Special senses

Question 1

perception

Answer 1

conscious awareness of a sensation

Question 2

general senses

Answer 2

temp
pain
touch
pressure
vibrations
proprioception

Question 3

special senses

Answer 3

smell/olfaction
taste/gustation
vision
hearing
balance/equilibrium

Question 4

where does olfaction occur

Answer 4

in nasal cavity either side of nasal septum
inferior to cribriform plate of ethmoid bone

Question 5

what do olfaction organs consist of

Answer 5

olfactory epithelium and olfactory glands

Question 6

process of smell

Answer 6

1. air swirls in nasal cavity
2. reaches olfactory organs diffusion into mucus
3. cilia attached to receptor extends into mucus and chemicals interact
4. binding of odorant’s changes permeability of membrane causing AP
5. info relayed to cns

Question 7

olfactory pathways

Answer 7

bundle of axons penetrate cribriform plate of ethmoid bone to reach olfactory bulb. axons leaving here go along olfactory tract to cortex of cerebrum, hypothalamus and limbic system

Question 8

gustatory receptors

Answer 8

on superior surface of tongue, adjacent to larynx and pharynx

Question 9

what are taste buds

Answer 9

taste receptors and specialised epithelial cells

Question 10

why are taste buds on the side

Answer 10

to protect from mechanical damage

Question 11

3 types of papillae

Answer 11

filiform (no buds)
fungiform (5)
circumvallate (100)

Question 12

primary taste sensations

Answer 12

sweet
salt
bitter
sour
umami
water

Question 13

what are gustatory cells

Answer 13

sensory receptor I taste buds extending microvilli into surrounding fluids through taste pore

Question 14

taste mechanisms

Answer 14

1. dissolved chemicals contact taste hairs
2. stimulates changes in potential = AP
3. monitored by 3 cranial nerves (facial, vagus, glossopharyngeal)

Question 15

vision structure

Answer 15

extrinsic eye muscles
lacrimal gland
cranial nerves
blood vessels
fat

Question 16

vision mechanism

Answer 16

1. light enter and refracted at cornea and lens
2. absorbed at retina by photoreceptors (rods and cones)
3. interacts with photopigments
4. photopigment splits altering flow of electrical current

Question 17

photopigments

Answer 17

rhodopsin
opsin
retinal

Question 18

cones and rods

Answer 18

central vision (colour)
periphery (intensity)

Question 19

visual pathways

Answer 19

1. 2 optic nerves reach into diencephalon at the optic chiasm
2. half nerve fibres from each eye cross to reach thalamus on opposite sides of brain
3. nuclei here relays info to reflex centres on brain stem and visual. cortex

Question 20

hearing receptors

Answer 20

in temporal bone of skull
mechanoreceptors (pressure)

Question 21

anatomy of middle ear

Answer 21

air filled cavity
separated from ear canal by tympanic membrane
contains auditory ossicles

Question 22

what are the 3 auditory ossicles

Answer 22

malleus
incus
stapes

Question 23

inner ear receptor location

Answer 23

in membranous labyrinth containing 2 fluids (endolymph and perilymph)

Question 24

inner ear structure

Answer 24

boney cochlear contains cochlear duct (between 2 perilymph chambers)
dense boney labyrinth walls

Question 25

round and oval window locations

Answer 25

round = base of tympanic duct oval = base of vestibular duct

Question 26

organ of corti

Answer 26

where hair cells of cochlear duct are just above basilar membrane stereoccllia of hair cells in contact with tectonal membrane

Question 27

process of hearing

Answer 27

1. sound waves arrive 2. vibrations in tympanic membrane 3. move 3 tiny bones 4. move oval window 5. move fluid 6. presses against hair cells 7. AP generated

Question 28

what monitors cochlear hair cells

Answer 28

sensory neurones in spiral ganglion

Question 29

auditory pathways

Answer 29

axons enter medulla and synapse at cochlear nucleus info brought together inferior colliculus synapsing synapse in thalamus auditory cortex of temporal lobe reaches awareness

Question 30

where are balance sensations provided

Answer 30

by hair cells of vestibular apparatus, semi circular canals and otoliths

Question 31

balance mechanics

Answer 31

semicircular canals and otoliths pick up info on rotational body movements (contain fluid filled chambers ) causes movement in canals fluid presses on cupula hair cells move AP

Question 32

where are hair cells for balance located

Answer 32

in ampulla

Question 33

cupula

Answer 33

gelentin fluid

Question 34

utricle and saccule

Answer 34

u = horizontal linear acceleration s = vertical

Question 35

equilibrium pathways

Answer 35

sensory neurones monitor hair cells of otoliths and canals afferent fibres form vestibular branch of vestibulocochlear nerve

Question 36

roles of vestibular nuclei

Answer 36

integrate sensory info from each side of head relay info to cerebellum relay info to cerebral cortex send motor commands along efferent fibres to brain stem