Quiz 1 Flashcards
(134 cards)
1
Q
What two cell types is the nervous system made of?
(and what percent of each?)
A
Neurons and glial cells
50% neurons and 50% glial cells
2
Q
What are the 3 types of glial cells?
A
- Oligodendrocytes (in CNS, Schwann cell in PNS)
- Astrocytes
- Microglia
3
Q
What is the purpose of oligodendrocytes?
A
- Provides physical support/structure
- Insulate neurons (myelinate/produce myelin)
4
Q
What is the purpose of astrocytes?
A
-Supply nutrients and oxygen
-Bridge b/w nervous and vascular system
5
Q
What is the purpose of microglia?
A
Clean up debris
6
Q
Which glial cell is only found in the PNS and what is its equivalent in the CNS?
A
Schwann cell (equivalent of oligodendrocytes)
7
Q
What is post-synaptic potential (PSP)?
A
A graded electrochemical response
(the PSPs from many dendrites converge at axon hillock)
8
Q
What is the convergence of post-synaptic potential (PSP)?
A
Integration
9
Q
What is Action Potential (AP)?
A
All or nothing electrochemical response
(resting @ -70mV and threshold @ -55mV)
10
Q
What is Spatial summation?
A
Multiple EPSPs (Excitatory post synaptic potential) happening close together.
11
Q
What are the (10) parts of a neuron?
A
-Dendrites
-Cell body
-Cell membrane
-Node of Ranvier
-Schwann Cell
-Nucleus
-Axon
-Axon hillock
-Myelin Sheath
-Axon terminal
12
Q
What part of a neuron receives signals from other cells?
A
Dendtrites
13
Q
What part of the neuron is responsible for organization and keeping the cell functional
A
Cell body
14
Q
What part of the neuron protects the cell?
A
Cell membrane
15
Q
What are the Nodes of Ranvier?
A
-Unmyelinated parts of axon
-Allow diffusion of ions
16
Q
What produces the myelin sheath? (in PNS)
A
Schwann cell
17
Q
What controls the entire neuron?
A
Nucleus
18
Q
What transfers signals to other cells/organs?
A
The axons
19
Q
What generates an impulse in neuron?
A
Axon hillock
20
Q
What increases speed of signal?
A
Myelin Sheath
21
Q
What forms junctions with other cells?
A
Axon terminal
22
Q
What is grey matter?
A
-Groups of cell bodies, dendrites and terminal endings.
-the site of integration and transformation
23
Q
What cell bodies are in the grey matter of the CNS?
A
Nuclei
24
Q
What cell bodies are in the grey matter of the PNS?
A
Ganglia
25
What is white matter?
-Bundles of myelinated axons
-Pathways or fiber tracts connecting areas of grey matter
(electric signals can skip past myelin, making them faster)
26
What is the central nervous system? (what makes it up)
Spinal cord, brain stem, cortex (within skeletal casing - skull/spinal column)
27
What is the peripheral nervous system?
Outside the skeletal casing. Further subdivided into the somatic (skeletal muscles) & autonomic (smooth muscles and glands)
28
Parts of the CNS: Spinal cord.
-Contains finer tracts:
-afferent or ascending (to the brain)
-efferent or descending (from the brain)
-Entry/exit zones of PNS
-Pods of interneurons that interact with ascending/descending pathways
29
What is a ganglion
Cluster of cell bodies in the PNS
30
What is nuclei
Cluster of cell bodies in the CNS
31
Parts of the CNS: Brain Stem
* Pons, medulla (hindbrain) & midbrain
* Contains the 12 cranial nuclei & sensory/motor nerves that innervate eyes, head, neck and upper trunk
(nuclei in brainstem are critical to autonomic function, alertness and eye/hand movement)
32
Parts of the CNS: Cerebellum
'little brain'
* contains >50% of brain neurons
* Has dense afferent and efferent connections with brainstem and cortex
* Influences cortex activity and ascending/descending projections
33
Parts of the CNS: Basal Ganglia
* Group of subcortical nuclei that are adjacent to the thalamus and descending motor tracts
* Important contribution to control of **movement, learning, cognition and emotions**
34
What structures are included in the Basal Ganglia
* Caudate Nucleus
* Putamen
* Globus Pallidus (internal and external)
* Substantia nigra
* Subthalamic Nucleus (STN)
35
Parts of the CNS: Thalamus
* Critical relay between cortex and other parts of CNS
* Essential to sensorimotor processing (also plays role in alertness)
* All sensory input from body (except smell) pass through thalamic nucleus
* Olfactory system bypasses thalamus
36
Parts of the CNS: Hypothalamus
* Contributes to control of many internal body functions & regulation of homeostasis
* Links between nervous system and endocrine system
37
Name the lobes of the cerebral cortext
| and where they are
Frontal lobe (front of head)
Parietal Lobe (behind frontal)
Occipital lobe (back of head)
Temporal lobe (by ears, under frontal/parietal)
38
What is sulci
Deep valleys of the folds of the cortex
## Footnote
Main sulci include central sulcus (between frontral and parietal lobe) and parieto-occipital sulcus (between parietal and occipital lobe)
39
Describe Frontal Lobe
* Action control (body/eye movement, speech)
* Control of high-level cognitive/executive function (planning)
* Behaviour and emotion control (including personality)
* Controls voluntary behaviour
* Most developed (in humans)
40
Describe Parietal Lobe
* Receives and processes touch and taste sensory info
* Receives **processed** visual and auditory information
* Integrates info from senses for object perception, spatial awareness and motor control
41
Describe Occipital Lobe
* Recieves raw visual input from the visual thalamus
* Early processing of colour, edges, motion of objects and self-movement through the environment
42
Describe the Temporal lobe
* Recieves raw auditory input from thalamus
* Early processing of sound (intensity, pitch, location)
* Storage and retrieval of memories
* Combines visual info into object perception
* Classification and grouping of objects
* Emotion processing
| **Amygdala and hippocampus** are sometimes lumped in with temporal lobe
43
# Cerebral cortex taxonomy
What is Brodmann area
* Regions of cortex grouped by cytoarchitechture
* cytoarchitecture mirrors function, creating a link between the Brodmann area and functional cortex taxonomy
44
what is cytoarchitecture
Density of cells contained in grey matter of cortex
45
# Cerebral cortex taxonomy
Explain the Primary cortex regions
1st arrival of sensory input or last stop for motor output (primary regions are very specific)
46
# Cerebral cortex taxonomy
What are the primary regions for each lobe
* Primary motor cortex (frontal)
* Primary somatosensory cortex (parietal)
* Primary visual cortex (occipital)
* Primary auditory cortex (temporal)
47
# cerebral cortex taxonomy
Explain secondary cortical regions
Recieves processed info and puts it into the big picture (right next to primary region)
48
# cerebral cortex taxonomy
Explain Association areas of cortex
Another name for 'secondary' that reflects integration of info. Integrates info among regions/cortexs/lobes
49
What are sensory receptors and what do they do
Specialized cells or endings that convert stimulus energy to electrical potential that can be transmitted and interpreted by nervous system
50
# Sensory receptors
What are the 4 main types of Sensory receptors
1. Mechanoreceptors
2. Photoreceptors
3. Chemoreceptors
4. Thermoreceptors
51
# Sensory receptors
What is common to all Sensory receptors
* They are a mechanism by which the stimulus energy leads to a change in electrochemical state of cell or axon (**receptor potential**)
* A mechanism to convert "passive" receptor potential into **action potential**
52
# Sensory receptors
What do mechanoreceptors do
convert mechanical enery (force)
53
# Sensory receptors
What to photoreceptors do
Convert light energy (photons)
| in retina
54
# Sensory receptors
What do chemoreceptors do
Convert chemical energy
| tastebuds; pain receptors
55
# Sensory receptors
What do thermoreceptors do
Convert thermal energy
| in skin
56
# Sensory receptors
Explain receptor potential
generated by the **passive** diffusion of ions in/out of cell (specific to sensory receptor)
57
# Sensory receptors
Explain Action potential
Generated by influx/efflux of ions. Constantly regenerated as it travels along axon
58
# Sensory receptors
How can a receptor represent certain types of stimulus info?
| 4 ways
1. Type or modality
2. Onset, offset, duration
3. Intensity
4. Location
| of stimulus
59
# Sensory receptors
Type or modality of stimulus
| how many stimulus types is each receptor tuned to
Each Sensory receptor is tuned into a specific type of stimulus
| 1 receptor : 1 stimulus type
60
# Sensory receptors
Onset, offset, duration of stimulus
| Stimulus timing (what happens to the activity)
the activity of the sensory receptor changes depending on the presence or absence of the stimulus
61
# Sensory receptors
Intensity of stimulus
| howdo sensoy receptors convey intensity
Sensory receptors scale their influence over nerves by adjusting how many AP are triggered per unit time
62
# Sensory receptors
Location of stimulus
| How do receptors convey location infomation
Sensory receptors project to the spinal cord, brain stem and cortex via **labelled lines**
63
# Sensory receptors
What are the (8) different types of stimulus modality
* Touch/ tactioception
* movement/proprioception
* orientation/equilibrioception
* hearing/ audioception
* sight/opthalamoception
* smell/olfacoception
* taste/gusaoception
* paint/nociception
64
# Sensory receptors: modality
what does tactioception sense
change to external/internal state of body
| touch
## Footnote
mechanoreceptors
65
# Sensory receptors: modality
what does proprioception sense
position/movement of body; force/effort of movement
| movement
## Footnote
mechanoreceptors
66
# Sensory receptors: modality
what does equilibrioception sense
body position/movement in relation to gravity
| orientation
## Footnote
mechanoreceptors
67
# Sensory receptors: modality
what does audioception sense
surrounding environment from sound waves
| hearing
## Footnote
mechanoreceptors
68
# Sensory receptors: modality
what does opthalamoception sense
objects/environment from visual light
| sight
## Footnote
photoreceptor
69
# Sensory receptors: modality
what does olfactoception sense
chemical odorants in nasal cavity
| smell
## Footnote
chemoreceptor
70
# Sensory receptors: modality
what does gustaoception sense
substances that chemically react in the mouth
| taste
## Footnote
chemoreceptor
71
# Sensory receptors: modality
what does nociception sense
pain related to injury/damage
| pain
## Footnote
mechano & chemo receptors
72
# Sensory Sytems
What are the main Sensory Sytems
1. Somatosensory
2. vestibular
3. visual
4. auditory
73
# Sensory Sytems
What is the somatosensory system made of
Any mechano, thermo or nociceptor in skin, fatty tissue beneath skin, muscles or musculoskeletal tissue (ligament, tedon, joint capsule)
74
# Sensory Sytems
What is the vestibular system made of
mechanoreceptors within otoliths/labrinths of inner ear
75
# Sensory Sytems
What is the visual system made of
photoreceptors in retina
76
# Sensory Systems
What is the auditory system made of (what receptors where)
mechanoreceptors in cochlea within inner ear
77
# Sensory Sytems and receptors
how do sensory receptors convey information about timing
they modulate dynamic properties of the receptor potential. 2 types:
1. Fast adapting
2. Slow adapting
78
# Sensory Sytems and receptors
Explain fast adapting
* Vigorous but transient response to changes in stimulus energy
* info about onset/offset but not a lot about signal itself
* optimal to detect **rate of change** in stimulus energy intensity
79
# Sensory Sytems and receptors
Explain slow adapting
* measured, but sustained, response while stimulus energy is constant
* info about duration/ intensity of signal
* reflects actual stimulus energy intensity
80
# Sensory Systems and receptors
Stimulus location: Labelled Lines
* axons innervate receptors of one modality, from a specific body area
* axons bundle together, but their signals remain separate until reaching 'higher' areas of NS
Afferent fibers contain specific modality and location information and this is referred to as labelled line coding
81
# Sensory Sytems and receptors
What is somatotopic
Perserved info about body location
82
# Sensory Sytems and receptors
What is tonotopic
perserved info about sound frequency
83
# Sensory Sytems and receptors
what is retinotopic
perserved into about spatial location in visual field
84
How does afferent info enter CNS
Dorsal root
85
How does efferent info exit CNS
Ventral root
86
# Photoreceptors
How do photoreceptors generate receptor potential
Photoreceptors absorb photons from visual light wavelengths leading to a chemical reaction that generates the receptor potential
87
# Photoreceptors
Describe the Photoreceptors process in light
1. Pigment (eg Rhodopsin) absorbs light
2. Initiates a 2nd messenger pathway that closes NA+ ion channels
3. Less Na+ influx decreases the amplitude of the receptor potential
4. Less neurotransmitter (glutamate) is released when the RP reaches the end of the receptor
| Opposite in dark (more neuroreceptor is released)
88
# Photoreceptors
How are Photoreceptors unique from other sensory receptors
They do not directly influence the sensory nerve (ganglion cell).
They instead act via an intermediary cell called **bipolar cell**
89
# Photoreceptors
When the RP is smaller, is the bipolar cells influence on the ganglion cell stronger or weaker?
Stronger
| smaller RP = stronger stimulus energy
90
# Photoreceptors
What are the two types of Photoreceptors
Rods and Cones
91
# Photoreceptors
Rods
* along boundary of retina
* contain the pigment rhodopsin
* all rods have same time of rhodopsin (tuned to detect cyan/green spectrum)
* ~96% of all Photoreceptors
92
# Photoreceptors
Cones
* Clustered in centre of retina
* contain pigment iodopsin
* each cone has different form of iodopsin that is sensitive to a specific wavelength
* 3 types (blue, red, green)
* ~4% of photoreceptors
93
# Hair cells
What are hair cells (and what senses/systems are they used for)
mechanoreceptors that mediate our auditory and vestibular senses
94
# Mechanoreceptors: Hair cells
Kinocilium
larger hair cell
95
# Mechanoreceptors: Hair cells
Stereocilia
shorter bunch of hair cells
96
# Mechanoreceptors: Hair cells
What happens if hair cells deflect towards kinocilium
depolarization or cell leading to increased firing rate
97
# Mechanoreceptors: Hair cells
What happens if hair cells deflect away kinocilium
hyperpolarization or cell leading to decreased firing rate
98
# Hair cells: Auditory
Describe auditory process
1. soundwaves apply pressure to tympanic membrane
2. movement of tympanic membrane creates vibration of small bones in ear
3. bone vibration creates waves in fluid of cochlea (inner ear)
4. fluid movement causes basilar membrane to vibrate, causing hair cell base to move back and forth
5. Techtoral membrane, connected to hair filament, is rigid and **does not move**
6. Differential movement of basilar tectorial membranes create a shearing force that **opens Ca2+ or K+** ion channels. This leads to **excitatory release of neurotransmitter** from receptor cell
99
# Hair cells: Auditory
What is the tonotopic map and how is it generated?
Location of specific axons generating AP represents specific frequency of sound. it is generated by differential compositions of the basilar membrane as it winds around the cochlea. Lower frequency must travel further into cochlea before activation/interaction
100
# Vestibular (anglular rotation)
How do we sense angular rotation
Hair cells embedded in the semicircular canals mediate our sense of angular head rotation
101
# Hair cells: Vestibular (anglular rotation)
What are the 3 semicircular canals
1. horizontal
2. superior
3. posterior
102
# Hair cells: Vestibular (anglular rotation)
What rotation does Horizontal canal sense
Side to side (**Yaw**)
103
# Hair cells: Vestibular (anglular rotation)
What rotation does the superior canal sense
Nodding (**pitch**)
104
# Hair cells: Vestibular (anglular rotation)
What rotation does the posterior canal sense
Head to sholder movement (**roll**)
105
# Hair cells: Vestibular (anglular rotation)
Describe left head rotation
1. Head accelerates forward
2. endolymph (viscous fluid) in canal experiences a moment of inertia
3. Inertial moment creates shearing force on hair filament
4. Left ear: pushes stereocilia towards kinocilium, opening K+ ion channels. Right ear: force pushes kinocilium towards stereocilia, closing ion channels
5. K+ influx into left ear generates strong RP leading to release of exitatory neurotransmitter and increase in # of AP in left nerve. Right hair cell becomes hyperpolarized and releases less neurotransmitter leading to less APs
106
# Hair cells: Vestibular (head translation)
Explain head translation
(what mediates our perception of this)
Hair cells embedded in otolith organs mediate our perception of head translation and gravitational forces
107
# Hair cells: Vestibular (head translation)
What does the Utricle sense
Horizontal acceleration of head. (ex. car moving away from stop sign)
| It is an otolith organ
108
# Hair cells: Vestibular (head translation)
What does the saccule sense
vertical acceleration (ex elevator)
| it is an otolith organ
109
# Hair cells: Vestibular (head translation)
Explain forwards acceleration
1. head accelerates forward, hair embedded in the bone moves with the head
2. Otolith membrane of utricle, floating in endolymph, experiences moment of inertia
3. Inertial moment created shearing force on hair filaments
4. Force pushes stereocilia towards kinocilium, opening K+ channels
5. K+ influx into hair cell generated strong RP, leading to release of excitatory neurotransmitter and increase in AP of both left and right nerves
110
# Mechanoreceptors: Cutaneos receptors
What do Cutaneos mechanorerceptors do
Translate mechanical forces acting on skin into RP through mechanically gated ion channels
111
# Mechanoreceptors: Cutaneos receptors
What are the 4 types of Cutaneos receptors
1. Merkel Disks
2. Ruffini Endings
3. Pacinian corpuscle
4. Meissner corpuscle
112
# Mechanoreceptors: Cutaneos receptors
Explain Merkel disks and Ruffini endings
* Slow adapting
* Na+ and CA2+ ion channels in receptor cells are mechanically deformed **as skin is stretched**
* Mech deformation creates pore for ions to flow through
113
# Mechanoreceptors: Cutaneos receptors
Explain Messner and Pacinian corpuscles
* Rapidly adapting
* ion channels on an exposed nerve ending are mechanically deformed as corpuscles is**compressed**
114
# Mechanoreceptors: Cutaneos receptors
Which mechanoreceptors are fast adapting
1. Meissner corpuscles
2. Pacinian corpuscle
115
# Mechanoreceptors: Cutaneos receptors
Which mechanoreceptor are slow adapting
1. Merkel disk
2. Ruffini ending
116
# Mechanoreceptors: Cutaneos receptors
Which mechanoreceptors are superficial
1. Meissner corpucle
2. Merkel disk
117
# Mechanoreceptors: Cutaneos receptors
Which mechanoreceptors are deep
1. Pacinian corpuscle
2. Ruffini ending
118
# Mechanoreceptors: Cutaneos receptors
Describe superficial receptors
* have small receptive fields
* are densly populated in areas of skin used to explore object
| small and concentrated
119
# Mechanoreceptors: Cutaneos receptors
Describe deep receptors
* Large receptive fields
* best suited to detect vibrations in objects (ex water inside bottle) and skin stretch created bu object weight (bottle slipping from grasp)
| large and blurry, not for details
120
# Mechanoreceptors: Proprioceptors
What to proprioceptors do/translate
translate mechanical forces generated by body's own position/ movement
121
# Mechanoreceptors: Proprioceptors
3 types of proprioceptors
1. Muscle spindle fibres
2. Golgi tendon organs (GTO)
3. Joint receptor
122
# Mechanoreceptors: Proprioceptors
What do muscle spindle fibres sense
Sense muscle length
123
# Mechanoreceptors: Proprioceptors
What do golgi tendon organs sense
Sense muscle force
| in series with muscle
124
# Mechanoreceptors: Proprioceptors
What do joint receptors sense
Sense extreme joint angle
125
# Mechanoreceptors: Proprioceptors
What are the 2 classes of spindle fibres
1. Dynamic (group 1a)
2. Static (group II)
126
# Mechanoreceptors: Proprioceptors
Describe dynamic spindle fibres (+ what group)
* Group Ia
* activity is a function of both muscle length and rate of change in muscle length
* more sensistive to rate of change
127
# Mechanoreceptors: Proprioceptors
Describe static spindle fibres
(what group?)
* Group II
* activity is a function of muscle length
* get faster as spindle lengthens but not as dynamic
128
# Mechanoreceptors: Proprioceptors
Describe golgi tendon organs (GTOs)
* Located in series between muscle fibre and tendon
* forces generated by muscle and transmitted to bone must act on the GTO
* **Muscle contraction and relaxation**
129
# Mechanoreceptors: Proprioceptors
Which causes more RP in spindle fibres, muscle contraction or relaxation
Muscle relaxation
130
# Mechanoreceptors: Proprioceptors
Explain muscle contraction
| GTO
* increased contractile force compressed GTO capsule
* collagen fibres pinch interwoven axon endings which lead to mech deformation of axon membranes that open ion channels
* influx generates RP
131
# Mechanoreceptors: Proprioceptors
Explain muscle relaxation
| wrt GTO
* decrease contractile force releases compression of GTO
* Fibres released and resume 'typical' shape, leading ion channels to become less permeable, decreasing RP
132
# Mechanoreceptors: Nociceptive receptors
What do Nociceptive receptors do
Translate mech, chem and thermal forces from damaged tissue or the threat of damage to tissue
133
# Mechanoreceptors: Nociceptive receptors
What are bare nerve endings sensitive to
* thermal (>45 or < 5 degrees)
* mechanical (intense pressure on skin)
* Chemical (internal or external toxins)
* Polymodal (more than 1 stimulus type)
134
# Mechanoreceptors: Nociceptive receptors
Describe the difference between a blunt object, pinprick and pinch (with same amount of force) as an example of noxious touch
Blunt object:
* nociceptive axon demonstrate no response (no AP)
* Not noxious
Pinprick:
* Concentrated nature of force increases potential to penetrate skin
* percieved as noxious but minimal threat of harm
Pinch:
* Large area of high force
* high potential to break or severly damage skin/tissue
* Noxious with high threat of harm
