Ch43 Sensory Systems Flashcards
(113 cards)
1
Q
What are Thermoreceptors?
A
Sensory receptors sensitive to heat and cold
2
Q
How to pits and boa locate their prey
A
By thermoreceptors
3
Q
How is change of temperature detected in mammals?
A
Cold receptors, warmth receptors and pain receptors. (Free nerve endings in skin and tongue)
4
Q
How is hypothalamus involved in tempareture regulation?
A
It integrates information from thermoreceptors and initiates homeostatic mechanisms to maintain constant body tempareture
5
Q
What are exteroceptors?
A
Receptors that receive stimuli from the outside environment
6
Q
What are electroreceptors?
A
Receptors that respond to stimuli in water.
7
Q
What are interoceptors?
A
Receptors that detect internal changes in chemistry or temperature
8
Q
What are electromagnetic receptors?
A
Receptors sensitive to Earth’s magnetic field.
9
Q
What are Nociceptors?
A
Are pain receptors with free nerve endings.
10
Q
To what stimuli do nociceptors respond to?
A
Strong tactile stimuli (mechanical nociceptors)
Tempareture extremes (thermal nociceptors)
Other damaging stimuli (chemical nociceptors)
11
Q
How do nociceptors transmit signals?
A
Through sensory neurons to interneurons in the spinal cord.
12
Q
What neurotransmitter is released by sensory neuron after pain stimuli?
A
Glutamate and neuropeptide substance P that enhances and prolongs the actions of glutamate.
13
Q
Where does the interneuron transmit pain signals?
A
To the opposite side of spinal cord to thalamus where pain perception begins.
To parietal lobe and limbic system
14
Q
What is the term relevant to when one is aware of a stimulus.
A
Perception
15
Q
When does full awareness of pain occur? When the signal reaches where?
A
The cerebrum.
16
Q
Can nociceptors become sensitized?
A
Yes, by continued stimulation, increasing perception of pain, stress, and annoyance.
17
Q
What are mechanoreceptors?
A
Sensory receptors that respond to deformation of the receptor (mechanically pulled or pushed)
Transducer mechanical energy to hear, feel, maintain balance
18
Q
What do mechanoreceptors respond to?
A
Touch, pressure, gravity, stretch, movement
19
Q
What are mechanoreceptors aware of other than external stimuli?
A
Posture that continuously sends messages to the central nervous system regarding position and movement of body.
Internal info (fullness of stomach, bladder, feces in rectum)
20
Q
What are tactile receptors in mechanoreceptors?
A
The simplest form of mechanoreceptors of free nerve endings in the dermis. Perceive touch, pressure, and pain at the base of hairs. Detect air and water vibrations and movement of hair
21
Q
What are Merkel discs (tactile receptors) sensitive to?
A
Touch, pressure, adapt slowly
22
Q
What are Meissner Corpuscles?
A
Tactile receptors
Light touch, pressure, adapt quickly
23
Q
What are Ruffini Corpuscles?
A
Tactile receptors.
Heavy continuous touch and pressure.
Slow to adapt.
24
Q
Pacinian Corpuscles
A
Onion shaped in dermis. (Concentric layers of connective tissue interspersed with fluid)
Rapid movement of deep tissues, especially vibration.
Quick to adapt
25
What are Proprioceptors?
Mechanoreceptors in muscles, tendons, and joints.
Help coordinate muscle movement, maintain postural relations and balance
26
Which receptor is critical for fine motor movement?
Proprioceptors
27
What are Muscle Spindles? Where are they located?
Sense movements in muscles and help maintain muscle tone.
Protect muscle from fracture if it overstretches
28
What are Golgi tendon organs?
Sense stretching in tendons (that attach muscle to bone)
29
What are joint receptors?
Sense movements in ligaments angles and movements and compression of synovial fluid in synovial joints
30
What are statocysts possessed by invertebrates?
Gravity receptors that contain sensory hairs
31
What are statoliths in statocysts?
Particles that move in response to movement of animals that stimulate sensory hairs
32
How do sensory hairs inform the CNS of the position change?
Through fiber cells that are connected to sensory hairs
33
The rate of firing of the associated neurons is proportional to what?
The intensity of stimulation.
34
What are hair cells?
Mechanoreceptors that detect movement. (Help maintain position, equilibrium, and important in hearing)
35
Where is hair cells found?
Lateral line of fish
In human ear: vestibular apparatus, semicircular canals and cochlea
36
What sort of projection do hair cells have?
Apical projections with long nonmotile *kinocilium* made of 9x2 arrangement of microtubules.
Stereocilia are in increasing order toward the kinocilium
37
What is stereocilia
Very stiff microvilli, filled with cross-linked **actin** filaments.
38
How does depolarization of hair cells occur?
Bending the stereocilia toward the kinocilium and release of neurotransmitter from the base
39
How does hyperpolarization occur between stereocilia and kinocilium?
Stereocilia bends away from the kinocilium
40
What is the lateral line organ in fish?
Supplement vision in fish by detecting water vibrations. The canal extends its body, hair cells covered with gelatinous cupola (like dome) stereocilia bend with cupula movement, the hair releases neurotransmitter
41
What is the vestibular system?
The sensory system that creates a sense of balance and equilibrium.
42
How many parts is the ear made of?
Three:
Outer ear: pinna, canal, eardrum
Middle ear: fluid fill space with fine auditory bones (Malleus, incus, and stapes) transmit sound from tympanic membrane to the inner ear
Inner ear: contains vestibular apparatus. The auditory apparatus: the cochlea
43
What is the tympanic membrane?
The eardrum
44
What is the Eustachian tube?
Connects the middle ear to the pharynx
45
What is the labyrinth in the inner ear?
Bony labyrinth that encloses the membranous labyrinth.
46
What is the membranous labyrinth composed of?
The utricle, saccule, and semicircular canals that make up the vestibular apparatus.
47
What are the utricles and saccules?
The utricle and saccule (diff. Planes) have granules of calcium carbonate called **otoliths** that rest on cupula of hair cells
48
How do otoliths work?
They change position when the head is tilted or when the body is moving in a straight line. Signal the brain to perceive direction.
49
How are hair cells in saccule and utricle?
Also having kinocilium and multiple stereocilia.
50
How are the semicircular canals organized?
3 canals. Hollow rings filled with endolymph. Send information about turning movements. All in different planes. Each has expansion at the end called Ampulla
51
What are Ampullae at the end of each canal?
Ampullae lack otoliths but have Cristal (cluster of hair cells)
52
What movement directions are humans used to?
Horizontal movement
53
What movement are humans not used to? What are the consequences?
We are not used to vertical movement. Motion sickness can result to nausea and vomitting.
54
How do canals work?
Angular acceleration causes the fluid in canal to move, stimulating hair cells in particular canals.
55
Which nerve transmit information from hair cells of the ear to the brain?
The vestibular nerve.
56
What happens upon rotational acceleration to canals?
Rotational acceleration causes endolymph to move, push cupula. Stereocilia bend and increase action potential frequency in sensory neurons.
57
What are auditory receptors?
Detect pressure waves, contain mechanoreceptors in cochlea of the inner ear.
58
What is the cochlea?
Snail shaped, three canals. Two canals are filled with perilymph, and continuous at apex of the cochlea.
Upper vestibular canal
Lower vestibular canal
59
What is the middle canal of the cochlea?
Cochlear duct, filled with endolymph
60
Are all cochlear canals filled with perilymph?
No, the cochlear duct is filled with endolymph
61
What is the organ of Corti?
Located in cochlear duct with hair on a basilar membrane.
62
What does the basal membrane seperate?
The cochlear duct from the lower tympanic canal
63
Where is the tech trial membrane?
Above the hair cells of the cochlea
64
Whats the different name of Malleus
Hammer
65
Whats the different name for Incus?
Anvil
66
Whats the different name for Stapes?
Stirrup
67
What do the three middle ear bones do?
Transmit and amplify the vibration to the oval window
68
What does the oval window of the ear do?
Transmits vibration to the perilymph in vestibular canal of the cochlea -> tympanic canal -> vibration of basilar membrane -> techtorial membrane stimulates hair cells of organ of corti -> cochlear nerve -> brain
69
How does techtorial membrane stimulates hair cells hair cells of organ of corti?
Stereocilia bend -> ion channels open -> Ca 2+ move into hair cells -> release of glutamate (depolarization) -> axons of sensory neurons join to cochlear nerve
70
What is loudness based on?
Number of hair cells responding
71
How roughly can the ear hear in terms of Hz?
20 to 20000 cycles per second (Hz)
72
What does pitch depend on?
Pitch depends on the frequency of the sound waves (number of vibrations per second Hz)
Various parts of the basilar membrane vibrate in response to specific frequencies
73
What are chemoreceptors?
Sensory receptors associated with the sense of gastation and olfaction
74
What do chemoreceptors detect?
They detect chemical substances in water/food and the air
75
What are sensilla?
Sensory hairs of taste and smell in insects
76
How many chemoreceptors does each sensilla have?
Four chemoreceptors
Dendrites running along the tip
Axons transmit sensory to brain
77
Where is the papillae? What do they respond to?
On the tongue. Taste buds has 50 taste receptor each cell. Respond to primary flavors: sweet, salty, sour, and bitter
78
Umami as a fifth taste is triggered by what neurotransmitter?
Glutamate
79
Why does smell affect flavor?
Odors pass from the mouth to the nasal chamber
80
How does tasting work?
Glucose, or other tasting, binds to G protein-linked receptor that activates second messenger system (cAMP, DAG,…)
When action potentials are generated, signals are transmitted (brain stem and thalamus) to gustatory area in parietal lobe as well as limbic emotional system
81
Where is olfactory epithelium located? What does it detect?
Olfactory epithelium is located in the nasal cavity. It detects the sense of smell
82
What are olfactory hairs?
Nonmotile cilia that respond to chemicals in the air
83
Where do the cilia of the olfactory epithelium extend?
To the layer of mucus on epithelium surface on the nasal passageway.
84
Where is the olfactory cortex?
In the limbic system of the brain. Associates smell with nostalgia.
85
How does the sense of smell adapt?
Very quickly but is very sensitive.
86
List the pathway of olfactory epithelium in sensing smell.
Stimulus -> activated G protein -> synthesis cAMP -> opens ion channels of Na+ and Ca 2+ -> depolarization -> calcium gated chloride channels open -> Cl- move out of cell -> further depolarization
87
What causes a more intense smell?
Greater number of odorous molecules
88
How do some animals react using olfactory epithelium?
By releasing pheromones and volatile molecules
89
What is an organ of mammals called vomeronasal organ?
The nose epithelium separates from the main olfactory epithelium which detects pheromones and sends signal to hypothalamus.
90
What are photoreceptors?
Use pigments to absorb light energy
91
What is the pigment used to absorb light in cephalopods, arthropods, and vertebrates?
Rhodopsin
92
How is the light transducer to an electric response by photoreceptors?
Light strikes the cells containing rhodopsins -> chemical change in pigment conformation
93
What are eyespot and what do they do in invertebrates?
Eyespots are simple / compound eyes found in cniardians and flatworms.
Detect light without images.
Cluster of light sensitive cells
94
What are true eyes?
Eyes that form images and have lenses, concentrating light on a group of photoreceptors.
95
What are ommatidia in compound eyes?
Multiple visual units that collectively produce **mosaic** image.
96
What is a facet in compound eyes?
One unit of ommatidium; convex cornea of one unit
97
What is the crystalline cones’ function in compound eyes?
Along with the lens, to focus light on receptor cells called **retinular cells**
98
How do ommatidium adapt to light or dark changes?
Migration of pigment proximally and distally within the ommatidium.
Sensitivity increased in dim light
Protected from excessive stimulation in bright light
99
What do retinular cells fuse to form?
Rod shaped rhabdome that is sensitive to light.
100
Are compound eyes sensitive to UV
Yes
101
How many layers is the retina composed of?
Ten layers.
102
What are rods in the retina?
Function in dim light and form images in black and white.
For shape and movement.
103
What are cones for in the retina?
Less abundant than rods. Function in bright light. Permit color vision. Perceive fine detail.
104
List pathway of light into eye.
Light passes through cornea -> aqueous fluid -> lens -> vitreous body->image orbs from photoreceptors in retina -> signal bipolar cells -> signal ganglion cells -> optic nerve transmits -> to thalamus -> integration by visual areas of cerebral cortex
105
What are the two types of lateral interneurons that integrate information in the eye?
Horizontal cells: receive signals from rods and cones and send to bipolar cells
Amacrine cells: receive signals from bipolar cells to ganglion cells or back to bipolar cells
106
How is the melatonin cycle regulated by photoreceptors?
A group of ganglion cells project to superchiasmic nucleus. Contain light sensitive pigment (melanoma in) important in nonvisual responses to light.
107
What does rhodopsin consist of?
Opsin: a large protein
Retinal: an aldehyde of vitamin A (cis and trans)
108
What happens in the pigment rhodopsin during the dark
Opsin binds to retinal in cis form. -> cGMP opens channels of Na+ ->rod cells depolarize -> glutamate is released -> hyperpolarization bipolar cells -> signals are not sent -> steady flow of ions when environment is dark
109
What happens to rhodopsin when there is light?
Retinal is transformed from cis to trans form. -> binds with transducin (G protein) -> cGMP drops -> Na+ channels close -> hyperpolarization ->rod cells decrease output -> release less glutamate -> an action potential results -> bipolar cells depolarize -> release neurotransmitter to ganglion cells
110
Explain what happens in dark adaptation to the eyes
Rhodopsin is restored to a form which it can respond to light (cis)
111
Explain what happens in light adaptation (from dark to light)
Photopigments break down and the sensitivity of the eyes decreases
112
What are the three colors that color vision depends on
Red, blue and green
113
Where are the visual pathways of the brain?
Lateral geniculate nuclei of the thalamus.
Primary visual cortex in the occipital lobe of cortex.
Reticular activating system is involved in this integration.`
