with the pumping of blood inside the
muscle or outside in the body. A second way the heart maintains a reliable pumping mechanism
is that in the event that the SA node for some reason becomes unable to function then another
area of the heart, like the atrioventricular node, will become the new pacemaker.
After six months of training an individual has a lower resting heart rate than she did prior to
training when running at the same speed. Her cardiac output, however, is essentially the same.
What do you think accounts for this? Define cardiac output and its components in your answer.
Do you think her resting HR is different after training? Why? - CORRECT ANSWER-The cardiac
output is the volume of blood pumped by either ventricle in the heart each minute. exercise
increases the size of the heart, enabling an athlete to have a higher stroke volume and lower
heart rate when at rest. Non-athletes on the other hand, are likely to have a higher heart rate
and lower stroke volume. The difference in value between the athlete's low heart rate, and the
non-athlete's high heart rate is made up for in the difference in value between the athlete's high
stroke volume, and the non-athletes low stroke volume. This essentially means that an athlete's
resting cardiac output can be the same as a non-athlete's resting cardiac output.
Compare and contrast the structure and function of elastic arteries, muscular arteries and
capillaries. List the functions of the circulatory system that each type of vessel contributes to. -
CORRECT ANSWER-ELASTIC ARTERIES:
AND VERIFIED CORRECT
ANSWERS GRADED A+
LATEST 100% GUARANTEED
PASS
Skeletal muscles are voluntary muscles attached to bones via tendons
Cardiac muscles are involuntary muscles found along the heart wall.
cardiac muscle fiber action potential lasts longer bc of slow diffusion of Ca2+ into the cell
Cardiac muscle has a Depolarization phase followed by a period of slow repolarization called the
plateau phase. At the end of the plateau phase, a rapid repolarization phase
Similarities:
Actin and myosin myofilaments form sarcomeres, which are joined to form myofibrils,
responsible for muscle contraction and organization
striated (banded) appearance relies on Ca2+ and ATP for contraction
Use same ions, K Ca, Na opening and closing of membrane channels is responsible for the
changes in the permeability of the cell membrane that produce action potentials
,What are the major differences between the cardiac action potential and the skeletal muscle
action potential? What causes these differences, why is it important for how the heart
functions? - CORRECT ANSWER-DEPOLARIZATION:
Skeletal:
the only ions involved are Na+ and K+.
Cardiac:
Thee initial diffusing on Na+ in stimulates volatage-gated Ca2+ channels to open, and Ca2+
diffuses into the membrane, contributing to the overall depolarization
PLATEAU PHASE:
Skeletal muscle
No plateau phase
In cardaic muscle
Na channels close, some K+ channels open, starting a slow repolarization. However, because the
Ca2+ channels remain open, they function to slow the repolarization even further. This is what
makes the cardiac action potential so much longer than the skeletal muscle action potential
(500ms vs 2ms)
REPOLARIZATION
In skeletal muscle repolarization the Na+ channels close while K+ channels remain open until
repolarization is complete and membrane potential has returned to rest. cardiac repolarization
is similar, however since the Na+ channels have already closed, instead the Ca2+ channels close
and many more K+ channels open allowing the potassium to diffuse out (similar to skeletal)
until resting membrane potential is restored.
What is the role of the Sinoatrial (SA) node in the heart? Describe the conduction system of the
heart. How does this conduction system facilitate the smooth coordinated contraction of the
heart that is important for it to function as a pump? - CORRECT ANSWER-The sinoatrial node in
the upper wall of the right atrium functions as the heart's pacemaker, controlling the timing of
the muscle contractions using action potentials.
, It does this by sending action potentials across the atrial walls causing atrial contraction, and to
another area called the atrioventricular (AV) node.
The AV node then transfers the action potentials down the atrioventricular bundle; specialized
cardiac muscle that extends through the fibrous skeleton of the atrium and down through the
interventricular septum of the heart. When the AV bundle reaches the bottom of the septum it
is divided into two left and right bundle branches the carry the action potentials to the apex of
the left and right ventricles.
Finally, at the ends of the AV bundle branches, small bundles form by the conducting tissue
called Purkinje fibers, which carry the action potentials to the muscle of the ventricular walls
causing ventricular contraction. The ventricles rely heavily on the conduction system to be able
to produce coordinated contractions. One way it allows the heart to function as a pump is that
the SA node will not send a new action potential until the ventricles have completely relaxed
from the last one. This coordinated succession of action potentials ensures that the muscles
does not get overworked, and that nothing interferes with the pumping of blood inside the
muscle or outside in the body. A second way the heart maintains a reliable pumping mechanism
is that in the event that the SA node for some reason becomes unable to function then another
area of the heart, like the atrioventricular node, will become the new pacemaker.
After six months of training an individual has a lower resting heart rate than she did prior to
training when running at the same speed. Her cardiac output, however, is essentially the same.
What do you think accounts for this? Define cardiac output and its components in your answer.
Do you think her resting HR is different after training? Why? - CORRECT ANSWER-The cardiac
output is the volume of blood pumped by either ventricle in the heart each minute. exercise
increases the size of the heart, enabling an athlete to have a higher stroke volume and lower
heart rate when at rest. Non-athletes on the other hand, are likely to have a higher heart rate
and lower stroke volume. The difference in value between the athlete's low heart rate, and the
non-athlete's high heart rate is made up for in the difference in value between the athlete's high
stroke volume, and the non-athletes low stroke volume. This essentially means that an athlete's
resting cardiac output can be the same as a non-athlete's resting cardiac output.
Compare and contrast the structure and function of elastic arteries, muscular arteries and
capillaries. List the functions of the circulatory system that each type of vessel contributes to. -
CORRECT ANSWER-ELASTIC ARTERIES:
