Neuro test

Question 1

What is a motor neuron

Answer 1

soma, dendrites, axon (frequently myelinated) innervates muscle

Question 2

What is a sensory neuron

Answer 2

• Receives input at top
• commonly bipolar
• two pseudo axons/ pseudodendrites
• both may be myelinated
  output from end

Question 3

Where do motor neuron signals travel

Answer 3

• down from the cortex
• through spinal chord
• to the muscle

Question 4

Where do sensory neuron signals travel

Answer 4

• from periphery
• feed through spinal cortex
• to various organs

Question 5

Name and describe the two types of glial cells

Answer 5

• Schwann - peripheral nervous system

- oligodendrocyte - central nervous sustem

Question 6

What is the process of neural development?

Answer 6

• ectodern forms ‘neural plate’ on dorsal surface of embryo
• neural plate invaginates - neural groove
• neural groove pinches off - internalisation
• neural crest cells migrate - peripheral ganglia

Question 7

Name the 4 segments of the spinal chord

Answer 7

• cervical
• thoracic
• lumbar
• sacral

Question 8

how many nerve roots are there

Answer 8

30

Question 9

Describe the different nerve fibers

Answer 9

• A alpha (I) - proprioceptive - 13-20um - 80-120 m/s veloity
• A beta (II) - touch/pressure - 6-12um - 25-75m/s
• A delta (III) - pain/temp - 1-5um - 5-30m/s
• C (IV) - pain - 0.2-1.5um - 0.5-2.5 m/s
• A are myelinated

Question 10

Describe a pain reflex

Answer 10

• up sensory neuron into cervical segment or thoracic for finger
• past cell body in dorsal root ganglion
• afferent axon
• received by motor neuron
• down the otor neurone to ventral horm of spinal chord
• signal passes backdown efferant axon
• muscle contraction

Question 11

describe a cross section of the spinal chord

Answer 11

• central grey matter- neuronal cell bodies and some axons
• surrounding white matter - carries axons, white due to myelination
• afferent at top dorsal, eg sensory like doral root ganglia
• efferent at bottom, ventral, eg motor

Question 12

describe ascending pathways

Answer 12

1) Dorsal column - medial lemniscal pathway - DCMLP - TOUCH PRESSURE - medulla
2) Anterolateral pathway (AS) pain/heat - detected in somatic sensory cortex after coming up lateral columns spinal chord

Question 13

describe the principle descending tracts

Answer 13

1) Corticospinal tracts - descend from motor cortex down through spinal cord, lateral tract 75% lower motor neurons muscle movement crosses @ medulla, ventral 25% does not cross over - limb movements
2) Corticobulbar tract - motor cortex - brain stem, control head and facial movements
3) Monoaminergic pathway - use NA & S-HT as NTs - control of pain

Question 14

What is a homunculus?

Answer 14

• diagramtic representation of body’s surface on the somatosensory cortex

Question 15

Name the lobes and their functtions

Answer 15

• Frontal lobe - personality concentration thought judgement emotions (motor cortex back of frontal for voluntary motor activity)
• Temporal - auditory, memoral/info retrieval, receptie speech (warnicks area - language comprehension)
• Parietal - processing sensory input, sensory discrimination, body orientation, primary and secondary somatic area
• Occipital - visual
• cerebellum - cpntrol of voluntary movement