BSI Lecture 52 Histology/Neurons and Glia

Question 1

Where do dendrites receive information?

Answer 1

Via chemical transmission across synapses

Question 2

How do the cell body and axons transmit information?

Answer 2

propagating action potentials away from the cell body towards a synapse/synapses

Question 3

What determines whether or not you get to threshold?

Answer 3

Axon Hillock

Question 4

How do dendrites receive information?

Answer 4

Via chemical transmission across synapses

Question 5

How do the cell body and axon transmit information?

Answer 5

By propagating action potentials away from the cell body towards a synapse(s).

Question 6

What are the transport systems in axons and dendrites?

Answer 6

Microtubules and molecular motors

Question 7

What does the axon increase?

Answer 7

conduction velocity

Question 8

What is most the common neuron and where is it located?

Answer 8

Multipolar neuron located in the cerebral cortex, cerebellum, and in multiple dendrites for many inputs.

Question 9

Where is the bipolar neuron located?

Answer 9

in the back of the eye (retina)

Question 10

What is a unipolar neuron?

Answer 10

It is the primary sensory neuron that will go into the spinal cord

Question 11

What is the general way that neurons can be characterized?

Answer 11

according to their processes/dendrites

Question 12

How are microtubules efficient transport systems?

Answer 12

they relay information quickly

Question 13

T/F? The physical position of synapses on dendrites is crucial integration.

Answer 13

True

Question 14

Neurons can and usually have multiple dendrites, but how many axons do they have?

Answer 14

One axon, however, the axon can split to innervate multiple effectors/neurons

Question 15

What are the variable shapes of the dendrites related to?

Answer 15

function

Question 16

What are pyramidal cells?

Answer 16

the principal neurons of the cerebral cortices

Question 17

What are Purkinje cells?

Answer 17

the cerebellar equivalent to pyramidal cells.

Question 18

What do astrocytes remove?

Answer 18

What do astrocytes remove?

They remove glutamate and terminate its action, which in excess would kill off neurons

Question 19

What do astrocytes help in the formation of?

Answer 19

They help in forming the vital “blood-brain-barrier” and with neuronal nutrition

Question 20

What are microglial cells?

Answer 20

immune cells

Question 21

Why are the glia “forgotten heroes” of the nervous system?

Answer 21

without their support, neurons couldn’t function correctly

Question 22

What do ependymal cells line?

Answer 22

the ventricular system of the brain and they actually secrete CSF.

Question 23

What is CSF?

Answer 23

A blood filtrate

Question 24

How do oligodendrocytes force a faster rate of information transfer?

Answer 24

They are myelinating, which means that they wrap their membranes tightly around the CNS axons, so insulating them

Question 25

Where do Schwann cells myelinate?

Answer 25

Outside the CNS

Question 26

By how much does myelination increase speed?

Answer 26

10 times

Question 27

What occurs at the nodes of Ranvier?

Answer 27

action potentials "hop" between the parts of the axon, which forces an increased rate of action potentials.

Question 28

What is the outer connective tissue covering a nerve (containing many axons and fascicles) called?

Answer 28

Epineurium

Question 29

T/F? Axons always start as a single process?

Answer 29

True

Question 30

Which type of glial cells are involved in neurotransmitter removal and recycling?

Answer 30

Astrocytes

Question 31

Which type of glial cells are involved in the blood-brain barrier?

Answer 31

Astrocytes

Question 32

Which type of glial cells are involved in neuronal nutrition?

Answer 32

Astrocytes

Question 33

Which type of glial cells are involved myelination within the CNS?

Answer 33

Oligodendrocytes

Question 34

T/F? If individual axons are not myelinated, they will still have enhanced conduction velocities.

Answer 34

FALSE; they will not have enhances conduction velocities

Question 35

T/F? The nerve has its own blood supply.

Answer 35

True

Question 36

Where is grey matter located?

Answer 36

dendrites and cell bodies

Question 37

Where is white matter located?

Answer 37

myelinated axons that transmit data

Question 38

At the level of the cerebellum, there is an extra outer grey layer. (Grey-White-Grey). What is it composed of?

Answer 38

neurons which migrate from the central grey area often with the help of glia.

Question 39

What is MS?

Answer 39

An autoimmune condition whereby your own immune system misidentifies the myelin as a pathogen and attacks it so seriously, which compromises data transmission/functions.

Question 40

What other cells be involved in MS?

Answer 40

Macrophages, microglia, beta-cells/plasma cells

Question 41

T/F? MS is the most common cause or neural disability in young adults.

Answer 41

True

Question 42

The disease is characterized by periods of ________ and ________.

Answer 42

remission and relapse

Question 43

What are some symptoms of MS?

Answer 43

numbness, pain, disrupted vision, poor balance, slurred speech, incontinence, fatigue, depression, and muscle weakness, paralysis

Question 44

Although the cause of MS is not fully understood, what can it be due to?

Answer 44

Due to the inappropriate targeting of several proteins found in myelin that may resemble certain viral proteins

Question 45

What are two things that could trigger a relapse for MS?

Answer 45

stress and injury

Question 46

What has recent research of MS identified an imbalance of?

Answer 46

regulatory T-cells (helpers and suppressors)

Question 47

T/F? Although remission allows for some repair of myelin sheaths, the accumulative effects can cause a rapid decline in health.

Answer 47

True

Question 48

What reduces the risk of MS?

Answer 48

Vitamin D

Question 49

What are some risk factors for MS?

Answer 49

Smoking; changing environment; geographic location

Question 50

What is a treatment for MS that reduces the severity and duration of relapses?

Answer 50

anti-inflammatory steroids

Question 51

Although anti-inflammatory steroids reduce severity and duration of relapses, what do they not help?

Answer 51

Frequency

Question 52

What is interferon Beta-1a thought to strengthen?

Answer 52

the blood-brain barrier

Question 53

How is an immunomodulator work?

Answer 53

It may "divert" or "decoy" the immune system from attacking myelin as it mimics the structure of myelin basic protein

Question 54

How has mitoxantrone, a cancer treatment drug had success in MS?

Answer 54

it suppresses lymphocyte activity, which are the primary immune system cells that attack myelin

Question 55

How does Natalizumab, a monoclonal antibody work?

Answer 55

It blocks the adhesion molecule alpha4-integrin to slow lymphocyte egress into the CNS, but it has been reported to cause/allow other unwanted side effects such as progressive multifocal leukoencephalopathy, which is a viral condition causing progressive damage to myelin

Question 56

The S-1-P analog Fingolimod (phosphorylated similarly to sphingosine) was approved for the treatment of MS. What does it reduce?

Answer 56

reduces lymphocyte agrees into the CNS, but does so by excessive stimulation of the S1PR (GPR receptor for S-1-P) causing it to be internalized.