Neurology Organization and Contol

Question 1

structural division of nervous system

Answer 1

1. CNS

2. PNS

Question 2

CNS

Answer 2

brain and spinal cord

processing center, main control center

housed by axial skeleton

Question 3

PNS

Answer 3

nerves outside the CNS (everything but)

relays information to and from the CNS to various endpoints in the body

Question 4

Functional breakdown of nervous system

Answer 4

1. somatic nervous system

2. autonomic nervous system

Question 5

somatic nervous system

Answer 5

provides sensory and motor innervation

controls voluntary movement

skeletal muscle (excludes viscera, smooth muscle, glands)

Question 6

autonomic nervous system

Answer 6

provides motor innervation to the smooth muscle, conduction of the heart, glands

without conscious thought

divided into: Parasympathetic and Sympathetic

Question 7

3 parts of a neuron

Answer 7

1. axon
2. dendrite
3. cell body

Question 8

2 types of neurons

Answer 8

afferent

efferent

Question 9

afferent nerve

Answer 9

SENSORY

carries information from skin/peripheral to the CNS

Question 10

efferent nerve

Answer 10

MOTOR

carries information from the CNS to the muscle

Question 11

Types of supporting cells

Answer 11

1. schwann cell
2. oligodendrocytes
3. astrocytes
4. ependymal cells
5. microglial cells

Question 12

energy requirements of nervous system

Answer 12

requires 15% of cardiac output , 20% of O2 consumption

obligate aerobic (can’t store oxygen so requires continues supply of O2 from blood – only lasts about 10 sec w/o before death)

Glucose is source of energy – can’t store so also gets it from the blood

Question 13

energy source of the brain

Answer 13

GLUCOSE

Question 14

3 meningeal layers

Answer 14

1. dura mater
2. arachnoid mater
3. pia mater

Question 15

Dura mater

Answer 15

pain sensitive

two layers: edosteum (attached to the skull) and meningeal (has potential space where it separates from arachnoid mater for dural venal sinuses)

Question 16

arachnoid mater

Answer 16

web of supportive collagen

acts as a shock absorber to prevent trauma

contains subarachnoid space

Question 17

subarachnoid space

Answer 17

exists between pia and arachnoid mater

collection of cerebral vasculature and CSF cisterns

site of hemorrhage

Question 18

pia mater

Answer 18

most inner meninge

covers every surface of the cerebrum

Question 19

Subarachnoid hemorrhage

symptoms:
workup:
treatment:

Answer 19

symptoms: sudden, “worst HA of life”
workup: non contrast CT - will show blood, lumbar puncture with Xianthrochromia
treatment: neurosurgical intervention to stop bleeding, high mortality if not identified

Question 20

Action potential

Answer 20

1. resting membrane potential: polarized but no activity
2. depolarization: influx of sodium ions that generate rapid electrical impulse
3. repolarization: Na+ channels close, K+ channels open, efflux of K+ causes the potential to decrease back to resting
   - — can’t be depolarized during this time

Question 21

which cells produce myelin

Answer 21

schwann cells (PNS)
oligodendrocytes  (CNS)

Question 22

benefits of myelin

Answer 22

speeds up conduction

protects axon

Question 23

astrocytes

Answer 23

largest and most numerous

fills intracellular space
tightens the BBB
regulates ionic concentrations and synaptic activity
repairs and scar formation

Question 24

microglia

Answer 24

phagocytes

cleans up debris

Question 25

ependymal cells

Answer 25

line the ventricular system combines with vascular network to form choroid plexus forms a very selective barrier (causes CSF to be sterile)

Question 26

choroid plexus fxn

Answer 26

formation of CSF

Question 27

disorders of the myelin sheath

Answer 27

guillain-barre | multiple sclerosis

Question 28

Guillan Barre

Answer 28

peripheral nervous system attacks schwann cells progressive paralysis from limbs towards center only attacks the myelin sheath so it can recover

Question 29

Multiple Sclerosis

Answer 29

central nervous system (oligodendrocytes) can attack either the whole axon or just the sheath (relapsing/remitting)

Question 30

BBB

Answer 30

blood brain barrier separates blood from brain parenchyma tight jxn so only lipid soluble can pass

Question 31

2 methods of neuronal communication

Answer 31

electrical synapse | chemical synapse

Question 32

electrical synapse

Answer 32

gap jxns b/t cells allow action potential to move from cell to cell

Question 33

chemical synapse

Answer 33

neurochemicals are released from the presynaptic structure and travel thru synaptic clef and interact with postsynaptic receptors on another neuron excite or inhibit

Question 34

Neurotransmitters

Answer 34

``` GABA glutamate serotonin dopamin norepinephrine epinephrine ```

Question 35

GABA

Answer 35

mediates most synaptic inhibition increases the threshold (harder to excite) ex. of drugs that work on GABA receptors are barbiturates and benzodiazopine

Question 36

glutamate

Answer 36

NT that mediates most synaptic excitation lowers the threshold so it is easier to generate action potential

Question 37

blood supply to anterior cerebrum

Answer 37

internal carotid arises from common carotid bifurcates into anterior cerebral and middle cerebral arteries

Question 38

common place for ischemia in the brain?

Answer 38

middle cerebral arteries emboli often lodge here

Question 39

blood supply to posterior cerebrum

Answer 39

vertebral arteries arise from subclavian forms basilar artery--> posterior cerebral arteries supplies brainstem, cerebellum, occipital lobes, temporal lobes, thalamus

Question 40

circle of willis

Answer 40

anastomosis that connects the anterior and posterior circulations of the brain via communicating arteries to allow for collateral blood flow

Question 41

circle of willis advantage

Answer 41

minimizes damage of ischemia by allowing oxygenated blood to flow in other paths to affected tissues

Question 42

Sequelae of the middle cerebral artery

Answer 42

fine manipulative skills of face and upper limbs to receptive and expressive communication aphasia when there is an emboli

Question 43

where does the spinal cord end?

Answer 43

L2 at the conus medullar is

Question 44

how many pairs of spinal nerves?

Answer 44

32 ``` 8 cervical 12 thoracic 5 lumbar 5 sacral 2 coccygeal ```

Question 45

clinical presentation of complete cord transection syndrome

Answer 45

dependent on level of transection will have numbness and loss of all sensory modalities, weakness and paralysis below effected level, bladder dysfunction

Question 46

transection of spinal cord at upper cervical level

Answer 46

1. quadriplegia (paralysis of 4 limbs) 2. areflexia of upper and lower extremities 3. anesthesia below transection level 4. loss of sphincter control, urinary and bowl retention

Question 47

injuries above which level involve cessation of respiration?

Answer 47

C3

Question 48

neurogenic shock

Answer 48

hypothermia and hypotension (low temp and low blood pressure) more likely to occur when transection is at higher levels on SC attempt to stabilize breathing and blood pressure to prevent

Question 49

transection at thoracic level

Answer 49

1. paraplegia (loss of lower limbs) 2. anesthesia of lower limb 3. areflexia of lower quadrant 4. urinary, bowel retention and loss of sphincter control spares respiratory muscles so less likely to have neurogenic shock

Question 50

Cauda Equina syndrome symptoms

Answer 50

``` asymmetric pain, leg weakness, sensory loss, bladder/bowel dysfunction, saddle anesthesia, decreased DTR in LE back pain ```

Question 51

cauda equina syndrome cause and diagnosis

Answer 51

compression of the caudal nerves, i.e. trauma, disc herniation, lesions, lumbar stenosis diagnosis: imaging (CT/MRI)

Question 52

cauda equina syndrome treatmetn

Answer 52

surgical decompression to relieve compression