Neurons

Question 1

Describe the cytoskeleton in an axon

Answer 1

Question 2

What is a perikaryon?

Answer 2

A neuron’s cell body or soma

Question 3

What are the myelin generating cells of the CNS and PNS?

Answer 3

Oligodendrocytes and Schwann Cells respectively

Question 4

How fast is slow anterograde transport in axons? What travels by this method?

Answer 4

2-4mm/day (effectively diffusion). cytosolic proteins, cytoskeletal elements are transported like this

Question 5

How fast is fast anterograde transport in axons? What travels by this method?

Answer 5

100-400 mm/day, as mediated by kinesins
organelles and particles travel in this fashion

Question 6

What protein is used for retrograde transport in axons?

Answer 6

dynein

Question 7

How fast do unmylinated nerves conduct signals?

Answer 7

0.6-2 m/s

Question 8

How fast do mylinated nerves conduct signals?

Answer 8

5-120 m/sec

Question 9

Can axons regenerate?

Answer 9

Yes, but only in the PNS. Seems to be heavily restricted by extrinsic factors

Question 10

What is the function of astrocytes?

Answer 10

Structural support
Physical isolation of neurons
Buffer of extracellular ions (f.e.sink for K+)
Uptake /clearance of of neurotransmitters
Metabolic functions to support neurons
Secretion of growth factors
Response to injury
Blood-brain barrier

Question 11

What is the function of microglia?

Answer 11

Macrophages of the brain

Question 12

What is the function of radial glia?

Answer 12

tracks for neuronal migration during brain development

Question 13

What is saltatory conduction?

Answer 13

The propagation of action potentials alongmyelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. This also has the happy effects of making the signal unidirectional and saving energy

Question 14

What triggers synaptic exocytosis and neurotransmitter release?

Answer 14

Depolarization-dependent opening of Ca++ channels in nerve terminals

Question 15

What is the target of the proteolytic action of tetanus and botulinum toxins?

Answer 15

The SNARE machinery. These toxins potently block synaptic transmission.

Question 16

What part does clathrin-mediated endocytosis play in synapse function?

Answer 16

It allows for the recovery and recycling of neurotransmitters and synaptic vesicle membranes from the synapse.

Question 17

Divide these neurotransmitters into excitatory and inhibitory categories: ACh, Amines, GABA, Glutamate, Glycine

Answer 17

GABA & glycine: inhibitory

Glutamate, ACh and Amines: excitatory

Generally, these neurotransmitters are seperated into different synapses

Question 18

What is the function of neuropeptides? Where are they stored?

Answer 18

They have slow modulatory effects, and are stored in large dense core vesicles

Question 19

What is the response of ionotropic neurotransmitter receptors to binding their respective neurotransmitters?

Answer 19

Opening connected ion channels (generally sodium at excitatory synapses, chloride at inhibitory synapses)

Question 20

What are metabotropic receptors?

Answer 20

They function in much the same way as ionotropic receptors, but use a signal transduction, often a G-protein moiety (but also tyrosine kinases and guanylyl cyclases), to more slowly modulate the potential in the postsynaptic neuron

Question 21

What are the 3 different shapes of neurons?

Answer 21

A multipolar neuron has multiple dendrites extending from the cell body and a single axon extending in the opposite direction.

A bipolar neuron has a single dendrite that extends from the cell body, opposite the side from which the single axon extends.

A pseudounipolar neuron is unique in that a single stem comes off the soma; this stem then splits into a single dendrite and axon

Question 22

There are 3 types of sensory nerve receptors (mentioned in the nervous system lab). What are the?

Answer 22

Exteroceptors carry sensations of pain, temperature, touch, and pressure from the skin and connective tissue. They may be encapsulated or unencapsulated.

Proprioceptors carry impulses of stretch and position from the muscles, tendons, and joints.

Visceroreceptors carry stimuli from the internal organs and circulatory system

Question 23

What is the typical shape of a motor neron

Answer 23

multipolar

Question 24

What are the 3 layers of the cerebellar cortex?

Answer 24

an outer molecular layer with nerve cell processes, a layer of Purkinje cells, and an inner granular layer with several other types of neurons. Purkinje cells are very large neurons that possess a tree of branching dendrites that extend into the molecular layer.

Question 25

What are Ependymal cells?

Answer 25

Ependymal cells line the ventricles of the brain and the central canal of the spinal cord. These are derived from epithelial cells and produce cerebrospinal fluid.