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Flashcards in Physiology of Nervous System Deck (90)
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1

How is the metabolism of nervous tissue unique from other body tissues?

- Constant, very high, metabolic rate
- Depend entirely on glucose
- Limited or no anaerobic capabilities
- Don't store an energy source (glycogen)

2

Effects of low glucose on neurons

- Neurons malfunction and if prolonged may die
- Primarily effects higher cortical levels
- patient "spaced out", irritable, diaphoretic, blurred vision, coma, seizure

3

Effects of low oxygen on neurons

- More dramatic than low glucose
- rapidly induces confusion and coma
- Neuronal death in 3-4 min

4

3 major embryologic divisions of the brain

1. forebrain (cerebral cortex, thalamus, hypothalamus, basal ganglia)
2. midbrain
3. hindbrain (cerebellum, pons, medulla)

5

What is the largest portion of the brain and what does it consist of?

cerebrum, consisting of cerebral cortex and basal ganglia

6

grey matter vs white matter in cerebrum

grey matter - cell bodies and dendrites
white matter - myelinated nerve fibers beneath cortex

7

reticular formation

Large network of nuclei (grey matter) in brainstem that regulate CV, respiratory rate, and wakefulness/consciousness

reticular formation + cerebral cortex = reticular activating system

8

General functions of the limbic system

emotions (rage, fear), feeding behaviors, bio rhythms, smell

eg. music/smell makes you think of particular memory

9

General functions of the frontal lobe

thought and judgement

10

Neuroglia

cells that support neurons of CNS
50% of brain and spinal cord volume

11

astrocytes

- Most abundant glial cells
- Surround BV of CNS and fill space between neurons
- Provide rapid transport of nutrient and metabolites
- Essential components of blood brain barrier
- “scar forming” cells (foci for seizures)

12

myelinated vs unmyelinated

myelinated have myelin sheath and use saltatory conduction

unmyelinated do not have and use continuous conduction

13

salutatory conduction

allows for faster conduction of a nerve impulse because impulses jump from node to node (gaps in myelin)

14

inhibitory vs excitatory neurotransmitters

inhibitory: hyperpolarize; make harder for neuron to reach threshold (GABA)

excitatory: depolarize; make neuron less negative; easier to reach threshold (glutamate)

15

What produces myelin?

Schwann cells in PNS
Oligodendrocytes in CNS

16

What type cells are damaged by Guillain-Barre? Effects?

Antibodies destroys Schwann cells and axonal myelin

prevents nerves from transmitting signals to brain, causing weakness, numbness, or paralysis

17

GABA

- most common inhibitory neurotransmitter in brain
- used to treat seizures
- GABA release is blocked in tetanus

18

IPSP vs EPSP

IPSP: passage of hyperpolarizing ions into cell (chloride)

EPSP: passage of depolarizing ions into cell (Na/K)

19

ependymal cells

neuroglia that line the ventricles and are involved in CSF production

20

microglia

neuroglia that remove debris via phagocytosis in CNS

21

plasticity

CNS capability of changing what a region of the brain does

Capability in children high, but declines with age

22

substantia gelatinosa

part of posterior horn with sensory axons involved in pain transmission

23

spinothalamic tract

pain and temp

crosses at spinal level

24

medial lemniscus tract

touch, pressure, vibration, proprioception

crosses at medulla

25

tracts that run through anterior horn?

MOTOR pathways - corticospinal tract and corticobulbar tract

26

Where do motor axons cross midline?

medullary pyramid

27

corticobulbar tract specifically controls what?

- muscles of head and face
- motor component of cranial nerves 5, 7, 9-12

28

spinal reflexes

reflexes contained within the spinal cord

afferent neuron (sensory) -> interneuron -> efferent neuron (motor) -> effector muscle or gland

29

_______ influence and modify reflex spinal arcs.

upper motor neurons

30

What nerves make up the PNS?

cranial nerves and spinal nerves