Exam 2 Flashcards
(182 cards)
1
Q
What arteries bring blood from the heart to the brain?
A
Vertebral
Internal Carrotied
2
Q
What is the only artery in the brain that gets blood from both the vertebral and internal carotid artery?
A
Posterior cerebral artery
3
Q
What nerves run with the labrythine artery?
A
Facial
Vestibulococlear
4
Q
What primary artery supplies the brain stem?
A
Verterbral Artery and it’s branches
5
Q
What vains drain the brain?
A
Only 1: internal jugular vain
6
Q
What are the branches of the vertebral artery?
A
Posterior Inferior Cerbellar Arter
Anterior Spinal Artery
Posterior Spinal Artery
7
Q
What is the funtion of phylogentically old structures?
A
Survival (of the species)
8
Q
True or False: The reticular formation is an unorgainized collection of neurons with a few fibers.
A
False: mostly fibers a few neurons
9
Q
What are the regions of the reticular formation?
A
Raphe
Magnocellular
Parvocellurar
10
Q
Define Sensory Unit
A
Stem fiber and ail its branches and receptors
Receptors and fibers it is connected to
Smallest unit of sensory response
11
Q
What is the receptive field?
A
Area covered by sensory unit
Territory from which sensory unit can be excited
NOT the same as a Dermatome.
12
Q
What is a dermatome?
A
Strip of skin innervated by single spinal nerve
Spinal nerve => several 1000 sensory units
13
Q
What 2 dermatomes are directly next to each other on the body, but do not have much overlap in terms of which nerve root might actually be supplying the sensation?
A
C4 and T2
14
Q
What is Sensory transduction?
A
Stimulus to electrical signal –> how info is carried though the nervous system.
15
Q
What are they 2 ways that neurons can be classified based on adaption?
A
Rapidly adapting receptor: Respond quickly to stimulus then stop
Slowly adapting receptor:Will continue to respond to stimulus
16
Q
What is the difference between phasic and tonic neurons?
A
Phasic => quickly spike
Tonic => continuous spiking pattern
17
Q
What are the classifications of neuron by source?
A
Exteroceptor: Stimuli from OUTSIDE environment
Interoceptor: Stimuli from INTERNAL environment
Proprioceptor: Where body is in relationship to space?
• Special type of interoceptor
• Found in muscles
• Position sense
18
Q
How can neurons be classified by function?
A
Nociceptor => respond to pain
Therrnoceptor => respond to changes in temperature
Mechanoceptor => respond to physical deformation or shape changes
19
Q
What do free nerve endings respond to?
A
Pain and Temp
20
Q
Where are free nerve endings found?
A
Near the surface of the skin
21
Q
Are free nerve endings fast adapting or slow adapting?
A
Slow adapting.
22
Q
Are Follicular cells encapsulated?
A
Nope
23
Q
Where are Follicular cells found?
A
Around the hair folloicle
24
Q
Are Follicular cells fast adapting or slow adapting?
A
Rapidly adapting (think of how annoying it would be to constantly feel your hat on your head).
25
What do merkel cells respond to?
touch
| Differences in touch => edge detection
26
Where are merkel cells located?
epidermis
27
are merkel cells encapsulated?
No
28
What do merkel cell communicate with?
Merkel discs
29
Are merkel cells fast or slow adapting?
Slow
30
Which cells are encapsulated? What is the main thing each responds to?
Meissner's => light touch
Ruffini's => shearing or drag
Pacinian => vibration
31
Which type of cell is the largest?
Pacinian.
| They can be seen without magnification
32
Which type of cell gives you information about the force you experience when walking against the wind?
Ruffini's.
33
Which encasulated cells are rapid adaptors?
Pacinian
| Meissner's
34
Which type of encapsulated cells are slow adapting?
Ruffini's
35
Where are Meissner's corpscles located?
The papillae of the demis. close to the surface.
36
Where is sensory info from joints, muscles and skin integrated?
parietal lobe
37
What are spinal reflexes?
Predictable response to stimulation. These involve at least 2 neurons
38
What is a motor unit?
1 nerve and all muscle fibers
Specifically an Alpha motor neuron and muscle fibers it innervates
Functional unit of motor system
39
What are the 4 components of a motor unit?
Cell body
Axon
Neuromuscular junction
Muscle fibers
40
Are the motor units in your fingers large or small?
Small --> 1 neuron to about 10 muscle fibers
41
Are the motor units in your quads large or small?
Large --> 1 nuron to about 1000 muscle fibers
42
What is the neuromuscular junction?
AKA Motor endplate
| Where nerve communicates to muscle
43
Go through the steps of communication that occur at the neuromuscular junction.
```
• Vesicles filled with neurotransmitters (Involves neurotransmitter => ACh)
• Migrate to edge of terminal
• Fuse with cell membrane
• Release contents to outside
• Muscle fiber cell has trough
.:. Where tenninal fits in
.:. Trough is highly folded
.:. More surface area
.:. Better chance to find receptor
• Neurotransmitters diffuse across gap
• Find receptor
• Excite muscle
```
44
What effect does aging have on motor units?
Loss of motor neurons from spinal cord and brainstem
- Through programmed cell death => apoptosis
- Through peripheral neuropathy => damage to nerve by disease or trauma End up with fewer neurons controlling muscles
Leads to loss of intricate movement
45
What part of the muscle spindle is a stretch receptor?
intrafusal fiber
46
Where are the Extrafusal fibers located?
outside muscle spindle
47
What type of neuron innervates the Extrafusal fiber
Alpha motor neurons.
48
Which part of the muscle fiber is multinucleate and striated?
Extrafusal fiber
49
What types of muscles surround the muscle capsule?
Interfusal fibers
50
What type of neuron innervates the interafusal fibers?
gamma motor neuron
51
Describe the location the intrafusal fibers.
These fibers wrap around the nuclear bag and nuclear chain.
52
What are the types/function of intrafusal fibers?
```
There are 2 types:
Annulospiral fibers (Primary)
Flower Spray Endings (secoundary) = Degree of stretch
```
53
What is the shape of the muscle capsule?
spindle shaped or fusiform
54
Where do the sensory interfusal fiber's neurons interact with the muscle fiber?
it wraps around the nuclear bag and chain
55
What types of fibers can actively be stretched? What do we mean by this?
Voluntarily stretch of the fibers.
| fusimotor fibers do the contracting.
56
What is the neural control of voluntary muscle stretch reflex?
This reflex deals with Lengthening
cortex at precentral gyrus --> gamma motor neuron on muscle spindle (remember these are at the end of the muscle) --> Muscle spindle contracts on ends --> this stretchs the middle of the muscle --> Afferent activated by stretch --> Stretch of the receptor goes back to excite alpha motor neuron to muscle --> muscle contracts.
57
What type of stimulus triggers the reflex from the Golgi Tendon Organ?
force o f contraction
58
What/where is the Golgi Tendon Organ located?
it is a receptor in the muscle tendon junctions
59
Describe the response to excessive force of contraction.
Too much force is detected by the golgi tendon --> Goes to interneuron--> Interneuron turns OFF alpha motor neuron and turns ON motor neurons for an antagonistic muscle.
(excites inhibitory neurons to turn off the muscle and simultaneously excites the antagonist muscles)
60
Which reflex (stretch or force) is considered monosynaptic? Which is disynaptic?
```
Stretch = Monosynaptic
Force = Disynaptic
```
61
What type of reflex is the knee jerk reflex?
Passive stretch reflex
62
Describe the knee jerk reflex.
Push in on tendon --> Pulls muscle with it --> Muscle stretches --> Receptor for muscle spindle feels stretch --> Sends message via spinal cord to alpha motor neuron --> 1a Alpha motor neuron goes back to muscle causing it to contract (excitatory reaction).
Simultaneously signal goes to inhibitory interneuron to turn off antagonistic muscle.
63
Is the knee jerk reflex monosynaptic or disynaptic?
****kind of unsure*****
| When there is an inhibitory response than it is disynptic. When it doesn't it isn't.
64
How are joints innervated?
Freely ending unmyelinated nerve fibers in ligaments, capsules and menisci
Nociceptors
65
Are the reflexes that are triggered by the joints being kept in a painful position excitatory or inhibitory?
Excitatory (flexor reflex)
66
Where is the sensory info the joints integrated?
Sensory information from joints, muscle, and skin are integrated in the parietal lobe
67
What receptors are found in the periosteum?
Pacinian corpuscle => vibration
| Ruffini's corpuscle => shearing or drag
68
Are the joints responding to input on the same side or opposite sides?
opposite
69
Where is the reticular formation located?
It fills in the core of the brain stem.
| Technically located in tegmentum of midbrain, pons, and medulla.
70
Are there more cell bodies or fibers in the reticular formation?
Fibers.
| The name actually means "net of fibers"
71
What structures in the core of the brain stem are defiantly NOT part of the reticular formation?
Cranial Nerve nuclei
| Ascending/descending tracks
72
How would you describe the function of the reticular formation?
```
functions aimed for survival (it is Phylogenetically old)
Levels of awareness – ARAS
Modulate muscle tone
Respiration and cardiac rhythm
Emotion of pain (limbic)
```
73
What are the regions of the reticular formation?
Raphe (A K A median region)-->Found at midline
Magnocellular --> In central median paramedian
Gigantocellular--> In pontomedullary region
Parvicellular/parvocellular --> Lateral group
(in my notes i have that the magnoceullar and gigantocellular are pretty much in the same place, the only difference is that giganto are larger than magno).
74
The reticular tract is what type of cell?
Magnocellular
75
What neurotransmitter does the raphe nucleus transmit?
serotonin
AKA 5HT
AKA 5 hydroxytrip
76
What does ACh normally control?
Motor function/autonomic effects
77
What releases Acytlecholene?
The pudonchlopontine nucleus.
78
Where is Noradrenergic (norepinephrine) released from?
locus coeruleus => close to sulcus limitans
Nucleus of solitary tract of midbrain
Ventrolateral medulla
79
When Norepinephrine has been released from the solitary tract nuclus, what will it likely do?
controls attention/awareness
80
What is the precursor of norepinephrine?
Dopomine
81
Where is dopamine found?
ventral tegmental area
82
What does dopamine do?
Motivation (make adrenalin)
| Decision making
83
What does Serotonin do?
Awareness
Mood
decrease pain
84
In the reticular formation, which types of fibers are afferent and which are efferent?
Motor => afferent
| Sensory => efferent
85
What part of the NS is the lymbic system associated with?
Autonomic
86
What does the reticular activating system do?
Everything and it goes everywhere:
- Awareness
- Muscle Tone (though ACh)
- Sets up respiration and cardiac rhythm (Norepinephrine, Dopamine, Epinephrine)
- Emotion of pain (Limbic system)
87
AKA for dorsal root ganglion?
Spinal Ganglion
88
Describe the neuron in the DRG.
pseudounipolar
Has cell body and one process comes out of cell body
Splits into two processes => centripetal and centrifugal Centrifugal => goes toward receptor
Centripetal => goes into CNS (spinal cord, brainstem)
89
Which area of the spine has the smallest ganglion?
Thoracic (50,000 neurons instead of the 100,000+ in the cervical and lumbar spine)
90
Why does the cervial and lumbar area have more neurons?
Plexuses (limb innervation)
91
What perceives conscious sensation?
cerebral cortex
92
What type of information is Exteroceptive?
information from the outside (Vision, hearing, touch, pressure, heat, cold, pain)
93
What information is Proprioceptive?
Know where body part perceived in space (Position sense, kinesthetic sense)
94
Where is unconscious sensation perceived?
cerebellum
95
What what type of information Enteroceptive?
Anything going on inside the body which may cause changes to occur.
• Visceral reflexes
• Example => blood pressure
96
Motor coordination, Minute changes in muscle tone, Fine motor tuning to maintain position in space are all what type of unconscious perception?
Proprioceptive
97
What type of infromatoin runs along the Somatosensory pathway?
Distinguish touch, temperature, pain
98
What is the first order neuron in all somatosensory pathways?
Dorsal Root Ganglion
99
Generally, where are the second order neurons located in the somatosensory pathways?
When the synapse is ipsilateral: CNS (spinal cord or medulla)
When the synapse is contralateral: Goes to thalamus on other side
100
Generally, where are the third order neurons located?
in thalamus
101
Where do the fibers from the thalamus run to?
postcentral gyrus => somatosensory cortex
102
If an area is somatotopic, what does that mean?
We can map the body within that area.
103
What area of the body is the Gracile fascicle somatotopic for?
Lower body
| Gracile fasicle is an AKA for the medial fascicle
104
What are of the body is the Cuneat fascicle somatotopic for?
The upper body
| cuneat fascicle is an AKA for the lateral fascicle
105
are interneurons important in the somatosensory pathway?
Yes
106
Is the dorsal coluImn-medial lenmiscus an ascending or descending pathway?
Ascending pathway
107
What makes up the dorsal column and medial lenmiscus?
Dorsal colunm => pertains to 2 colunms on dorsal side of spinal cord (Gracile fasciculus and Cuneate fasciculus)
Medial lemniscus => pertains to fibers running through brainstem
108
What is the function of the dorsal column - medial lenmiscus?
Function
1. Proprioception (sensation of where limbs are, how muscle contracts, etc)
2. Discriminative touch AKA epicratic touch
• Know difference between two points
• Adjust pressure => how much pressure to apply
• Light touch
109
True or false: the cunate fascicle runs the entire length of the spinal column, while the Gracile fascicle only runs the upper 1/2 of the spinal column.
FALSE (flip it an reverse it)
Cunate - upper 1/2 (carrying info about the upper limbs)
Gracile - whole spin (carrying info about the lower limbs)
110
Describe the path of the dorsal column - medial lenmiscus tract.
1st order neurons DRG --> fibers enter the spinal cord and runs up to the medulla --> synapses at cuneate nucleus or gracile nucleus in medulla onto 2nd order neurons --> Medial internal arcuate fibers from second order neurons exit nucleus and cross over to other side in medulla --> Ascend up the Posterior fibers of the medial lenmiscus --> Synapse on 3rd order neurons thalamus at ventral posterior lateral nucleus (VPL) -->somatosensory cortex --> Sends fibers to internal capsule and corona radiate
111
What are the parts of the Anterolateral system (ALS)?
Spinothalamic tract
Spinotectal tract
Spinoolivary tract
Spinoreticular tract
112
Which part of the ALS is a direct pathway?
Spinothalamic tract
113
Which part of the ALS is an indirect pathway?
Spinoreticular tract
114
What is the function of the ALS?
Detection of:
Pain
Temperature
crude touch
115
Specifically, which region of the spinothalmic pathway deals with which sensation?
Lateral:
Noxious => pain
Thermal => temperature
Anterior:
Light touch
116
Describe the path of the spinothalmic pathway.
1st order neuron DRG --> fibers run into the spinal cord --> Ascends anterior lateral system (ALS) 1 or 2 levels to spinal lemniscus --> synapse on 2nd order neurons in lamina I, IV, V, (III) --> fibers cross over diagonally at anterior white commissure --> fibers ascend up to the thalamus --> synapse on 3rd order neurons in the ventral posterior lateral nucleus (VPL) --> project up to the post central gyrus through internal capsule and corona radiata
117
How many segments do the spinothalamic pathway cross over?
Lateral => cross over 1 segment
| Anterior => cross over several segments
118
What is the AKA for the spinoreticular tract?
paleospinothalamic tract
119
What is the function of the spinoreticular tract?
Function
Awareness
Emotion of sensation (eg pain)
120
Describe the path of the spinoreticular pathway.
DRG --> Dorsal Horn V and VII --> DO NOT CROSS but ascend in the Anteriolateral system/ Anterior lateral funiculus --> synapse in thalmus at Posterior thalamic
nucleus, Peri- aqueductal gray, VPL --> Runs to the reticular formation
121
Describe the path of the Spinotectal pathway.
DRG --> Dorsal Horn V and VII --> Cross at anterior white commissar --> Assend in the ALS --> to superior colliculus of midbrain
122
What is the funtion of the spinotectal tract?
Turns head toward stimulus
123
Are the spinorecticiral or spinalthemic pathways somatotopic?
The spinothalamic is.
| The spinoreticular is not.
124
Describe the pathway of the Posterior spinocerebellar tract AKA Dorsal spinal cerebellar tract (DSCT).
DRG --> synapse onto the 2nd order neuron at Clark's Nucleus (Dorsal thoracic Nucleus, Lamina VII) --> DO NOT CROSS --> Ascend up the dorsal lateral and gracile fascicles --> To inferior cerebeller peducncle and Rostral/caudal vermis
125
What does the posterior spinocerebeller track control?
Unconscious proprioception => LOWER body (leg)
Homologous to gracile portion of dorsal column medial lemniscus pathway
126
What spinal levels are the posterior spinocerebeller track found?
from TI - L2
127
What is the path of the Cuneocerebellar tract?
1st order neuron in the DRG--> Fibers enter spinal cord--> Ascend up cuneate fascicles --> 2nd order neuron at accessory cuneate nucleus in medulla (lateral to cuneate nucleus) --> Enter cerebellum through inferior cerebellar peduncle
128
What is the function of the cuneocerebellar tract?
Unconscious proprioception => UPPER body (arm)
Homologous to cuneate fasciulus of dorsal column medial lemniscus pathway
129
What is the path of the cuenocerebellar tract?
DRG --> Fibers enter spinal cord and ascend up cuneate fasciculus --> 2nd order nucleus is synapsed on at the accessory cuneate nucleus in the medulla (lateral to cuneate nucleus) --> fibers enter cerebellum through inferior cerebellar peduncle
130
What is the function of the Anterior spinocerebellar tract?
Monitor reflex arc
Maintains reflexes run smoothly
Responsible for LOWER body
131
What is the path of the anterior spinocerebellar tract?
DRG --> synapes onto 2nd order neuronLumbar cord V,VI,VII --> fibers cross at the anterior white commisure --> ascend up the ventral lateral fascicles --> enters the cerebellum though the superior peduncle --> fibers recross to the opposite side (the side they originally started on).
132
What is the function of the Rostral spinocerebeller tract?
Monitor reflex arc
Maintains reflexes run smoothly
Responsible for UPPER body
133
Describe the path of the rostral spinocerebeller tract
Importantly this track is the least known. it is believed to do some of the same things as anterior spinocerebellar. This track does not cross however.
Fibers enter from 2 places:
• Fibers near the anterior spinocerebeller track enter superior cerebellar peduncle
• Fibers near the Posterior spinocerebeller enter inferior cerebellar peduncle
134
What does the Spinoolivary tract do?
Attends to
Cutaneous info
Proprioception (more important)
How body responds to small changes in movement
135
Where do the spinoolivary fibers enter?
Through middle cerebellar peduncle
136
What is the AKA for the Corticospinal tract?
pyramidal pathway
137
Is the Pyramidal pathway ascending or descending?
Descending
138
Where do the neurons of the corticospinal tract come from?
60% to 80% come from primary motor cortex
20% to 40% come from supplemental motor areas or parietal motor area
139
Describe the corticospinal track pathway.
1st order upper motor neurons from the precentral gyrus --> Goes through internal capsule --> Goes though corona radiate --> in the midbrain 80% cross at pyramidal decussation as lateral corticospinal, 20% continue on the same side as anterior corticospinal tract--> Continue down through either lateral or anterior corticospinal tract in spinal cord --> 10% of anterior cortioico spinal fibers cross over in the anterior white commisure --> synapses on second order (lower motor) neurons in the anterior horn.
140
Which tract becomes the cerebral peduncle?
corticospinl tract
141
What is the corticospinal tract called in the pons?
pontine corticospinal tract
142
What is the corticospinal tract called in the medulla?
pyramids
143
What are the corticobulbar fibers?
Branches of the cortiospinal tract that go to cranial nerve nuclei in brainstem.
144
What are the targets of corticospinal neurons?
Motor neuron
Renshaw cell => feedback to motor neuron (interneuron)
Excitatory interneuron
Presynaptic inhibitory neuron
145
What are the types of motor neurons?
upper and lower motor neurons.
146
Which type of motor neurons begin in the cortex?
Upper motor neurons
147
Which type of motor neurons being someplace besides the cortex in the CNS
lower motor neuorons
148
Which type of motor neurons go to the PNS?
lower motor neurons
149
Which type of motor neurons go to the CNS?
Upper motor neurons
150
What motor neuron goes to the majority of voluntary muscle?
Alpha Motor neurons
151
What are the groups of alpha motor neurons and what do they innervate?
Groups
Medial group => innervates axial musculature
Dorsal medial group => innervates anterior trunk (ex: rectus abdominis, intercostals)
Ventral medial group => innervates back muscles (ex: erector spinae)
Lateral group => innervates appendicular musculature (limbs)
Flexor group => dorsal
Extensor group => ventral
intermediolateral group => parasympathetic system (Sacral region of spinal cord)
Central group => innervates diaphragm (c3c4c5 only)
152
What are the 2 parts of the Reticulospinal tract?
Medullary reticulospinal tract
| Pontine reticulospinal tract
153
What is the function of the reticulospinal tract?
* Help locomotion
* Keep muscles toned and ready
* Posture
* Coordination o f activity
* Fibers involved with ANS => pre-preganglionic neuron
154
What NT does the reticulospinal tract work with?
Adrenergic/noradrenergic pathway (epinephrine nor epinephrine)
155
What is the funtion of the tectospinal tract?
Act on contralateral muscles involved in head movement
Keep head straight => posture
Reflex head turning
156
What motor neuron dose the tectospinal tract act on?
axial motor neurons
157
Do the fibers of the tectospinal tract cross?
Yes
158
AKA for Vestibulospinal tract?
Lateral Vestibulospinal tract
159
Where does the lateral vestibulospinal tract begin?
lateral vestibulospinal nucleus
160
Do fibers of the lateral vestibulospinal tract cross?
No
161
What is the function of the lateral vestibulospinal tract?
* Maintains postural reflex
* Keeps balance
* Helps understand what balance is
* Maintains center of gravity
162
What NT does the Raphespinal tract use?
Serotoinin
163
Where does the raphespinal tract begin?
raphe neurons => midline neurons
164
Where does the raphespainl tract extend to?
dorsal lateral tract (posterolateral tract of Lissaur)
165
What track is in control of all sensory info?
Raphespinal track
166
How does the raphespainl track control pain sensation?
Stimulate raphespinal nuclei to block or deaden pain
167
How do the Central autonomic pathway fibers descend?
Fiber descent in intermediate gray matter
| • Between dorsal horn and ventral horn in the Intermediolateral cell colullum (preganglionic neuron)
168
Where are the sympathetic neurons located?
T1-L2
169
Where are the parasympathetic neuron located?
sacral region and brain stem
170
What are the 2 ways that blood gets to the brain?
Internal carotid artery
| Vertebral artery
171
What does the anterior cerebral artery supply?
Supplies medial part of cerebrum
172
What is the path of the anterior cerebral artery?
Branch off internal carotid artery
Runs anterior
Curves posteriorly over corpus callosum
173
Which artery receives the majority of the internal carotid artery flow?
Middle cerebral artery
174
What is the path of the middle cerebral artery?
```
Goes out laterally from internal carotid
Enters lateral fissure
Splits into 2 branches
.:. Upper => frontal and parietal lobes
.:. Lower => parietal and temporal lobes
```
175
What do the Lateral striate arteries branch off of?
middle cerebral artery
176
What problem can ocure at the lateral striate arteries?
Susceptible site for strokes
Will lesion pyramidal tract fibers at internal capsule
Affects motor more
177
What is the posterior cerebral artery a branch of?
25% of blood flow comes from internal carotid artery
| 75% of vertebral artery
178
What does the posterior cerebral artery supply?
Supplies posterior part of cerebrum
Supplies inferior part of occipital and temporal lobes
Supplies posterior part of forebrain
179
What are the branches of the cerebral artery and what do they supply?
```
Posterior inferior cerebellar artery
Lateral side of medulla
Posterior inferior cerebmm
Anterior spinal artery
Ventral and medial aspect of medulla
Anterior spinal cord
Posterior spinal artery
Dorsal and medial aspects of medulla
Posterior spinal cord
Anterior inferior cerebellar artery
Supplies lateral sides of pons, inner ear, anterior inferior
cerebmm
Labyrinthine artery
Supply inner ear
Pontine artery
Supply midpons
Posterior cerebral artery
Supplies midbrain
```
180
What vain drains the brain?
Internal jugular through sinuses
181
Name the superfical sinuses and what they drain.
Superior sagittal sinus -- Superior brain
Cavernous sinus -- Middle brain
Transverse sinus -- Inferior brain
182
What drains the thamus and basial gangion?
```
Great cerebral vein of Galen (AKA great vein)
Drains into straight sinus
Which drains into confluens
Which drains into transverse sinus
Which drains into sigmoid sinus
Which drains into internal jugular
```
