L2: Intro to Neurophysiology

Question 1

How is the nervous system divided and why?

Answer 1

Nervous system divided into CNS and PNS based on processing power

Question 2

What is included in the CNS?

Answer 2

CNS: brain and spinal cord

Question 3

What is included in the PNS?

Answer 3

PNS: peripheral nerves and glia

Question 4

What is glia?

Answer 4

Glia = glue, supporting cells

Question 5

What are the parts of a neuron (4), and what are their functions?

Answer 5

• soma = body
• dendrites = receive info
• axon hillock = summation zone, decided if AP happens
• axon terminals + synapses = output zone

Question 6

What are the 4 types of glia in the CNS?

Answer 6

Oligodendrocytes
Astrocytes
Microglia
Ependymal cells

Question 7

What do Oligodendrocytes do?

Answer 7

Oligodendrocytes form the myelin sheath.

Question 8

What do Astrocytes do?

Answer 8

Astrocytes (star shaped) provide nutrients, maintain extracellular environment, and provide structural support.

Question 9

What do Microglia do?

Answer 9

Microglia mount the immune response in the brain

Question 10

What do Ependymal cells do?

Answer 10

Ependymal cells circulate and produce CSF (protects brain)

Question 11

What are the 2 types of glia in the PNS?

Answer 11

Schwann cells
Satellite cells

Question 12

What do schwann cells do?

Answer 12

Schwann cells form the myelin sheath (same role as oligodendrocytes but do it slightly differently because in a different environment)

Question 13

What do Satellite cells do?

Answer 13

provide nutrients and structural support to neurons

Question 14

What is the difference between a nerve and a neuron?

Answer 14

Neuron = one cell
Nerve = bundle of axons
- can be myelinated or unmyelinated
- during embryonic development nerves grow out, follow chemical path
- input and output along a nerve

Question 15

What are the characteristic features of an electrical synapse?

Answer 15

• pores of two cells line up, basically continuous cytoplasm,
• ions travel through gap junctions
• very fast

Question 16

What are the characteristic features of an chemical synapse?

Answer 16

• slower (still milliseconds), because relies on neurotransmitters have to be released (in vesicles) and travel across the gap
• easily modified, scaled

Question 17

Describe the Primary somatosensory cortex

Answer 17

Primary somatosensory cortex –> body is mapped in brain = homunculus

Question 18

Describe the route of information flow in the body

Answer 18

PNS: sensory afferent = input → CNS: Integration and coordination in brain → PNS: motor efferent = output

Question 19

sensory afferent = input or output?

Answer 19

input

Question 20

motor efferent = input or output

Answer 20

output

Question 21

what are the divisions of the PNS?

Answer 21

somatic and autonomic

Question 22

What are the 2 divisions of the autonomic nervous system? What are their roles?

Answer 22

sympathetic = fight, fright or flight
parasympathetic = rest and digest

Question 23

Which neurotransmitters are used at the pre- and post-ganglionic synapses of each?

Answer 23

sympathetic
- ACh pre ganglionic,
- noradrenaline post ganglionic

parasympathetic
- ACh (pre and post ganglionic - 2 a’s in para-)