CNS/Sensory Flashcards
1
Q
Afferent
A
Sensory input
Cell bodies out of CNS
2
Q
Efferent
A
Motor output
Cell bodies in CNS
3
Q
Cranial Nerves
A
Somatic, Visual, olfactory, taste, auditory, vestibular
4
Q
Spinal Nerves
A
Somatic sensation
- touch
- temperature
- pain
5
Q
innervates skeletal muscle only excitatory (ACH)
A
Somatic efferent
6
Q
Autonomic efferent
A
innervates interneurons
smooth & cardiac muscle
excitatory & inhibitory
Enteric Nervous system
7
Q
Steps of Nervous System development
A
- Fertilized egg (ovum)
- Ball of cells
- Blastocyst (week 1)
- Blastocyst (week 2)
- Blastocyst (week 3)
- Week 3
8
Q
Week 1 Blastocyst develops
A
inner cell mass
9
Q
Week 3 Blastocyst develops
A
embryonic disk
neural plate
10
Q
Ectoderm
A
Outermost layer
11
Q
Mesoderm
A
middle layer
12
Q
Endoderm
A
Inner Layer
13
Q
the 3 layers (ectoderm….) make up the _______
A
embryonic disk
14
Q
Neural groove
A
a shallow median groove of the neural plate between the neural folds of an embryo
15
Q
What develops in week 4 of the neural tube
A
vesicles
16
Q
Neural Crest becomes part of CNS or PNS
A
PNS
17
Q
Neural tube becomes “CNS or PNS or both*
A
CNS and part of PNS
18
Q
Neural Tube is composed of
A
Forebrain, Midbrain, Hindbrain
19
Q
Forebrain becomes
A
Cerebal hemispheres and Thalamus
20
Q
Midbrain becomes
A
Midbrain
21
Q
Hindbrain becomes
A
Cerebellum, pons, medulla
22
Q
Rest of Neural tube becomes
A
Spinal cord
23
Q
Cavity becomes
A
the ventricles and central canal
24
Q
What do ventricles contain
A
150 ml of cerebral spinal fluid (CSF)
25
Cerebrospinal spinal fluid
- produced by the
- rate of production
Produced by the choroid plexus (in the four ventricles, but mainly the two lateral)
at a rate of 500 ml/day.
26
Cerebrospinal spinal fluid function
1) Supports and cushions the CNS. Specific gravity of CSF and the brain are equal.
2) Provides nourishment to the brain.
3) Removes metabolic waste through
absorption at the arachnoid villi.
27
Cerebrospinal spinal fluid composition
Sterile, colorless, acellular fluid that contains glucose.
28
Cerebrospinal spinal fluid circulation (active or passive)
passive (not pumped)
29
Where does CSF enter?
The subarachnoid space
30
an abnormal buildup of fluid in the ventricles (cavities) deep within the brain
Hydrocephalus
31
Communicating Hydrocephalus
The flow of CSF is blocked after it exits the ventricles
32
Noncommunicating Hydrocephalus
The flow of (CSF) is blocked along one or more of the narrow passages connecting the ventricles.
33
Meninges cover the
brain and spinal cord
34
Three membranes of CNS
Pia matter, arachnoid membrane, Dura mater
35
CSF returns to the blood at the
dural sinus
36
The only substate metabolized by the brain
Glucose
37
T/F: There is a lot of glycogen in the brain
F: Very little glycogen in the brain.
38
What does the brain need continuous supply of? (2)
glucose and oxygen
39
Glucose transport into the brain does not require ____
insulin
40
A few seconds of blood supply interruption can lead to
loss of consciousness
41
A few minutes of blood supply interruption can lead to
neuronal death (stroke)
42
Brain receives ___ % of total blood
15%
43
Brain is __% of total mass
2
44
Function of circle of willis
safety factor
45
CSF moves from the heart through ............ then back to the heart
```
Chorioid plexus
ventricles
subarachnoid space
archnoid villi
dural sinus
venous system
```
46
Blood can move from the heart either through ... arteries
..... arteries move straight to the circle of willis
..... arteries move through the basilar artery to the circle of Willis
vertebral arteries
carotid arteries
carotid arteries
vertebral arteries
47
Blood-brain barrier
capillary wall
48
astrocytes (glia) functions (4)
1. provide strucutral support
2. induce tight juctions
3. glutamate K+
4. phagocytosis of debris
49
Awareness of sensory stimulation
Sensation
50
The understanding of a sensation’s meaning
Perception
51
T/F: We perceive energy of a sensory stimulus directly
F: We do not perceive the “energy” of a sensory stimulus directly.
52
T/F: We only perceive the neural activity that is produced by sensory stimulation.
T: We only perceive the neural activity that is produced by sensory stimulation.
53
Law of specific nerve energies:
Regardless of how a sensory receptor is activated, the sensation felt corresponds to that of which the receptor is specialized.
54
Law of projection:
Regardless of where in the brain you stimulate a sensory pathway, the sensation is always felt at the sensory receptors location.
55
(Law of specific nerve energies/projection):
| Rub your eyes hard and you will see light.
Law of specific nerve energies
56
(Law of specific nerve energies/projection): Penfield electrically stimulated somatic sensory cortex and patients perceived somatic sensation in the body.
Law of projection:
57
(Law of specific nerve energies/projection): Phantom limb pain after amputation.
Law of projection:
58
6 sensory systems:
Visual, Auditory, Vestibular, Somatosensory, Gustatory, Olfactory
59
Modality of visual
Vision
60
Modality of Auditory
Hearing
61
Modality of Vestibular
Balance
62
Modality of Somatosensory
Somatic Senses
63
Modality of Gustatory
Taste
64
Modality of Olfactory
Smell
65
Vision stimulates
B/W, colour
66
4 Somatic Senses
Touch
Pain
Proprioception
Thermal
67
Taste stimulates
```
"BUSSS"
Bitter
Umani
Sweet
Sour
Salt
```
68
Stimulus Energy of Visual sensory system
Light
69
Stimulus Energy of Auditory sensory system
Sound
70
Stimulus Energy of Vestibular sensory system
Gravity, Acceleration
71
Stimulus Energy of Somatosensory system
Mechnical, thermal, chemical
72
Stimulus Energy of Gustatory sensory system
Chemical
73
Stimulus Energy of Olfactory sensory system
Chemical
74
Receptor class of Visual sensory system
Photorecptors
75
Receptor class of Auditory sensory system
Mechanoreceptors
76
Receptor class of Vestibular sensory system
Mechanoreceptors
77
Receptor class of Somatosensory system
Mechanoreceptors
Chemoreceptors
Thermoreceptors
Nociceptors
78
Receptor class of Gustatory sensory system
Chemoreceptors
79
Receptor class of Olfactory sensory system
Chemoreceptors
80
Which of sensory systems use photoreceptors?
Visual
81
Which of sensory systems use mechanoreceptors?
Auditory
Vestibular
Somatosensory
82
Which of sensory systems use chemoreceptors?
Somatosensory
Gustatory
Olfactory
83
Which of sensory systems use thermoreceptors?
Somatosensory
84
Which of sensory systems use nociceptors?
Somatosensory
85
Modaility
General class of a stimulus
86
The brain “knows” the modality and location of every sensory afferent.
Labelled Line
87
Steps of sensory receptors (5)
1. Stimulus energy
2. receptor membrane
3. transduction
4. ion channel activation
5. afferent
88
For stimulus energy there must be
adequate stimulus (specificity)
89
Stimulus energy is converted into
afferent activiity
90
Steps of stimulus energy being converted into afferent activity (5)
1. Stimulus energy
2. receptor potential
3. action potentials
4. propagation of action potentials
5. release of neurotransmitters
91
Magnitude of receptor potential
determines the frequency with which action potentials are generated
92
Non-adapting afferent response
Encodes stimulus intensity and slow changes
93
Slowly adapting afferent response
Some stimulus intensity and moderate stimulus changes
94
Rapidly adapting afferent response
Fast stimulus changes
95
Afferent adaption allows us to be
sensitive to changes in sensory input
96
Receptive field
The region in space that activates a sensory receptor or neuron
stimuilus location
97
Overlapping RFs produce a
population code
98
Acuity
ability to differentiate one stimulus from another
99
High/Low acuity location: Lips
High
100
High/Low acuity location: Back
Low
101
High/Low acuity location: Hands
High
102
High/Low acuity location: Face
High
103
High/Low acuity location: Lips
High
104
High/Low acuity location: Thigh
Low
105
High/Low acuity location: Shoulder
Low
106
Small RF means ____ acuity
High
107
Large RF means ____ acuity
Low
108
Lateral Inhibition
- Sharpens sensory acuity
| - Process by which stimulated neurons inhibit the activity of nearby neurons by interneurons
109
neurons that carry signals from the spinal cord to the thalamus
2nd order
110
Interneurons
Found only in CNS
| It also connects to other interneurons, allowing them to communicate with one another.
111
Descending pathways modulate (not motor)
sensory inputs
112
Sensory information is shaped by two types of mechanisms:
“bottom up” and “top down” mechanisms
113
Mechanoreceptors with specialized end organs that surround the nerve terminal.
These end organs allow only selective mechanical information to activate the nerve terminal.
Touch
114
Fluid-filled structure enclosing the nerve
| terminal. Rapidly adapting. Light stroking and fluttering.
Meissner’s corpuscle
115
Slowly adapting. Pressure and texture.
Merkel disk
116
Merkel disk, Meissner’s corpuscle are examples of
Superficial layers receptors
117
Pacinian corpuscle, Ruffini endings are examples of ....
Deep layers receptors
118
Large concentric capsules of connective tissue
| surround the nerve terminal. Rapidly adapting. Strong vibrations.
Pacinian corpuscle
119
Nerve endings wrap around a spindle-like structure. Slowly adapting. Stretch and bending of the skin (shape of an object).
Ruffini endings
120
Muscle spindles provide sense of static position and movement of limbs and body.
Proprioception
121
Stretching the cytoskeletal strands activates
Mechanoreceptors
122
Thermoreceptors are free nerve endings containing ion channels that respond to different temperature ranges.
Temperature
123
Temperature of cold afferents
0 – 35 Celcius
124
Temperature of warm afferents
30 – 50 Celcius
125
cold afferents can be activated by
menthol
126
warm afferents can be activated by
capsaicin and ethanol
127
Extreme temperatures activate
pain receptors
128
Nociceptors are free nerve endings containing ion channels that open in response to intense mechanical deformation, excessive temperature, or chemicals.
Pain
129
T/F: Pain afferents are highly modulated
T: Pain afferents are highly modulated (enhanced and suppressed).
130
Visceral pain receptors are activated by
inflamation
131
Nociceptors are enhanced by many
mediators
132
Steps leading to Hyperalgesia
1. cut occurs
2. action potential
3. susbatnce P released in spinal cord
4. pain
5. enhancement of surrounding nociceptors by injured tissue & afferent feedback onto mast cells
6. Dilation of nearby blood vessels
133
Hyperalgesia
An increased sensitivity to feeling pain and an extreme response to pain
134
Dorsal columns
Touch and Propioception
135
Touch and Proprioception route
```
Dorsal Root ganglion
Dorsal columns
Medulla
Medial lemniscus
Thalmus
Somatosensory cortex
```
136
(Contralateral or Ipsilateral) Touch and proprioception
Ipsilateral
137
(Contralateral or Ipsilateral) Temperature and Pain
Contralateral
138
Temperature and Pain route
```
Dorsal Root ganglion
Dorsa, horn
Anterolateral column
Branches into the reticular formation
Thalamus
Somatosensory cortex
```
139
Which afferents commonly synapse on the same neurons in the spinal cord?
Visceral & somatic pain afferents
140
Heart attacks commonly produce pain in the
in the left arm.
141
Descending pathways regulate
nociceptive information
142
Analgesia
Reduction of pain through presynaptic inhibition
143
What do opiate neurotransmitters do?
Presynaptic inhibition
| Stop substance P from being released in spinal cord
144
______ perception is dependent on context
Visual
145
part of eye that refracts (bends) light to a single point
Lens
146
Light is refracted by (2)
the cornea and lens
147
What refracts more light: Cornea or lens
Cornea
148
What accommodates for changes in object location?
Lens
149
Nearsighted (eyeball)
eyeball too long
150
Farsighted (eyeball)
eyeball too short
151
Nearsightedness is corrected by a ____ lens
concave
152
Farsightedness is corrected by a ____ lens
convex
153
Cataract
changes in lens colour
154
Presbyopia
the lens gets stiff and is unable to accommodate near vision
155
Astigmatism
the lens or cornea are not spherical
156
myopic
nearsighted
157
hyperopic
farsighted
158
Fovea centralis
the retinal circuitry is shifted out of the way
159
only neurons that connect the outer retina to the inner retina
Bipolar cells
160
Help integrate and regulate the input from multiple photoreceptor cells
Horizontal cells
161
the major carriers of rod signals to the ganglion cells in the retina
Amacrine cells
162
Ganglion cells
the projection neuron
| Make up the optic nerve
163
Phototransduction
Light causes photoreceptors to hyperpolarize
Four different opsin molecules (rhodopsin is found in the rods)
164
Rods/Cones:
| High sensitivity, night vision
Rods
165
Rods/Cones:
| Low sensitivity, day vision
Cones
166
Rods/Cones:
| More rhodopsin, captures more light
Rods
167
Rods/Cones:
| High amplification, single photon closes many Na+ channels
Rods
168
Rods/Cones:
| Slow response time
Rods
169
Rods/Cones:
| Faster response time
Cones
170
Rods/Cones:
| Lower amplification
Cones
171
Rods/Cones:
| Less opsin
Cones
172
Rods/Cones:
| More sensitivity to scattered light
Rodes
173
Rods/Cones:
| Most sensitive to direct axial rays
Cones
174
Rods/Cones system:
| Low acuity: not present in central fovea, highly convergent
Rod System
175
Rods/Cones system:
| High acuity: concentrated in fovea, less convergent
Cone system
176
Rod/Cone system:
| Achromatic: one type opsin
Rod System
177
Rods/Cones system:
| Chromatic: three types of opsin
Cone system
178
Bright Light which rod/cones are active/inactive
Rods are inactivate Cones are active
179
Dark which rods/cones are active/inactive
Cones are inactive Rods are active
180
Why does temporary blindness occur when going from light to dark?
Temporary blindness until rods “re-activate” and take over
181
Why does temporary blindness occur when going from dark to light?
Rods are initially saturated. Temporary blindness until rods “inactivate” and cones take over
182
What breaks in phototransduction
lights breaks the bond between opsin and retinene (chromophore)
183
T/F: It takes time to put the chromophore and opsin back together
T
184
Retina reports relative/absolute intensity of light
relative
185
signal the relative differences of the light (contrast) across their receptive fields
- B/W
- Colour
Retinal ganglion cells
186
Photoreceptors are sensitive to ________
wavelength
187
What determines the chromatic sensitivity of the photoreceptor
opsin molecule
188
What encodes the relative values of brightness and colour
the output of the retina
189
both eyes with contralateral visual field
Optic tract
190
one eye with both visual fields
optic nerve
191
Cervical Nerves
- body part
- pairs
Neck, shoulders, arms and hands
| 8
192
Thoracic Nerves
- body part
- pairs
Shoulders, chest, upper abdominal wall
| 12
193
Lumbar Nerves
- body part
- pairs
Lower abdominal wall, hips, and legs
| 5
194
Sacral Nerves
- body part
- pairs
Genitals and lower digestive tract
| 5
195
What muscles control lens shape?
Ciliary muscles
