Special Senses

Question 1

3 main regions of the ear

Answer 1

external, middle and internal

Question 2

what does the external ear do?

Answer 2

collects soundwaves and channel them inwards

Question 3

what does the middle ear do?

Answer 3

conveys sound vibrations to the oval window

Question 4

what does the internal ear do?

Answer 4

houses receptors for hearing and equilibrium

Question 5

Cerumen

Answer 5

wax

Question 6

what does the external ear consist of?

Answer 6

auricle, external auditory canal and eardrum

Question 7

what does the middle ear consist of?

Answer 7

auditory tube, auditory aussicles and oval window

Question 8

what does the internal ear consist of?

Answer 8

bony labyrinth, membraneous labyrinth, spiral organ

Question 9

spiral organ

Answer 9

organ of hearing

Question 10

why is thick mucus in middle ear a problem?

Answer 10

can move bones and cause deafness

Question 11

which canals help with balance?

Answer 11

vestibule and semicircular canals

Question 12

temporal bone in children

Answer 12

is very thin so infection in middle ear can spread through bone, causing meningitis

Question 13

process of hearing

Answer 13

Sound transfers into the ear canal and causes the eardrum to move, The eardrum will vibrate with the different sounds, These sound vibrations make their way through the ossicles to the cochlea. Sound vibrations make the fluid in the cochlea travel like ocean waves, Movement of fluid in turn makes the hair cells bend. The auditory nerve picks up any neural signals created by the hair cells. Hair cells at one end of the cochlea transfer low pitch sound information and hair cells at the opposite end transfer high pitch sound information, The auditory nerve moves signals to the brain where they are then translated into recognizable and meaningful sounds. It is the brain that “hears”.

Question 14

names of small bones in middle ear

Answer 14

malleus, incus and stapes

Question 15

what does the eustachian tube do?

Answer 15

allows pressure in middle ear to be equalised with atmospheric pressure

Question 16

static equilibrium

Answer 16

orientation of head in relation to gravity. The maculae of utricle and saccule are the sense organs of the static equilibrium

Question 17

dynamic equilibrium

Answer 17

maintenance of body position in response to rotational acceleration or deceleration

Question 18

3 layers of eye

Answer 18

fibrous tunic, vascular tunic and retina

Question 19

what is in the fibrous tunic?

Answer 19

sclera and cornea

Question 20

what is in the vascular tunic?

Answer 20

choroid, ciliary body, iris

Question 21

accessory structures of eye

Answer 21

eyebrows, eyelashes, eyelids, extrinsic eye muscles, and the lacrimal apparatus

Question 22

what do the extrinsic eye muscles do?

Answer 22

move the eyeballs

Question 23

what do the lacrimal apparatus do?

Answer 23

produce tears

Question 24

what does the lens divide interior of eyeball into?

Answer 24

two cavities - anterior and vitreous

Question 25

what does the anterior cavity contain?

Answer 25

aqueous humor which produces intraocular pressure within the eye

Question 26

what does the vitreous chamber contain?

Answer 26

vitreous body which keeps eyeball from collapsing and holds the retina

Question 27

flow of tears

Answer 27

the lacrimal glands secrete tears into the exretory lacrimal ducts which distribute tears over the surface of the eyeball. The superior or inferior lacrimal canaliculi drain tears into the nasolacrimals duct which drains tears into the nasal cavity (why you have a runny nose when you cry)

Question 28

what is the sclera?

Answer 28

the white part of the eye and is covered by a clear membrane called conjunctiva.

Question 29

what is the iris covered by?

Answer 29

cornea

Question 30

what can the upper eyelid covering too much of the iris indicate?

Answer 30

excess thyroid hormones or a tumour

Question 31

optic disc

Answer 31

blind spot

Question 32

area of greatest visual acuity?

Answer 32

fovea

Question 33

what does the oculomotor do?

Answer 33

controls contraction of the circular smooth muscle of the iris

Question 34

pupil’s response to light

Answer 34

constricts as circular muscles contract (bright light) and dilate as radial muscles of iris contract (dim light)

Question 35

what is restriction of the pupil a result of?

Answer 35

parasympathetic nerves

Question 36

what is dilation of the pupil a result of?

Answer 36

sympathetic nerves

Question 37

what can a lack of sensitivity to light be a result of?

Answer 37

brain injury

Question 38

vision

Answer 38

refraction of light rays by cornea and lens which focus an inverted image on central fovea of retina

Question 39

what happen when we view close objects?

Answer 39

lens increases its curvature and the pupil restricts to prevent light rays from entering through the periphery of lens

Question 40

what can improper refraction be a result of?

Answer 40

myopia (nearsightedness), hyperopia (farsightedness) or astigmatism (irregular curvature of the cornea or lens)

Question 41

convergence

Answer 41

movement of eyeball towards the nose to view an object

Question 42

photopigment

Answer 42

a substance that can absorb light and undergo and change in structure. Require vitamin A.

Question 43

Rhodopsin

Answer 43

the photopigment in rods

Question 44

Cones

Answer 44

function in bright light and provide colour vision

Question 45

visual pathway

Answer 45

nerve impulses arise in ganglion cells and conduct along the optic nerve, through the optic chiasm and optic tract to the thalamus. From the thalamus, impulses extend to the primary visual area in the occipital lobe of the cerebral cortex.

Question 46

How could a child show signs of a petituary tumour?

Answer 46

unable to see properly - walking into things