Unit 4: Special Senses

Question 1

Olfactory

Answer 1

Epithelium: strip of mucous membrane containing millions of olfactory receptor cells

Nerves: leave through cribiform plate on ethmoid bones

What type of receptor does olfaction use?

Question 2

Taste

Answer 2

Sensations: sweet (tip of the tongue), salty, anterior sides, sour (posterior sides), bitter (back), and umami (not known in detail)

Innervation: anterior— glossopharangeal, posterior-facial

Taste threshold: lowest concentration of a taste you can detect

• bitter has lowest threshold
• sweet/salty are the highest

Question 3

The eye

Answer 3

Sclera, cornea, choroid, ciliary body, iris, retina, macula lutea, fovea centralis, optic disc, photoreceptors, accessory structures

Question 4

Sclera

Answer 4

Whites if the eyes, eyeball

Prevents light from entering eyeball

Question 5

Cornea

Answer 5

Avascular transparent dome

Refracts light toward pupil

Question 6

Choroid

Answer 6

Dark, brown layer containing blood vessels

Question 7

Ciliary body

Answer 7

smooth muscle, supports lens and iris, adjusts curvature of lens

Question 8

Iris

Answer 8

pigmented rings of smooth muscle– pupillary constrictor and dilator muscles

Question 9

Retina

Answer 9

Contains photoreceptors

Question 10

Macula lutea

Answer 10

small area cells directly in line with the lens, area of clearest vision and contains only cone receptors

Question 11

Fovea centralis

Answer 11

Vision is most accurate

Question 12

Optic disc

Answer 12

blind spot, ganglion cells from retina leave the back of the eye forming optic nerve

Question 13

Photoreceptors

Answer 13

Rods and cones

Question 14

Rods

Answer 14

sensitive to low light levels, provide black and white vision

Question 15

Cones

Answer 15

Sensitive to high light levels, provide color vision

Question 16

Accessory structures

Answer 16

Lacrimal gland produce tears, moistens surface of the eye (conjunctiva)

Question 17

The ear and hearing

Answer 17

Sebaceous and ceruminous glands from earwax (cerumen)

Tympanic cavity

External acoustic meatus -> tympanic membrane -> malleus-> incus-> stapes-> oval window-> cochlea

Organ or corti

Question 18

Tympanic Cavity

Answer 18

connected to the throat by the pharyngotympanic/eustachian tube

Question 19

Organ of Corti

Answer 19

transduction of sound waves

hair cells: primary transducers

outer hair cells: high sensitivity and sharp turning ability (amplifiers)

Question 20

Equilibrium

Answer 20

Vestibule and semicircular canals

Vestibule contain mechanoreceptors called maculae (movements of body relative to forces of gravity)

Semicircular canals

Otoliths

Question 21

Semicircular canals

Answer 21

crista ampullairs– dynamic equilibrium (angular movements)

Question 22

Otoliths

Answer 22

calcium carbonate crystals that increase inertia of membrane moving the stereocilia and kinocilia