Hearing, Taste And Movement

Question 1

Whats the tasting system?

Answer 1

Taste buds are grouped papillae on the tongue
Number of fungiform papillae affect peoples sensitivity to all tastes

Question 2

How do taste buds work?

Answer 2

1 = 50 receptor cells

They behave like neurons: release neurotransmitters to excite nearby neurons

By they are not neurons: modified skin cells, replaced

Question 3

What are the types of primary taste?

Answer 3

Sweet
Salty
Sour
Bitter

Question 4

How does the brain encode taste?

Answer 4

1. Taste nerves
2. Medulla
3. Insula - primary taste cortex
4. Somato-sensory cortex

Question 5

How do we detect smell?

Answer 5

Olfaction - sense of smell
- important - toxic substances

Olfactory
- in nasal cavity
- hundreds of types (unlike taste) - for many different chemicals

Olfactory bulb
- processes the information

Question 6

What is sound?

Answer 6

A complex set of acoustic information is transferred

Sound waves = periodic compressions, causing vibrations

Frequency = number of compressions per time
- related to perceived pitch

Amplitude = intensity of the sound wave
- relates to perceived loudness

Question 7

How are sound waves detected?

Answer 7

Pinna (outer ear)

Tympanic membrane (eardrum)

Cochlea (3 fluid filled tunnels)
- snail shaped - allows us to distinguish between frequencies

Vibrations displace hair cells in cochlea

Auditory nerve (nerve bundle)

Question 8

Where is the sound info processed in the brain?

Answer 8

Ear
Cochlear nucleus

(Crossover)

Primary auditory cortex
- allows us to distinguish between frequencies

Question 9

Why can we distinguish between frequencies?

Answer 9

Pitch

Basilar membrane of cochlea
Primary auditory cortex

Question 10

What does the basilar membrane do?

Answer 10

Place theory
- each area of the basilar membrane refers to a specific pitch
- but the areas are too tightly linked to resonate

Frequency theory
- vibrations of basilar membrane in sync with sound waves
- but neurons cant fire quick enough

Current view: combination of the two

Question 11

What does the primary auditory cortex do?

Answer 11

Neighbouring cells respond to neighbouring frequencies

If damaged could cause deafness?
- sound processing would be affected
- no cause of deafness

Question 12

Whats deafness?

Answer 12

Conductive deafness
- damage of bones of the middle ear
- hammer, anvil, stirrup
- any age - temporary if treated

Nerve deafness
- damage of cochlea, hair cells, auditory nerve
Often early - inherited, prenatal problems

Question 13

How can we locate sounds?

Answer 13

Both ears received different information

1 - difference in time of arrival
2 - difference in intensity
3 - phase difference in sound waves

Question 14

Whats vestibular sensation?

Answer 14

Vestibular organ - detects positions and movement of the head
- crucial for balance

Three semicircular canals
- next to inner ear
- filled with jelly-like substance, lined with hair cells

Head moves
Within the 3 semicircular canals - jellylike substance moves
Calcium carbonate particles (otoliths) move against hair cells
Brainstem
Cerebellum

Question 15

Whats Huntington’s disease?

Answer 15

Motor disorders: Arm jerks, facial twitches, severe body movements
Psychological disorders: Depression, anxiety, hallucinations

Gradual brain damage
- first the basal ganglia (caudate nucleus, putamen, globus pallidus);
- Cerebellum, cerebral cortex, and more

Strong genetic influence
- dominantgene(pre-symptomatictests)

Question 16

Whats Parkinson’s disease?

Answer 16

Motor disorders: tremor, rigidity, slowness etc.

Cognitive disorders: imagining movement and events (difficulties)

Gradual death of neurons in substantia nigra (mid brain area)
- decreased dopamine activity
- reduced stimulation of the motor cortex

Causes?
– Genetic: 20 genes that increase risk
– Exposure to toxins

Question 17

How do we move?

Answer 17

Brain
Spinal cord
Skeletal muscles

Question 18

Whats the cerebral cortex?

Answer 18

Control of complex movement (many voluntary actions)

Question 19

Areas in the cerebral cortex?

Answer 19

Primary motor cortex and primary somatosensory cortex
- map of areas of body movements
- stimulation at each sport causes specific movement (including thinking about them)

Posterior parietal cortex
- planning and initiation of movement; monitoring position of body in space

Supplementary motor cortex and prefrontal cortex
- planning a rapid sequence of movement

Question 20

Areas not in the cerebral cortex?

Answer 20

Cerebellum - precise timing associated with movement, attention and balancing

Basal ganglia - spontaneous self-initiated actions

Question 21

Muscles and their movements

Answer 21

Skeletal (or striated) muscles
- control movement of body in relation to the environment
- long cylindrical with stripes

Question 22

Whats the neuromuscular junction?

Answer 22

Synapse of muscle fibre and motor neuron axon
Each muscle fibre is innervated by 1 motor neuron axon