Cells of the Nervous System (10)

Question 1

What do neurons do?

Answer 1

receive stimuli and create and propagate electrical signals throughout the body

Question 2

What does non-neural cell mean?

Answer 2

It means they cannot generate action potentials or send electrical signals

Question 3

What is a dendrite?

Answer 3

short, extensions of the cell body, input part of the neuron, can interact with axons of other neurons

Question 4

Axons

Answer 4

arises at the cone shaped axon hillock, start of the axon is called the initial segment, diameter is constant, but length can vary from mm up to 1m

Question 5

Cytoplasm

Answer 5

axoplasm, membrane - axolemma,
terminal end - presynaptic terminal or synaptic end

Question 6

Axonal Transport

Answer 6

• vesicles – neurotransmitters – in the presynaptic terminal (synaptic vesicles)
• vesicles can release neurotransmitter to stimulate or inhibit postsynaptic cell
• vesicles can move up and down the axon transporting neurotransmitter
• axonal transport is also the way disease can be transmitted to the CNS (i.e.
  rabies, herpes)

Question 7

Sensory (afferent) neurons

Answer 7

action potentials toward CNS

Question 8

Motor (efferent) neurons

Answer 8

action potentials away from CNS

Question 9

Interneurons or association neurons

Answer 9

within the CNS from one neuron to another

Question 10

Bipolar Neuron

Answer 10

1 dendrite, 1 axon - sensory organs ie. eye

Question 11

Multipolar Neuron

Answer 11

many dendrites, single axon - most neurons in the CNS and motor neurons

Question 12

Unipolar

Answer 12

single process extending from cell body - divides into 2 branches - part extending to periphery has dendrites that typically function as sensory receptors

Question 13

Neuroglia

Answer 13

• numerous - account for >50% of brain weight, 4 types of neuroglial cells in the CNS, 2 types in the PNS

Question 14

Astrocytes

Answer 14

star shaped, cytoplasmic extensions branch to form foot processes - cover the surface of blood vessels, release chemicals to form tight junctions between endothelial cells of capillaries (help regulate movement),

Question 15

Blood Brain Barrier

Answer 15

protects against toxic substances

Question 16

Ependymal cells

Answer 16

lines the ventricles of the brain and central canal of the spinal cord, helps form the choroid plexus - produces CSF, where cerebrospinal fluid is produced

Question 17

Microglia

Answer 17

specialized macrophages in the CNS
- job is to float around and digest any damaged tissues, microorganisims or any other foreign invaders

Question 18

Oligodendrocytes

Answer 18

cytoplasmic extensions - surrond axons
form myelin sheaths around portions of several axons
1- multiple axon

Question 19

Schwann Cells

Answer 19

1 - 1 axon
forms myelin sheath around a portion of only one axon
tight wraps pull the cytoplasm towards the outside along with the neurons
layers of phospholipid bi-layer folded helps insulate and protect the axon

Question 20

Satellite Cells

Answer 20

surround neuron cell bodies in ganglia
provides nutrients to cell body

Question 21

Myelinated Neurons

Answer 21

protects and insulates axons from one another

Question 22

Unmyelinated Neurons

Answer 22

only a single wrap around axon not forming a myelin sheath. conducts signals much slower

Question 23

Ganglion

Answer 23

cell bodies outside the CNS bundled together

Question 24

Tract

Answer 24

bundle of myelinated axons in the CNS

Question 25

Nucleus

Answer 25

collection of neuron cell bodies in the CNS

Question 26

White Matter

Answer 26

myelinated axons. Nerve tracts propagate action potentials from one area to another

Question 27

Gray Matter

Answer 27

unmyelinated axons. cell bodies, dendrites, neuroglia