MT1 Flashcards
1
Q
3 main functions of the BS?
A
Conducts all the communication between the brain and SC
Regulates the level of consciousness (reticular formation)
Targets or source of the CNs (motor and sensory information to the head and face)
2
Q
what structures make up the BS?
A
Midbrain
PONS
Medulla
3
Q
what are the main functions of the medulla?
A
Important for
• HR, BP, breathing, pressure
• Reflexes: vomiting, sneezing, digestion, balance
4
Q
what fibers/tracts decussate in the medulla and where?
A
CST in the pyramids
DCML at medial leminiscus
5
Q
what is the function of the inferior olives? where are they found?
A
• Involved in fine motor control
• Major source of input to the cerebellum from the SC
found in the medulla
6
Q
what is the pons?
A
Mass of decussated fibers that cross the midline
7
Q
what are the main structures found in the pons?
A
pontine nuclei
cerebellar peduncles
mesopontine cholinergic system
locus coeruleus
8
Q
what is the pontine nuclei? fucntion?
A
• Involved in motor activity and relies information from M1 to cerebellum
9
Q
what tracts are contained by the cerebellar peduncles?
A
o spinocerebellar tracts (VST,DST, CUNEOCEREBELLAR)
10
Q
what is the mesopontine cholinergic system involved in?
A
• arousal, attention, learning, rewards, voluntary movement, locomotion
11
Q
what is the pudunculopontine?
A
ACH projecting cells to the inferior frontal cotex and projects to BS MNs
12
Q
what system is locus coeruleus part of?
A
reticular system
13
Q
what biogenic amine is formed in locus coeruleus?
A
NE
14
Q
what is the main function of locus coeruleus?
A
mediates arousal, emotions, mood, sleep & ANS
15
Q
what structures form the midbrain?
A
superior colliculus inferior colliculus substancia nigra red nucleus cerebellar peduncles
16
Q
what tract originates from the superior colliculus
A
tectospinal tract
17
Q
what is mediated by superior colliculus
A
• vision, multisensory integration, ocular movements
18
Q
what is mediated by the inferior colliculus?
A
auditory system
19
Q
what biogenic amine is produced by substancia nigra?
A
dopamine
20
Q
substancia nigra recieves input from where?
A
basal ganglia
21
Q
what tract originated from the red nucleus?
A
rubrospinal tract
22
Q
what are the cerebellar peduncles?
A
• massive projections from the cerebral cortex to brainstem and SC targets
23
Q
where does the reticular formation range from?
A
ranges across the entire brainstem
24
Q
what are the main functions of the reticular formation?
A
- Cardiovascular & respiratory digestive controls
- Sleep & wakefulness regulation
- Mood (Serotonine)
- Origin of the reticular spinal tract which is responsible for Limb and trunk movement
- Relays eye and ear signal to the cerebellum
25
in what order are the somatic/visceral motor and sensory tracts organized from posterior to anterior?
somatic sensory
visceral sensory
visceral motor
somatic motor
26
what are some consequences associated with CN lesions?
* Vision disturbances
* Pupil abnormalities
* Changes in sensation
* Muscle weakness
* Hearing problems
* Vertigo
* Voice change
* Difficulty swallowing
* Speech difficulty
* Coordination problems
27
what portion of phinease Gage was affected?
frontal lobe
28
through phinease gage’s accident what function could be attributed to the frontal lobe?
personality
29
how did broadman manage to organize the cortex of the brain
using microscope and identifying brain patterns and thickness to associate to specific functions
30
how many cortical laayers can be found in the neocortex?
6
31
what are the layers of the neocortex?
1: neurophils - cortico-cortical information processing
2- small pyramidal cells- cortico-cortical information processing
3 - small pyramidal cells- interhemispheric
4: stellate neurons - local ramifying axxons
5: large pyramidal cells - output leaving cortex
6: large pyramidal cells and other cells - output leaving cortex
32
what are some of the complex functions associated to the brain?
-thoughts and feelings
-language
-memory
-speech
-emotions
etc
33
what is the function of the primary visual cortex?
recieves, integrates and processes visual stimuli
34
where is the premotor cortex located based on broadman’s areas?
6
35
what is the function of the premotor cortex?
programming of motor sequence in response to visual stimuli
36
what is the main function of amygdla?
regulates emotions
37
what is the main function of the hypothalamus
regulation of certain processes involved in homeostasis
38
what is the main function of motor cortex?
sends motor signal to muscles
39
what is the main function of basal ganglia?
induces control of volontary movements
40
what is the main function of cerebellum?
coordination
41
what is the main function of the posterior partietal cortex?
regulates planned movements and spatial resoning
42
what is the function of the BS nuclei?
regulates cardiac and respiratory functions
43
what is the main function of hippocampus ?
storage of memory
44
what is the main function of the parietal association cortex?
mediates attention
45
what is the main function of the temporal association cortex?
identification of stimuli
46
what is the main function of the frontal association cortex?
planning and decision making
47
what association cortex is associated with extrapersonal/far space?
posterior parietal association cortex (area 5& 7)
48
the posterior parietal association cortex recieves input from where?
S1 (3A,3B, 1,2) Visual and auditory system
49
what is the main function of the posterior parietal association cortex
integrates somatic sensory info to form spatial percepts in the extrapersonal space
50
what happens in the case of a right lesion in the posterior parietal cortex?
apraxia
| left personal neglect syndrom
51
what is integrated by the parietal lobe?
Cutaneous maps and other body sensations
Visual inputs
Auditory functions
52
what are the main functions integrated by the temporal lobe?
- recognition of speech
- detection of sounds signals
- olfaction
- memory
- face recognition
53
the inability to recognize and identify objects/ shapes/ things is known as? how does this occur?
agnosia
| caused by lesion in the temporal lobe
54
the inability to recognize faces is known as?
prosopagnosia
55
whta are the major parts of the frontal lobe
premotor, motor and prefrontal cortex
56
what is controlled by the premotor cortex?
limb representation
| ability to speak
57
what are is responsible to comprehension of speech?
wernike’s area
58
what area is association for speech production?
broca’s area
59
a lesion on what side will affect speech and listening?
on the left side
60
what happens in the case of a lesion in the prefrontal cortex?
- loss of memory
- attention deficity
- lack of social inhibitions
- flattening of affect
61
what is the main function of the occipital lobe?
o Primary visual functions
o Visual perception
o Recognition of colors
o Recognition of form
62
where is the hippocampus located?
temporal lobe
63
what hemisphere is better in organizing and using visuo-spatial stimuli?
right
64
what is the right hemisphere specialized in?
recognizes global elements (Whole)
65
what is the left hemisphere specialized in?
manipulates local elements (details/parts)
66
what hemisphere is better for facial recognition?
right hemisphere
67
how are the DCML path involved in visceral pain
visceral pain can travel through it. important in cases of cancer with excruciating pain, lesion to the tract may be done to lose sensation and hence pain
68
what is the main function of the caudal portion of the nucleus of the solitary tract?
integrative center for reflexive control of visceral motor function & relay for visceral sensory info to reach other structures
69
what is the main function of the rostral portion of the nucleus of the solitary tract?
gustatory system
70
how do General sensory afferents from thoracic and upper abdomen organs + viscera neck and head - enter brainstem
directly from the nucleus of the solitary tract
71
what are the two main roles of sensory control in the ANS?
- movement to movement visceral motor activty
- informs higher integrative centers of more complex stimulation patterns which can signal potential threatening conditions
72
what is the function of the myenteric plexus?
o controls intrinsic musculature of the gut - peristalsis
73
what is the function of the submucosal plexus?
o Provides chemical monitoring and glandular secretion
74
how are the neurons in the ENS?
intrinsic
75
does the ENS require VNS and CNS integrity?
no
76
what are the main functions exclusively controled by the SNS?
Sweat glands
Adrenal medulla (release of Adrenaline/NA)
Piloerector muscles of the skin
Most arterial blood vessels
77
how does the PSNS function?
PreG neurons release ACH which activates PostG through NACh receptor. the PostG neurons release ACH to modulate target organ via muscarinic receptor
78
what are the main functions of the PSNS?
```
REST AND DIGESTION
Constricts pupils
Slows heart rate
Increases peristalsis of the gut
Promote voiding of the urine from the bladder
```
79
Describe the pre/postG fibers in PSNS?
long pre
| short post
80
Describe the pre/postG fibers in SNS?
short pre
| long post
81
where are the primary and seconday neurons in the PSNS located?
pre: BS and SC
post: Ganglia near target organ
82
what is the main fucntion of the SNS?
fight or flight
Pupils dilate and eyelids retract
Blood vessels of skin and gut constrict
Piloerection & Bronchodilation
Heart rate & contractile force increases
Quiescent digestive and other vegetative functions
The adrenal medulla is activated to release epinephrine and noradrenaline in bloodstream
Pancreas releases glucagon
83
how does the SNS function?
PreG neurons release ACH which activates PostG through NACh receptor. the PostG neurons release NE to modulate target organ via adrenergic receptors (a, b)
84
where are the pregangliuonic neurons found for SNS?
LATERAL HORN (T1-L3)
85
what are the main functions of the hypothalamus?
maintains homeostasis
86
what are some functions accomplished by the hypothalamaus
```
interacts with
o Blood flow
o Energy metabolism
o Reproductive activity
o Coordination sympathetic & parasympathetic responses
```
87
what are the 3 components that make up the VNS?
SNS
PSNS
ENS
88
what is acute pain?
results from an injury and serves as a role of protection, as healing occurs, pain diminished
89
what is chronic pain?
persists after healing
can be due to hyperactivation of nociceptors
pain syndrome
90
how does sensory gating function?
mechanosensory stimuli enters the dorsal column and activates inhibitory local cells blocking pain afferent
91
what is the aim of enkephalin producing cells?
modulate/decrease pain
92
give an example of enkephalin producing cell?
canabis
93
how do endogeneous opioids funciton?
o Exogenously anti-nociceptive compounds suppress nociceptive neurons in the dorsal horn of the SC (opioid, cannabis)
94
what is allodynia?
central sensitization caused by high activity in nociceptive afferents. a non painful stimuli now triggers a nociceptive message?
95
what is hyperalgesia?
a result of inflammation and substance P release relsulting from an injury in the aims to promote healing and protection. hence a weak painful stimuli will now be exaggereated and cause greater pain
96
how does referred pain happen?
convercence of visceral nociceptors on the same neurons in the dorsal horn as cutaneous nociceptors
97
where in the dorsal horn (what laminae) do c fibers synapse in?
1 and 2
98
where in the dorsal horn (what laminae) do Adelta fibers synapse in?
1 and 5
99
what type of neurons synapse in lamina 5
• Neurons in layer V receive nociceptive and non-nociceptive inputs
100
what modalities other than pain and temperature can be sensed by ALS?
* Non-discriminative touch (in the absence of dorsal columns)
* Innocuous warm & cold temperature sensations
* Histamine – itch
* Slow mechanical sensation – sensual touch
* Sensors of lactic acid released during muscle contraction
101
where are TRP channels located? what type of channels are these?
in DRG
| ion channels
102
what is mediated by TRP channels?
• They mediate a variety of sensation, pain, hotness, warmth/coldness, different types of tastes, pressures and vision
103
what can be used to differentiate vertebrates and invertebrates?
TRP channesl
104
what type of pain is carried by A delta fibers?
initial, sharp pain
105
what type of pain is carried by C fibers?
longer lasting diffuse second pain
| Duller, burning quality
106
how big is the diameter of nociceptors?
myelinated 1-5 um
| unmyelinated up to 1.5 um
107
under what circumstances does silent noiceptors function?
o Only work when sensitized by local inflammation and injury (hyperalgesia)
108
what do polymodal C fibers respond to?
o High intensity mechanical, thermal or chemical stimuli
109
what do Adelta 2 fibers respond to
o Intense mechanical pressure applied to skin
110
what do Adelta I fibers respond to
extreme temperatures >45 or <17
111
a lesion in what area of S1 will cause for Inability to use tactile information to discriminate the size and shape of objects
area 2
112
what is the main function of area 2 in S1
proprioception andcutaneous
113
a lesion in what area of S1 will cause for Inability to use tactile information to discriminate texture of objet
1
114
what is the main function of area 1
cutaneous hence responds to pressure and vibration
115
what happens if we have a lesion in area 3B of S1?
deficits in all forms of tactile sensation from mechanoreceptors
116
what is the main function of area 3A of S1?
proprioception, activated during movements, muscle spindles
117
what is the diameter range of mechanosensory receptors?
6-12 um
118
what is the diameter range of muscle spindles??
13-20 um
119
what is the main function of rufini corpuscle? RF? rapid/slow adapting cellS? %
-slow adapting
Rf ~60 mm2
sensitive to cutaneous stretch during movements
20%
120
what is the main function of pacinian corpuscle?RF? rapid/slow adapting cellS? %
rapidly adapting
Rf is the size of finger/hand
sensitive to high frequency vibrations
15%
121
what is the main function of merkel cell? RF? rapid/slow adapting cellS? %
rapidly adapting
rf ~22 mm 2
sensitive to low frequency vibration
40%
122
what is the main function of messiner corpuscle? RF? rapid/slow adapting cellS? %
slowly adapting
rf= 9 mm2
sensitive to points, edges, curves
25%
123
what is two point discrimination threshold?
minimum interstimulus distance required to perceive 2 simultaneous applied stimuli as distinct
124
what happens if we touch center of RF?
increases cell firing
125
what happens if we touch surround of RF?
decreases cell firing
126
what happens if there is an absence of receptors between two fields
discrimination is impossible
127
how can a mechanosensory afferent be transduced?
stretch opens cation channel, Na+ influx which depolarizes and causes for AP to be generated thus mechanical stretch is converted to electrical energy
128
what afferent is responsible for conveying information about muscle tension?
Ib (golgi tendon)
129
what is the function of II afferent?
its a slow adapting cell
provides sustained response about muscle length
conveys information about the static position of the limb
130
what is the function of IA afferent?
rapdily adapting cells that are activated by stretching of the muscle. conveys information about velocity and direction of the movement
131
where do pain and temperature fibers decussate?
SC
132
where do fibers from proprioception and fine touche decussate (Aa, AB)
in the medulla
133
what is the main function of CPG?
CPG controls timing and coordination of complex movements
134
what type of reflex is the flexion withdrawl reflex?
polysynaptic reflex
135
what is a myopathic disease due to muscle fiber degenerate?
muscular dystrophy/DMD
136
what are some neuropatic diseases that arise due to demyelination of axons?
MS
GBS
Diabetes
137
what are some neuropatic diseases that arise due to decrease in amount of MNs?
polyio
138
what is the main target of ALS neuropathic disease?
a-MNs
139
how can spasticity be treated?
```
PTOT TO RELIEVE CONTRACTURES
physical modalities such as FES
botox
gaba agonists
rhizotomy
```
140
WHAT IS THE FUNCITON OF THE STRETCH REFLEX?
assists in maintaing balance and muscle tone
141
what does the coactivation of a and gamma MNs allow?
spindles to function- sends info centrally
| • Regulate the gain of stretch reflex so it can operate efficiently at any length
142
Ia interneurons recieve input from?
muscle spindles and descending pathways
143
what can be accomplished by Ia interneurons?
o Enhance speed and efficiency of movements
| o Stiffen the joint for stabilization
144
how can the force in muscles be controled?
varies on the type of MN recruited (bigger= more force)
| amount fo AP generated (closer AP= accumulation of force)
145
what is the motor unit
aMN & the muslce fibers it innervates
146
what was discovered by charles sherrington?
• Discovered the stretch reflex and describes the motor unit
147
what is the posterior cord syndrome?
o Incomplete lesion
o Often caused by tumors, hernia, (often non-traumatic)
o loss of 2 point discimination and vibration and proprioception at the level below injury
148
what is brown sequad syndrome?
o Lesion in the spinal cord which leads to weakness or paralysis on one side of the body (motor) but loss of sensation to pain and temperature on the opposite side and ipsilateral loss of two point discrimination and vibration
o Segmental flaccid paralysis at the level of the lesion and spastic paralysis at the level below
o Often result of stab or gunshot wound
149
what lesion leads to loss of all sensation and motor functions other than the DCML?
anterior spinal A syndrome
150
what is affected by the central cord syndrome?
o Loss of proprioception and vibration
o Caused by hyperextension of the neck or whiplash or spinal cord compression
o Most often in the cervical region
o Anterior spinal A. bursts causing for hematoma and death of neuronal tissue in the spinal cord
o Tends to affect the UE more than the LE
o Loss of motor, sensory and pain mostly in the arms, along with loss of two point discrimination and vibration on both sides
151
what spinal levels are most affected by partial transections
C4,C5,C6
152
what population group is most at risk of traumatic SCI?
males ~40yo
153
what are some symptoms associated with complete SCI?
```
spinal shock
paralysis
loss of sensation
+ babinski
loss of bladder and bowel control
```
154
SCI in the cervical region leads to?
full/partial tetraplegia
155
SCI in the thoracic region leads to?
paraplegia
156
what is more common traumatic or nontraumatic SCI?
Ntsci (58%)
157
what is essential for peripheral nerve repair?
schwann cells
158
why are peripheral nerve injuries a challenge for rehab?
- long distance
- disorganized pattern
- larger and more fasciles
- tension, crushing and tissue loss is often involved
159
at what speed does the spout grow if it reaches the neurolemma?
1-3mm/day
160
under what condition can axons grow back?
only if they are still connected to the cell body
161
what is wallerian degeneration?
degeneration of axon and myelin sheath using macrophages
162
when does wallerian degeneration happen?
generally ~24H of
163
what follows wallerian degeneration?
axonal sprouting
164
what are neutrites?
the sprouts sent out to reach the neurolemma
165
do we have more myelinate or unmyelinated axons
more unmyelinated, they occupy all the surrounds in the fascicles
10:1 ratio
166
what type of axon has the greatest condution velocity?
larger diameter axons
167
which MN between alpha and gamma has a greater diameter?
Alpha
168
how does AP in myelinated axons?
saltatory conduction
169
how does AP propagate?
* 1. Stimulation (beyond threshold) opens the Na channels. Na enters the cell, which depolarizes the cell (AP)
* 2. Depolarization current travels passively and causes further opening of Na channel; therefore the AP propagates down the axon
* 3. Upstream, the closing of Na channels is followed by the opening of K+ channels. K+ leaves the cell, which locally terminates the AP.
170
what are opioids?
```
o Family of ~20 different molecules
o Widely distributed in the brain
o Functions
Depressant
Analgesic
Sexual attraction
```
171
what functions are regulated by serotonin?
o Regulates sleep and wakefulness
| o Implicated in emotions, circadian rhythm, state of arousal, feeling of satiety
172
serotonin dysfunction leads to what? how to treat it?
o Depression, schizophrenia, Alzheimer’s eating disorders
| -SSRI
173
tryptophan produces what biogenic amine?
serotonine
174
histidine produces what biogenic amine?
histamine
175
tyrosine produces what biogenic amine?
NE/E/Dopamine
176
where does histamine originate from
hypothalmaus
177
what is the main function of histamine
o Mediates attention and arousal
| o Involved in the vestibular system (autonomic system)
178
histamine antagonist are useful for?
allergic reactions
179
epinephine? origin? projection? function?
o From cell bodies in the medulla
o To thalamus and hypothalamus
o Role: regulation of respiration and cardiac function
180
origin and projection of NE?
o From Locus Coeruleus in brainstem to entire brain
181
function of NE?
o Involved in sleep, attention, feeding behaviors
o Present in ganglion cells in the sympathetic system
o Major role in the visceral motor system (autonomic system)
182
what does amphetamine stimulate?
increases norepinephrine levels
183
where is dopamine produced?
substancia nigra
184
what is dopamined involved with
o In structures involved in control of movement
| o Motivation/reward
185
biogenic amines function on what type of receptor?
metabotropic
186
what type of NT is GABA?
Inhibitory
187
what is gaba derived from? degraded? receptor?
derived from glutamate
degraded by glial cell reputake
both receptors
188
function of GABA?
Very common in local circuits interneurons or highly inhibitory system such as cerebellum
189
gaba agonists?
* benzodiazepines, barbiturates
* Sedatives and anesthetics
* Management of epilepsy
* Baclofen which serves as a muscle relaxant in cases of spasticity
190
glutamate
excitatory NT, occupies 1/2 synapses in the brain
191
what is glutamate derived from? degraded? receptor?
glutamine
glial cell reputake
both receptors
192
function of glutamate?
Involved in cellular mechanisms of learning and memory
Involved in pain transduction
Excitotoxicity (secondary cell death)
• Can cause secondary cell death
General anesthesia decreases glutamate activity (amongst other effects)
• Less excitation
193
ACh?
excitatory and inhibitory
194
ach precursor, degraded, receptor?
o Precursors: Acetyl Coenzyme A and Choline
o Degraded rapidly by enzyme Acetylcholine Esterase
-Nach and muscarinic
195
what is sarin gas?
prevents degradation of ACh which causes death
196
what drug block muscarinic receptors to prevent motion sickness
scapolamen
197
what type of receptor is muscarinic ACh receptor? where does it function?
metabotropic
| brain cells
198
what type of receptor is Nach? where does it function?
iontropic
| neuromuscular junction
199
how is ACH on muscarinic receptor involved on ANS?
In PSNS released by postganglionic fibers thus decreases HR
