Special senses Flashcards
(152 cards)
1
Q
When the ciliary muscle is relaxed
A
ligaments pull on the lens making it flat
-better for seeing far
2
Q
Ciliary muscle contracts
A
releases tension from ligaments, lens becomes rounded
-good for close vision
3
Q
Cataracts
A
improper folding of chrystallin proteins
-reduces ability to transmit light to back of eye
4
Q
What wavelengths of electromagnetic radiation do humans perceive
A
400-700nm
5
Q
Concave lens
A
Bent away from centre point
-light rays are scattered
6
Q
convex lens
A
bends light toward the focal point
-light rays converge
7
Q
how is the image displayed on the retina
A
the image is inverted
- Convex lens in eye
- converges light onto fovea
- image is flipped across horizontal and vertical plane
8
Q
what is the pathway of light entering the eye
A
cornea - aqueous humour - lens - vitreous humour - neural layer of retina - photoreceptors
9
Q
in its path through the eye, where is light refracted
A
1) Cornea
2) entering the lens
3) exiting the lens
10
Q
Optic disk
A
blind spot
- no photoreceptors
- optic nerve and BVs exit eye
11
Q
Fovea
A
region of sharpest image
12
Q
what is the region of the retina that produces the sharpest image
A
Fovea
13
Q
where is the centre of the visual field
A
Macula
14
Q
macula
A
centre of the visual field
15
Q
converts light rays into electrical signals
A
Photoreceptors
16
Q
do arteries and veins overlap in the macula
A
No
17
Q
from what structure do the central vein and arteries enter/exit the eye
A
optic disk
18
Q
Fovea
- location
- role
- what photoreceptors in high conc
A
- center of the macula
- responsible for central and sharpest vision
- hgih concentration of cones (colour vision)
19
Q
Focusing on distant objects
A
(light needs adjustment to focus)
- relax ciliary muscles, lens flattens
- sympathetic process
far point of vision
-distance beyond which the lens does not need to change shape to focus (6meters)
20
Q
What division of nervous system is responsible for the relaxation of the ciliary muscles to enable distant vision
A
sympathetic
-ciliary muscles relax, ligaments pull, lens flattens
21
Q
Close vision
- distance
- accommodation
- pupil response
- eyeball rotation
- NS division for ciliary muscle behaviour
A
- less than 6 meters
- constriction of the ciliary muscles relaxes the ligaments rounding the lens
- pupillary reflex constricts the pupils, prevent divergent light rays enter the eye (would red qual img)
- convergence of the eyes, rotate medially
- parasympathetic
22
Q
what NS division for focusing on close objects
A
parasympathetic
-ciliary muscles contract
23
Q
what NS division for far objects
A
Sympathetic, ciliary muscles relax
24
Q
what is an emmetropic eye
A
a normal shaped eye with no refraction problems
25
Myopic eye
- nearsighted
- eye too long
- need concave lens
- focal point needs be moved posteriorly
26
what type of lens to correct for myopic eye vision
concave
27
what is wrong with the length of a myopic eye
too long
28
myopic eyes are BLANK sighted
near
29
Hyperopic eye
- too short
- needs convex lens
- farsighted
- Focal point needs be moved twd anterior portion of eye
30
hyperopic eye is BLANK sighted
farsighted
31
what is wrong with the length of a hyperopic eye
too short
32
what type of lens corrects a hyperopic eye
convex
33
Photoreception
process by which eye detects light energy
34
Rods and cones contain:
-visual pigments called photopigments
35
what are photopigments
visual pigments found in rods and cones
36
Pigmented epithelial layer
- membrane projections help surround/support rods and cones
| - takes up cellular debris from rods and cones (keep clean for photoreception)
37
Melanin granules
- dark staining
| - prevent light scattering
38
Study slide 52/53 BS
asdf
39
Rods and cones
| Where are visual pigments stored
stored in membrane discs in the outer segment
40
visual pigments are stored in the membrane discs of what segment of the Rods and Cones
outer segment
41
what is in the outer segment of rods and cones
membrane discs containing visual pigments
42
membrane discs of outer segment of rods and cones
contain visual pigemnts
| -opsin and retinol
43
Connecting stalk of rods and cones
connects outer and inner segments
44
where does most of the cellular function take place in rods and cones
the connecting stalk
45
RODS
- image
- abs what wavelengths of visual light
- sens to what what light lvl
- fuzzy grey indistinct images
- absorb all wavelengths of visible light
- sensitive to dim light best suited for night vision
46
photoreceptor best suited for night vision
rods
47
produces grey indistinct fuzzy image
rods
48
Retinal
- combines with what to form visual pigments
- synthesized from what vitamin
- what are the two isomers
light absorbing molecule
- combines with opsin to form visual pigments
- synthesized from vitamin A
- 11-cis and all trans
49
what are the two isomers of retinal
11-cis and all-trans
50
what vitamin is retinal synthesized from
vitamin A
51
the combination of what two molecules makes a visual pigment
retinal and opsin molecules
52
what initiates electrical impulses in optic nerve
isomerization of retinal
53
11-cis retinal sturcture
kinked/bent
54
all-trans retinal structure
straight and more elongated
55
How do we detect light (wrt isomerization)
light converts 11-cis retinal into all-trans retinal
56
outer pigmented layer, functions
- absorb light to prevent scattering in eye
- act as phagocytes to remove dead/dmg'd photoreceptor cells
- converts all-trans retinal to 11-cis
57
SLIDE 56 STUDY conversions of retinal btwn outer and inner layer
asdf
58
what form of retinal is converted into all-trans retinol
11-cist retinilidine
59
excitation of rods
Rod outer segment
11-cis retinilidine reacts with light forming all-trans retinol (moves to Retinal pigment epithelium and converts)
Retinal pigment epithelium
-all-trans retinal (AL form OL) to 11-cis retinol to 11-cis retinal (moves to outer segment becoming initial 11-cis retinilidine)
60
Cones
- where highest concentration of cones
- pigments give what vision
- synapse with how many ganglion
- vision quality
- light level for activation
- highest concentration of cones in fovea
- pigments give vividly coloured view
- synapse with ONE ganglion cell (gives vivid and high res img)
- vision is detailed and high resolution
- need bright light for activation
61
photoreceptor that needs bright light for activation
cones
62
photoreceptor that gives high resolution and vivid image
cones
63
photoreceptor that synapses with one ganglion cell
cone
64
photoreceptor with high concentration in fovea and macula
cones
65
what opsin molecules give primary colour info in cones
red green blue opsin mols
66
Visual pigments in cones are made of what 2 mols
opsin and retinal make the visual pigments
67
three types of opsin molecules in cones
red
green
blue
68
how are intermediate colour perceived in cones
activation of more than one type of cone (RGB)
69
order of wavelength activation for cones
blue (462nm) < Green (529nm) < Red (611nm)
70
STUDY SLIDE 59,60,61 Phototransduction GPR
| VERY IMPORTANT SO DO IT DUMBASS
asdf
71
does light turn signalling from rods and cones ON or OFF
off
72
neurotransmitter release from rods and cones wrt light lvl
neurotransmitter release form rods and cones decreases in proportion to amount of light
-light turns off signalling
73
Signal transduction: cone in the dark (7 steps)
1) Na/Ca channels remain open (in outer segment), cell is depolarized
2) Ca channels at axon bulb are open
3) NT released to bipolar cell postsynaptic membrane
4) IPSPs in bipolar cell
5) no NT released from bipolar cell
6) No EPSP in ganglion cell
7) no AP gen
74
Signal transduction: cone in the light (7 steps)
1) photoreceptor is hyperpolarized ( Na/Ca channels are closed in outer segment)
2) Ca channels on axon bulb are closed
3) no inhibitory NT released by cone
4) no IPSPs in the bipolar cell (bipolar cell depolarizes)
5) NT released from bipolar cell
6) EPSPs in the Ganglion cell
7) AP gen
75
Adaptation: dark to light
- retinal sensitivity
- photoreceptor system
- dramatic decrease in retinal sensitivity, rod function is lost
- switch from rod to cone system, gain visual acuity
76
dark to light, what happens to visual acuity
gain visual acuity as switch from rod to cone system
77
dark to light, what happens to retinal sensitivity
dramatic decrease, lose function of rods
78
Why does it take ~20 minutes for your eyes to adjust to the dark
takes ~20 minutes to convert the all-trans back to 11-cis
| in light the 11-cis is all converted to all-trans
79
Adaptation: light to dark
- photoreceptor function
- what molecule accumulates
- cones lose function in low light
| - rhodopsin accumulates in the dark and retinal sensitivity is restored (all-trans reconverted to 11-cis)
80
Receptive fields are accounted for by what cells
ganglion cells
81
ganglion cells have receptive fields (T/F)
T
82
Receptive fields
- what cells
- imp for what
- sensitive to what
- define convergence in this scenario
-ganglion cells
-important for sensitivity of shapes of objects
-sensitive to movements in environment
-CONVERGENCE (multiple rods - sev bipolar cells - one ganglion cell_
+converge to one ganglion
83
On-centre off-surround field
stimulated by light hitting the centre of the field
| inhibited by light hitting periphery of field
84
off-centre on-surround
inhibited by light hitting centre of field
| stimulated by light hitting periphery of field
85
Visual pathway
eye - optic nerve -optic chiasm - optic tract - lateral geniculate nucleus (body) of the thalamus - visual cortex (in occ lobes)
86
Where does the information from the right side of the visual field go
- RS of R eye
- RS of L eye
left side of the LGN
87
Left side of visual field goes:
right side of LGN
88
Why do the R/L visual field info go to the opposite (R/L) side of the LGN?
Depth perception, lets us see 3D
89
LGN sends info where (3 places)
1) visual cortex of the occipital lobe
2) midbrain (superior colliculus with CN III outputs for eye mvmnt cntrl)
3) SCN (info processing for CR)
90
why does LGN send info to the midbrain
imp for eye mvmnt cntrl (cranial nerve III)
91
what region of the midbrain has CNIII outputs
superior colliculus
92
What cranial nerve controls pupillary constriction
CN III
93
Thalamic processing of visual info happens where
LGN
94
LGN roles (4)
1) relays info on mvmnt
2) separates retinal axons in preparation for depth perception
3) emphasizes visual inputs from regions of high cone density (fovea/macula)
4) sharpens the contrast info received by the retina
95
Depth perception
- how
- type of vision provided and how
- what if one eye used?
- both eyes view same image form slightly different angles
- provides 3D vision via cortical fusion of slightly different images
- only one eye used, DP lost and observer must rely on learned cues to det depth
96
what happens to depth perception when lose Fx of one eye
rely on learned cues to determine depth
97
What are the Chemical senses
Gustation (taste)
| Olfaction (smell)
98
How do the chemical senses function
(Olfaction and gustation)
- chemoreceptors respond to chemicals in aqueous solution
- taste - CR respond to substances dissolved in saliva
- Smell - substances dissolved in the fluid of the nasal membranes
99
Chemoreceptors involved in olfaction detect
substances dissolved in the fluids of the nasal membrane
100
chemoreceptors in taste detect
substances dissolved in saliva
101
covers superior nasal concha
olfactory epithelium
102
olfactory epithelium
covers superior nasal concha
103
Olfactory cells are bipolar cellss (T/F)
T
104
what polarity are olfactory cells
bipolar
105
Olfactory foramina fx
allows projection of olfacotry receptors into olfacotry bulb
106
What structure contains the chemoreceptors responsible for smell
olfactory cilia
107
STUDY SLIDE 72
asdf
108
Glomeruli (olfaction)
neuronal connections with olfactory receptor cells in neuronal epithelium and with the mitral cells
109
Mitral cells
connected to the glomeruli, axons of mitral cells give rise to the olfactory tract found within the olfactory bulb
110
what cell creates the olfactory tract found within the olfactory bulb
mitral cells
111
Olfacotry cells
sensory neurons
| -olfactory cilia (dendrites) bind oderants (contain oderant receptors)
112
where must oderants be located to be recieved by the olfacotry cilia of the olfactory cells
dissolved within the mucus layer
113
Olfactory transduction uses what secondary messenger
cAMP
114
phototransduction uses what secondary mesenger
cGMP
115
papillae of the tongue bearing tastebuds
fungiform
circumvallate
foliate
116
how many tastebuds
| -where are most found
10000
| most on tongue
117
What 3 cells make up the taste bud
- supporting cell
- basal cell
- gustatory cell
118
Supporting cell (tastebud)
insulate the receptor
| -insulate and protect the gustatory cell
119
Basal cell (tastebud)
dynamic stem cell
| -give rise to other gustatory cells
120
gustatory cells
taste cells
| -sensitive to taste and has taste buds on it
121
Mechanism of stimulation of gustatory cells
main mechanism of stimulation is a rise in Ca
| -rise in Ca causes NT release
122
Gustatory Pathway
| what carries neural impulses form the taste buds to the solitary nucleus
CN VII
| CN IX
123
Where is the solitary nucleus
medulla
124
Cranial nerves VII and IX
carry neural impulses form the tastebuds to the solitary nucleus of the medulla
125
APs at the solidary nucleus continue to where
the thalamus
-directs to the :
+gustatory cortex (taste)
+the Hypothalamus and limbic system (appreciation of taste)
126
what brain structures are responsible for the appreciateion of taste
hypotalamus and limbic system
127
what region of the brain processes taste
gustatory cortex
128
the 3 parts of the ear
outer, middle, inner
129
Outer ear parts
auricle (pinna)
Ear canal
Tympanic membrane
130
Auricle or pinna (outer ear) parts
Helix (rim)
| Lobule (ear lobe)
131
What glands fill the ear canal and what do they produce
ceruminous glands, produce wax
132
Ear wax
produced by ceruminous glands in ear canal
| -protect, anti bacterial, anti infection, prevent bug infestation
133
Tympanic membrane (ear drum)
CT memb that vibrates in response to sound
| -transfers sound E to ossicles in middle ear
134
where are the ossicles located
middle ear
135
epitympanic recess
superior portion of middle ear
| -prone to infection
136
pharyngotympanic tube
connects middle ear to nasopharynx
| -equalizes P in ME with the external air P
137
Auditory ossicles
Incus (anvil)
Malleus (hammer)
Stapes (stirrup)
138
Where is the entranse to the mastoid antrum
epitympanic recess
139
Ear ossicles
- the 3 bones
- f(x) and target
- what dampens
Incus, Malleus, Stapes
- transmit vibrations from tympanic membrane to the oval window
- dampened by the tensor tympani and the stapedius muscles
140
Dampen the ossciles
tensor tympani and stapedius muscles
141
Stapedius muscle
helps stabilize the stapes
| -reduces hyperactivity of stapes bone
142
tensor tympani muscle
helps with the stabilization and localization of sound waves
| -interacts with the malleus
143
Stapedius and tensor tympani muscles
reduce dmg done by ext loud noises
| modify sound to some degree
144
Inner ear (2 labyrinths)
Bony Labyrinth
| membranous labyrinth
145
bony labyrinth
tortuous channels worming way through temporal bone
| -filled with perilymph
146
Membranous Labyrinth
membranous sacs w/ potassium rich endolymph fluid
| -vestibule, cochlea, semicircular canals
147
superior olivary nuclei
lateralization of sound
148
superior colliculus is auditory reflex center
149
loudenss perception
number of cochlear cells stimd
| varying thresholds of cochlear cells
150
pitch is percieved by
cochlear nuclei
| primary auditory cortex
151
vestibular receptors
static equilibrium or linear acceleration
152
semicircular canals receptors
