Exam 3 Nervous System 1

Question 1

what are the three types of neurons?

Answer 1

bipolar, pseudounipolar, and multipolar

Question 2

what do bipolar neurons function in?

Answer 2

sensory function; specifically vision and olfactory reception (sight and smell)

Question 3

what do bipolar neurons look like?

Answer 3

two prominent extensions going off the cell body in opposite directions

Question 4

what do pseudounipolar neurons look like?

Answer 4

continuous dendrite and axon that bypass the major part of the cell body

Question 5

what is special about pseudounipolar neurons?

Answer 5

the dendrite can carry an AP (functions like an axon)

Question 6

what is the dendrite of the pseudounipolar neuron called and why?

Answer 6

peripheral axon; carries sensory information from the peripheral sensory receptors in the body toward the cell body)

Question 7

what is the axon proper of the pseudounipolar neuron called and why?

Answer 7

central axon; carries sensory information from the dendrite/peripheral axon toward the CNS where it connects to part of the CNS

Question 8

pseudounipolar neuron cell body

Answer 8

DOES NOT appear to function in integration of incoming sensory signals, unlike motor neurons

Question 9

what do multipolar neurons look like?

Answer 9

dendrites at the top (multiple coming off the cell body) with one long prominent axon which ends at the terminals

Question 10

what do multipolar neurons function as?

Answer 10

motor neurons

Question 11

what are neurons in the CNS called and why?

Answer 11

post-mitotic cells; once they mature, they no longer divide

Question 12

what is the exception to post-mitotic cells in the CNS?

Answer 12

neurons in the hippocampus; they continually divide in order to form and maintain new memories

Question 13

what is the function of Schwann cells and Oligodendrocytes?

Answer 13

synthesis myelin, incorporate it into their cell membranes, cell membranes grow, and they envelop the axons of neurons in a concentric circular arrangement

Question 14

where are Schwann cells found?

Answer 14

Peripheral NS

Question 15

where are Oligodendrocytes found?

Answer 15

Central NS

Question 16

what does myelin act as?

Answer 16

an insulator on the axons because it’s nonpolar lipid so there is no Na/K current

Question 17

what do myelinated cells exhibit?

Answer 17

saltatory conduction

Question 18

what is the relationship between one Schwann cell and the axon of a neuron that it will myelinate?

Answer 18

1:1

Question 19

how many axons of different neurons can Oligodendrocytes myelinate?

Answer 19

many

Question 20

what is the general function of Astrocytes?

Answer 20

regulate the cellular environment and the surrounding environment that neurons exist in

Question 21

what are the specific functions of Astrocytes?

Answer 21

• connect the capillaries that feed blood to the brain to the neurons
• involved in transporting nutrients from the blood to the neurons
• nourishing function to the neurons of the CNS

Question 22

what percent accounts for the weight of the brain on the body’s weight? and how much is the brain responsible for metabolism?

Answer 22

brain weight is about 8% of body weight, but is responsible for about 25% of total metabolism

Question 23

what is the function of Astrocytes and foot processes?

Answer 23

astrocytes surround groups of neurons or individual neurons and help isolate them from other groups of neurons

Question 24

what else do Astrocytes do?

Answer 24

• take up and recycle K
• help facilitate the electrical function of neurons
• help take up/recycle NTs used in the brain

Question 25

what is laid down first in the development of the brain?

Answer 25

Astrocytes; they provide scaffold for the way neurons grow and form neural pathways

Question 26

what are Microglia apart of?

Answer 26

defense within the CNS

Question 27

how are Microglia at rest?

Answer 27

non-activated, non-differentiated

Question 28

how are Microglia activated?

Answer 28

usually in response to some injury or damage to the neurons in the CNS

Question 29

what is the main function of activated Microglia?

Answer 29

phagocytosis

Question 30

what is the function of Ependymal cells?

Answer 30

form the epithelial lining that separates the interstitial fluid of the brain that surrounds the neurons and the outer fluid (cerebrospinal fluid)

Question 31

what do some specialized forms of Ependymal cells do?

Answer 31

secrete the cerebrospinal fluid

Question 32

where do all the glial cells come from?

Answer 32

there is an undifferentiated population of stem cells (precursor cells) that can give rise to any of the 4 types of glial cells

Question 33

what does uncontrolled glial cell precursor growth result in?

Answer 33

tumors

Question 34

Astrocytoma

Answer 34

usually slow-growing tumor; from astrocyte overgrowth

Question 35

Glioblastoma

Answer 35

fast growing and very dangerous

Question 36

anatomical POV of the NS

Answer 36

central: brain and spinal cord peripheral: cranial and spinal nerves that leave the CNS and travel out to the peripheral parts of the body

Question 37

functional POV of the NS

Answer 37

peripheral NS divided into Afferent and Efferent NS based on which direction the AP is traveling

Question 38

Afferent NS

Answer 38

carries signals TOWARD the CNS (sensory system)

Question 39

Efferent NS

Answer 39

carries signals AWAY from the CNS back out to the peripheral parts of the body (motor system)

Question 40

Somatic NS

Answer 40

motor neurons that connect to the skeletal muscle

Question 41

Autonomic/Visceral NS

Answer 41

connects to the cardiac muscle and smooth muscle that surrounds the bodies internal organs

Question 42

what is the Enteric NS also known as?

Answer 42

solarplexus

Question 43

what are the three classes of senses for Afferent/sensory neurons?

Answer 43

- external (somatic senses) - special senses - internal senses (visceral senses)

Question 44

external (somatic) senses

Answer 44

come from skin, muscle, joints ex: touch, pressure, heat, cold, external environment stimuli

Question 45

special senses

Answer 45

vision, hearing, equilibrium, smell, taste

Question 46

internal (visceral) senses

Answer 46

things that are adjusted but don't have conscious thought of doing it ex: how full is your stomach? HR monitoring, BP monitoring

Question 47

how are afferent/sensory neurons names?

Answer 47

in which one is stimulated first

Question 48

where are first-order neurons/primary afferent neurons usually found?

Answer 48

peripheral NS, usually associated with sensory receptor; carries info to the CNS (usually spinal cord) where it then synapses with second-order sensory neurons

Question 49

what is the function of the thalamus?

Answer 49

relay station in the brain that sends the signals to the appropriate areas so they will register as conscious sensations

Question 50

reflex arc

Answer 50

neural circuit that serves as a template for how neural systems work; most start with a peripheral sensory receptor and sensory neuron, they go toward the spinal cord, connect with a motor neuron, the motor neuron leaves the spinal cord and activates the effector

Question 51

ganglion

Answer 51

a cell body or group of cell bodies located outside the CNS

Question 52

dorsal route ganglion

Answer 52

at the base/root of spinal nerve; sensory neuron comes in and the cell body is outside of the CNS

Question 53

what does the organization of reflex arcs usually follow?

Answer 53

Bell-Magendie Rule

Question 54

Bell-Magendie Rule

Answer 54

in reflex arcs, the sensory neurons enter the brain or spinal cord by way of the dorsal route of the cranial or spinal nerves and the motor neurons exit the brain and spinal cord by the ventral route of the cranial or spinal nerves

Question 55

multiple synapses in the reflex arc

Answer 55

first: between the sensory neuron and the interneuron second: between the interneuron and the motor neuron (then the motor neuron leaves the CNS)

Question 56

what is a reflex arc with interneurons involved called?

Answer 56

a polysynaptic reflex arc

Question 57

what are the two layers that the spinal cord has?

Answer 57

outer layer = white matter inner layer = grey matter

Question 58

what is the outer white matter of the spinal cord from?

Answer 58

axons of the sensory and motor neurons that are myelinated

Question 59

what is the inner grey matter of the spinal cord from?

Answer 59

cell bodies of interneurons and motor neurons that are not myelinated