module 7

Question 1

five special senses

Answer 1

smell, taste, hearing, vision, balance

Question 2

three receptors

Answer 2

mechanoreceptors, photoreceptors, chemoreceptors

Question 3

mechanoreceptors

Answer 3

hearing and balance

Question 4

photoreceptors

Answer 4

vision

Question 5

chemoreceptors

Answer 5

smell and taste

Question 6

physiology of smell

Answer 6

• odorant must be volatile (gaseous)
• odorants must reach olfactory epithelium and dissolve in mucus
• odorant then binds to receptors and opens gated
  channels
• generate an action potential

Question 7

olfactory pathway

Answer 7

• olfactory sensory neurons form olfactory nerve (CN I)
• action potentials travel to olfactory
  cortex of temporal lobe
• from olfactory cortex the information takes 2 pathways
  1 to frontal lobe: smell consciously interpreted and
  identified
  2 some information travels to hypothalamus and
  other regions of limbic system: emotional
  responses to odour elicited

Question 8

physiology of taste

Answer 8

• food chemical must be dissolved in saliva
• the food chemical must diffuse into the taste pore
• the food chemical must contact the gustatory hairs
• the food chemical binds to the receptor of the hair cells
• action potential is generated

Question 9

gustatory pathway

Answer 9

• Facial (VII), Glossopharyngeal (IX) and Vagus (X)
  nerves carry action potentials from taste buds to
• gustatory cortex of the insula
• hypothalamus and limbic system (appreciation of
  taste)

Question 10

three major areas of the ear

Answer 10

1. External (outer) ear – hearing only
2. Middle ear (tympanic cavity) – hearing only
3. Internal (inner) ear – hearing and balance

Question 11

external ear consists of

Answer 11

pinna, external acoustic meatus, tympanic membrane

Question 12

pinna

Answer 12

funnels sound waves into the external acoustic meatus

Question 13

external acoustic meatus

Answer 13

sound waves entering external acoustic meatus travel to and vibrate tympanic membrane

Question 14

tympanic membrane

Answer 14

vibrates in response to sound waves which then transfers sound energy to bones of middle ear

Question 15

middle ear consists of

Answer 15

auditory ossicles (malleus, incus, stapes), pharyngotympanic tube

Question 16

auditory ossicles function

Answer 16

transmit and amplify the vibratory motion of the tympanic membrane to the oval window

Question 17

pharyngotympanic tube function

Answer 17

equalises air pressure in the middle ear cavity with external air pressure

Question 18

internal ear consists of

Answer 18

body labyrinth and membraneous labyrinth

Question 19

body labyrinth consists of

Answer 19

vestibule, semicircular canals, cochlea

Question 20

bony labyrinth fluid

Answer 20

perilymph

Question 21

membraneous labyrinth fluid

Answer 21

endolymph

Question 22

pathway of sound waves

Answer 22

pinna, external acoustic meatus, tympanic membrane, auditory ossicles, oval window, cochlea, pressure waves in perilymph, spiral organ, movement of basilar membrane, vestibulocochlear nerve

Question 23

oval window

Answer 23

opening in the bone that partitions middle ear to the start of cochlea. movement causes pressure waves within the perilymph

Question 24

round window

Answer 24

thin membrane that seperate the end of the cochlea from middle ear. absorbs pressure waves and prevents perilymph from leaking into the middle ear

Question 25

static equilibrium

Answer 25

head is motionless, or moving in a straight line. detected by hair cells in the vestibule

Question 26

dynamic equilibrium

Answer 26

head rotating, or moving in an angular directed. detected by hair cells in semicircular canals

Question 27

accessory structures of the eye

Answer 27

eyebrows, eyelids, conductive

Question 28

eyebrows

Answer 28

protect the eye from sweating, shade from direct sunlight

Question 29

eyelids

Answer 29

fringed with hair, secrete oily lubricant that prevent eyelids from sticking together

Question 30

conjunctiva

Answer 30

produces fluid to prevent drying out

Question 31

pupil

Answer 31

allows light to enter the eye

Question 32

iris

Answer 32

change size of pupil

Question 33

lens

Answer 33

changes shape to focus light on retina

Question 34

ciliary muscles

Answer 34

hold lens in place

Question 35

ciliary muscles contracts

Answer 35

loosen and becomes round - close vision

Question 36

ciliary muscles relax

Answer 36

flattens - distant vision

Question 37

anterior segment

Answer 37

contain aqueous humour

Question 38

aqueous humour

Answer 38

supplies nutrients and oxygen to lens and cornea, removes waste

Question 39

posterior segment

Answer 39

contain vitreous humour

Question 40

vitreous humour

Answer 40

support posterior surface of eye and holds retina in place

Question 41

fibrous layer (outer layer) consists of

Answer 41

sclera, cornea

Question 42

vascular layer (middle layer) consists of

Answer 42

choroid, ciliary body, iris

Question 43

retina (inner layer) consists of

Answer 43

photoreceptors, fovea centralis, optic disc

Question 44

rods

Answer 44

dim light

Question 45

cones

Answer 45

colour

Question 46

refraction

Answer 46

bending of light rays as it passes through different mediums

Question 47

accommodation

Answer 47

increasing or decreasing the refractory power of the lens (increase/decrease the amount of bending of the light rays)