Chapter 7: Other Sensory Systems Flashcards
1
Q
Pinna
A
- outer ear
- flesh and cartilage
- helps locate sound by altering reflections of sound waves
2
Q
Auditory Canal
A
-sound waves pass through
3
Q
Tympanic Membrane
A
- ear drum
- middle ear
- vibrates at same frequency as sound waves that strike it
4
Q
Oval window
A
- membrane of inner ear
- small bones increase pressure of waves on small oval window
- more force = necessary to move viscous fluid
5
Q
Cochlea
A
- has 3 long fluid filled tunnels (scala vestibuli, scala media, scala tympani)
- stirrup makes oval window vibrate which moves the fluid inside the cochlea
6
Q
Hair cells
A
- auditory receptors
- inside cochlea
- vibrations displace the hair cells that open ion channels in the membrane
- hair cells excite the cells of the auditory nerve (8th cranial nerve)
7
Q
Pitch Perception: Place Theory
A
- each area along basilar membrane is tuned to a specific frequency
- each frequency activates the hair cells at only one place along basilar membrane and neurons distinguish the frequency based on what neuron responds
8
Q
Pitch Perception: Frequency Theory
A
- basilar membrane vibrates in synchrony with a sound which causes auditory nerve axon to produce action potentials at the same frequency
- not valid due to refractory period of neuron
9
Q
Current Theory of Pitch Perception: Low Frequency Sounds (up to 100Hz)
A
-modification of place theory and frequency theory
LOW FREQUENCY SOUNDS: up to 100Hz
-basilar membrane vibrates in synchrony with sound waves (frequency theory)
-auditory nerve axons generate 1 axon potential per wave
-soft sound activates fewer neurons
-stronger sound activates more neurons
-frequency of impulses identifies pitch
-#of cells identifies loudness
10
Q
Current Theory of Pitch Perception: High Frequency Sounds (above 100Hz)
A
- fire every 2nd, 3rd, or 4th etc later wave
- only at peak of sound wave
- action potentials are phase locked
- can have multiple auditory neurons that fire but not at the same time therefore take the sum of the neurons
11
Q
Volley Principle
A
-auditory nerve as a whole produces volleys of impulses for sounds up to 4000 Hz even though there is no one specific axon that does that frequency
12
Q
Sound localization
A
- determining direction and distance of a sound requires comparing responses of the 2 ears
- difference in intensity between 2 ears
- difference of time of arrival
- low frequency: phase difference, at different angles sounds are out of phase
- high frequency: loudness differences
- localize most by time of onset
13
Q
types of hearing loss and the conditions that can cause them.
A
-disease, infections, or tumorous bone growth prevent middle ear from transmitting sound waves to cochlea
=conductive deafness
=middle ear deafness
-damage to cochlea, hair cells, or auditory nerve
=nerve deafness
=inner ear deafness
-can be inherited or from a variety of disorders
-exposure to loud noises=long term damage to synapses and neurons of auditory system
14
Q
Tinnitus
A
- ringing in ear
- can be from nerve deafness
15
Q
Role of otoliths
A
- calcium carbonate particles next to hair cells
- when head tilts in different directions otoliths push against different sets of hair cells and excite them
16
Q
Role of semi-circular canals
A
- oriented in perpendicular plane filled with jelly substance
- lined with hair cells
- acceleration of head causes jelly to push against hair cells
- action potentials initiated by cells of vestibular system travel through 8th cranial nerve to brainstem and cerebellum
17
Q
Action Potentials initiated by vestibular system go…
A
-action potentials initiated by cells of vestibular system travel through 8th cranial nerve to brainstem and cerebellum
18
Q
Free nerve ending
A
- unmyelinated or thinly myelinated axons
- near base of hairs and elsewhere in skin
- pain, warmth, cold
19
Q
Hair follicle receptors
A
- hair covered skin
- movement of hairs
20
Q
Meissner’s corpuscles
A
- hairless areas
- sudden displacement of skin
- low frequency vibration (flutter)
21
Q
Pacinian corpuscles
A
- Both hairy and hairless skin
- sudden displacement of skin
- high frequency vibration
22
Q
Merkel’s disks
A
- both hairy and hairless skin
- light touch
23
Q
Ruffini endings
A
- both hairy and hairless skin
- stretch of skin
24
Q
Krause end bulbs
A
- mostly or entirely hairless areas
- may include genitals
- uncertain what they respond to
25
cortical processing of somatosensory information
- information from touch receptors on head enter CNS through cranial nerves
- information from below head goes through spinal nerves
- info travels through spinal cord on well defined pathways to brain
- separate axons/pathways for deep touch and light touch
- nervous system codes differences in sensory sensations in terms of which cells are active
- areas of somatosensory thalamus send impulses to different areas of primary somatosensory cortex in parietal lobe (2 strips respond mostly to touch on skin, 2 others respond to deep pressure and movement of joints and muscles)
- damage impairs body perception
26
roles of the various neurotransmitters in the production of pain
- pain starts with bare nerve ending
| - pain axons release 2 NTs in spinal cord
27
NTs for mild pain
-glutamate
28
NTs for strong pain
- glutamate
| - substance P
29
Alleviation of pain
- opioid mechanisms that respond to opiate drugs and similar chemicals
- opiate receptors act by blocking release of substance P
- endorphins produced by brain are body's own opioids
- morphine post surgery block dull slow pain
- large diameter axons are unaffected by morphine (sharp pain)
- cannabinoids also block some types of pain
30
Roles of NTs in production of itch
1) histamines that dilate blood vessels produce itch sensation
2) contact with certain plants
- axons are spcific for itch types also respond to heat
- itch axons activate gastrin releasing peptide
- itch pathway is slow to respond
31
Alleviation of itch sensation
- scratching produces mild pain
| - pain alleviates itch meaning itch is not a types of pain
32
Labelled line principle (application to senses)
- each receptor would respond to a limited range of stimuli
| - meaning would depend on which neurons are active
33
Across-fibre pattern principle (application to senses)
- each receptor responds to a wider range of stimuli
- response by given axon means little except in comparison to what other axons are doing
ex) colour perception
- nearly all perceptions depend on pattern across array of axons (auditory, taste, smell)
34
mechanisms of the taste receptors
- stimulation of taste bud receptors on tongue
- different chemicals excite different receptors and produce different rhythms of action potentials
- temporal pattern may be important
- neuron responds to tastes with different patterns
- patterns code for different taste experiences
35
taste receptors
- modified skin cells
- have excitable membranes
- release NTs into brain
36
flavour
-flavour=combination of taste and smell, taste and smell axons converge in endopiriform cortex which influences food selection
37
Salty receptor
-permits Na+ to cross membrane
38
Sour receptor
-detects presence of acids
39
Sweetness receptor and umami receptor
- metabotropic synapse
| - molecules bind and activate G-protein
40
Bitter receptor
- metabotropic synapse
| - 25+ types of receptors
41
Anterior 2/3 Taste nerve pathway
-anterior 2/3 receptors travel along chorda tympani (part of cranial nerve 7 (facial nerve)
42
Posterior receptors and throat receptors pathway
-travel along 9th and 10th cranial nerves
43
Taste pathway
-from NTS information goes to pons, lateral hypothalamus and somatosensory amygdala, ventral posterior thalamus, and somatosensory cortex and insula (primary taste cortex)
44
Primary taste cortex
Insula
45
describe the operation
- response to chemicals that make contact with membranes inside the nose
- olfactory cells line olfactory epithelium in rear of nasal passage
- olfactory cell has no cillia
- olfactory receptors located on cillia
- metabotropic receptors that respond to an odorant molecules instead of NT
- each chemical excites several types of receptors
- most strongly excited receptor inhibits activity of other ones via process similar to lateral inhibition
46
number of olfactory receptors
-humans have several hundred olfactory receptor proteins
47
the implications of the numbers of receptors for coding olfactory information
-large number of types of olfactory receptors makes it possible to identify chemical precisely
48
why do we have so many olfactory receptors?
-olfaction processes airborne chemicals that do not range along a single continuum like wavelength
49
types of stimuli that the vomeronasal organ responds to and differences between the vomeronasal and olfactory systems
- sets of receptors close to olfactory receptors that respond only to pheromones
- each VNO receptor responds to 1 pheromone
- VNO receptor continually responds strongly even after prolonged stimulation (contrary to olfactory receptors)
- alter autonomic responses
ex) skin temperature
50
Pheromones
-chemicals released by an animal that affect behaviour of other members of same species
51
describe synesthesia and its possible anatomical basis
- experience some people have in which stimulation of one sense evokes a perception of that sense and also another on
ex) smelling colours
- people who experience synesthesia have increased gray matter in certain brain areas and altered connections to other areas
- possible genetic predisposition
