Q: During an action potential, at what membrane potential (in mV) does a typical neuron reach threshold, and what is the peak membrane potential during the action potential?

$$\text{Threshold: } -55\ \mathrm{mV};\ \text{Peak: } +30\ \mathrm{mV}$$

Question 1

Which of the following best describes the main difference between neurons and neuroglia in nervous tissue?

Accepted Answer

Neurons are responsible for transmitting electrical signals, while neuroglia provide support, protection, and nourishment to neurons.

Question 2

A patient presents with loss of voluntary motor control on the right side of the body. Damage to which area of the brain is most likely responsible, and why?

Accepted Answer

The left precentral gyrus, because the primary motor cortex controls contralateral voluntary movements.

Question 3

Which of the following correctly matches the neuroglial cell with its function in the CNS?

Accepted Answer

Oligodendrocytes: produce myelin sheaths around CNS axons

Question 4

During an action potential, at what membrane potential (in mV) does a typical neuron reach threshold, and what is the peak membrane potential during the action potential?

Accepted Answer

$$	ext{Threshold: } -55\ \mathrm{mV};\ 	ext{Peak: } +30\ \mathrm{mV}$$

Question 5

Which of the following best explains why the sympathetic division of the autonomic nervous system is also called the 'thoracolumbar division'?

Accepted Answer

Its preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord.

Question 6

A person is exposed to a sudden loud sound. Trace the pathway of the sound from the external environment to the auditory cortex, including the main structures involved.

Accepted Answer

External auditory canal → tympanic membrane → ossicles → oval window → cochlea → hair cells → cochlear nerve → brainstem nuclei → thalamus → auditory cortex

Question 7

Which of the following statements about the organization of gray and white matter in the brain and spinal cord is correct?

Accepted Answer

In the brain, gray matter is superficial and white matter is deep; in the spinal cord, white matter is superficial and gray matter is deep.

Question 8

Which cranial nerve is responsible for innervating the diaphragm and what is its clinical significance?

Accepted Answer

Phrenic nerve (arising from the cervical plexus); damage can result in respiratory failure.

Question 9

Which neurotransmitter is released by all preganglionic neurons of the autonomic nervous system, and what is the main neurotransmitter released by postganglionic sympathetic neurons?

Accepted Answer

Acetylcholine; norepinephrine

Question 10

A patient has difficulty with balance and coordination, but no loss of sensation or muscle strength. Which brain region is most likely affected?

Accepted Answer

Cerebellum

Question 11

Which of the following best describes the function of the blood-brain barrier and the neuroglial cells that help maintain it?

Accepted Answer

It restricts passage of harmful substances from the blood into the brain; astrocytes help maintain it.

Question 12

Which of the following is TRUE regarding the organization of a nerve?

Accepted Answer

A nerve is composed of bundles of axons (fascicles) surrounded by connective tissue sheaths: endoneurium, perineurium, and epineurium.

Question 13

Which of the following best describes the difference between rods and cones in the retina?

Accepted Answer

Rods are responsible for vision in low light and do not detect color; cones are responsible for color vision and visual acuity.

Question 14

Which of the following is a correct sequence of events in chemical neurotransmission at a synapse?

Accepted Answer

Action potential arrives at axon terminal → voltage-gated $$\mathrm{Ca}^{2+}$$ channels open → $$\mathrm{Ca}^{2+}$$ influx → neurotransmitter vesicles fuse with membrane → neurotransmitter released into synaptic cleft

Question 15

Which of the following best describes the function of the hypothalamus?

Accepted Answer

It regulates homeostasis by controlling the autonomic nervous system and the endocrine system.

Question 16

Which of the following is TRUE regarding the organization of the spinal cord gray matter?

Accepted Answer

Somatic motor neurons are located in the ventral horns; interneurons receiving somatic sensory input are in the dorsal horns.

Question 17

Which of the following best describes the function of the reticular formation in the brainstem?

Accepted Answer

It regulates consciousness, arousal, and filters sensory input.

Question 18

Which of the following is a correct description of saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 19

Which of the following best explains why damage to the left Wernicke’s area results in language comprehension deficits?

Accepted Answer

Wernicke’s area is responsible for understanding spoken and written language, and is typically located in the left temporal and parietal lobes.

Comprehensive Study Guidance for Human Anatomy Nervous System Exam (BIOL 120)

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