Sensory Systems Flashcards
2
Q
Sensory receptor cells
A
transduce physical/chemical stimuli into signals taht are transmittable/interpretable
3
Q
Most sensory cells are ______ . specialized for different stimuli
A
modified neurons
4
Q
Membrane receptor proteins
A
a component of sensory cells that detect a stimulus and respond by altering the flow of ions across the plasma membrane
5
Q
Sensory cells transduce energy into
A
action potentials
6
Q
First step in sensory cells is
A
activation of a receptor protein by stimuli
7
Q
After the the stimuli is recognized, the receptor protein
A
opens/closes ion channels
8
Q
Machanoreceptor
A
response to pressure
9
Q
Chemoreceptor
A
response to taste/smell
10
Q
Lightreceptor
A
responds to light…
11
Q
The change in membrane potential causes the sensory cell to ____ or change its secretion of a ____ to a neuron that will fire the potential
A
fire an action potential ; neurotransmitter
12
Q
Intensity of the stimuli is related to the ____ of the action potential
A
frequency
13
Q
sensory cells form
A
sensory organs
14
Q
sensory systems include
A
sensory cells, associated structures, and neuronal networks
15
Q
Sensory data are basically
A
depolarization events
16
Q
Sensory data can be interpreted in different ways depending on
A
the different places and cells in the CNS where messages arrive (heat, pressure, movement)
17
Q
Information can be sensed without being conscious
A
True
18
Q
ionotropic sensory detection
A
receptor protein is a part of the ion channel
19
Q
How does a ionotropic sensory detector open and close channel pores?
A
changes it conformation
20
Q
metabotropic sensory detection
A
receptor protein is link to a G protein
21
Q
How does a metabotropic sensory detector work?
A
It activates a cascade of intracellualr events that open/close channels
22
Q
Pressure involves ________ receptors while taste/smell and light involve ________ receptors
A
ionotropic ; metabotropic
23
Q
To feel the stimuli, the receptor must trigger an _______ to be transmitted
A
action potential
24
Q
A change in the resting membrane potential of a sensory cell in response to stimuli is
A
receptor potential
25
Q
Primary sensory cells (example)
A
directly generates action potentials (exL crayfish stretch receptor)
26
Secondary sensory cells
induces the release of a neurotransmitter to generate action potentials
27
Adaptation
tolerance of a stimuli by a cell
28
Animals can ignore _____ stimuli but still be sensitive to ______ stimuli
continuous; changing
29
Categories of chemoreceptors
Olfaction- smellGustation-taste
30
Olfactory sensors are ____ embedded in a layer of _____ cells
neurons; epithilial cells
31
Olfactory sensors are located at the top of the \_\_\_
nasal cavity
32
Axons of the olfactory sensors project to the _____ of the brain
olfactory bulb
33
Dendrites of olfactory axons are on the
nose hairs (olfactory hairs)
34
Outside substances diffuse through ______ to reach the olfactory hairs
mucus
35
odorants are _____ that bind to the _____ proteins
chemicals; olfactory receptor proteins
36
When an odorant binds to a receptor it activates a
G protein
37
What does a G protein do
activates and enzyme that increases the level of the second messenger cAMP
38
After the G protein activates the enzyme cAMP, it opens a _____ channel
cation
39
The opening of a cation channel in ordorant reaction leads to the ______ of the membrane to \_\_\_\_\_\_
depolarization; fire and action potential
40
Humans have how many olfactory receptor neurons?
20 million
41
Each olfactory receptor neuron in the nose expresses ____ type(s) of olfactory receptor
ONE
42
Humans have how many genes for olfactory receptors?
1K
43
How many of the human OR genes actual make OR receptors?
380
44
What are the rest of the OR genes?
Pseudogenes with mutations
45
The number of ordorant molecules is less than the number of receptor proteins
False
46
Each odorant may bind to one or more specific RP's
True
47
A specific orderant is distinguished according to
the different combo of cells it activates
48
higher concentration of orderant molecules means a higher _____ which means a stronger \_\_\_\_\_\_
frequency of action potentials- stronger small
49
How is the olfactory system like the immune system?
It characterizes unknown molecules
50
Taste buds
clusters of sensory cells recognizing taste
51
Humans have how many taste buds?
10K
52
Papillae
raised bumps of sensory cells on the tongue
53
\_\_\_\_\_ expose the tips of the sensory cells
Pores
54
\_\_\_\_\_ increase the surface area of the cells
Microvilli
55
Sensory cells from _____ with dendrites of sensory neurons
synapses
56
Taste buds remain on the tongue indefinitely
False- they are replaces every few days
57
Five basic tastes
Sweet, bitter, umami (savoury), salty, sour
58
Sweet, bitter, and savoury are detected by
G-protein coupled receptors
59
Describe umami
a meaty savoury taste triggered by amino acids and MSG
60
Salty and sour are detected by
ion channels
61
Mechanoreceptors
cells sensitive to physical "mechanical" forces
62
What causes mechanoreceptor channels to open?
physical distortion of the plasma membrane
63
Basically when ion channels open
action potentials are fired
64
Skin is packed with diverse ______ that sense _____ sensations
mechnoreceptors - various sensations
65
Merkel's Discs
provide continuous information about things touching the skin
66
Meissner's coupuscles
very sensitive, on non-hair skin. they adapt rapidly and provide info on changes of things touching the skin
67
Ruffni endings
provide info about vibrating stimuli of low frequencies
68
Pacinian copuscles
vibrating stimuli of high frequencies
69
\_\_\_\_\_ of mechnoreceptors influences how _______ stimulation can be "resolved"
density- finely
70
Photosensitivity is sensitivity to
light
71
Rhodopsins
pigments (light receptor molecule) that perceive light
72
Rhodopsin absorb photons of light and undergo \_\_\_\_\_\_\_\_
conformational changes
73
Rhodopsin molecules consist of a protein called \_\_\_\_\_
Opsin
74
Rhodopsin molecules consist of a light absorbing group called
11-cis-retinal
75
11-cis-retinal is ________ to the center of the opsin molecule
covalently bound
76
11-cis-retinal absorbs a _____ and it changes to \_\_\_\_\_\_
a photon, all-trans-retinal
77
When 11-cis-retinal changes to all-trans-retinal it changes the _____ of opsin
conformation
78
Change in conformation signals \_\_\_\_\_\_\_
that light is detected
79
Blindness is due to lack of
Vitamin A
80
What is the first sign of vitamin A deficiency?
Night blindness-the inability to see well in dim light
81
Without adequate amounts of ____ rhodopsin cannot regenerate and leads to \_\_\_\_
retinal, night blindness
82
Carrots are a good source of
beta-carotene
83
Rod cell is a _______ that releases _______ that influence other neurons
a photoreceptor (modified neuron) that releases neurotransmitters that influence other neurons
84
3 Parts of the rod cell
outer segment, inner segment, and a synaptic terminal
85
The inner segment of a rod cell consists of
a nucleus and many mitochondria
86
The outer segment of a rod cell consists of
a stack of plasma membrane disks
87
The stacks of membrane disks in the rod call are densely packed with
rhodopsin
88
Stacked disks in the rod cell do what?
capture photons
89
In the dark, a rod cell has a ___________ resting potential because...
depolarized ; Sodium channels are continually open
90
The outer segment of the rod cell becomes _____ upon light exposure
hyperpolarized
91
Photoreceptor cells can also fire action potentials
FALSE
92
Sclera
connective tissue that holds together the eye
93
Cornea
transparent structure that allows light passage
94
Iris
pigmented structure that controls the amount of light that enters
95
Pupil
where light actually enters
96
Lens
focuses the images/light for the retina
97
Retina
photosensitive area at the back of the eye
98
Fovea
the most sensitive area of the retina
99
Optic nerve
transmits the info from photoreceptors
100
Light must pass through all the layers of the eye before reaching the rhodopsin
True
101
Two types of vertebrate photoreceptors
Rods and cones
102
The human retina is organized into how many layers of cells?
5
103
Cells at the front of the retina are
ganglion cells
104
The axons of the ganglion cells of the retina form the ______ and do what?
optic nerves and fire action potentials
105
Photoreceptor cells are located where on the retina?
the back
106
Bipolar cells
what connects ganglion cells and photoreceptors
107
Release of NTs from ______ cells causes the rate of of NT release from _____ to change
photoreceptor cells ; bipolar cells
108
Release of NTs from ____ cells cause ____ cells to fire action potentials
bipolar; ganglion cells
109
What connects neighboring pairs of photorecpetors and bipolar cells?
Horizontal cells
110
Horizontal cells provide a _____ flow of information
lateral
111
\_\_\_\_ connect neighboring bipolar and ganglion cells
Amacrine cells
112
Amacrine cells help
make eyes more sensitive to small rapid changes
113
Which of the two vertebrate photoreceptors are more sensitive to light?
Rod cells
114
Rod cells provide the ______ vision at low light levels
black/white
115
Human retina has how many rods?
125 million
116
Cone cells are more light sensitive than rod cells
FALSE
117
Cone cells are responsible for _____ vision
color
118
Cones provide the sharpest vision
True
119
Human retina has how many cones?
6 million
120
The fovea consists of what cells/photoreceptors?
Cones
121
Three types of cone cells
L, M, S types
122
L-type cones
absorb long wavelength light (yellow-green)
123
M-type cones
medium wvlngth (blue-green)
124
S-type cones
short wavelength (blue-violet)
125
LMS type cones differ in the _____ which absorb different light wavelengths
opsins
126
The macula is
an oval yellow spot near the center of the retina. used for high acuity vision (diameter is about 5 mm)
127
High Acuity Vision
the ability to detect fine material (reading)
128
The ___ is the center of the Macula
fovea
129
The fovea is responsible for
sharp central vision (visual detail, reading)
130
The human fovea has how many cone cells per mm sq? A hawk?
160K ; 1 million
131
The blind spot
where there are no photoreceptors, where blood vessels and bundles of axons from the back of the eye go into the brain
132
Age-related macular degeneration ( AMD)
photoreceptors in the macula degenerate over time; may lead to blindness past the age of 50
