Special Senses Flashcards
1
Q
Sensation definition
A
action potential that reaches the brain through sensory neurons
2
Q
Perception definition
A
interpretation of the stimuli after the brain is aware of the sensation
3
Q
what is the process of sensory reception?
A
- sensory transduction
- amplification
- transmission
- integration
4
Q
What is sensory transduction?
A
conversion of stimulus energy into a change in the membrane potential
5
Q
what does transduction result in?
A
a graded membrane - receptor potential
if it passes threshold, it will lead to an action potential
6
Q
what is a receptor potential?
A
graded potentials produced in response to a stimuli
7
Q
what performs sensory transduction?
A
sensory receptors
8
Q
what are sensory receptors?
A
specialized neurons that can detect the stimulus and convert it to a receptor potential (graded membrane potential)
9
Q
What are the two main types of sensory receptors?
A
exteroreceptors
interoreceptors
10
Q
What is an exteroreceptor?
A
sensory receptors that detects stimuli outside the body
11
Q
What is an interoreceptor?
A
sensory receptors that detects stimuli within the body
12
Q
what are the types of exteroreceptors?
A
- photoreceptors
- chemoreceptors
- mechanoreceptors
- nociceptors
- thermoreceptors
13
Q
What is the stimuli and sensory organ for photoreceptors?
A
light - eyes
14
Q
What is the stimuli and sensory organ for mechanoreceptors?
A
pressure, movement - skin, muscles, ears
15
Q
What is the stimuli and sensory organ for nociceptors?
A
pain - skin
16
Q
What is the stimuli and sensory organ for thermoreceptors?
A
temperature - skin
17
Q
What is the stimuli and sensory organ for chemoreceptors?
A
chemicals - nose, tongue
18
Q
what is amplification?
A
the strengthening of stimulus energy that is otherwise too weak to be carried into the nervous system
19
Q
what can amplification be performed by?
A
by the sensory receptors or other parts
20
Q
what is transmission?
A
conduction of impulses to the CNS
21
Q
what can perform transmission?
A
- sensory receptor - transduce, and transmit, acting like the afferent neuron
- sensory (afferent) neuron: sensory receptors will synapse with the afferent neuron which will then tansmit
22
Q
what is integration?
A
processing of information that occurs in the central nervous system, in particular the lobes of the brain
23
Q
what is sensory adaptation?
A
a type of integration where there is a decrease in responsiveness with continued stimulation
24
Q
what are the 4 special Senses with their specialized organs?
A
- vision - eyes
- hearing - ears
- smell - nose
- taste - tongue
25
What is the 1 somatic sense and its organ?
tough - skin
26
what does the iris do?
regulates the amount of light entering the pupil
27
what do the cornea and lens do?
lenses help focus the image on the retina
28
Cornea has the larger body of nerve bundles and is extremely sensitive to pain
29
What are the 3 tissue layers of the eye?
- sclera muscles
- choroid: blood vessels
- retina: light sensitive cells
30
what does the optic nerve do?
neurons send visual stimuli to the brain
31
what 2 types of cells does the retina consist of?
rodes and conves
32
where is the retina?
the back of the eye
33
what does the retina do?
converts light signal into an electrical signal that is transmitted through the optic nerve to the occipital lobe of the brain
34
When do cone cells function best?
in bright light - requires more light to stimulate
35
What do cone cells do?
distinguish colours in daylight
36
what do rod cells detect?
detects black, white and shades of grey - explains why night vision is in black and white
37
when do rod cells function?
- function in less intense light like the night
can be triggered by as few as 6 photons of light
38
what are examples of photoreceptors?
rod and cone cells?
39
what are photoreceptors?
specialized neurons that perform phototransduction
converts light energy to receptor potential
40
what do photoreceptors contain?
disks which are similar to thylakoids in chloroplast
41
What do the disks in the photoreceptors contain?
protein + pigment complex (similar to photosystems)
42
What is the protein inside the photoreceptor?
opsin
43
Describe opsin
- light sensitive
- 4 different types
- 1 for rod cells
- 3 for cone cells
44
what is the pigment in photoreceptors?
retinal
45
describe retinal
- light absorbing
- derived from vitamin
46
what is rhodopsin?
opsin + retinal found in rod cells
47
What is photpsin?
1 of the 3 opsin + retinal in cone cells
48
What are the 3 types of photopsin? What are they based on?
S- cones
M-cones
L-cones
they are based on the 3 primary colours of light
49
What do S-cones see?
short wavelength, blue cones
50
What do M-cones see?
medium wavelength, green cones
51
What do L-cones see?
long wavelength, red cones
52
what is a photoisomer?
molecule changes shape when it absorbs a photon of light
53
retinal is a photoisomer
54
how does rhodopsin work in light?
- photons hit photoreceptors
- photons change the shape of the retinal from cis to trans
- trans retinal isomer detaches from opsin
- free opsin is activated resulting in closed Na channels
- membrane hyperpolarizes
55
what does the hyperpolarization result in?
decreased release of neurotransmittter glutamate
56
what is the effect of glutamate at the synapse?
can have inhibitory or excitatory effect depending on type of glutamate receptor on the bipolar cell
57
how does rhodopsin work in light?
- opsin free from retinal
- becomes activated
- close Na channels
- hyperpolarize
- decrease release of NT glutamate
- IPSP or EPSP on post-synaptic bipolar cells
58
how does rhodopsin work in the dark?
- opsin is attached to retinal (inactive)
- Na channels open
- depolarize
- increased release of NT glutamate
- IPSP or EPSP on post-synaptic bipolar cells
59
what order does sensory reception for vision follow?
photoreceptor -> bipolar cells -> ganglion cell
60
what happens where there is an action potential at the ganglion cell?
the impulse is transmitted along the optic nerve to the occipital lobe of the brain
61
what cells perform sensory transduction?
rod & cone cells
62
what cells perform amplification?
rode & cone cells
63
what performs transmission?
optic nerve
64
what performs integration?
the occipital lobe
65
what is the process of hearing?
1. sound waves hit the ear drum
2. vibration in middle ear that amplifies the sound 22x
3. bones tap on cochlea which is filled with fluid
4. cochlea lined with ciliated cells that bend in response to vibration
5. movement of cilia signals
66
what is cochlea composed of?
2 large chambers filled with fluid
67
what are the 2 large chamber in the cochlea?
- the upper vestibular canal = scala vestibuli
- the lower tympanic canal = scala tympani
68
What separates the 2 large chambers in the cochlea?
the cochlear duct
69
where is the organ of corti?
on the floor of the cochlear duct
70
what does the organ of corti have?
hair cells which are auditory receptor cells that are attached to the tectorial membrane
71
how does auditory transduction work?
- sound waves translated as pressure moves through the cochlea, dissipating at the round window
- movement vibrates tectorial membrane in organ of corti which bends hair cells
- stimulates opening of ion channels and release of neurotransmitters at synapse
- sensory (post-synaptic) neurons (cochlear nerve) conducts action potential to temporal lobe of brain
72
what are volume changes determined by?
the amplitude of sound waves which translates in frequency of the action potential
73
What can overly loud noises do?
damage cochlear cilia
74
how is pitch interpreted in sounds?
sound wave frequencies
75
How is ditch distinguished in the body?
by stimulating hair cells in different sensory neurons located at different parts of the cochlea with each sensory neurons being mapped to a particular auditory area in the brain
76
what is the vestibular system involved in?
stability and balance
77
what does the vestibular system consist of?
semicircular canals
78
where are the semicircular canals located?
above the cochlea
79
what are the semicircular canals filled with?
gel-like substance containing otoliths
80
what are otoliths? Describe them.
- ear stones
- CaCO3 granules
- denser than the gel
81
what does hair cells in contact with otoliths do?
gravity causes otoliths to pull downward on hair cells and then the direction of bend indicates position to the brain
82
what is the scientific term for smell?
olfaction
83
what is the scientific term for taste?
gustation
84
what is the specialized structure for smell?
the nose
85
what is the specialized structure for taste?
the tongue
86
what is the chemoreceptor for taste?
gustatory receptors cells in taste buds
87
what is the chemoreceptor for smell?
olfactory receptor cells in upper portion of nasal cavity
88
what si the form of the chemical for smell?
airborne
89
what is the form of the chemical for taste?
in solution
90
what are the 5 basic taste perceptions?
- sweet
- salty
- sour
- bitter
- umami
91
where are gustatory receptors cells?
inside the taste buds
92
describe the chemotransduction of taste
- molecule binds to chemoreceptor in gustatory receptors cells of taste bud
- open Na+ or close K+ channels
- depolarization
- releases neutransmitter
93
what structure does the sensory transduction for taste?
taste buds
94
what structure does the sensory amplification for taste?
taste buds
95
what structure does the sensory transmission for taste?
gustatory (taste) nerve
96
what structure does the sensory integration for taste?
parietal lobe
97
describe the chemotransduction of smell
- chemical binds to chemoreceptors on the membrane of the cilia in the mucus lining of the nasal cavity
- open Na+ channels
- depolarization
- releases neurotransmitter
98
what structure does the sensory transduction for smell?
olfactory receptor cells
99
what structure does the sensory aplification for smell?
olfactory receptor cells
100
what structure does the sensory transmission for smell?
olfactory nerve in olfactory bulb
101
what structure does the sensory integration for smell?
temporal lobe
102
