;Chapter 18-General and Special Senses Flashcards
(72 cards)
1
Q
sensory receptor
A
- specialized receptor that sends sensations to CNS
- tonic receptor
- phasic receptor
2
Q
tonic receptor
A
always sending signals to CNS
3
Q
phasic receptor
A
becomes active only with changes in the conditions they monitor
4
Q
types of receptors
A
chemoreceptors -taste -smell nociceptors -cell damage (mechanical, electrical, thermal) thermoreceptors -thermal mechanoreceptors -hearing -stretching -body position photoreceptors -light
5
Q
receptor characteristics
A
receptive field: area monitored by a single receptor cell
receptor specificity:
-each receptor responds to a specific stimulus
-example: photoreceptor will no respond to a chemical stimulus
more receptor fields=more precise responses
6
Q
sensation vs perception
A
sensation: -sensory information arriving at the CNS Perception: -conscious awareness of sensation --all nerve impulses are identical (just action potentials) --brain interprets impulses --"feeling" that occurs when sensory impulses are interpreted sensation=perception?
7
Q
sensory adaptation
A
- occurs when sensory receptors are subjected to continuous stimulation
- results in a reduction of sensitivity
- at some point along the pathway, impulses are conducted at a decreased rate
- several types
8
Q
types of sensory adaptation
A
- peripheral adaptation
- central adaptation
9
Q
peripheral adaptation
A
when sensory receptors decrease their level of activity
10
Q
central adaptation
A
- sensory neurons are still active
- CNS causes reduced perception
11
Q
sensory limitations
A
sensory information from receptors is incomplete
- do not have receptors for every stimulus
- other animals can detect things we cannot: infrared, ultraviolet, ultrasound, etc.
- receptors have limited ranges
- stimulation requires a neural event that is interpreted
12
Q
general vs special senses
A
general senses
-do not have specialized receptor cells or sensory organs
special senses
-can have specialized receptor cells separate from the sensory neuron
-structurally more complex
-receptors localized in sense organs
13
Q
general senses
A
3 major groups
- exteroceptors
- propriocepts
- interoceptors
14
Q
exteroceptors
A
relay info about external environment
15
Q
proprioceptors
A
-depict body position in space
16
Q
interoceptors
A
monitor the internal environment
17
Q
nociceptors
A
-sense tissue damage
-perceived as pain
-free nerve endings with large receptive field
–found everywhere except brain
–provide a protective function
–do not adapt well (do not want to prolong injury)
deters behavior that is damaging
18
Q
types of pain
A
fast pain: quick, inducing a reflex usually; end when stimulus unds
slow pain (burning): begins later; persists longer; ache
referred pain
-visceral pain that feels like it is coming from a more superficial region
-due to superficial structures being innervated by the same spinal nerves as damaged viscera
-“brain freeze”
19
Q
thermoreceptors
A
- invovle heat and cold
- -no difference in structure between the two
- free nerve endings in skin
- quick to adapt
- felt as pain
- -if temp goes above 45C
- -if temp goes below 10C
20
Q
mechanoreceptors
A
- sensitive to mechanical forces that cause tissues to be deformed
- types:
- tactile
- baroreceptors
- proprioceptors
21
Q
tactile receptor
A
touch, pressure and vibration
22
Q
baroreceptors
A
pressure changes in walls of vessels, etc
23
Q
proprioceptors
A
position of joints and muscles
24
Q
tactile receptors: two categories
A
unencapsulated (3 types)
encapsulated (3 types)
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tactile receptors: unencapsulated
```
free nerve endings
-in papuillary of dermis
-general touch
root hair
-monitor distortions and movement across body surface
tactile sic
-expand nerve terminal that synapses with merkel cell
-sensitive to fine touch
```
26
tactile receptors: encapsulated
```
tactile corpuscles
-found where tactile sensitivities are very well developed
-hands
lamellated corpuscle
-respond to deep pressure
-squeeze arm
ruffini corpuscle
-in dermis
-detect pressure with little adaptation
```
27
baroreceptors
-stretch receptors
-monitor changes in pressure
--detect stretching of tissue walls
-regulates autonomic activities
--digestive tract
--bladder
-carotid sinus
--lung
-colon
--major arteries
similar to ruffini corpuscles but difference is location
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proprioceptors
- monitor position of joints, tension in tendons, state of muscle contraction
- everywhere, skeletal muscle
- no adaptation to stimulus
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types of proprioceptors
muscle spindle: monitor length of muscle
golgi tendon organ
-monitor tension in a tendon during contraction
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chemoreceptors
- respond to substances dissolved in surrounding fluids
- monitor chemical composition of body fluids
- -example: sensitive to pH, CO2 changes
- found:
- -inside CNS, medulla
- -aortic bodies
- -carotid bodies
31
special senses
next ones
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olofaction
- sense of smell
- olfactory organ
- -located within the nasal cavity on either side of nasal septum
- -covers the cribiform plate of ethmoid
- -made up of olfactory epithelium
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olfactory cells
olfactory epithelium consists of
-olfactory receptors: chemoreceptors
-supporting cells: surround the receptors
-basal cells: stem cells that grow new cells
covered in secretions from olfactory glans
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olfactory receptors
- highly modified bipolar neurons
- have cilia that extend into mucus secreted by olfactory glands
- odorous particles dissolve into mucus and cause depolarization
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olfactory nerve pathway
- impulses travel along axons of receptor cells
- pass through openings in cribiform plate
- go to olfactory bulb and cranial nerve I
- unique in that the impulse does NOT go through the thalamus
- travel along tracts to limbic system
- -smells can trigger strong emotions
- interpreted as smell in temporal lobe and base of fronts
36
olfactory discrimination
- no structural difference in receptor cells
- olfactory can turn over (reproduce)
- -but numbers decrease with age
- 50 primary smells
- -combinations allow us to distinguish thousands of smells
- adapt quickly
37
gustation
- taste
- chemoreceptors in structures called taste buds
- taste buds on superior surface of tongue in papillae
- gustatory receptors found in taste buds found in papillae found on your tongue
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papillae
- epithelial projections
- taste buds lie along papillae
- three types of papillae
- filiform
- fungiform
- cicumvallate
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taste buds and receptors
- gustatory cells: receptor clusters
- -about 40 per bud
- also have basal cells
- -replace receptors every 10-12 days
- gustatory cells extend microvilli called a taste hair into taste pore
40
gustatory pathway
- uses cranial nerves VII, IX, and X
- afferent fibers synapse with nucleus solitarius in medulla
- goes to thalamus and cerebral cortex
41
gustatory discrimination
primary tastes
- sour
- sweet
- salt
- bitter
- water
- umami-meat
- individual differences in taste
- number and sensitivity decrease with age
42
external ear
- auricle: external structure supported elastic cartilage
- external acoustic meatus: canal to middle ear
- -ceruminous glands: make wax
- -hairs
- ends at tympanic membrane
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middle ear
consists of tympanic cavity
-air filled space between external and inner ear
tympanic membrane
-thin, transparent connective tissue sheet
auditory tube
-when open
--middle ear equalized to atmospheric pressure
--can be induced by chewing or yawning
--allows for microbes to get in and cause an 'ear infection'
44
middle ear ossicles and muscles
-tiny bones in middle ear
-transfer vibrations from the tympanic membrane to inner ear
-includes: malleus, incus, stapes
muscles:
-tensor tympani muscle
--inserts on malleus
-stapedius muscle
--inserts on stapes
45
inner ear
- a series of tubes and cavities
- split into two sections:
- -vestibule (balance)
- -cochlea (hearing)
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layers of inner ear
- memranous labyrinth
- -contains endolymph fluid
- bony labyrinth
- -dense bone layer of the temporal
- -contains perilymph fluid
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cochlea
- converts vibrations to sound
- contacts the stapes at the oval window
- coiled tube with cochlear duct
- divided into three ducts
- -vestibular duct: divided by vestibular membrane
- -cochlear duct: divided by basilar membrane
- -tympanic duct
48
organ of corti
found on the basilar membrane
-mass of epithelial cells
contains:
-hair cells: mechanoreceptors with stereocilia (stick out in order to be deformed, send signals to dendrites)
-cranial nerve VIII: cochlear branch contacts hair cells
-tectorial membrane: positioned right above hair cell stereocilia, deforms sterocilia
49
the path of vibrations
1. auricle funnels vibrations into meatus
2. tympanic membrane vibrates
3. transmits to ossicles
- malleus to incus to stapes
4. stapes connected to oval window
- transmits vibrations to inner ear
5. oval window vibrates; perilymph moves
6. membranous labyrinth vibrates
- cochlear duct vibrates within
7. basilar membran bounces
- hair cell stereocilia contact tectorial membrane
- become deformed and creates depolarization
- transmits an action potential down of CN VIII
50
pathway for auditory sensations
-carried by cochlear branch of cranial nerve VIII
-goes to cochlear nucleus of medulla
-travels through thalamus
-processed in auditory cortex of temporal lobe
mechanoreceptors detect different pitches of sound in different portions of the cochlea
51
vestibule
consists of:
semicircular canals
utricle and saccule
52
semicircular canals
- three total: anterior, posterior, lateral
- surrounding semicircular ducts
- ampulla (swellings) at base: each possess cristae that attaches to a cupula (inside critae, creates action potential)
53
utricle and saccule
- paired membranous sacs
- connected by endolymphatic duct
- saccule possess maculae (creates action potential
54
semicircular canals
- contains fluid thats pulled on by gravity
- cupula has hair cells
- head rotation:
- -causes fluid to move through canals
- -fluid moves cupula
- hair cell stereocilia bends
- depolarization occurs
55
utricle and saccule
```
deal with head orientation
Maculae consists of
-hair cells
-otolith:
--small calcium carbonat ecrystals
--gel like substance
Head orientation changes
-gravity pulls on crystals
-moves otolith
-deforms hair cell stereocilia
-depolarization occurs
```
56
pathway for balance sensation
hair cells
- activate neurons of vestibular branch of cranial nerve VIII
- synapses with vestibular nuclei
57
eye accessory structures
- eyelids or palpebrae
- tarsal glands
- conjunctiva
- lacrimal apparatus
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eyelids or palpebrae
- protect and lubricate
| - epidermis, dermis, CT
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tarsal glands
-oily secretions keep lids from sticking together
60
conjuctiva
- thin protective mucus membrane-what you see when you look at eye
- palpebral (eyelid) and bulbar (on eye)
- stopes at coneal edge
- dilated BV--bloodshot
61
lacrimal apparatus
-produce tears
consists of:
-lacrimal gland: produces tears
-lacrimal punctum: drains tears into lacrimal canaliculi
-lacrimal canaliculi: passageway that leads to the lacrimal sacc
-lacrimal sac: fills groove on lacrimal bone, connects to the nasolacrimal duct
-nasolacrimal duct: delivers tears to nasal cavity
62
eye layers
3 layers
- fibrous tunic
- vascular tunic
- neural tunic
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fibrous tunic
outer
- sclera
- -white of eye
- -dense irregular CT
- Cornea
- -transparent layer
64
vascular tunic
```
iris
-smooth muscles and pigments
choroid
-vascularized, pigmented layer
lens
-layered proteins
-refracts light
```
65
vascular tunic: ciliary body
- below the iris
- has ciliary processes
- -attach to suspensory ligaments
- -attach to lens
- ciliary muscles change the lens shape
- -focus
66
vascular tunic: functions
- route for BV's
- regulate amount of light
- secrete and absorb aqueous humor
- control shape of lens
67
neural tunic
- inner most layer
- retina
- 5 groups of retinal neurons
68
retinal neurons
- receptor cells
- -rods and cones
- -detect light
- bipolar neurons
- -synapse with above
- ganglion cells
- -synapse with above
- amacrine cells
- -modulate communication between bipolar and ganglion cells
69
rods and cones
```
rods
-very light sensitive
-do not discriminate color
-require less light
cones
-color vision
-three types: red, blue, green
-give sharper image
```
70
neural tunic: regions of the retina
- macula lutea: area of no rods
- fovea centralis: area of most cones, within macula
- optic disc: beginning of optic nerve, "blind spot"
71
visual pathway
- photoreceptors to
- bipolar cells to
- ganglion axons converge on optic disc into optic nerve (cranial nerve II)
- optic tract to optic chiasm
- relayed to lateral geniculate nucleus
- on the visual cortex of occipital lobe-finally see, associate it with previous sights
72
cavities
posterior cavity (behind lens)
-contains gelatinous vitreous body-gel like
anterior cavity( between leans and cornea)
-contains clear aqueous humor-watery
