Neural Tissues

Question 1

What is the purpose of the nervous system?

Answer 1

communication
sensory detection 
information processing
motor activity 
behaviour

Question 2

What is the CNS responsible for?

Answer 2

information processing
reflexes
behaviour

Question 3

What is the PNS responsible for?

Answer 3

sensory detection

motor activation

Question 4

What is the difference between an afferent and an efferent neuron?

Answer 4

afferent neuron: transmits sensory information to the brain/spinal cord
efferent neuron: motor neurons transmitting information from the brain to the effector organ

Question 5

What is a ganglion?

Answer 5

a group of cells outside the CNS

motor: eccentric (peripheral) nuclei, small neurons
sensory: central nuclei, big neurons

Question 6

What are Brodmann areas?

Answer 6

regions of the cortex numbered 1-52
boundaries determined by cell architecture
each has particular set of inputs/outputs
often functionally distinct

Question 7

What is Brodmann Area 17?

Answer 7

primary visual cortex

Question 8

What is Brodmann Area 4?

Answer 8

primary motor cortex

Question 9

What is a ‘process’?

Answer 9

generic term for any outgrowth from the cell bdy

Question 10

A CNS neuron: …

Answer 10

has a nucleus within the cell body

extends one or more processes

Question 11

What is myelin?

Answer 11

electrical insulator
wrapped around axon
made up of many layers of cell membrane
increases conduction velocity

Question 12

Neuron classifications

Answer 12

multipolar
bipolar
unipolar

Question 13

Features of a chemical synapse

Answer 13

big gap (~30nm)
common throughout nervous system
signalling not in retrograde direction
presynaptic cell releases neurotransmitter
postsynaptic cell produces electrical signal

Question 14

What is the difference between divergent and convergent signals?

Answer 14

divergence = single neuron sends output signal to many neurons
convergence = multiple inputs influence single neuron

Question 15

What are interneurons?

Answer 15

only present in CNS 
neither motor nor sensory - relay 
process signals
can be excittory or inhibitory 
= 80% of the brain

Question 16

What are glia?

Answer 16

supply and protect neurons 
oligodendrocytes 
astrocytes
microglia 
ependymal cells
Schwann cells 
satellite cells

Question 17

What are oligodendrocytes?

Answer 17

glia in CNS
produce/maintain myelin sheath
one cell can myelinate multiple axons

Question 18

What are astrocytes?

Answer 18

glia in CNS
support neurons - assists in development/growth
protect neurons from harmful substances
star-shaped
‘feet’ on processes on blood vessel endothelium
influence blood flow and blood-brain barrier
controls local vasodilation

Question 19

What are microglia?

Answer 19

glia in CNS 
immune cells - protect neurons from disease
migrate to injury sites
engulf microbes/debris 
mesodermal origin

Question 20

What are ependymal cells?

Answer 20

glia in CNS
lines brains ventricles and central canal of spinal cord
forms CSF
cilia and microvilli on apical membrane

Question 21

What are Schwann cells?

Answer 21

glia in PNS
produce/maintain myelin sheath
PNS regeneration
1 axon wrapped per Schwann cell

Question 22

What are satellite cells?

Answer 22

glia in PNS
support neurons
regulate exchange of materials between neurons and interstitial fluid
perform similar role to astrocytes

Question 23

Give an example of a glial pathology.

Answer 23

glioma
largest group of primary tumours derived from glial cells 
usually highly malignant 
grows rapidly 
difficult to surgically remove 
usually inside cranium

Question 24

Give an example of a neural pathology.

Answer 24

neuroblastoma
tumour (cancer)
most common in children and infants
derived from neural crest cells from sympathetic nervous system
often increases catelcholamine levels
survival rates vary
survivors often develop neurological problems ~30 years later