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Flashcards in Intro, nerves, etc Deck (16)
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1
Q

Define somatotopy

A

The correspondence of an area of the body to a point in the CNS

2
Q

Define Hebb’s postulate

A

Lasting changes in neuronal circuitry occur through growth at synapses

3
Q

Define commissure

A

The midpoint in cerebrum where R & L cross

4
Q

Define decussation

A

The midpoint in midbrain where R & L cross

5
Q

What is the function of Microglia? Are these in the CNS or PNS?

A

CNS; phagocytic & development of chronic pain syndrome

6
Q

What is the function of Oligodendrocytes? Are these in the CNS or PNS?

A

CNS; myelin-forming, 1 cell –> many axons

7
Q

What is the function of Schwaan cells? Are these in the CNS or PNS?

A

PNS; myelin-forming, 1 cell –> 1 axon

8
Q

What is the function of Astrocytes? Are these in the CNS or PNS?

A

CNS; Maintain ionic equilibrium, clearing/recycling of NTs, take up glutamate and convert to glutamine, transport of nutrients from vessels to neurons, local regulation of blood flow

9
Q

When the PNS is damaged, what is the order of events of recovery?

A

Neuron emits signals such as ATP, attracts microglia which proliferate and produce cytokines and trophic factors, these attract astrocytes. Microglia also promote synaptic organization.

10
Q

Is the PNS microglial response rapid or slow? Short-lived or sustained?

A

Rapid and shortlived

11
Q

Is the PNS astrocyte response rapid or slow? Short-lived or sustained?

A

Slow and sustained

12
Q

How is CNS damage response different from PNS damage response?

A

Unlike Schwaan cells, oligodendrocytes do not clear myelin debris & allow axonal elongation. Instead, oligodendrocyte precursors proliferate and upregulate expression of molecules that inhibit axonal outgrowth. Microglia activate local astrocytes which proliferate to form a glial scar which is also a chemical and physical barrier to axonal regeneration.

13
Q

What are circumventricular organs?

A

At small sites along the ventricular walls in the caudal medulla and hypothalamus, there’s no BBB. Here blood is monitored or secretions into blood are produced. Astrocytes wall off these areas from rest of CNS.

14
Q

What is a healthy blood flow to the brain?

A

50ml/min per 100g

15
Q

What blood flow is considered ischemic to the brain?

A
16
Q

How do arterioles in the brain autoregulate?

A

When BP rises, arteriole walls stretch, 2nd messenger cascade is activated which culminates in inhibition of Ca-activated K channels (Kca) which leads to depolarization of cell and muscle activation.