Sensory Physiology

Question 1

What are the special senses?

Answer 1

Vision, Hearing (auditory), Equilibrium, Taste (gustatory), Smell (olfactory)

Question 2

What are the somatic senses?

Answer 2

Touch / Pressure, Pain, Itch, Temperature, Proprioception

Question 3

Where is the primary somatic sensory cortex located?

Answer 3

In the middle of the brain, above the gustatory cortex

Question 4

What is the role of the thalamus in sensory pathways?

Answer 4

Most pathways pass through the thalamus on their way to the cerebral cortex

Question 5

Do olfactory pathways project through the thalamus?

Answer 5

No, they project through the olfactory bulb to the olfactory cortex

Question 6

What is sensory transduction?

Answer 6

Conversion of sensory stimuli into electrical signals

Question 7

What is a generator potential?

Answer 7

Membrane potential change when receptor and sensory fibre are one cell

Question 8

What is a receptor potential?

Answer 8

Membrane potential change where receptor is distinct from sensory fibre

Question 9

What type of potentials are generated by sensory receptors?

Answer 9

Graded potentials

Question 10

What determines the modality of a stimulus?

Answer 10

Which sensory neurons are activated

Question 11

What is the difference between sensation and perception?

Answer 11

Sensation is the recognition of an event; perception is the interpretation of that event

Question 12

What types of stimuli can nociceptors detect?

Answer 12

Mechanical, chemical, thermal

Question 13

What are the two types of fast pain fibres?

Answer 13

A-delta fibres (small myelinated), C fibres (small unmyelinated)

Question 14

What is the gating theory of pain?

Answer 14

Non-painful stimulus may lessen pain by activating Aβ fibres

Question 15

What are the five different taste sensations?

Answer 15

• Sweet * Bitter * Umami * Sour * Salt

Question 16

What is the role of Type II receptor cells in gustation?

Answer 16

Activate gustducin for sweet, bitter, and umami tastes

Question 17

What do taste cells release as a signal molecule?

Answer 17

ATP

Question 18

What is the function of olfactory sensory neurons?

Answer 18

Ascend to amygdala and hypothalamus

Question 19

What is the pupillary light reflex?

Answer 19

Constriction and dilation of the pupil to control light entry

Question 20

What is presbyopia?

Answer 20

Age-related decline in the ability of the lens to change shape

Question 21

What are the components of visual pigments?

Answer 21

Opsin and 11-cis-retinal

Question 22

What is a cataract?

Answer 22

Opacity of the lens leading to reduced vision or blindness

Question 23

What is retinitis pigmentosa?

Answer 23

Progressive degeneration of photoreceptor cells

Question 24

What are the common causes of hearing loss?

Answer 24

• Ageing * Exposure to excessive noise * Genetic conditions

Question 25

What is the difference between conductive and sensorineural hearing loss?

Answer 25

* Conductive: sound transmission impairment through external/middle ear * Sensorineural: damage to inner ear structures

Question 26

How do sound waves differ in terms of frequency and amplitude?

Answer 26

Frequency is pitch (Hz), amplitude is loudness (dB)

Question 27

What is the role of hair cells in the cochlea?

Answer 27

Bend to create electrical signals when stimulated

Question 28

What is the function of the organ of Corti?

Answer 28

Contains hair cell receptors and support cells for sound processing

Question 29

What are the two types of fluid in the cochlea?

Answer 29

* Perilymph (in vestibular and tympanic ducts) * Endolymph (in cochlear duct)

Question 30

What is the auditory pathway from hair cells to the brain?

Answer 30

Primary sensory auditory nerves to cochlear nuclei, then to thalamus and temporal lobe

Question 31

What factors determine loudness and duration of sound?

Answer 31

Pattern of action potentials in sensory fibres

Question 32

What is the significance of the tympanic membrane in hearing?

Answer 32

Vibrates in response to sound waves

Question 33

What is the frequency range that humans can hear?

Answer 33

20-20,000 Hz

Question 34

What are the common symptoms of macular degeneration?

Answer 34

Reduced central vision, does not progress to blindness

Question 35

What is the role of connexin 26 in hearing?

Answer 35

Necessary for recycling K+ ions in auditory transduction