FINAL: special senses Flashcards
1
Q
What are the general senses? What are the associated sensory receptors?
A
- Pain (nociceptors)
- Temp (thermoreceptors)
- Touch (mechanoreceptors)
- Pressure (mechanoreceptors)
- Vibration (mechanoreceptors)
- Proprioception (Proprioceptors)
2
Q
List the special senses
A
- smell
- taste
- vision
- hearing and equilibrium
3
Q
What is the sense of smell called?
A
Olfaction
4
Q
What are the 3 types of cells involved in olfaction?
A
- olfactory receptor cells
- supporting cells
- basal stem cells
5
Q
Olfaction: Describe olfactory receptor cells. (include function and location)
A
- bipolar neurons
- sites of olfactory transduction
- respond to chemical stimulation of an odorant molecule (initiate olfactory response)
- single axons project thru cribiform plate into the olfactory bulb
6
Q
Olfaction: describe supporting cells. (include location, function, and associated cranial n.)
A
- columnar epithelial cells lining the nose
- provide physical support, nourish, and insulate the olfactory receptor cells
- help detoxify chemicals that come in contact w/ olfactory epithelium
- CVII (parasympathetic function in nose)
7
Q
Olfaction: describe basal cells (include location, and function)
A
- lie btwn bases of supporting cells
- continually undergo cell division to produce new olfactory receptor cells
(olfactory receptor cells live around 1 month, # decreases w/ age, decreased sensitivity w/ age)
8
Q
What is the sense of taste called?
A
Gustation
9
Q
Gustation: what are the classes of stimuli
A
- sour
- sweet
- bitter
- salty
(- umami)
10
Q
Gustation: how does odour affect taste?
A
odours from food pass up into nasal cavity and stimulate olfactory receptor cells: enhance taste by increasing flavour perception
11
Q
Gustation: where are the taste buds? (approx 10 000) how does age affect them?
A
on tongue, soft palate, pharynx, and larynx
- decrease w/ age
12
Q
Each taste bud has: (3)
A
- supporting cells
- gustatory receptor cells
- basal cells
13
Q
Gustatory receptor cells synapse with:
A
dendrites of a sensory neuron
- branch out and contact many gustatory receptor cells in several taste buds
14
Q
Taste buds are housed in the following papillae:
A
- circumvallate (vallate)
- fungiform
- foliate
- filiform (only contain tastebuds in early life)
15
Q
Gustation: what are the cranial nerves involved?
A
VII, IX, X
16
Q
Describe the pathway
A
- taste buds
- impulses propagate along cranial nerves (VII, IX, X)
- reach medulla oblongata
- some go to limbic system areas and hypothalamus
- others go to thalamus and extend to primary gustatory area in parietal lobe
17
Q
What are the accessory structures of the eye?
A
- eyelids
- eyelashes
- eyebrows
- lacrimal apparatus
- extrinsic eye muscles
18
Q
what is the palpabral fissure of the eye?
A
opening btwn upper and lower eyelids
19
Q
EYE: what are the lateral and medial commissures?
A
junctions on each side of eye where eyelids meet
20
Q
what is the lacrimal caruncle and what does it contain?
A
pink elevation in medial commissure
- contains sebaceous (oil) glands and sudoriferous (sweat) glands
21
Q
Where is the levator palpabra superioris muscle? What is it innervated by?
A
above the eye, lifts the eyelid (CIII)
22
Q
What are the layers of the eyelids, superficial to deep?
A
“even dirty sluts own their cunts”
- epidermis
- dermis
- subcutaneous tissue
- orbicularis oculi muscle
- tarsus
- conjunctiva (palpabae part)
23
Q
What are the functions of the eyelashes/eyebrows
A
protect eyeball from: foreign object, perspiration, direct rays of sun
24
Q
What kinds of the glands release lubricating fluid at the base of eyelashes onto the hair follicles? (what is an infection of this called?
A
sebaceous glands (infection = sty)
25
What is does the lacrimal apparatus do?
Produce and drain lacrimal fluid (tears)
26
What do tears contain?
- salts
- mucous
- lyzosyme
27
What is the function of tears?
- protect
- clean
- lubricate/moisten
28
What are the associated structures of the lacrimal apparatus?
- lacrimal glands
- lacrimal (excretory) ducts
- lacrimal punctum
- lacrimal canals
- lacrimal sac
- nasolacrimal duct
29
What are the extrinsic muscles of the eye and their functions?
- sup. rectus (moves eye sup. and med.)
- inf. rectus (moves eye inf. and med.)
- lateral rectus (abducts eyeball)
- medial rectus (adducts eyeball)
- sup. oblique (moves eye inf. and lat.)
- inf. oblique (moves eye sup. and lat.)
30
What are the 3 layers of the eyeball?
1. Fibrous tunic (sclera)
2. Vascular tunic (choroid)
3. Retina
31
What are the 2 parts of the fibrous tunic (superficial layer of eyeball)? describe each one.
ant.: cornea
- transparent
- helps focus light onto retina
post.: sclera
- "white" of eye
- gives shape and protect inner parts of eyeball
32
What are the 3 parts of the vascular tunic (intermediate layer of eye)? describe each
1. choroid
- provides nutrients to retina
2. ciliary body
- ciliary processes (release aqueous humour)
- ciliary muscle (alters shape of Lens)
3. iris
- responds to changes in light levels
- circular & radial muscles
33
When you focus on something far, how do you adjust the lens?
Lens needs to be flat:
- circular ciliary m. need to relax
- suspensory ligs need to be tight
34
When you focus on something close, how do you adjust the lens?
Lens needs to be round:
- circular ciliary m. need to constrict
- suspensory ligs need to be loose
35
What happens in the iris when there is a bright light? name the NS involved
Pupil constricts as circular (inner) muscles of iris contract (parasympathetic)
36
What happens in the iris when there is a normal light?
pupil avg size, circular/radial muscles midway contracted/relaxed
37
What happens in the iris when there is dim light? name the NS involved
Pupil dilates: radial (outer) muscles contract (sympathetic)
38
What are 2 structures found in the retina, and what are the 2 portions of the retina?
- optic disc: blind spot (no rods or cones)
- central retinal a. and v.
Non-visual portion (outer layer): pigment epithelium
Visual portion: neural portion
39
Is the optic disc more medial or lateral?
medial
40
Describe the macula lutea vs. the fovea centralis
- macula lutea: dense area of rods and cones
- fovea centralis: area of cones, sharpness of vision
41
Eye: What is pigment epithelium and where is it located?
sheet of melanin containing epithelial cells
- located btwn choroid and neural portion
42
Eye: Where is melanin also found (apart from pigment epithelium)? what does it do?
in choroid
- absorbs stray light rays: prevents reflection and scattering of light within eyeball
(image case by retina remains sharp and clear)
43
Eye: What is the neural portion, what is it's function
multi-layered part which processes the visual data before transmitting nerve impulses to the thalamus
44
Eye: What are the 3 layers of the neural portion in the direction processing? (opposite of light coming in)
- photoreceptor layer
- bipolar cell layer
- ganglion cell layer
45
Eye: What are 2 other types of cells found in the neural portion?
horizontal and amacrine cells
46
What are the 2 types of photoreceptors? what are each for?
Rods:
- low light threshold
- allow us to see in dim light
Cones:
- stimulated by brighter light
- produce colour vision
47
Eye: where is the lens? how is it held in place
- post. to pupil and iris
- held in place by suspensory ligaments
48
Eye: is the lens vascularized?
no (avascular)
49
Eye: what is the lens composed of? What is it's function?
- composed of protein (crystallins): normally transparent
- fine tunes focusing of light rays
- facilitates clear vision
50
Interior of eyeball: what are the 2 cavities? name their location and the humor in each one.
Anterior cavity (aqueous humor)
- btwn cornea and lens
Posterior cavity (vitrous humor)
- btwn lens and retina
51
What are the subdivisions of the anterior cavity of the eye? where are they located?
- ant. chamber: btwn iris and cornea
- post. chamber: btwn iris and lens
52
Eye: What is the pathway of a light particle all the way to the pigment epithelium?
Light, cornea, ant. chamber, pupil, post. chamber, lens, post. cavity, retina (at fovea centralis), ganglion cell layer, bipolar cell layer, photoreceptor cell layer, pigmented epithelium
53
Eye: where is the beginning of significant processing of visual signals?
in the retina
54
Eye: axons from which part of the retina provide output from retina to the brain? in what form?
axons of retinal ganglion cells
- in the form of CII
55
What is the role of rods and cones in the visual pathway?
release neurotransmitters which lead to the generation of nerve impulses
56
Eye: where do axons of the optic n. go?
- pass through optic chiasm
(some fibers cross, others stay uncrossed)
- fibers form the optic tract and enter brain
- synapse in thalmus (some bypass and go directly to sup. colliculi)
- optic radiations project to visual areas in occipital lobes
57
What are the 3 regions of the ear?
- external ear
- middle ear
- internal ear
58
What are the 3 main parts of the external ear?
1. auricle
2. external auditory canal
3. tympanic membrane
59
What are the parts of the auricle of the external ear?
- helix
- antihelix
- lobule
- tragus
- antitragus
- concha
60
How is the auricle of the ear attached to the head?
ligs and muscle
61
External ear: location and what does it secrete?
in temporal b.
- Ceruminous oil glands secrete cerumen (ear wax)
62
What is the role of cerumen? what happens if there's too much?
- along w hair, protect from dust/foreign objects
- too much: muffled incoming sound
63
what is the tympanic membrane, where is it, what is it covered by?
thin, semi-transparent membrane btwn auditory canal and middle ear
- covered by epidermis
64
where is the middle ear? what is it? what are the main parts?
- in temporal b.
- air-filled cavity lined w/ epithelium
- 3 bones: malleus (hammer), incus (anvil), stapes (stirrup)
- eustachian tube
65
What does each ossicle do?
Malleus: articulates w/ tympanic membrane and incus
Incus: articulates w/ stapes and malleus
Stapes: articulates w/ incus and sits on oval window
66
What are the muscles attaching to ossicles?
- tensor tympani m. (CV3)
- stapedius m. (CVII)
67
What is the eustachian tube made of?what does it connect to?
bone and hyaline cartilage
- connect middle ear and nasopharynx (upper portion of throat)
68
What is the role of the eustachian tube?
allows air to enter/leave the middle ear until: pressure in middle ear = atmospheric pressure
69
What are the 2 labyrinths of the inner ear?
outer bony labyrinth & inner membranous labyrinth
70
What are the parts of the outer bony labyrinth of the inner ear? what fluid does it contain?
- semi-circular canals
- vestibule
- cochlea
(contains perilymph (similar to CSF))
71
What are the parts of the inner membranous labyrinth of the inner ear? what fluid does it contain?
- utricle and saccule
- semi-circular duct
(contains endolymph (high concentration of K+ ions))
72
What are the branches of CVIII?
vestibular branch (S/M):
- ampullar, utricular and saccular n.
- synapse w receptor cells for EQUILIBIRUM
cochlear branch (S):
- HEARING
73
Where is the cochlear?
ant. to vestibule, spirals around MODIOLOUS
74
What are the 3 channels of the cochlea?
- scala vestibule (ends at oval window)
- scala tympani (ends at round window)
- cochlea duct
75
scala tympani and vestibuli connect at:
helicotrema
76
What does the vestibular membrane separate?
cochlear duct from scala vestibuli
77
what does the basilar membrane separate?
cochlear duct and scala tympani
78
What is the organ of corti and where is it?
coiled sheet of epithelial cells on basilar membrane
- have 16 000 hair cells (receptors for hearing)
79
What do the cells of the organ of corti synapse with?
sensory and motor neurons from the cochlear branch of CVIII
80
Explain the mechanism of hearing
1. sound waves enter external auditory canal
2. hit tympanic membrane (vibrates)
3. vibrations transferred to ossicles
4. stapes pushes on oval window, transmitting vibrations to fluid of inner ear
5. fluid sends waves up scala vestibuli to helicotrema to scala tympani
6. pushed out round window
7. basilar membrane vibrates (activates organ of corti)
8. signal is sent to brain
81
What are the structures involved in the mechanism of static equilibrium in the ear
utricle and saccule (contain maculae)
82
What are the structures involved in the mechanism of dynamic equilibrium in the ear
semicircular canals
