Exam 2 (Chapter 10) Flashcards
1
Q
what types of senses are apart of the special senses?
A
vision, hearing, taste, smell, equilibrium
2
Q
what types of senses are apart of the somatic senses?
A
touch, temp, nociception (pain, itch), proprioception (awareness of body movement & position)
3
Q
what are the steps to a general sensory pathway?
A
- stimulus
- sensory receptor
- change in membrane potential
- afferent signal
- CNS
4
Q
what are the three receptor types?
A
free nerve endings
complex neural receptors
non-neural
5
Q
what are free nerve endings?
A
they don’t have a separate receptor cell
-primary sensory neuron is the receptor & the signal
6
Q
what are complex neural receptors?
A
encased in connective tissue capsules
-no separate receptor cell (primary neuron is both)
7
Q
what are non-neural receptor cells?
A
separate receptor cell that forms a synapse w/ primary sensory neuron
-releases NT for special senses!
8
Q
what are chemoreceptors?
A
changes in chemicals (O2, CO2, pH, glucose)
9
Q
what are mechanoreceptors?
A
changes in pressure, vibration, stretch
10
Q
what are thermoreceptors?
A
changes in temperature
11
Q
what are photoreceptors?
A
changes in light
12
Q
what are proprioceptors?
A
found in joints & muscles
13
Q
what are nociceptors?
A
changes in pain & itch
14
Q
what type of receptor does taste and smell bind to?
A
chemoreceptors
15
Q
what type of receptor does hearing, equilibrium, and touch bind to?
A
mechanoreceptor
16
Q
what type of receptor does vision bind to?
A
photoreceptors
17
Q
what is meant by saying an adequate stimulus?
A
the stimulus a receptor is most sensitive to
18
Q
what is receptor potential?
A
another word for graded potential
-change in sensory receptor membrane potential that can generate an AP if it reaches the threshold
19
Q
what is a receptive field?
A
physical area that activates somatic senses or vision neurons
20
Q
larger the receptive field….
A
the less sensitive it is to a stimulus and the more convergence
21
Q
1-point discrimination
A
less stimuli converge to a single secondary neuron
-perceived as a single point
22
Q
2-point discrimination
A
more convergence onto secondary neuron
-perceived as two points
23
Q
how does sensory information enter the CNS via the spinal cord?
A
through ascending pathways
24
Q
how does sensory information enter the CNS directly into the brain?
A
through cranial nerves
25
which sense does NOT have to go through the thalamus to get into the CNS?
smell (olfaction)
26
what is perceptual threshold?
level needed to be aware or perceive a sensation
27
what are the four properties of a simulus?
modality
location
intensity
duration
28
what is modality?
which sensory neurons are activated & where pathways terminate
-each receptor most sensitive to particular form of energy
-labeled line coding
29
what is labeled line coding?
1 modality with one type of receptor
-stimulation of cold receptor = always a cold sensation
30
what is location?
which receptive fields are activated
-topographical arrangement of cerebrum
-lateral inhibition and population coding
31
what is lateral inhibition?
secondary neuron with most activation will inhibit it's neighbors
-makes sensation more localized
32
what is population coding?
multiple receptors work to send info to CNS
-can determine characteristics of a stimulus
33
what is intensity?
number of receptors activated and frequency of APs
-stronger stimulus = more APs
34
what is duration?
longer the stimulus = longer the AP's occur
-two types: tonic & phasic
35
what are tonic receptors?
slow adapting
-fire rapidly at first, then slow & maintain firing as long as stimulus presents
-only fire when we need to monitor something
-proprioceptors, baroreceptors
36
what are phasic receptors?
fast adapting
-fire rapidly at first, then cease firing if stimulus remains constant
-touch / tactile receptors
37
what three types of senses go through the medulla?
fine touch, proprioception, vibration
38
what three types of senses go through the spinal cord?
nociception, temperature, coarse touch
39
what two areas do pathways for somatic perception project to?
cortex and cerebellum
40
what is the somatosensory cortex?
-area at the front of the parietal lobe
-registers and processes body touch and movement sensations
-has sensory fields (bigger = more sensitivity)
-has cortical columns
41
what are pascinian corpuscles? tonic or phasic receptors?
respond to vibration and deep pressure
-phasic receptors (fast adaptation)
42
what are meissner's corpuscles? tonic or phasic receptors?
respond to flutter, stroking movements, and light touch
-phasic receptors (fast adaptation)
43
what are ruffini corpuscles? tonic or phasic receptors?
respond to skin stretch
-tonic receptor (slow adaptation)
44
what are merkel receptors? tonic or phasic receptors?
respond to steady pressure and texture (fingertips)
-tonic receptor (slow adaptation)
45
what are free nerve endings? tonic or phasic receptors?
respond to temp, pain, and hair movement
-can be BOTH tonic & phasic
46
what are thermoreceptors?
type of TONIC free nerve ending
-Cold (less than 37C): majority
-Hot (37C - 45C): anything above 45C activates pain receptors
-no adaptation outside of the 20C-45C range
-use transient receptor potential (TRP) channels
47
what are TRP channels?
cation channel that initiates APs
-used for pain and temp
48
nociceptors use which type of neural cell?
free nerve endings
49
what are the two types of primary sensory fibers used for pain? describe them
A-delta fibers: small, unmyelinated, FAST pain
C fibers: small, unmyelinated, SLOW pain
50
what are the two types of pain? describe them
Fast Pain: A-delta fibers, sharp, localized
Slow Pain: C-fibers, dull, diffuse
51
itch and pain show what type of relationship?
antagonistic relationship
-pain can decrease itch sensation (EX: bug bite)
52
where does the primary sensory neuron go to during nociception?
dorsal horn of the spinal cord
53
what are the two ways the primary sensory neurons enter the spinal cord during nociception?
protective spinals reflex
-coordinated entirely in the spinal cord
-withdrawal reflex (move hand to hot stove)
ascending pathway to cerebral cortex
-somatosensory pathway
-able to consciously feel pain (emotional distress)
54
what are some examples of chemical modulators of nociception?
histamine, prostaglandins, serotonin, substance P
55
what is inflammatory pain?
increased sensitivity to pain at damaged tissue
56
are there pain receptors in the CNS?
NO!
-found in skin, joints, muscles, bones, internal organs
57
where does pain modulation occur at?
-descending pathways from thalamus
-inhibits in dorsal horn before reaching ascending spinal tracts
58
what is the gate control theory?
A-beta fibers (lg, myelinated) synapsing w/ inhibitory interneurons to enhance it's activity
-activated through mechanical stimuli such as rubbing your elbow when you have pain
59
what do exogenous substances (drugs) do to modulate pain?
slow pain transmission
60
what do endogenous substances (opioid system) do to modulate pain?
decrease NT release
-endorphins, enkephalins, dynorphins
61
what is the oldest sense?
olfaction
62
which cranial nerves does olfaction use?
CN1 (olfaction nerve)
63
does olfaction use a separate receptor cell?
NO!
64
what is the olfactory pathway?
1. olfactory neuron extends out from olfactory epithelium and binds odor through a GRCP (1°)
2. activates G(olf)
3. increases cAMP, opens cation channels (depolarization)
4. AP sent along CN1
5. olfactory bulb (2°)
6. 2° goes along olfactory tract
7. olfactory cortex (temporal lobe)
8. cerebral cortex & limbic system
65
what are the five taste sensations? which types of molecules activate them?
sweet: glucose
sour: H+ (acidic)
salty: Na+
bitter: alkaline (basic)
umami: glutamate
66
which taste sensations use a type 2 TRC?
sweet, bitter, umami
67
which taste sensation uses a type 3 TRC?
sour
68
what is the gustatory pathway?
1. TRC in the taste buds binds taste sensation
2. binds to GPCR
3. Type 2 releases ATP, Type 3 releases serotonin
4. activates 1°
5. sends APs down axons that form CN7, 9, 10
6. medulla (2°)
7. thalamus (3°)
8. gustatory cortex (insula, b/w frontal & temporal lobes)
69
what are the parts in the external ear?
pinna -> tympanic membrane
70
what are the parts in the middle ear?
tympanic membrane -> oval window
-three bones are here
71
what are the parts of the inner ear?
oval window -> the rest of the ear
72
how are sound waves coded for pitch?
frequency
-high: hair cells closest to oval window are bent (fast vibrations)
-low: hair cells closest to helicotrema are bent (slow vibrations)
73
how are sound waves coded for loudness?
amplitude
-more hair cells activated = louder the sound
74
what is the hearing pathway?
1. sound enters ear canal
2. sound wave hits tympanic MB, it vibrates
3. auditory osscles (malleus, incus, stapes) amplifies sound
4. oval window vibrates, creating waves in the cochlea
5. perilymph in vestibular duct
6. endolymph (high in K+) in cochlear duct causes basilar membrane to shift hair cells against tectorial membrane
7. release NT
8. AP acts on 1° neurons to form CN8
9. medulla (2°)
10. midbrain (3°)
11. thalamus
12. auditory cortex (temporal lobe)
75
when the hair cells bend during the shifting of the basilar MB and tectorial MB, what causes a depolarization? hyperpolarization?
shift towards tallest hair cell -> depolarization (increase NT)
shift away from tallest hair cell -> hyperpolarization
76
what is equilibrium mediated by?
the hair cells in the vestibular apparatus
77
what part of the hair cell determines if it depolarizes or hyperpolarizes during equilibrium? explain
tallest part of hair cell = kinocilium
-bending towards kinocilium: depolarization
-bending away from kinocilium: hyperpolarizatoin
78
what do the semicircular canals do?
detect rotational movement
-horizontal canal, posterior canal, superior canal
79
what does the horizontal canal detect?
turning around an axis
-figure skater
80
what does the posterior canal detect?
left to right motion
-cartwheel
81
what does the superior canal detect?
forward & backward motion
-somersault
82
what does the otolith organ do?
detects linear movement / acceleration
-saccule, utricle
83
what does the saccule detect?
vertical drop
-rollercoaster
-arranged vertially
84
what does the utricle detect?
forward & backward acceleration, head tilt
-arranged horizontally
85
what is the ampula?
chamber at end of each semicircular canal
-contains the crista, hair cells, and cupula (gelatinous mass)
-full of endolymph
-endolymp moves the cupula
86
what is the macula?
utricle and saccule
-contain hair cells
-otolith membrane (gelatinous mass)
-otoliths = protein particles and calcium carbonate (create some weight in gelatinous mass)
87
what is the equilibrium pathway?
1. movement of head causes endolymph / fluid to move
2. fluid initially goes opposite direction, then same direction (inertia)
3. cupula shifts causing hair cells to bend
4. depolarization causes NT release
5. vestibular branch of CN8 (1°)
6. cerebellum (terminates) or goes to the medulla
7. medulla goes to the reticular formation
8. thalamus
9. motor cortex (frontal lobe)
88
what is the orbit?
bony cavity where the eyes sit
89
how many different muscles are used in the eye?
6
90
what is the pupil?
where light enters and changes size
-can determine depth of field
91
what is the iris?
surrounds the eye, pigmented
92
what is the lens?
light refraction to bend light to a focal point on the retina
-biconvex shaped
-separated the two chambers of the eye (vitreous chamber, aqueous humor)
93
what is the retina?
contains photoreceptors to start phototransduction
-optic disk, fovea/macula
94
what is the optic disk?
where CN2 exits & blood vessels enter & exit
-lacks photoreceptors creating a BLIND SPOT
95
what is the fovea/macula?
where light is focused on the retina
-gives high acuity vision (detailed, focused)
-high concentration of CONES
96
what do the circular pupillary sphincter muscles do?
pupil constriction (smaller)
-parasympathetic NS
97
what do radial / dilator muscles do?
pupil dilation (larger)
-sympathetic NS
98
what do ciliary muscles do?
lens shape, lens accommodation
-autonomic NS
99
what does a flat & elongated lens shape mean?
more than 20ft away
-suspensory ligaments are tight
-ciliary muscles are relaxed
100
what does a round & short lens shape mean?
less than 20ft away
-suspensory ligaments are less tense
-ciliary muscles are contracted
101
what is the visual pathway?
1. light enters cornea
2. pupil controls amount of light that enters (changes size)
3. lens refracts light to a single focal point
4. focal point of light hits the fovea / macula of retina
5. phototransduction (photoreceptors)
6. CN2 exits and goes to optic chiasm (1°)
7. lateral geniculate body of thalamus (2°)
8. visual cortex (occipital lobe)
102
what is the pupillary reflex?
signals sent that are separate from the normal pathway
1. CN2
2. optic chiasm
3. LG-B of thalamus
4. midbrain
5. CN3 sends info back to pupil to constrict or dilate
103
what are rods?
active in low light (nighttime)
-B&W
-majority (20:1)
104
what are cones?
active in high light (daytime)
-color (red, blue, green)
105
is there a lot of divergence or convergence during phototransduction?
convergence!
106
what is the rod pathway in the dark? (only the photoreceptor part)
1. rhodopsin inactive (opsin + retinal (vit. A))
2. transducin (G-protein) inactive
3. CNG channels open, cGMP high
4. Na+ and K+ enter, depolarizes
5. high glutamate release
107
what is the rod pathway in the light? (only the photoreceptor part)
1. rhodopsin active
2. transductin active
3. CNG channel close, cGMP low
4. K+ exits, hyperpolarization
5. low glutamate release
108
what types of receptors do ON-bipolar cells use? when are they activated, light or dark?
metabotropic receptors
-activated in the light
-glutamate is inhibitory
109
what types of receptors do OFF-bipolar cells use? when are they activated, light or dark?
ionotropic receptors
-activated in the dark
-glutamate is excitatory
110
what happens to the ON and OFF bipolar cells when glutamate is high?
ON: glutamate inhibits, HYPERPOLARIZES
OFF: glutamate opens cation channels, DEPOLARIZES
-activated
111
what happens to the ON and OFF bipolar cells when glutamate is low?
ON: no inhibition, DEPOLARIZES
OFF: glutamate can't bind, channels close, HYPERPOLARIZES
112
what do ganglion cells do for vision?
contrast (shades)
113
what is the On-center / Off-surround ganglion cell?
-fires when it hits center
-if it hits surround, ganglion is inhibited
114
what is the Off-center / On-surround ganglion cell?
-fires when it hits surround
-if it hits center, ganglion is inhibited
115
what is the difference b/w the binocular zone and monocular zone?
binocular: 3D images, depth perception, visual fields overlap
monocular: 2D, visual fields don't overlap
