L3 Cellular structure of the N.S

Question 1

Stimulus

Answer 1

• graded potential changes
• signal decays over 1-2 mm
• all directions outer
• “de”polarising
• exciting

Question 2

Axon Hillock

Answer 2

• voltage-gated sodium channel
• action potential
• all-or-nothing
• unidirectional

Question 3

White Matter

Answer 3

Myelinated Axons

Question 4

Grey Matter

Answer 4

• Cell bodies
• Dendrites
• Axons

Composition:

Nuclei/Ganglia

Layers

Functional segregation

Question 5

White/gray matter organisation

Answer 5

In Brain:

• White matter - on inside
• Grey matter - on outside

In Spinal Cord:

• White matter - on outside
• Grey matter - on inside

Question 6

Projection neurons

Answer 6

Tend to be excitatory usually

Question 7

Local interneurons

Answer 7

Smaller

usually a mix of inhibitory and excitatory neurons

Question 8

CNS

Answer 8

Anterior horn - motor

Dorsal horn - sensory/peripheral

Question 9

Peripheral sensory neuron cell bodies

Answer 9

lie outside the CNS

in the Dorsal root ganglion

Question 10

Glia

Neural progenitors/ guide neural migration

Answer 10

Radial glia

provide a guide for newly born glial cells to go outwards and form brain

Question 11

Glia that Deposit Myelin

Answer 11

• Oligodendrocytes - in CNS
  
  • more than 1 axon
• Schwann Cells - in PNS
  
  • 1 axon only

Question 12

Phagocytic Glial cells

clear debris

Answer 12

CNS microglia

Question 13

Glial cells that maintain

Physiological Homeostasis

Answer 13

Blood/brain barrier

Astrocytes

Question 14

Neural stem cells

Answer 14

Another form of Glial cells