Week 8 - Auditory + Somatosenses

Question 1

What is sound?

Answer 1

Changes in air pressure caused by vibrations.

Question 2

What are the physical and perceptual dimensions of sound?

Answer 2

Amplitude (loudness), frequency (pitch), and location (spatial perception).

Question 3

What is the function of the pinna?

Answer 3

Funnel sound into the auditory canal.

Question 4

What is impedance matching?

Answer 4

Middle ear increases pressure from tympanic membrane to oval window.

Question 5

What is the middle ear reflex?

Answer 5

Muscles contract to protect from loud or self-generated sounds.

Question 6

What are the three canals of the cochlea?

Answer 6

Scala vestibula, scala media, scala tympani.

Question 7

What does the Organ of Corti contain?

Answer 7

3500 inner and 12000 outer hair cells on the basilar membrane.

Question 8

What is the function of hair cells?

Answer 8

Convert vibrations into electrical signals.

Question 9

What is tonotopic organisation?

Answer 9

Nerve fibres correspond to specific frequencies.

Question 10

What are the three auditory cortex regions?

Answer 10

Core (A1), belt, and parabelt.

Question 11

What is the ventral stream responsible for?

Answer 11

Sound identification – the ‘what’ pathway.

Question 12

What is the dorsal stream responsible for?

Answer 12

Sound location – the ‘where’ pathway.

Question 13

How is loudness perceived?

Answer 13

By the rate of neuron firing.

Question 14

How is pitch perceived?

Answer 14

By place coding and temporal (rate) coding.

Question 15

What are the components of the vestibular system?

Answer 15

Vestibular sacs and semicircular canals.

Question 16

What do vestibular sacs detect?

Answer 16

Gravity and head orientation.

Question 17

What do semicircular canals detect?

Answer 17

Angular acceleration in three planes.

Question 18

What functions does the vestibular system support?

Answer 18

Balance, head position, and eye movement stability.

Question 19

What does the somatosensory system detect?

Answer 19

Touch, temperature, pain, body position, visceral sensations.

Question 20

What are the three types of skin layers?

Answer 20

Epidermis, dermis, subcutaneous tissue.

Question 21

What are mechanoreceptors?

Answer 21

Touch receptors responding to pressure/vibration.

Question 22

What fibres do mechanoreceptors use?

Answer 22

Large myelinated Aβ fibres.

Question 23

What are thermoreceptors?

Answer 23

Free nerve endings detecting temperature.

Question 24

What fibres carry temperature information?

Answer 24

Warm: unmyelinated C fibres; Cold: Aδ and C fibres.

Question 25

What are nociceptors?

Answer 25

Pain receptors responding to harmful stimuli.

Question 26

What are the types of nociceptors?

Answer 26

Mechanical, thermal, chemical, and polymodal.

Question 27

What fibres carry pain?

Answer 27

Lightly myelinated Aδ and unmyelinated C fibres.

Question 28

What does the dorsal column-medial lemniscus pathway carry?

Answer 28

Tactile sensation and proprioception.

Question 29

What does the spinothalamic pathway carry?

Answer 29

Pain and temperature information.

Question 30

What are S1 and S2?

Answer 30

Primary and secondary somatosensory cortices.

Question 31

What is somatotopic representation?

Answer 31

Body parts mapped proportionally by sensitivity, not size.

Question 32

What are the components of pain perception?

Answer 32

Sensory (S1/S2), immediate emotional (insula, ACC), and long-term emotional (PFC).

Question 33

What is olfaction?

Answer 33

Chemical sense with ~10 million receptor cells, second only to vision.