NURS 5315 Advanced Patho Exam 1 Questions and Answers
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Course
Advanced pathophysiology
Institution
Advanced Pathophysiology
NURS 5315 Advanced Patho Exam 1
Questions and Answers
Steps of the Action Potential - Answer️️ -Depolarization
Repolarization
Hyperpolarization
Depolarization - Answer️️ -movement of the intracellular charge towards
zero (more positive charge)
Voltage gated Na channels open and allow...
NURS 5315 Advanced Patho Exam 1
Questions and Answers
Steps of the Action Potential - Answer✔️✔️-Depolarization
Repolarization
Hyperpolarization
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.
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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.
-Results in tetany, hyperreflexia, circumoral paresthesias, seizures,
dysrhythmias
Action potential altered by hypercalcemia - Answer✔️✔️--Causes a decrease
in cell permeability to Na
-Causes the RMP and the TP to increase in distance - the cells are less
excitable and requires more of a stimulus to initiate an action potential.
-Leads to weakness, hyporeflexia, fatigue, lethargy, confusion,
encephalopathy, a shortened QT segment and depressed widened T waves
on EKG.
Atrophy - Answer✔️✔️-decrease or shrinkage in the size of the cell
-Imbalance between protein synthesis and degradation, , reduction of the
intracellular contents, also includes a self-eating process called autophagy.
-Example: aging brain cells, malnutrition, uterus decreasing in size after
childbirth
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