Check Your Understanding - Sensory Physiology

Question 1

Differentiate between the two types of sensory receptors.

Question 2

What type of stimulus activates a thermoreceptor? What about a chemoreceptor? Photoreceptor? Nociceptor?

Question 3

Where is an action potential typically generated on a sensory receptor?

Question 4

The volume of noise increases. What effect does this have on the receptor potential generated in auditory receptor cells? What effect does it have on the action potentials generated in the same auditory receptor cells

Question 5

Differentiate between slow- and fast-adapting receptors and give an example of each (try not to use the examples provided in the lecture notes).

Question 6

What effect does receptive field size have on the ability to identify the location of a “touch” stimulus?

Question 7

Define “adequate stimulus.”

Question 8

What is the difference between a specific and non-specific sensory pathway?

Question 9

What type of sensory receptors relay information about touch and pressure?

Question 10

What ions cause depolarization in thermoreceptors?

Question 11

What two neurotransmitters are common in transmission of pain signals?

Question 12

An individual has injured their finger but is feeling pain in their wrist. Identify a mechanism that might help explain this phenomenon.

Question 13

Explain how endogenous and exogenous opioids affect neurological signaling.

Question 14

Identify the layers and functions of the three layers of the eye.

Question 15

Why is it important that light from nearby objects converges on the retina?

Question 16

What are the photoreceptor cells? Which of these cells is more sensitive to light?

Question 17

What portion of the photoreceptor cells responds to light?

Question 18

Explain the function of photopigments and chromophores in processing visual information.

Question 19

Briefly explain the sensory transduction pathways of photoreceptors.

Question 20

Explain the pathway that sounds waves take from external auditory canal to round window.

Question 21

Explain how sound waves cause depolarization of hair cells.

Answer 21

Sound waves entering the ear cause vibrations of the oval window, which in turn creates pressure waves within the cochlea. These pressure waves cause the basilar membrane to vibrate, bending the hair cells against the tectorial membrane. This mechanical deflection of the stereocilia opens mechanically-gated ion channels, allowing cations to enter the hair cell and depolarize it. The depolarization triggers neurotransmitter release, stimulating nearby sensory neurons to generate action potentials that are transmitted to the brain as sound signals.

Question 22

Where is the vestibular system found? What is its function?

Answer 22

The vestibular system is found within the inner ear, specifically within the bony labyrinth. Its main components include the vestibular apparatus, which consists of the semicircular canals and the otolithic organs (utricle and saccule).

The function of the vestibular system is to contribute to the body’s sense of balance, spatial orientation, and coordination of movement. It detects changes in head position and movement in three-dimensional space. The semicircular canals detect rotational movements of the head, while the otolithic organs detect linear acceleration and changes in head position relative to gravity. The information collected by the vestibular system is integrated with visual and proprioceptive input to help maintain posture, stabilize gaze, and coordinate movements of the body and head. Dysfunction of the vestibular system can lead to symptoms such as dizziness, vertigo, and loss of balance.

Question 23

What type of sensory information do the utricle and saccule provide? Explain how the sensory receptors of each are stimulated.

Answer 23

The utricle and saccule, both parts of the vestibular system, provide sensory information about linear acceleration and changes in head position relative to gravity. They contain hair cells embedded in gelatinous material, with calcium carbonate crystals called otoliths on top. When the head moves, the otoliths shift, bending the hair cells. In the utricle, hair cells are oriented horizontally, detecting horizontal movements, while in the saccule, they are oriented vertically, detecting vertical movements. This bending of hair cells generates electrical signals that are sent to the brain, providing information about the direction and magnitude of head movements.

Question 24

What type of sensory information do the semicircular canals provide? Where are the sensory receptors found? Explain how these sensory receptors are stimulated

Question 25

Explain how salty food stimulate taste receptors to depolarize.

Question 26

Explain how olfactory neurons differ from typical afferent neurons. Where are the proteins responsible for initiating receptor potentials found?

Question 27

Describe the pathway for detection of odourants, from nasal cavity to olfactory cortex.