BIO 242 FINAL EXAM Questions and

BIO 242 FINAL EXAM Questions and Answers (Solved Papers) The threshold of a neuron is the - Correct Answers ✅voltage at which the inflow of sodium ions causes reversal of the resting potential.An neuronal circuit in which one presynaptic neuron stimulates a group of neurons, each of which then synapses

with a common postsynaptic cell is a: - Correct Answers

✅parallel after discharge Following injury to a peripheral neuron, chromatolysis occurs, which is - Correct Answers ✅breakup of the Nissl bodies Cerebrospinal fluid normally circulates in the - Correct Answers ✅subarachnoid space The part of a spinal nerve that contains only efferent fibers is the - Correct Answers ✅ventral root.The nerve that stimulates the diaphragm to contract arises from the - Correct Answers ✅cervical plexus.

Spinal nerves emerge from the vertebral column via: -

Correct Answers ✅intervertebral foramina.

The highly vascular, innermost layer of the meninges is the: -

Correct Answers ✅pia mater. 1 / 3

BIO 242 FINAL EXAM Questions and Answers (Solved Papers)

Ascending tracts contain: - Correct Answers ✅sensory

neurons.

Efferent neurons transmit impulses from: - Correct Answers

✅the CNS to effectors.Neuroglia in the central nervous system that produce the

myelin sheath are the: - Correct Answers

✅oligodendrocytes.

Nissl bodies are: - Correct Answers ✅clusters of rough ER

in the cell body.

The function of Schwann cells is to: - Correct Answers

✅form the myelin sheaths of neurons in the PNS.ALL of the following are TRUE concerning action potentials

EXCEPT:

• According to the all-or-none principle, all action potentials

fired by a given neuron are of the same amplitude.

• During depolarization, sodium ion inactivation gates close

a few 10,000ths of a second after the activation gates open.

• after-hyperpolarization is due to rapid outflow of potassium

ions. 2 / 3

BIO 242 FINAL EXAM Questions and Answers (Solved Papers)

• the threshold of a given neuron varies considerably

depending on local conditions.

• once threshold is reached, both sodium ion and potassium

ion voltage-gated channels open. - Correct Answers ✅d.the threshold of a given neuron varies considerably depending on local conditions.

The term saltatory conduction refers to: - Correct Answers

✅conduction of a nerve impulse along a myelinated axon.The voltage across a neuron's membrane has changed from its resting potential of -70mV to -60mV. Which of the following is most likely to be TRUE regarding this situation?

• The membrane has bound an excitatory neurotransmitter.
• The membrane has bound an inhibitory neurotransmitter.
• An anesthetic drug has been applied to the neuron.
• Voltage-gated potassium ion channels have been opened.
• The metabolic activities of the cell have caused production

of more anions that are now trapped inside the cell. - Correct Answers ✅a. The membrane has bound an excitatory neurotransmitter.

The spinothalamic tracts convey: - Correct Answers

✅sensory impulses regarding temperature

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