EXAM 3 NURS 5315 UTA CARDIAC AND
PULMONARY COMPLETE STUDY GUIDE WITH
SOLVED QUESTIONS
◉ Depolarization.
Answer: movement of the intracellular charge towards zero (more
positive charge)
Voltage gated Na channels open and allow Na to enter the cell ->
voltage inside the cell moves towards zero
◉ Repolarization.
Answer: Once the intracellular charge reaches zero, the negative
polarity of the inside of the cell is restored back to its baseline of -70
to -85 mV
-Na channels close, K channels open
◉ Hyperpolarization.
Answer: when the cell's resting membrane potential is greater than -
85mV. Is less excitable, because there is a greater distance between
the resting membrane potential and the threshold potential.
◉ In order for the action potential to be sucessful.
,Answer: t has to depolarize by 15-20 mV (threshold potential) to
reach -55 to -65 mV.
◉ An alteration in action potential may result from.
Answer: neurologic diseases, muscle disease or electrolyte
imbalances.
◉ What is the main protein responsible for maintaining the correct
balance of extracellular Na and intracellular K, which is needed for
cellular excitation and membrane conductivity..
Answer: Na+-K+ ATPase
◉ Resting membrane potential.
Answer: when the cell is in a nonexcited state and is at -70 to -85 mV.
◉ Refractory Period.
Answer: is a period of time during most of the action potential which
the cell membrane resists stimulation and it cannot depolarize
◉ Absolute refractory period.
Answer: occurs when the membrane will not respond to ANY
stimulus no matter how strong.
,◉ Relative Refractory Period.
Answer: occurs when the membrane is repolarizing and will only
respond to a very strong stimulus.
◉ Hyperpolarized.
Answer: when the cell's resting membrane potential is greater than -
85mV.
Is less excitable, because there is a greater distance between the
resting membrane potential and the threshold potential.
◉ Hypopolarized.
Answer: when the cell's resting membrane potential is closer to
zero, for instance it is -65mV.
Is more excitable because the resting membrane potential is closer
to the threshold potential, there is less distance between them.
◉ Action potential altered by hypokalemia.
Answer: (serum outside of cell is low)
-Hyperpolarized (cell becomes more negative, ex: -100)
-Affects the resting membrane potential of cells
-The cell is less likely to depolarize and transmit impulses
Can cause a decrease in neuromuscular excitability and leads to
weakness, smooth muscle atony, paresthesias, and cardiac
dysrhythmias
, ◉ Action potential altered by hyperkalemia.
Answer: Hypopolarized
-Also has an effect on the resting membrane potential
-If the ECF potassium increases without any change in the ICF
potassium levels, the resting membrane potential of the cell
becomes more positive.
-The cells are more excitable and conduct impulses more easily and
more quickly because the resting membrane potential is closer to
the threshold potential. Therefore, the person will have peak T
waves on EKG.
-As potassium rises, the resting membrane potential will continue to
become more positive and it will eventually become equal to the
threshold potential. As this happens the EKG will show a widening
QRS complex. If the resting membrane potential equals the
threshold potential, an action potential will not be generated and
cardiac standstill will occur. Paralysis and paresthesias may also
occur.
◉ Action potential altered by hypocalcemia.
Answer: -Causes an increase in the cell permeability to Na causing a
progressive depolarization
-Causes the RMP and the TP to be closer to one another & making it
easier to initiate an action potential - the cells are more excitable.
PULMONARY COMPLETE STUDY GUIDE WITH
SOLVED QUESTIONS
◉ Depolarization.
Answer: movement of the intracellular charge towards zero (more
positive charge)
Voltage gated Na channels open and allow Na to enter the cell ->
voltage inside the cell moves towards zero
◉ Repolarization.
Answer: Once the intracellular charge reaches zero, the negative
polarity of the inside of the cell is restored back to its baseline of -70
to -85 mV
-Na channels close, K channels open
◉ Hyperpolarization.
Answer: when the cell's resting membrane potential is greater than -
85mV. Is less excitable, because there is a greater distance between
the resting membrane potential and the threshold potential.
◉ In order for the action potential to be sucessful.
,Answer: t has to depolarize by 15-20 mV (threshold potential) to
reach -55 to -65 mV.
◉ An alteration in action potential may result from.
Answer: neurologic diseases, muscle disease or electrolyte
imbalances.
◉ What is the main protein responsible for maintaining the correct
balance of extracellular Na and intracellular K, which is needed for
cellular excitation and membrane conductivity..
Answer: Na+-K+ ATPase
◉ Resting membrane potential.
Answer: when the cell is in a nonexcited state and is at -70 to -85 mV.
◉ Refractory Period.
Answer: is a period of time during most of the action potential which
the cell membrane resists stimulation and it cannot depolarize
◉ Absolute refractory period.
Answer: occurs when the membrane will not respond to ANY
stimulus no matter how strong.
,◉ Relative Refractory Period.
Answer: occurs when the membrane is repolarizing and will only
respond to a very strong stimulus.
◉ Hyperpolarized.
Answer: when the cell's resting membrane potential is greater than -
85mV.
Is less excitable, because there is a greater distance between the
resting membrane potential and the threshold potential.
◉ Hypopolarized.
Answer: when the cell's resting membrane potential is closer to
zero, for instance it is -65mV.
Is more excitable because the resting membrane potential is closer
to the threshold potential, there is less distance between them.
◉ Action potential altered by hypokalemia.
Answer: (serum outside of cell is low)
-Hyperpolarized (cell becomes more negative, ex: -100)
-Affects the resting membrane potential of cells
-The cell is less likely to depolarize and transmit impulses
Can cause a decrease in neuromuscular excitability and leads to
weakness, smooth muscle atony, paresthesias, and cardiac
dysrhythmias
, ◉ Action potential altered by hyperkalemia.
Answer: Hypopolarized
-Also has an effect on the resting membrane potential
-If the ECF potassium increases without any change in the ICF
potassium levels, the resting membrane potential of the cell
becomes more positive.
-The cells are more excitable and conduct impulses more easily and
more quickly because the resting membrane potential is closer to
the threshold potential. Therefore, the person will have peak T
waves on EKG.
-As potassium rises, the resting membrane potential will continue to
become more positive and it will eventually become equal to the
threshold potential. As this happens the EKG will show a widening
QRS complex. If the resting membrane potential equals the
threshold potential, an action potential will not be generated and
cardiac standstill will occur. Paralysis and paresthesias may also
occur.
◉ Action potential altered by hypocalcemia.
Answer: -Causes an increase in the cell permeability to Na causing a
progressive depolarization
-Causes the RMP and the TP to be closer to one another & making it
easier to initiate an action potential - the cells are more excitable.
