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Flashcards in SPECIAL SENSES Deck (28)
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1

What is the cranial nerve of smell

olfactory nerve (CN 1)

sensory

2

What is the cranial nerve of sight

Optic nerve (CN 2)

sensory

3

What is the cranial nerve of hearing

vestibulocochlear nerve (CN 8)

sensory

4

What are the cranial nerves of taste

Facial nerve (CN 7)
sensory and motor

Glossopharyngeal nerve (CN 9)
sensory and motor

5

what cells secrete mucous

respiratory type epithelium cells which contain seromucus glands

6

What are the borders of the nasal cavity

external/anterior openings = nares

posterior openings = choanae

medial wall = septum

lateral walls = cartilage and cranial bones (conchae and meatus)

floor = hard palate

roof = cranial bones + olfactory region

7

Explain the nerves of smell

Olfactory nerve fibres and receptors in olfactory epithelium pass into cranial bones to olfactory bulbs

bulbs become olfactory nerve tracts (CN 1) and project to olfactory cortex of temporal lobe

8

What is the orbit

bony cavity for eye made of 7 cranial bones.

orbicularis oculi: circular muscles that close eyelids

extra ocular muscles: move eye and open eyelid

lacrimal apparatus: production, drainage of fluid from eye (tears)

9

List the parts of the eye

Cornea
conjunctiva
iris
lens
anterior and posterior cavities

10

Outline the cornea

refracts bends light

anterior and posterior surfaces are epithelium

anterior surface continuous with conjunctiva

avascular

11

Outline the conjunctiva

Provides mechanical protection and lubrication

epithelium, secretory cells, fibrous tissue and blood vessels.

covers posterior surface of eyelids and reflects to cover anterior surface of eyeball

extends over the anterior sclera

12

Outline the iris

Regulates amount of light entering eye

thin diaphragm of tissue on lens

sphincter papillae arranged circularly around pupil, constrict, parasympathetic

dilator papillae arranged radially, dilate, sympathetic

13

Outline the lens

Refracts/bends light onto retina to focus on images

avascular biconvex disc

CT capsule

suspensory ligaments anchor edges of lens to ciliary smooth muscles which contract to adjust lens

parasympathetic

flatter = distant
rounder = closer

14

Outline anterior cavity

Anterior: contains fluid aqueous humor and supplies nutrients to avascular cornea and lens

maintains intraocular pressure ans shape of anterior eye

fluid continuously produced

15

Outline posterior cavity

Gelatinous mass called vitreous humor

Formed in development, not replaced

Stabilises shape of eye due to muscles

16

Outline the layers of the eye

fibrous tunic (sclera, white of eyes): protects eye, muscle attachment

vascular tunic (choroid): vascularised, smooth muscles of ciliary and iris, blood vessels enter at optic nerve to supply retina/pupils/lens

Neural tunic: explained in another

17

Describe the neural tunic (retina)

innermost, avascular

macula: all cones, no rods

fovea: within macula, densest conc of cones

optic disc: where optic nerve attaches to eye

18

What are the photoreceptors of the eye

rods: sensitive to light, night, no colour distinction

cones: red, green and blue, require light to function

19

Explain the nerves of sight

Visual info of photoreceptors sent to optic nerve, then primary visual cortex of occipital lobe.

partial decussation at optic chiasm

20

Describe the outer ear

auricle/pinna: funnels sound into the auditory meatus

external auditory meatus/acoustic canal: traps foreign particles a by hair cells and ceruminous glands which secrete ear eax. Protect tympanic membrane

Tympanic membrane: Lateral side epidermis, medial side thin mucous membrane, separate external and middle ear

21

Describe the middle ear

Tympanic cavity: contains oval window

pharyngotympanic tube: opens to equilibrate pressure in cavity with outside

auditory ossicles: amplify sound. malleus, incus, stapes. connect to tympanic membrane and oval window. skeletal muscles prevent excessive movement

22

Describe the internal ear

Oval window: connects to series of cavities like bony labyrinth

Bony labyrinth: vestibule, three semicircular canals and cochlea, lined with periosteum

Membranous labyrinth: suspended within the fluid, cochlear duct

Cochlea and cochlear duct: in another

23

Describe the cochlea and cochlear duct

cochlea: transduces sound, curls, contains clear lymphatic fluid and cochlear duct

cochlear duct: contains hair cells/stereocilia, clear lymphatic fluid

24

explain the nerves and physiology of hearing

Auricle directs sound into auditory meatus

Waves hit tympanic membrane converting sound to mechanical movement

Ossicles movement cause vibration of oval window

Oval window vibration generates wave in lymphatic fluid, travels through cochlea

Waves bend stereocilia which are detected by receptors of the cochlear nerve fibres

Cochlear nerve branch of vestibulocochlear nerve that sends info to primary auditory cortex

25

Describe the 4 papillae of the tongue

Vallate/circumvallate: largest, V-shaped
line anterior to the terminal groove. many receptors

Foliate: folds on lateral surfaces of tongue anterior to terminal groove. few receptors

Fungiform: small, found on dorsum of tongue. Some receptors

Filiform: smallest, cone-shaped projections. No receptors

26

What are the receptors of the tongue papillae

Gustatory receptors

27

What are the 5 tastes

sweet
salty
sour
bitter
umami

28

Outline the nerves involved in taste

Gustatory receptors project to facial nerve for the body of tongue (anterior 2/3) and glossopharyngeal nerve for the root of tongue (posterior 1/3). Project to gustatory cortex