Neuro Flashcards
(68 cards)
1
Q
Astrocytes
A
- Most abundant glial cell
- regulate metabolic environment
- repair neuron after neuronal injury
2
Q
Ependymal cells
A
Concentrated in roof of 3rd and 4th ventricles & spinal cord
3
Q
Oligodendrocytes
A
Form myelin sheath in the CNS
Schwann cells form myelin sheath in PNS
4
Q
Microglia
A
Macrophages - phagocytize neuronal debris
5
Q
Frontal lobe
A
motor cortex
6
Q
Parietal lobe
A
somatic sensory
7
Q
Occipital lobe
A
vision cortex
8
Q
Temporal lobe
A
auditory
Wernicke’s area - understanding speech
Broca’s area = motor control of speech
9
Q
Cerebral cortex
A
cognition, sensation, movement
10
Q
Hippocampus
A
memory and learning
11
Q
Amygdala
A
emotion, appetite, responds to pain & stressors
12
Q
Basal ganglia
A
fine control of movement
13
Q
Diencephalon
A
thalamus & hypothalamus
14
Q
Thalamus
A
relay station that directs info to cortical structures
15
Q
Hypothalamus
A
primary neurohumoral organ
16
Q
Brainstem
A
- midbrain
- pons
- medulla
- reticular activating system
17
Q
Midbrain
A
auditory and visual tracts
18
Q
Pons
A
autonomic integration
19
Q
Medulla
A
autonomic integration
20
Q
Reticular Activating System
A
controls consciousness, arousal, and sleep
21
Q
Cerebellum
A
- Archiocerebellum
- Paleocerebellum
- Neocerebellum
22
Q
Archeocerebellum
A
maintains equilibrium
23
Q
Paleocerebellum
A
regulates muscle tone
24
Q
Neocerebellum
A
coordinates voluntary muscle movement
25
All cranial nerves are part of the Peripheral Nervous System except...
Optic n.
| - only CN surrounded by dura
26
Bell's palsy results from an injury to which nerve
Facial (CN VII)
| - ipsilateral facial paralysis
27
Tic douloureux
```
Trigeminal neuralgia (CN V)
- excruciating pain in the face
```
28
Eye movement is controlled by which cranial nerves?
CN III, IV, VI
29
Parasympathetic output is carried out by which cranial nerves?
CN III, VII, IX, and X
| - vagus is responsible for 75% of all ParaSNS activity
30
Where is CSF located?
- Ventricles ( L lateral, R lateral, 3rd and 4th)
- Cisterns around the brain
- Subarachnoid space in the brain and spinal cord
31
Blood Brain Barrier is not present at...
- chemoreceptor trigger zone
- posterior pituitary gland
- choroid plexus
- parts of the hypothalamus
32
CSF volume?
150 ml
33
Specific gracvity?
1.002-1.009
34
What cells is CSF produced by and at what rate?
- ependymal cells of choroid plexus
| - rate of 30 ml/hr
35
Choroid plexus is located in what cerebral ventricles?
All 4
36
CSF pressure?
5-15 mmHg
37
How is CSF reabsorbed into the venous circulation?
via arachnoid villia in the superior sagittal sinus
38
Global cerebral blood flow
45-55 mL/100g tissue/min
| - 15% of CO
39
Cortical cerebral blood flow
75-80 mL/100g tissue/min
40
Subcortical cerebral blood flow
20 mL/100g tissue/min
41
Cerebral Perfusion Pressure autoregulation is abolished by?
- intracranial tumor
- head trauma
- volatile anesthetics
42
5 determinants of cerebral blood flow
- cerebral metabolic rate for oxygen
- cerebral perfusion pressure
- venous pressure
- PaCO2
- PaO2
43
Conditions that impair cerebral venous drainage
- jugular compression r/t improper head position
- inc. intrathoracic pressure r/t coughing or PEEP
- vena cava thrombosis
- vena cava syndrome
44
For every 1 mmHg inc or dec in PaCO2, CBF will inc or dec by what?
1-2 mL/100g brain tissue/min
45
Cerebral max vasodilation and vasoconstriction occur at what PaCO2 levels?
vasodilation: PaCO2 = 80-100 mmHg
vasoconstriction: PaCO2 = 25 mmHg
46
Does metabolic acidosis affect CBF?
No - because H+ does not pass through the BBB
- only respiratory acidosis affects CBF
47
How does PaO2 affect CBF?
- PaO2 < 50-60mmHg causes vasodilation and inc CBF
| - PaO2 > 60mmHg does NOT affect CBF
48
Grey Matter
- contains neuronal bodies
| - processes afferent signals from periphery
49
Laminae I-VI
- dorsal grey matter
| - sensory
50
Laminae VII-IX
- ventral grey matter
| - motor
51
Grey matter is larger in two regions of the spinal cord
- C5-C7 (houses cell bodies for neurons that supply upper extremities)
- L3-S2 (houses cell bodies for neurons that supply lower extremities)
52
White Matter
- contains axons of ascending and descending tracts
| - divided in dorsal, later, ventral columns
53
Tracts
group of fibers inside white matter in the CNS that relay information up or down the spinal cord
54
Dorsal column - medial lemniscal system
- transmits mechanoreceptive sensations - fine touch, proprioception, vibration, pressure (fine degree of intensity)
- transmits sensory info faster than anterolateral system
- ascends spinal cord on ipsilateral side
- crosses contralateral side in the medulla and ascends towards thalamus (via medial lemniscus)
- ends in cerebral cortex (postcentral gyrus - parietal lobe)
55
Anterolateral system - spinothalmic tract
- transmits pain, temp, crude touch, tickle, itch, sexual sensation
- may ascend 1-3 levels on ipsilateral side via lissauer tract
- pain neurons synapse in substantia gelatinosa (laminae I and II)
- crosses contralateral side and ascends via anterior spinothalmic tract and lateral spinothalmic tract
- most tactile signals are relayed to the thalamus and advance towards somatosensory cortex in the postcentral gyrus - parietal lobe
- most pain fibers synapse in the RAS and are then connected to the thalamus
56
Corticospinal tract
"pyramidal tract" - pyramids are formed by neurons as they run through the medulla
- motor neurons exit precentral gyrus of frontal lobe
57
Lateral Corticospinal Tract
- fibers innervate limbs
- cross to contralateral side in medulla
- descend via spinal cord via lateral corticospinal tract
58
Ventral Corticospinal Tract
- fibers innervate axial muscles
- remain on ipsilateral side as they descend via ventral corticospinal tract
- most fibers crossover to contralateral side of spinal cord when they reach the cervical or upper thoracic area
59
Upper Motor Neuron
- begin in cerebral cortex and end in the ventral horn
60
Lower Motor Neuron
- begin in ventral horn and end at NMJ
61
Upper Motor Neuron Injury
- injury above level of decussation in the medulla, paralysis will be on opposite side
- injury below level of decussation in the medulla, paralysis will be on the same side
- manifests as hyperreflexia and spastic paralysis
- Ex upper motor neuron dz: cerebal palsy, ALS
62
Babinski Sign
- tests integrity of corticospinal tract
- Normal response: firm stimulus to underside of foot produces downward motion of all toes
- Damage: upward extension of big toe and fanning of others
63
Lower Motor Neuron Injury
- peripheral motor fibers link spinal cord to a muscle
- injury results in paralysis on the same side as injury
- manifests as impaired reflexes and flaccid paralysis
- Babinski sign is absent in lower motor neuron injury
64
Neurogenic Shock
- hypotension, bradycardia, hypothermia
- pink, warm extremities
- can last 1-3 wks
65
Autonomic Hyperreflexia
- 85% of pts w/injury above T6
- presentation: HTN and bradycardia
- profound vasoconstriction below level of injury
- activates baroreceptor in carotid bodies & dec HR
- body attempts to dec afterload w/vasodilation above the injury
66
Amyotrophic Lateral Sclerosis
- progressive degeneration of motor neurons in corcticospinal tract
- affects upper & lower motor neurons
67
ALS Signs and Symptoms
- upper neuron involvement: spasticity, hyperreflexia, loss of coordination
- begins in hands and spreads to rest of body
- ocular muscles not affects
- sensation remains intact
- resp failure = most common cause of death
- autonomic dysfxn = orthostatic hypotension & resting tachycardia
68
ALS Management
- Succs can cause lethal hyperkalemia (lower motor neuron dysfxn is associated w/proliferation of postjunctional nicotinic receptors)
- Inc. sensitivity to NDNMB
- bulbar muscle dysfxn and inc. risk pulm aspiration
- chest weakness dec. vital capacity and max min. ventilation
- consider post-op ventilation
