lecture 5 - neurons & nerves

Question 1

What are the components of a neuron?

Answer 1

Dendrites, soma/cell body, axon, synapses

Question 2

What is the name for the cell body of a neuron?

Answer 2

Soma

Question 3

What is the function of neuron dendrites?

Answer 3

Receive signals from other neurons via synapses

Question 4

What are axons?

Answer 4

Processes that leave a neuron’s soma to propagate an action potential for signalling to other neurons via synpases

Question 5

What are the 4 morphological types of neuron?

Answer 5

multipolar, bipolar, unipolar, anaxonic

Question 6

What is the structure of a multipolar neuron?

Answer 6

Multiple processes emanate from the cell body

Question 7

What is the structure of a bipolar neuron?

Answer 7

2 processes emanate from the cell body

Question 8

What is the structure of a unipolar neuron?

Answer 8

One process emanating from the cell body that branches into the dendrite and axon

Question 9

What is the structure of an anaxonic neuron?

Answer 9

No distinct axon because all processes look alike

Question 10

What are glia?

Answer 10

Non-neuronal support cells of the CNS or PNS

Question 11

What are the 4 key glia types of the CNS?

Answer 11

oligodendrocytes, astrocytes, microglia, ependymal cells

Question 12

What are the 2 key types of glia in the PNS?

Answer 12

Schwann cells, satellite cells

Question 13

What is the function of oligodendrocytes?

Answer 13

Form the myelin sheath around neurons in the CNS

Question 14

What is the function of astrocytes?

Answer 14

Provide nutrients, maintain extracellular environment and structural support to neurons in the CNS

Question 15

What is the function of microglia?

Answer 15

Mount the immune response within the CNS

Question 16

What is the function of Ependymal cells?

Answer 16

Circulate and produce cerebrospinal fluid in the CNS

Question 17

Which cells produce CSF in the CNS?

Answer 17

Ependymal cells

Question 18

What is the function of Schwann Cells?

Answer 18

Form the myelin sheath around neurons in the PNS

Question 19

What is the function of Satellite Cells?

Answer 19

Provide nutrients and structural support to neurons in the PNS

Question 20

What is the name for a unit of neurons with a nerve that is surrounded by perineurium?

Answer 20

Fascicle

Question 21

Where does sensory information enter the spinal cord?

Answer 21

Dorsal root

Question 22

Where does motor information leave the spinal cord?

Answer 22

Ventral root

Question 23

What type of peripheral nerve has the fastest relative conduction velocity?

Answer 23

Motor neurons

Question 24

What type of peripheral nerve has the slowest relative conduction velocity?

Answer 24

Sensory - pain/temperature, etc.

Question 25

What are the characteristics of motor neurons?

Answer 25

Large diameter, heavily myelinated = fast conduction velocity

Question 26

Which 2 factors influence the relative conduction velocity of a nerve?

Answer 26

Diameter, myelination

Question 27

What happens to the conduction velocity of a nerve as its diameter increases?

Answer 27

Increases

Question 28

What is the resting membrane potential inside of neurons?

Answer 28

~-70mV

Question 29

Which factors contribute to the resting membrane potential?

Answer 29

Concentration gradient of ions across membrane, differential permeability of membrane to K+ vs Na+

Question 30

Are cell membranes more permeable to K+ or Na+?

Answer 30

K+

Question 31

Which ion has the greatest influence on resting membrane potential?

Answer 31

K+

Question 32

What creates the electrochemical gradient across a cell membrane?

Answer 32

The difference on the concentration of ions on either side of the membrane, and the permeability of the membrane to these ions

Question 33

What ion channel maintains the electrochemical gradient across a cell membrane?

Answer 33

Na+,K+ - ATPase

Question 34

What does Na+,K+-ATPase pump, and in what directions?

Answer 34

3Na+ out of cell, 2K+ into it

Question 35

Which equation calculates the equilibrium potential for an ion?

Answer 35

Nernst equation

Question 36

How does the ratio of ions in/outside a cell influence the voltage across the membrane?

Answer 36

The greater the concentration difference between outside and inside, the greater the voltage

Question 37

Which equation calculates the resting membrane potential of a cell?

Answer 37

Goldman-Hodgkin-Katz

Question 38

What are voltage-gated ion channels?

Answer 38

Ion channels that provide selective permeability to certain ions due to changes in membrane potential

Question 39

What are mechanically gated ions channels?

Answer 39

Ion channels that open when a physical stimulus causes membrane deformation

Question 40

What are chemically gated channels?

Answer 40

Ion channels that open when a ligand binds