Histology + Embryology of CNS

Question 1

where are unipolar neurons found?

Answer 1

found in numerous sensory ganglia and peripheral nerves

Question 2

where are bipolar neurons usually found?

Answer 2

found in retina, organs of hearing and equilibrium of the ear, olfactory epithelium of the nose
note: purely sensory

Question 3

where are multipolar neurons found?

Answer 3

include all motorneurons and interneurons of the brain, cerebellum and spinal cord
note: most common type in cns

Question 4

where are pseudounipolar neurons found?

Answer 4

has 2 branches: one central- from cell body to spinal cord and one peripheral- from cell body to periphery (skin, joint, muscle); cell body in dorsal root ganglion

Question 5

what are the three types of cerebral cortex?

Answer 5

• paleocortex: olfactory
• archicortex: hippocampal formation
• neocortex: remainder of cerebral cortex

Question 6

1 climbing to 7 purkinje and 1 purkinje to 1 climbing. T or F.

Answer 6

T

Question 7

CNS has more neurons than glial cells. T or F.

Answer 7

F- tenfold more glial cells than neurons

Question 8

what are the functions of astrocytes?

Answer 8

• support metabolic exchange between neurons and capillaries
• perivascular feet of astrocytes cover the capillary basement membrane and form the blood brain barrier
• contain reserves of glycogen from which they release glucose for energy metabolism
• control chemical environment by re-uptake of excessive potassium ions and neurotransmitters
• role in brain inflammation and brain scar tissue

Question 9

what are microglial cells?

Answer 9

phagocytes of the CNS when tissue is damaged microglial cells migrate to the area, proliferate and become phagocytic and remove dead or foreign tissue

Question 10

what do ependymal cells do?

Answer 10

line the ventricles in the brain and central canal of the spinal cord

Question 11

what are the functions of the ependymal cells?

Answer 11

• moves CSF with ciliae; produces csf and absorption of csf thru villi
• provides nutrients to stem cells of subventricular zone
• role in immune defense (produce cytokines, TLR; protection against viruses, bacteria)

Question 12

whats the epithelium of the choroid plexus?

Answer 12

simple cuboidal epithelium

Question 13

upper end of the neural tube makes what structure?

Answer 13

prosencephalon (forebrain)

Question 14

lower end of the neural tube makes what structure?

Answer 14

spinal cord

Question 15

neural crest cells form which structures?

Answer 15

facial bones and sagittal suture

Question 16

paraxial mesoderm forms which suture?

Answer 16

coronal suture

Question 17

the telencephalon becomes which structures?

Answer 17

cerebral hemispheres containing corpus striatum,
cerebral cortex, white matter, olfactory system

Question 18

the diencephalon becomes which structures?

Answer 18

thalamus, hypothalamus, subthalamus, epithalamus

Question 19

the mesecephalon becomes which structures?

Answer 19

midbrain (tectum and cerebral peduncles)

Question 20

the metencephalon becomes which structures?

Answer 20

pons and cerebellum

Question 21

the myelencephalon becomes which structures?

Answer 21

medulla oblongata

Question 22

Proliferation of cells at the cephalic end of the neural tubes causes it to dilate and form three primary brain vesicles about 3 weeks after the closure of the caudal neuropore. T or F.

Answer 22

T

Question 23

closure of the cranial neuropore occurs when?

Answer 23

day 25 (somite stage 18-20)