Q: During the generation of an action potential, which sequence correctly describes the changes in ion concentrations across the neuron membrane?

Depolarization: $$\text{Na}^+$$ influx; Repolarization: $$\text{K}^+$$ efflux

Question 1

Which neuroglia cell is responsible for forming the myelin sheath in the peripheral nervous system (PNS), and what is the primary function of the myelin sheath?

Accepted Answer

Schwann cell; increases the speed of impulse conduction by insulating axons

Question 2

A patient presents with rapid, predictable, and involuntary responses to stimuli. Which of the following best describes the type of neural pathway involved, and what are the correct order of elements in this pathway?

Accepted Answer

Reflex arc; receptor, sensory neuron, integration center, motor neuron, effector

Question 3

During the generation of an action potential, which sequence correctly describes the changes in ion concentrations across the neuron membrane?

Accepted Answer

Depolarization: $$	ext{Na}^+$$ influx; Repolarization: $$	ext{K}^+$$ efflux

Question 4

Which of the following best explains why impulses are conducted more rapidly on myelinated nerve cells compared to unmyelinated nerve cells?

Accepted Answer

Myelinated axons facilitate saltatory conduction, where the action potential jumps between Nodes of Ranvier

Question 5

A patient with multiple sclerosis experiences loss of motor function. Which of the following best describes the underlying cause of this disease?

Accepted Answer

Autoimmune attack on oligodendrocytes in the CNS, leading to demyelination

Question 6

Which structure in the brain stem is primarily responsible for regulating cardiovascular and respiratory functions, and what would likely occur if it were damaged?

Accepted Answer

Medulla oblongata; disruption of heart rate and breathing

Question 7

Which of the following best describes the difference between the dorsal and ventral horns of the spinal cord?

Accepted Answer

Dorsal horn: sensory function; Ventral horn: motor function

Question 8

A patient suffers a stroke (CVA) affecting the left parietal lobe. Which function is most likely to be impaired?

Accepted Answer

Somatosensory perception (touch, pain, temperature)

Question 9

Which cranial nerve is associated with the cervical plexus and is essential for breathing by innervating the diaphragm?

Accepted Answer

Phrenic nerve

Question 10

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

Accepted Answer

Maintains homeostasis by controlling body temperature, hunger, and endocrine activity

Question 11

Which of the following is true regarding the flow of light and neural signals in the eye?

Accepted Answer

Light passes through the cornea, lens, and retina; signals travel from photoreceptors to bipolar cells, then ganglion cells, and finally to the optic nerve

Question 12

Which structure separates the outer and middle ear, and what is its primary function?

Accepted Answer

Tympanic membrane; transmits sound waves from the external ear to the ossicles

Question 13

A patient is diagnosed with sensorineural deafness. Which structure is most likely damaged?

Accepted Answer

Cochlea or auditory nerve

Question 14

Which of the following best describes the function of the maculae and otoliths in the vestibule?

Accepted Answer

Detect linear acceleration and maintain static equilibrium

Question 15

Which of the following equations best represents the relationship between the focal length ($$f$$), object distance ($$d_o$$), and image distance ($$d_i) $$for the lens in the eye?

Accepted Answer

$$\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$$

Question 16

Which of the following best explains the difference between the sympathetic and parasympathetic divisions of the autonomic nervous system?

Accepted Answer

Sympathetic: increases heart rate and prepares body for 'fight or flight'; Parasympathetic: promotes rest and digestion

Question 17

Which of the following is NOT a function of astrocytes in the central nervous system?

Accepted Answer

Forming myelin sheath around axons

Question 18

Which special sense is NOT fully functional at birth, and what is the physiological reason for this?

Accepted Answer

Vision; neural connections in the retina and visual cortex are immature

Question 19

A patient with damage to the ventral root of a spinal nerve would most likely experience which of the following?

Accepted Answer

Loss of motor function

BIO 163: Nervous System and Special Senses Study Guide

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