Exam 2 - Lecture 17 (Neuroglia 1)

Question 1

What are the neuroglia of the CNS?

Answer 1

1. Ependymal cells
2. Astrocytes
3. Oligodendrocytes
4. Microglia

Question 2

What are the neuroglia of the PNS?

Answer 2

Schwann cells

Question 3

Where are ependymal cells located?

Answer 3

Line central canal and ventricles

Question 4

What % of nervous tissue do neuroglia make up?

Answer 4

> 90%

Question 5

What is the basic structure of neuroglia?

Answer 5

Small cells with little cytoplasm; only its nucleus can be seen with routine stains.

Question 6

What is the division rate of neuroglia?

Answer 6

Continue to divide throughout life.

Question 7

Ependymal cells and astrocytes provide optimal _____ environment for neurons.

Answer 7

extracellular

Question 8

What is on the apical surface of ependymal cells?

Answer 8

Cilia

Question 9

What is the role of ependymal cells?

Answer 9

Assist with CSF circulation

Question 10

What do ependymal cells form?

Answer 10

choroid plexus

Question 11

What is the choroid plexus made up of and what does it do?

Answer 11

choroid epithelium; produces CSF

Question 12

What cells make up the choroid epithelium?

Answer 12

modified ependymal cells lined with microvilli

Question 13

Why do the modified ependymal cells of the choroid epithelium have microvilli and not cilia?

Answer 13

To increase SA due to production of CSF

Question 14

What are the cell types/shapes of ependymal cells?

Answer 14

Cuboidal to columnar

Question 15

What does the choroid epithelium serve as a barrier for?

Answer 15

Blood-CSF barrier

Question 16

What type of junctions are present in the choroid epithelium and why?

Answer 16

tight junctions so that nothing can travel between cells

Question 17

What is special about the c.t. of the choroid plexus?

Answer 17

Has fenestrated capillaries that cause it to be “leaky” so that Na+ can leave endothelial cells

Question 18

What is CSF?

Answer 18

Filtrates of the blood that pass through capillary endothelium and choroid epithelium of the choroid plexus.

Question 19

Where does CSF circulate?

Answer 19

Ventricles and subarachnoid space

Question 20

How does CSF get from the ventricles to the subarachnoid space?

Answer 20

Through a channel

Question 21

What are the 3 functions of the CSF?

Answer 21

1. Physical support of the CNS
2. Maintains chemical environment of the CNS
3. Regulates intracranial pressure

Question 22

What does CSF remove from the CNS?

Answer 22

metabolites

Question 23

How is the ICP maintained within normal limits?

Answer 23

CSF volume and blood volume vary inversely

Question 24

What occurs with CSF absorption/production in regulation of ICP?

Answer 24

Absorption increases, production decreases

Question 25

What are astrocytes?

Answer 25

Most abundant neuroglia of the CNS (~50%)

Question 26

What 3 things do astrocytes do?

Answer 26

1. Respond to injury 2. Proliferate to form scar tissue 3. Maintain optimal CSF environment

Question 27

What are the 5 ways in which astrocytes maintain optimal CNS environment?

Answer 27

1. Induct and maintain capillary endothelium as the BBB 2. Help transport glucose to neurons 3. Store glycogen - energy reserves 4. Promote neuronal survival 5. Prevent glutamate toxicity

Question 28

What is the morphology of astrocytes?

Answer 28

Neuroglia with numerous cell processes

Question 29

What does the capillary endothelium/BBB do?

Answer 29

Regulates exchange of solutes between blood and CNS tissue

Question 30

What do astrocytes release?

Answer 30

Glial cell line-derived neurotrophic factor (GDNF)

Question 31

Why do astrocytes release GDNF?

Answer 31

To promote formation and maintenance of capillary tight junctions

Question 32

What is the structure of the capillary endothelium?

Answer 32

Perivascular endfeet of astrocytes contact the basement membrane, which contacts the endothelium

Question 33

What are 3 ways in which things get across the BBB?

Answer 33

1. Diffusion 2. Transporter 3. Carrier-mediated transport

Question 34

What 3 things can get thru the BBB by diffusion?

Answer 34

1. Water 2. Gases 3. Lipophilic substances (alcohol, heroin, nicotine, cyanide)

Question 35

What can get thru the BBB by transporter?

Answer 35

Glucose

Question 36

What is the transporter for glucose that gets it across the BBB?

Answer 36

GLUT 1

Question 37

What 2 things can get thru the BBB by carrier-mediated transport?

Answer 37

1. Amino acids | 2. Vitamins

Question 38

What AAs are transported vs. which ones aren't?

Answer 38

Transported if not synthesized in brain (large neutral) | Not transported if synthesized in the brain

Question 39

What 4 AAs are large and neutral and not synthesized in the brain?

Answer 39

1. Leucine 2. Tyrosine (NTM = catecholamine) 3. Valine 4. Tryptophan (NTM = serotonin)

Question 40

What AAs are small and neutral and synthesized in the brain?

Answer 40

1. Glycine | 2. GABA