special senses

Question 1

rods

Answer 1

shades of grey light
discriminates shapes and movements

Question 2

cones

Answer 2

sharp, coloured vision
fovea of macula lutea
densely packed region at the exact visual axis of the eye

Question 3

pathway of nerve signal in retina

Answer 3

retina -> rods and lights traduces action potential to ganglion cells -> through optic nerve -> thalamus -> primary visual cortex

Question 4

emmetropic eyes

Answer 4

normal eyes, reflects light at 20 ft away

Question 5

myopia

Answer 5

nearsighted
eyeball too long
glass concave

Question 6

hypermetropia

Answer 6

far sightedness
eyeball too short
glass convex

Question 7

astigmatism

Answer 7

corneal surface wavy
parts of image out of focus

Question 8

color blindness

Answer 8

absence of certain cone photopigments

Question 9

nyctalopia

Answer 9

night blindness, difficulty seeing in low light
- cant make enough rhodopsin
- decency of vitamin A

Question 10

‘near point’

Answer 10

the closest distance from an eye an object can be in focus from

Question 11

near points for different ages

Answer 11

4 in young adult
8 in 40 y/o (lens lest elastic, may need reading glasses)
31 in 60-80 y/o

Question 12

presbyopia

Answer 12

gradual loss of ability to focus on nearby objects

Question 13

tastebuds # and location

Answer 13

100k
- tongue, soft palate, larynx
- in tongue: circumvallate & fungiform

Question 14

cell types in gustation

Answer 14

supporting, receptor, basal cells

Question 15

pathway of gustation

Answer 15

first order to cranial nerve
- VI (facial) serves anterior 2/3 tongue
- IX serves posterior
- X (vagus) serves palate or epiglottis

these signals go to thalamus/limbic system/primary gustatory area on parietal lobe

Question 16

taste bud anatomy

Answer 16

• oval body, 50 gustatory receptor cells
• singular gustatory hair through taste pore

[basal cells develop into new receptor cells every 10 days]

Question 17

olfactory cells

Answer 17

1. olfactory receptors: bipolar neurone with cilia/olfactory hairs
2. supporting cells: columnar epithelium
3. basal cells: replace receptors (stem cells)
4. olfactory glands: produce mucus

Question 18

olfactory pathways

Answer 18

axon from olfactory receptor (cranial nerve I) synapse in olfactory bulb

second order neutron in olfactory bulb form olfactory tract to synapse in primary olfactory area of temporal lobe

other tracts to frontal

Question 19

brodmanns area ii

Answer 19

identifications of door