lecture 2

Question 1

neuroglia in PNS

Answer 1

Schwann cell

Question 2

neuroglia in CNS

Answer 2

1. oligodendrocyte
2. astrocyte
3. ependymal cell
4. radial cell
5. microglia

Question 3

how does Schwann cell myelinate axons?

Answer 3

1. one Schwann cell wraps one axon, but one axon is wrapped by many Schwann cells.
2. myelin wraps about 100 times with almost no cytoplasm.

Question 4

which syndrome is due to PNS demyelination?

Answer 4

Guillain-Barre syndrom

Question 5

which system is myelinated axons associated with?

Answer 5

touch system

Question 6

which system is non-myelinated axons associated with?

Answer 6

pain sensation

Question 7

what is the function of non-myelinating Schwann cells?

Answer 7

bundle small axons and help maintain peripheral synapses.

Question 8

what is Remak Bundles?

Answer 8

Schwann cells bundle small diameter c-fibers into Remak Bundles.
Schwann cells keep them from touching each other by squeezing its cytoplasm between axons

Question 9

what are the common antigens expressed by oligos (and myelinating Schwann cells)?

Answer 9

1. Myelin Basic Protein (MBP)

2. Proteolipid Protein (PLP)

Question 10

what are the myelin associated growth inhibitors that oligos (but not Schwann cells) express?

Answer 10

MAG, Nogo, OMgp

Question 11

which disease could be a CNS demyelinating disease?

Answer 11

Multiple Sclerosis

Question 12

how can Astrocyte be identified?

Answer 12

identifiable by expression of glial fibrillary acidic protein(GFAP) and Aldehyde Dehydrogenase(ALDHL1)

Question 13

what factors do astrocytes release during development?

Answer 13

cholesterol and throbospondins that help promote synapse formation

Question 14

what does Tripartite synapse mean?

Answer 14

the functional synapse is not just presynaptic axon and postsynaptic dendrite. The associated glial process should be considered to participate as well

Question 15

the function of astrocyte at synapses?

Answer 15

1. neurotransmitter uptake, processing and recycling
2. responding to neural activity (astrocytes express some neurotransmitter receptors which can cause intracellular increases in Ca2+ in response to neural activity)
3. releasing neuromodulatory factors, including D-serine, ATP, and glutamate)

Question 16

how is astrocyte used to cure ALS?

Answer 16

ALS is being treated using drugs that enhance glutamate transporter activity in glia.

Question 17

How do astrocytes interconnect to form networks?

Answer 17

astrocytes interconnect through gap junctions to form networks.

Question 18

how do astrocytes link neuronal activity to local blood flow?

Answer 18

it is an intermediate for the exchange of nutrients and other molecules between neurons and blood

Question 19

what is the basis of fMRI BOLD signal?

Answer 19

astrocyte link neuronal activity to local blood flow

Question 20

what is the function of ependymocytes?

Answer 20

1. ependymal cells line the ventricles
2. they beat cilia to circulate cerebrospinal fluid (CSF)
3. the Choroid Plexus, which is makes CSF, is composed of ependymal cells and blood vessels.

Question 21

what are the functions of radial cells?

Answer 21

1. serve as a scaffold for radially migrating neurons
2. radial glia give rise to all classes of macroglia and neurons
3. radial glia are developmentally transient except for the Muller Glia in the retina and the Bergmann glia in the cerebellum.

Question 22

where are microglia derived from?

Answer 22

microglia are foreigners in the brain.

myeloid mileage cells are derived from mesoderm (yolk sac) rather than ectoderm (radial glia)

Question 23

what are the three primary germ layers in the very early embryo?

Answer 23

1. endoderm (most proximal layer)
2. mesoderm (middle layer)
3. ectoderm (most distal layer)

Question 24

what are the functions of microglia?

Answer 24

1. microglia are dedicated immune cells for the CNS (because of the blood-brain barrier, the CNS is isolated from the immune system, so microglia serve as an immune system for CNS)
2. they respond to infection or injury by producing rapid morphological and biochemical changes-they release inflammatory cytokines.
3. microglia are small migrating cells that scavenge debris in the CNS

Question 25

you have discovered a new ion transporter that you guess only exports Na ions. You wish to see if this new transporter either a) harness some other inward ionic concentration gradient to export the Na or b) uses energy from ATP hydrolysis to export Na. which of the following would be futile towards answering this question?

Answer 25

decrease the external concentration of the other likely ion and see if the export of Na decreases as you do so. use a drug to block ATP synthesis to see if the export of Na decreases.