Cells of the nervous system

Question 1

2 cells that make up nervous system

Answer 1

Neurons

Glial cells

Question 2

What do Neurons do?

Answer 2

Receive stimuli, conduct action potentials, and transmit signals to other neurons or organs

Question 3

What do glial cells do

Answer 3

Support and protect neurons

Question 4

Neurons

Answer 4

electrically excitable cells of the nervous system

Question 5

3 parts to a neuron

Answer 5

Cell body

2 types of cellular projections

Question 6

Dendrite

Answer 6

A cellular projection from a neuron with a branching organization

Receiving portion of the neuron - get info from other axons

Question 7

Axon

Answer 7

Nerve fiber; projection with a straight and uniform diameter

Arises from a cone-shaped area of the neuron cell body called Axon hillock

Question 8

Parts of an axon

Answer 8

Axon hillock (part of nueron body)
Initial segment (where the axon technically starts)
Trigger zone (Axon hillock + initial segment)
Axoplasm (cytoplasm)
Axolemma (plasma membrane)
Presynaptic terminals (end of the axon)
Neurotransmitters (single molecules found in presynaptic terminals)

Question 9

Anterograde

Answer 9

the movement away from the cell body

Question 10

Retrograde

Answer 10

The movement toward the cell body

Question 11

3 types of neurons, functional classification

Answer 11

Sensory - afferent
Motor - efferent
Interneurons - conduction action potentials from one neuron to another

Question 12

3 types of neurons, structural classification

Answer 12

Multipolar // many dendrites, single axon
Bipolar // one dendrite adn one axon
Psuedo-unipolar // single process extending from cell body

Question 13

Functions of glial cells (4)

Answer 13

1) form a protective permeability barrier between the blood & the brain/ spinal cord;
2) phagocytize foreign substances
3) produce cerebrospinal fluid
4) Form myelin sheaths around axons

Question 14

4 types of Glial cells

Answer 14

1) Astrocytes
2) Ependymal cells
3) Microglia
4) Oligodendrocytes

Question 15

Astrocytes

Answer 15

Star-shaped glial cells

Regulate the composition of extracellular brain fluid and form the blood-brain barrier

Question 16

Reactive astrocytosis

Answer 16

A result of most injuries to CNS
Astrocytes wall off the injury site and limit the spread of inflammation to surrounding healthy tissue (good)
Limit regeneration of axons of injured neurons (bad)

Question 17

Ependymal cells

Answer 17

Cells that line the ventricles of the brain and central canal of the spinal cord
Create choroid plexuses

Question 18

Choroid plexuses

Answer 18

Secrete cerebrospinal fluid

Question 19

Microglia

Answer 19

CNS-specific immune cells

Are mobile and phagocytic in response to inflammation

Question 20

Oligodendrocytes

Answer 20

Cells form myelin sheaths around axons, which insulates the axon.

Question 21

2 types of Glial cells in the PNS

Answer 21

Schwann cells > form myelin sheaths (but only around one axon)
Satellite cells > surround neuron cell bodies in sensory adn autonomic ganglia. Provide nutrition to neuron cell bodies, protect neurons from heavy-metal poisons

Question 22

Myelinated axons

Answer 22

Shwann cells or oligodendrocytes extensions repeatedly wrap around a segment o fan axon, forming tightly wrapped membranes rich in phospholipids

Like a hotdog (axon) in a tortilla (myelin)

Action potentials travel faster along myelinated axons than unmyelinated axons

Question 23

Nodes of Ranvier

Answer 23

Gaps in myelin sheaths

Question 24

When do myelin sheaths form

Answer 24

late in fetal development until the end of the first year after birth; then continues more slowly

Question 25

What makes a nerve likely to regrow?

Answer 25

Close proximity between the two ends of an injured axon