APEX Cardiovascular A&P Question
and answers correctly solved
2026/2027
What is the ability to spontaneously generate an action potential? - correct answer Auto maticity
Name 3 ways that cardiac myocytes differ from Skeletal muscle cells. - correct answer tight junctions
serve as low resistance pathways to help spread cardiac action potential, tight junctions are also called
gap junctions or nexi, &
they have more mitochondria than skeletal muscles
What is the ability to respond to an electrical stimulus by depolarizing and firing an action potential -
correct answer Excitability
The ability of an ion to cross across a membrane is called what? - correct answer Conductance
What can predict an equilibrium potential? - correct answer Nerst equation
When there is no concentration gradient, and the charges on the outside of the cell balance the inside,
what is this called? - correct answer Equilibrium
What is the Nerst Equation? - correct answer E Ion= 61.5log [ion] inside/[ion] outside
Name the equilibrium potentials for potassium, sodium, calcium, chloride, & calcium - correct answer
potassium:-93
sodium: +60
chloride-: -97
,calcium: +132
Resting Membrane Potential is established by what 3 mechanisms? - correct answer Chemical force,
Electrostatic counter force, &
Sodium/Potassium A.T.P.ase aka sodium/potassium pump
The internal voltage at which a cell depolarizes is called what? - correct answer Threshold potential
The restoration of membrane potential toward a resting membrane potential after depolarization is
called? - correct answer Ree polarization
Why is potassium the primary determinant of Resting Membrane Potential? - correct answer Leaky
channels are constantly leaking potassium out of the cell as it's the only ion that is permeable to the
membrane
Explain the effect of hyper kalemia and hypo kalemia on Resting Membrane Potential? - correct answer
Hype rkalemia: Resting Membrane Potential more positive= making Depolarization more easy. Resting
membrane potential Closer to threshold potential.
Hypokalemia: Resting membrane potential less positive= Depolaization more difficult or Resting
membrane potential further from threshold potential.
Which ion depolarizes the cell? - correct answer Sodium
For every ____ sodium ions leaving the cell,____ potassium ions returns into the cell. - correct answer 3
sodium
2 potassium
, What type of mechanism/pump is the sodium/potassium A.T.P.ase - correct answer Active transport-
requires ATP
Why is there a prolonged plateau phase in ventricular muscle contraction? What phase number is this? -
correct answer To allow myocyte time to contract so the heart can eject its stroke volume.
Phase 2
Name the following for Phase 0 of the ventricular action potential.
Ion movement
Transport
Voltage
Name of phase
ECG correlation - correct answer Ion: sodium in. Fast.
Transport: Sodium voltage gated ion channels opening.
Voltage: -70 Threshold potential.
Phase: 0-Upstroke.
ECG: P wave.
Name the following for Phase 1 of the ventricular action potential.
Ion movement
Transport
Voltage
Name of phase
ECG correlation - correct answer Ion: potassium out, Chloride in.........
Transport: potassium and Chloride channels open.
sodium Channels in activate.
and answers correctly solved
2026/2027
What is the ability to spontaneously generate an action potential? - correct answer Auto maticity
Name 3 ways that cardiac myocytes differ from Skeletal muscle cells. - correct answer tight junctions
serve as low resistance pathways to help spread cardiac action potential, tight junctions are also called
gap junctions or nexi, &
they have more mitochondria than skeletal muscles
What is the ability to respond to an electrical stimulus by depolarizing and firing an action potential -
correct answer Excitability
The ability of an ion to cross across a membrane is called what? - correct answer Conductance
What can predict an equilibrium potential? - correct answer Nerst equation
When there is no concentration gradient, and the charges on the outside of the cell balance the inside,
what is this called? - correct answer Equilibrium
What is the Nerst Equation? - correct answer E Ion= 61.5log [ion] inside/[ion] outside
Name the equilibrium potentials for potassium, sodium, calcium, chloride, & calcium - correct answer
potassium:-93
sodium: +60
chloride-: -97
,calcium: +132
Resting Membrane Potential is established by what 3 mechanisms? - correct answer Chemical force,
Electrostatic counter force, &
Sodium/Potassium A.T.P.ase aka sodium/potassium pump
The internal voltage at which a cell depolarizes is called what? - correct answer Threshold potential
The restoration of membrane potential toward a resting membrane potential after depolarization is
called? - correct answer Ree polarization
Why is potassium the primary determinant of Resting Membrane Potential? - correct answer Leaky
channels are constantly leaking potassium out of the cell as it's the only ion that is permeable to the
membrane
Explain the effect of hyper kalemia and hypo kalemia on Resting Membrane Potential? - correct answer
Hype rkalemia: Resting Membrane Potential more positive= making Depolarization more easy. Resting
membrane potential Closer to threshold potential.
Hypokalemia: Resting membrane potential less positive= Depolaization more difficult or Resting
membrane potential further from threshold potential.
Which ion depolarizes the cell? - correct answer Sodium
For every ____ sodium ions leaving the cell,____ potassium ions returns into the cell. - correct answer 3
sodium
2 potassium
, What type of mechanism/pump is the sodium/potassium A.T.P.ase - correct answer Active transport-
requires ATP
Why is there a prolonged plateau phase in ventricular muscle contraction? What phase number is this? -
correct answer To allow myocyte time to contract so the heart can eject its stroke volume.
Phase 2
Name the following for Phase 0 of the ventricular action potential.
Ion movement
Transport
Voltage
Name of phase
ECG correlation - correct answer Ion: sodium in. Fast.
Transport: Sodium voltage gated ion channels opening.
Voltage: -70 Threshold potential.
Phase: 0-Upstroke.
ECG: P wave.
Name the following for Phase 1 of the ventricular action potential.
Ion movement
Transport
Voltage
Name of phase
ECG correlation - correct answer Ion: potassium out, Chloride in.........
Transport: potassium and Chloride channels open.
sodium Channels in activate.
