Nervous System - MCAT Questions with Detailed Verified Answers

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Nervous System - MCAT Questions
with Detailed Verified Answers
Question: Soma
Answer: neuron cell body


Question:
Oligodendrocytes
Answer: cells that produce MYELIN in CENTRAL NERVOUS SYSTEM


Question:
Schwann Cells
Answer: cells that produce MYELIN in the PERIPHERY


Question:
Resting Membrane Potential
Answer: about -70mV


inside of neuron is negative relative to outside


Question:
Discuss ion concentrations inside neuron.
Answer: [K+] is high inside neuron


[Na+] is low inside neuron


Question:

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Discuss ion concentrations outside neuron
Answer: [K+] is low inside neuron


[Na+] is high inside neuron


Question:
K/Na ATPase
Answer: important for restoring chemical gradient after action potential has
been fired


transports 3 Na+ out of cell for every 2 K+ into the cell at the expense of 1 ATP


both Na and K are moved again their gradients thus ATP must be consumed
to restore resting potential


whenever the ATPase pump works, it results in making the interior of the cell
more negative


Question:
Depolarization
Answer: caused by excitatory inputs


makes the cell less negative (relatively more positive)


if axon hillock is depolarized to threshold value action potential will be
triggered

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Question:
hyperpolarization
Answer: caused by inhibatory inputs


occurs when the cell becomes more negative


Question:
saltatory conduction
Answer: electrical transmission in the neuron's axon as the electrical signal
hope from node to node (node of ranvier)


Question:
Speed of Action Potentials
Answer: depends on Axon Length and Cross-sectional area


1. longer axon = higher resitance and slower electrical conduction


2. greater axon diameter = faster signal propagation (greater effect)


myelin is excellent insulator, preventing loss of electrical signal


Question:
Action Potential Initiation