Lab Exercise 16

Question 1

What do neurons do?

Answer 1

conduct action potentials, electrical signals, that are generated in response to a strong stimulus

Question 2

What do neuroglial cells do?

Answer 2

support, protect, furnish nutrients to neurons, augment the speed of action potentials

Question 3

What four neuroglial cells are in the CNS?

Answer 3

astrocytes, oligodendrocytes, microglia, ependymal cells

Question 4

What do astrocytes do?

Answer 4

guide neurons during development and control the composition of the chemical environment of the neurons by forming a blood-brain barrier that only allows certain substances to enter the nervous tissue at the blood vessel sites

Question 5

What do oligodendrocytes do?

Answer 5

support the CNS and have processes that form the myelin sheaths around axons to increase the speed of nerve impulses

Question 6

What do microglia do?

Answer 6

the phagocytes of the CNS that engulf debris, necrotic tissue, and invading bacteria or viruses

Question 7

What do ependymal cells do?

Answer 7

line all 4 ventricles of the brain, as well as the central canal of the spinal cord, form cerebrospinal fluid and their cilia move the CSF through the ventricles

Question 8

What do neuroglial cells are in the PNS?

Answer 8

Schwann cells and satellite cells

Question 9

What do Schwann cells do?

Answer 9

wrap around the axons in the PNS, form myelin sheaths around one axon

Question 10

What do myelin sheaths do?

Answer 10

increase nerve impulse speed and aid in the regeneration of PNS axons

Question 11

What do satellite cells do?

Answer 11

surround sensory neuron cell bodies located in ganglia in the PNS and give support to these neurons and regulate their chemical environment

Question 12

What do dendrites do?

Answer 12

receive information and convert it to a change in membrane potential called a graded potential that travels to the neuron cell body/soma

Question 13

What is an axon hillock?

Answer 13

a triangular or cone-shaped area of the cell body

Question 14

What is the trigger area?

Answer 14

the first part of the axon where the action potential begins

Question 15

What are axon collaterals?

Answer 15

side branches off of an axon

Question 16

What are axon terminals?

Answer 16

axons and axon collaterals conduct action potentials along their full lengths to end in many fine branches called axon terminals, many axon terminals end in synaptic end bulbs which contain neurotransmitter molecules that transmit signals across a synapse

Question 17

What are multipolar neurons?

Answer 17

neurons that have several dendrites and one axon

Question 18

What are bipolar neurons?

Answer 18

have one dendrite and one axon on either side of the cell body

Question 19

What are unipolar neurons?

Answer 19

have only one process leading to and from the neuron cell body formed by the fusion of the dendrites and the axon

Question 20

What are the functional classifications of neurons?

Answer 20

sensory (afferent), interneuron (association), motor (efferent)

Question 21

What are sensory neurons?

Answer 21

if there is strong enough stimuli to the receptors associated with the dendrites of sensory neurons, it will generate an action potential or nervous impulse that travels along the axon to the spinal cord; most sensory neurons are unipolar; in the spinal cord, the axon of the sensory neuron synapses with either a motor neuron or an interneuron

Question 22

What are interneurons?

Answer 22

multipolar neurons that make up 90% of the neurons in the CNS; in the spinal cord, the interneuron can synapse with a chain of interneurons that sends the signal to the brain, and/or it can synapse with a motor neuron

Question 23

What do motor neurons do?

Answer 23

takes the impulse out of the CNS via a spinal or cranial nerve to an effector (muscle or gland); multipolar neurons

Question 24

How does the neurolemma form?

Answer 24

multiple layers of the plasma membrane surround the axon, and the cytoplasm and nucleus are pushed to the periphery

Question 25

What do myelin sheath gaps do?

Answer 25

allow the nerve impulse to jump from node to node

Question 26

What is white matter?

Answer 26

groups of myelinated axons in the CNS, inner area of white matter in the brain, outer layer of white matter in the spinal cord

Question 27

What is gray matter?

Answer 27

unmyelinated areas comprised of neuron cell bodies, dendrites, axon terminals, and neuroglia; outer area or cortex in brain, inner H shaped shaped in spinal cord

Question 28

What do presynaptic neurons do?

Answer 28

action potentials in the presynaptic neuron causes the release of neurotransmitter into the synaptic cleft

Question 29

What do postsynaptic neurons do/

Answer 29

has receptors that bind the neurotransmitter and in response generates a graded potential called a postsynaptic potential

Question 30

What is an axo-axonic synapse?

Answer 30

axon to axon

Question 31

What is an axodendritic synapse?

Answer 31

axon to dendrite

Question 32

What is an axosomatic synapse?

Answer 32

axon to the cell body