Chapter 17 - Special Senses Flashcards
1
Q
Chemoreceptor
A
Molecule must be dissolved to be detected
2
Q
Impulses sent to the hypothalamus
A
For memory triggered reaction
3
Q
Impulses sent to the limbic system
A
emotional reactions to info
4
Q
Olfaactory E
A
Where receptors for olfaction are found
5
Q
Olfaction First oder neuron
A
Olfactory receptors on the cilia
6
Q
Where does the axon of the olfactory receptor cell go?
A
Cribiform plate then synapses when the olfactory neuron
7
Q
Olfactory receptor
A
Bipolar cells with cilia
8
Q
Path of olfaction
A
O. cilia on the receptor cell dendrites - axons go through cribiform plate - bulb - tract - Primary olfactory area - some go to the thalamus and the limbic system
9
Q
Olfactory glands
A
found in the O.E produce mucus
10
Q
Basal cells
A
Act as stem cells, replace the receptors monthly
11
Q
Things in the O.E
A
basal cells, O receptor cells, O glands
12
Q
When happens when a O receptor binds w an odourant.?
A
Odourant binding causes SODIUM channels to open which depolarizes causes a GRADED POTENTIAL. First order neuron is triggered
13
Q
Physiology of Olfaction
A
- Axons of first order neurons pass though the cribiform plate
- First order synapse with second-order neuron in O. bulb
- axons of the second-order neurons form the olfactory tract
4.Second order neuron synapse with neurons in the primary olfactory area
14
Q
What makes the path of olfaction special?
A
Bypass the thalamus
15
Q
Classes of tastants
A
Salt, sour, sweet, bitter, umami
16
Q
Taste buds
A
have gustatory cells that have gustatory microvilli which contains receptors that bind to a dissolved tastant molecule. Found between the ridges of the papillae.
17
Q
All the types of Papillae
A
Vallate, fungiform, foliate, filiform
18
Q
Vallate Papillae
A
V shaped on the back of the tongue
19
Q
Fungiform Papillae
A
found everywhere on the tongue
20
Q
Foliate Papille
A
Found on the sides of the tongue
21
Q
Filiform papillae
A
NO TASTEBUDS. To increase friction btwn tongue and food
22
Q
Path of gustation
A
- Gustatory microvilli stimulated.
- Release of NT to the 1st order neuron
- 1st order synapse w 2nd order in the medulla
- 2nd order synapse w the 3rd order neuron in the thalamus.
- Impulse travel to the primary gustatory are and the sometimes the hypothalamus and the limbic system
23
Q
Which cranial nerves send impulses for gustatation
A
Facial - Anterior 2/3 of tongue
Glossopharyngeal - Posterior 1/3 of tongue
Vagus - epiglottis and pharynx
24
Q
Accessory structures of the eye
A
Eyelashes, eyebrows, eyelids (palpebrae), levator palpebrae superioris muscle, lacrimal caruncle
25
Lacrimal caruncle
contains sebaceous and sudoriferous glands
26
Orbicularis oculi
closes eye
27
Tarsal Plate
thich CT gives shape/supprt to eyelid, tarsal glands lubricate the eye
28
Palpebral conjunctiva
lines the inner aspect of eyelids (protective mucous membrane)
29
Bulbar conjunctiva
covers the sclera but not the cornea. Dilation of the blood vessels hear cause the appearance of blood shot eyes
30
What is an enzyme found in tears?
Lysozyme
31
Lacrimal Apparatus
1. Lacrimal gland
2. Lacrimal duct
3. Lacrimal canal
4. Lacrimal Sac
5. Nasolacrimal duct
6. Nasal cavity
32
Cornea
focus light into the retinal. Refracts 75% of the light
33
Sclera
Formed of dense irregular CT. Gives shape to the eyeball
34
Choroid
Highly vascular and provides nutrients to the retina. Absorbs stray light rays
35
Ciliary body
Ciliary process - secretes aq humour
Ciliary muscles - pull on the zonular fibres to alter the shape of the lens
36
Iris
Control the amount of light the enters the eye to prevent excessive UV damage.
Circular muscle fibres - constrict the pupils in bright light
Radial muscle fibres dilate the pupils in dim light
37
Anterior cavity
Anterior Chamber- btwn cornea and the iris
Posterior chamber - btwn iris and lens
Both fiilled w aq humour
38
Vitreous body
holds the retina against the choroid
39
Lens
Focuses light onto retina. Filled w layers of thin transparent cells and proteins called crystalline. Responsible for 25% of light refracation.
Lense shape changes to adapt to near/far sightednes
40
Image focused on retina
Inverted and reversed (the brain flips it)
41
Viewing FAR objects
Ciliary muscles relax, Zonular fibers stay taut, lens is flat.
42
viewing CLOSE objects
ciliary muscles contract Zonular decrese tension, lens is more curved
43
Correction for Refraction problems
Eyeball too long/thick - myopic - need concave lens (spread)
Eyeball too thin - hyperopic - need convex lens (tighten)
44
Retina
Has photoreceptors that respond to light and transduce them into Action potentials
45
macula lutea
has the fovea centralis which only has cones and has the highest acuity
46
Optic disc
Blind spot. Where optic nerves exit
47
Cones
Bright light, colours
48
Rods
Dim light , black and white. More rods than cones
49
Bipolar cells in eye
Assist transmission of signal on to the first order neuron. Can be inhibited of excited depending on the release of NT in response to light levels
50
Ganglion cells
1st order neurons their axons form the optic disc
51
Photopigments
Opsin, Retinal. Absorb light.
52
Opsin
protein portion
53
Retinal
light absorbing portion - this changes shape when detects light
54
isomerization
Retinal changes shape which lead to the generation of a graded potentials. Cis to trans
55
Bleaching
The retinal leaves the opsin. Now photopigment is unresponsive to light.
56
Conversion
retinal converts from trans to cis
57
Regeneration
The retinal binds to the photopigment and can now detect light again
58
Which photoreceptor regenerated faster?
Cones. Making it always ready to be struck in daylight. Rods regenerate slower so they are "out of service during bright light
59
Why are rods more sensitive in dark light
Many rods synapse onto a single bipolar cell which increases light sensitivity but decreases acuity
One cones synapses to a bipolar cell which produces the best visual acuity at the expense of sensitivity
60
Complete darkness
Na channels are opened leaving the photoreceptor partially depolarized. This causes the release of inhibitory neurotransmitters of glutamate on to the bipolar cell making it less likely to produce AP for vision
61
Let there be light
Na channels close causing the photoreceptors to be hyperpolarized. This inhibits the release of inhibitory NT, which allows the bipolar cell to be more likely to produce an action potential to trigger the 1st order neuron (Ganglion cell).
62
Light stimulus to the brain
1. light penetrates retina
2. rods and cones transduce light into receptor potentials
3. rods and cones excite bipolar cells
4. bipolar cells excite ganglion cells which are the 1st order neurons
5. Axons of the ganglion cells form the optic nerve
6. Optic nerves (nasal retina fibres) cross at the optic chiasm
7. thalamus
8. primary visual area, some to the hypothalamus and the limbic system and brainstem
63
Retinal detachment
Retina detaches from the pigmented epithelium which causes distorted vision and blindness
64
Cataract
loss of transparency of the lens
65
Glaucoma
Increase intraocular pressure due to the build of aq humour. This destroys the neurons of the retina
66
External ear
collects sound waves
67
middle ear
conveys sound vibrations to oval window
68
internal ear
houses receptors for hearing and balance
69
Auricle
Outer eat and channels in sound waves on to the tympanic membrane
70
External Auditory Meatus
channels sound waves on to the the tympanic membrane
71
Tympanic membrane
vibrates in response to sound waves. Passes vibrations on to the middle ear
72
Auditory ossicles
Transmit sound vibrations from outer ear to the inner ear
73
Stapedius muscle and tensor tympani
prevent excessive vibrations of the ossicles and eardrum in loud noise
74
Semicircular canals
Contains crista which are receptors for dynamic equilibrium
75
Cochlea has receptors for hearing
has receptors for hearing
76
bony labyrinth
Contains perilymph
77
Inner membranous labyrinth
contains endolymph
78
Sound waves
bro wgaf
79
Hair cells
Have stereocilia which are the receptors for hearing. Hair cell synapse w 1st order neuron CN viii
80
How do the stereocilia work?
Movement of the basilar membrane cause the stereocilia to rub against the tectorial membrane. Bending of the stereocilia cause the opening of K+ channels.
Influx of K depolarizarzation. Cause release of NT onto 1order neuron triggering cochlear branch
81
Hair cell physiology
At rest Ca, K are open but not many coming into the hair cell so few NT released
Stereocilia bend, large amounts of K enter the cell which creates strong depolarizing receptor potential. Many NT released onto 1st order neuron which causes stimulation of cochlear branch.
Stereocilia bend to the other side (hyperpolarized)
All channels are closed
82
Summary of the physiology of hearing
you got this baddie
83
Auditory pathway
1. Vestibulocochlear Nerve to medulla
2. Soma axons go grom the MO to pons to locate the source of sound
3. from MO and pons to inferior colliculi of midbrain
4. from midbrain to thalamus
5. From thalamus to primary auditory area od cerebral cortex
84
Static equilibrium
Linear acceleration and deceleration. As you tilt your head otolithic membrane moves and causes the bending of the stereocilia (receptors). Bending causes the K changes to open, influx of K. Depolarization causes the release of NT from hair cells onto first order neurons which trigger vthe estibular branch.
85
Dynamic equilibrium
rotational acceleration and deceleration. Receptors are found in the semicircular canals.
85
Utricle
horizontal acceleration and deceleration
86
Which part of the ear has receptors for static equilibrium
vestibule
87
Saccule
Verticle acceleration and deceleration
88
Macula
Within the walls of the saccule and utricle. Contains receptors for linear acceleration and deceleration.
89
Otololiths
Calcium carbonate crystals that cover the otolithic membrane. This membrane causes the movement of stereocilia which are receptors for equilibrium.
90
Ampulla
have crista which are receptors for dynamic equilibrium
91
Capula
Capula are on top of the crista and cover the hair cells. When you turn your head. fluid in the ampulla causes capula to move followed by the bending of stereocilia. Causes K open, K influx. Depolarization causes release of NT on to the first order neurons causing the triggering of the vestibular branch.
92
Equilibrium Pathway
1. CN VII to vestibular nuclei in medulla and pons.
2. From vestibular nuclei to the cerebellum for balance and posture.
3. From vestibular nuclei to CN II. IV, XI for movements of eyeball, head, and neck.
4. Impulses also go to primary somatosensory area via thalamus
93
Why do visual info travel to the hypothalamus
Sleep patterns and circadian rhthyms
94
Why do visual info travel to the brainstem?
To regulate the size of the pupil CN III and for coordination of head and eye movements (superior colliculi)
