Glia (Quiz 2)

Question 1

How many types of neuroglia/glia are there?

Answer 1

6 types

Question 2

Do glia participate directly in synaptic transmission or in electrical signaling?

Answer 2

NO

Question 3

Cells with glial characteristics act as ____________ giving rise to new glia and occasionally neurons

Answer 3

stem cells

Question 4

Glial membranes contain transporter proteins that facilitate uptake of _______ and remove __________________. They regulate function

Answer 4

ions, neurotransmitters

Question 5

What are some functions of glia?

theres a lot

Answer 5

-maintaining ionic composition around neurons (homeostasis)
-modulating the rate of propagation (myelination)
-modulating synaptic transmission and neurotransmitter uptake
-guiding neuronal development and axon outgrowth
-forming synaptic connections
-aiding or impeding neural injury
-forming BBB
-providing an interface between the brain and immune system
-regulates interstitial fluid flow (washing out waste)
-clean and remove debris (phagocytic)
-potentially acting as stem cells (can still divide whereas neurons cannot, glia are mitotically active)

Question 6

Where is neuroglia located?

Answer 6

in all neural tissue from CNS to PNS

Question 7

What are the glia of the PNS?

Answer 7

schwann cells and satellite cells

Question 8

What are the functions of satellite cells?

Answer 8

-surround neuron cell bodies in ganglia for protection
-regulate oxygen, carbon dioxide, nutrient, and neurotransmitter levels around neurons in ganglia, and make sure sodium potassium is homeostatic
-satellite cells exist for biological isolation of PNS

Question 9

What are the functions of schwann cells?

Answer 9

-surround all axons in PNS
-responsible for myelination of peripheral axons
-participate in repair process after injury
-provide a covering to support and protect unmyelinated axons
-provide insulating material that allows rapid conduction of APs along axon

Question 10

What are the glia of the CNS?

Answer 10

1) astrocytes
2) oligodendrocytes
3) microglia
4) ependymal cells

Question 11

What are the functions of ependymal cells?

Answer 11

-line ventricles (brain) and central canal (spinal cord)
-assist in producing, circulating, and monitoring CSF and the choroid plexus

Question 12

What are the functions of oligodendrocytes?

Answer 12

-myelinate CNS axons
-provide structural framework

Question 13

What are the functions of astrocytes?

Answer 13

-maintain BBB
-provide structural support
-regulate ion, nutrient, and dissolved gas conc.
-absorb and recycle neurotransmitters
-form scar tissue after injury

Question 14

What are the functions of microglia?

Answer 14

remove cell debris, wastes, and pathogens by phagocytosis

Question 15

T/F: astrocytes have a lot of branching processes but no dendrites

Answer 15

TRUE, only neurons have dendrites not neuroglia

Question 16

What are the 2 types of astrocytes?

Answer 16

1) protoplasmic astrocytes
2) fibrous astrocytes

Question 17

Where are protoplasmic astrocytes found?

Answer 17

in the gray matter of the cerebral cortex

Question 18

Where are fibrous astrocytes found?

Answer 18

in the white matter of the brain

Question 19

What is the most common glial cell?

Answer 19

astrocytes

Question 20

Astrocytes are star shaped glia found in….

Answer 20

all areas of the brain

Question 21

Astrocytes and neurons communicate to modulate….

Answer 21

synaptic transmission

Question 22

Astrocytes regulate __________________ and ________________ levels

Answer 22

extracellular ions, neurotransmitter

Question 23

Astrocytes have many processes (very thin) that cover _________________ within the brain

Answer 23

all blood vessels

Question 24

When neurons fire an AP, K+ is released into the extracellular space. ____________ have many K+ channels and act as spatial buffers taking up the potassium

Answer 24

Astrocytes

Question 25

Astrocytes have high-affinity transporters to clear ______________ from the synaptic cleft

Answer 25

glutamate (Glu)

Question 26

Excess extracellular glutamate causes _______________ and can lead to neuronal death

Answer 26

excitotoxicity

Question 27

Astrocytes contain digestive enzymes that help degrade and metabolize what 4 molecules?

Answer 27

1) dopamine 2) NE 3) epi 4) serotonin

Question 28

What is a tripartite synapse?

Answer 28

3 components: pre and post synaptic terminal and astrocyte

Question 29

What glial cell prepares the surface of a neuron for synapse formation/development and stabilizes/connects adjacent neurons?

Answer 29

astrocytes

Question 30

Which glial cell releases thrombospodins that promote synaptogenesis?

Answer 30

astrocytes (helps with adult plasticity to change)

Question 31

During axonal damage, astrocytes retract from the....

Answer 31

post synaptic neuron

Question 32

Which glial cells can protect other cells against oxidative stress?

Answer 32

astrocytes

Question 33

Which glial cells contain glycogen and are capable of gluconeogenesis? How?

Answer 33

astrocytes -it has been shown that astrocytes next to neurons in the cortex and hippocampus store and release glucose -astrocytes can fuel neurons with glucose during periods of high rate of glucose consumption and glucose storage -astrocytes also provide lactate

Question 34

Astrocytes in vitro become activated by _______ glucose

Answer 34

low

Question 35

What is the BBB?

Answer 35

-no blood in brain because it is toxic to neurons so there has to be a barrier (a CVA/stroke leads to neuronal death) -to function, glia and neurons require a highly specialized environment that is almost fully impermeable -macromolecules within blood and plasma compositional changes must be isolated from neurons -endothelial cells have tight junctions with the brain and are ensheathed in astrocyte processes

Question 36

What are the 4 entryways to get into a brain?

Answer 36

-lipid soluble diffusion of oxygen and carbon dioxide through BBB -facilitated diffusion -ATP mediated transport -ion channels

Question 37

What are end feet?

Answer 37

1 individual process of an astrocyte that is usually wrapped around small blood vessels and decides what goes in and out of the brain multiple end feet is called astrocyte foot processes

Question 38

Which glial cells is this? -restricted to CNS only -form and lay down laminated lipid rich wrapping called myelin around some axons -they are small cells with 5-20 processes -in the white matter, each cell envelopes multiple axonal segments called internodes/ myelin sheaths depending on the axon diameter -in the gray matter, they support/surround the soma of neurons

Answer 38

oligodendrocytes

Question 39

ALS is caused by degenerative ____________

Answer 39

oligodendrocytes (they start to degenerate before disease onset and are replaced with new oligodendrocytes that don't provide trophic support and lactate to neurons)

Question 40

In ________________, oligodendrocytes are damaged and myelin that normally insulates the axons of nerve cells is lost, a process known as demyelination

Answer 40

multiple sclerosis (MS)

Question 41

It has been suggested that oligodendrocyte __________ may activate a cascade of neuro-inflammatory events leading to the induction of an autoimmune response targeted against oligodendrocytes and myelin

Answer 41

apoptosis

Question 42

______________________ forms a tight junction or boundary between CSF and brain tissue

Answer 42

ependymal cells/ ependyma

Question 43

____________ are specialized ependymal cells found in the 3rd and 4th ventricle and have long processes extending deep into the hypothalamus (hypothalamus regulates homeostasis of basically everything, so it can be assumed that this is a signaling mechanism) test q

Answer 43

tanycytes

Question 44

How do microglia move through the CNS?

Answer 44

ameboid-like movement (like a water balloon with gravity can just flop over and continually change shape as its moving)

Question 45

Which glial cells share many properties with macrophages found within tissues?

Answer 45

microglia

Question 46

Unlike astrocytes, oligodendrocytes, and neurons, microglia are derived from....

Answer 46

bone marrow and are hemopoietic

Question 47

Which glial cells remove cellular debris from sites of injury or neuronal replacement and turnover?

Answer 47

microglia

Question 48

Which glial cells have immunological surveillance functions (similar to NK cells) that present antigens to lymphocytes, neutrophils, and monocytes and have been shown to secrete signaling molecules like cytokines?

Answer 48

microglia

Question 49

Glioma tissue is not only composed of cancer cells, but also contains non-transformed cells that are predominantly ___________ that appeared to have lost their function

Answer 49

microglia

Question 50

microglia and its loss of function has been studied to look at its correlation with many diseases and issues. What are some examples? test q (remember at least one)

Answer 50

-spinal cord injury -ataxia -viral encephalitis -ischemic stroke -schizophrenia -ALS and frontotemporal dementia -alzheimers disease

Question 51

Schwann cells wrap ______________ many times

Answer 51

concentrically

Question 52

T/F: one schwann cell produces a single myelin sheath for one segment of one axon test q

Answer 52

true!!!!!!! so you will need multiple schwann cells on 1 neuron

Question 53

T/F: the number of layers in myelin is proportional to the diameter of the axon test q

Answer 53

true! larger axon= thicker sheath

Question 54

An axon lies in a __________ formed by a schwann cell

Answer 54

trough (during development)

Question 55

Schwann cells line up the axon at regular intervals and are __________ organized

Answer 55

perfectly

Question 56

The external membrane of the schwann cell surrounds the axon to form a double membrane called the....

Answer 56

mesaxon (note: the mesaxon spirals around forming layers, the last loop holds the nucleus and has the most cytoplasm, the cytoplasm is squeezed out and a lipid layer known as myelin remains)

Question 57

The gaps between schwann cells are exposed axon called...

Answer 57

nodes of Ranvier or just nodes