Neuroanatomy & Neurophysiology

Question 1

What is the integrative area of the neuron where all membrane potentials converge?

Answer 1

axon hillock

Question 2

What is the “receptive” area of neurons in the CNS?

Answer 2

dendrite and soma/cell body

Question 3

What are 3 types of Glial cells in the CNS?

Answer 3

1. Astrocytes - can be supportive & reparative cells
2. Oligodendrocytes - mechanism of myelination in the CNS (schwann cells are the myelingating cell of PNS)
3. Microglia - macrophage of the CNS

Question 4

What cells are responsible for myelination in the PNS?

Answer 4

Schwann cells

Question 5

What are the 4 connective tissue coverings of a neuron?

Answer 5

1. Mesoneurium: outer layer of connective tissue (surrounds the epineurium)
2. Epineurium: encloses entire nerve trunk
3. Perinerium: surrounds bundles of axons (=fascicles)
4. Endoneurium: surrounds & separates each axon

Question 6

What are the 3 main synaptic types that we learned in class?

Answer 6

1. Axodendritic (axon terminal –> dendrite)
   
   • Primarily facilitatory
2. Axosomatic (axon terminal –> soma)
   
   • Primarily inhibitory
3. Axoaxonic (axon terminal –> axon terminal) = most efficient for change
   
   • Presynaptic inhibition and presynaptic facilitation

Question 7

What are the 3 types of Post-synaptic potentials?

Answer 7

1. Excitatory Postsynaptic potentials (EPSP) - electrical activity or membrane polarity becomes more + w/ respect to resting membrane potential
2. Inhibitory Postsynaptic potentials (IPSP) - electrical activity or membrane polarity becomes more - w/ respects to resting membrane potential

Question 8

What is an action potential?

Answer 8

A change in membrane potential along the axon of a neuron; requires the presence of voltage gated channels (only location on axon)

Question 9

What does “all or none response” mean for action potentials?

Answer 9

The strength by which a neuron responds to a stimulus is not proportional to the strength of the stimulus

The axon potential fires when the neuron reaches a threshold. If it doesn’t reach it, it will not fire.

Question 10

What is always a response to an action potential?

Answer 10

transmitter release

Question 11

What is the difference between habituation and sensitization?

Answer 11

habituation: dec in response to a repeated, benign stimulus

sensitization: when you activate some circuits, the response gets more and more.

central sensitization = excessive responsiveness of central neurons developed in response to ongoing nociceptive input - alterations in central neural activity outlast that tissue injury