Lecture 5: nervous system

Question 1

neural tube differentiates into

Answer 1

CNS (brain and spinal cord)

Question 2

anterior/ cranial neuropore closure

Answer 2

before caudal

day 25

Question 3

posterior/ caudal neuropore

Answer 3

after cranial

day 28

Question 4

notochord

Answer 4

has important role in inducing development of the spinal cord

Question 5

primordial dilations

Answer 5

primary brain vesicles in the cranial end
prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)

Question 6

spinal cord develops below

Answer 6

the level of the hindbrain

Question 7

neurpepithelial layer

Answer 7

rapidly dividing neuroepithelial cells that form a thick, pseudostratified epithelium

Question 8

neurogenesis and gliogenesis

Answer 8

occur simultaneously from proliferating neuroepithelial cells
-neurogenesis is more prominent in the embryonic period while gliogenesis is more prominent later in development

Question 9

layers of the neural tube

Answer 9

• inner layer: ventricular zone
• intermediate layer: mantle zone
• outer layer: marginal zone

Question 10

ventricular zone

Answer 10

• line canal and give rise to other layers (site of cell proliferation- contains neuroblasts)
• remaining cells form the ependyma (line the central canal of the spinal cord and ventricles of the brain)

Question 11

mantle zone

Answer 11

• formed by neuroblasts

- becomes the gray zone of the spinal cord

Question 12

marginal zone

Answer 12

-formed by neural processes that give rise to the white matter of the spinal cord

Question 13

ventricular zone gives rise to..

Answer 13

all neurons and microglial cells

Question 14

glioblast become…

Answer 14

astocytes or oligodendrocytes

Question 15

microglial cells are derived from

Answer 15

mesenchymal cells and migrate into the CNS during the fetal period

Question 16

ventral thickening of the mantle layer

Answer 16

basal plates- ventral motor horn cells

differentiate into voluntary motor neurons to innervate skeletal muscle

Question 17

dorsal thickening of the mantle layer

Answer 17

alar plates - sensory are of the spinal cord

differentiate into interneurons and receive first input from sensory neurons of the peripheral NS

Question 18

sulcus laminates of the mantle layer

Answer 18

a groove on each side that separates alar from basal

Question 19

roof and floor plates of the mantle layer

Answer 19

no neuroblasts, pathways for nerve fibers crossing from one side to the other

Question 20

intermediate zone of the mantle layer

Answer 20

lateral horns

differentiate to autonomic or involuntary motor neurons

Question 21

growth of basal plate

Answer 21

nerve fibers of the basal plate grow out to form the ventral root

Question 22

dorsal root ganglion

Answer 22

neural crest cells that migrate dorsolaterally give rise to the DRG

Question 23

central processes of the DRG…

Answer 23

grow into dorsal horns

Question 24

distal processes of the DRG…

Answer 24

meet the ventral roots to form a spinal nerve

Question 25

positional changes of the spinal cord

3rd month

Answer 25

the spinal cord extends entire length vertebral column

-spinal nerves pass at the level of origin

Question 26

positional changes of the spinal cord

6th monts

Answer 26

due to differential growth, the cord ends at higher levels

-the 1st sacral vertebra

Question 27

positional changes of the spinal cord

birth

Answer 27

spinal cord ends at the level of the 2nd or 3rd lumbar vertebra

Question 28

vertebral column and dura….than the spinal cord

Answer 28

grow more rapidly

Question 29

the brain can be divided into 2 parts

Answer 29

• brain stem: similar to the spinal cord organization (alar and basal plates)
• higher centers (prosencephalon): specialized centers that lack the spinal cord organization-alar plates only

Question 30

primary brain vesicles

Answer 30

• prosencephalon
• mesencephalon
• rhombencephalon

Question 31

division of the prosencephalon (forebrain)

Answer 31

into the

• telencephalon
• diencephalon

Question 32

division of the mesencephalon (midbrain)

Answer 32

does not divide

Question 33

division of the rhombencephalon

Answer 33

into

• metencephalon
• myelencephalon

Question 34

telencephalon gives rise to

Answer 34

cerebral hemispheres and lateral ventricles

Question 35

diencephalon gives rise to

Answer 35

thalami, etc, and third ventricle

Question 36

mesencephalon gives rise to

Answer 36

midbrain and aqueduct

Question 37

metencephalon gives rise to

Answer 37

pons, cerebellum, and upper part of the fourth ventricle

Question 38

myelencephalon gives rise to

Answer 38

medulla and lower part of the fourth ventricle

Question 39

pituitary gland arises from

Answer 39

• ectoderm invaginations of the ectodermal stomatodeum (primitive oral cavity) called rathke’s pouch or adenohypophysis
• downward extension of the diencephalon called the neurohypophysis

Question 40

rathke’s pouch (the surface ectoderm) forms

Answer 40

• pars distalis: anterior lobe of the pituitary gland
• par tuberalis: surrounds the infundibulum
• pars intermedia: adjacent to posterior lobe

Question 41

infundibulum gives rise to

Answer 41

• median eminence
• infundibular stem
• pars nervosa (posterior lobe)

Question 42

Adenohypophysis

Answer 42

– Formed from Rathke’s Pouch
• Out pocketing (diverticulum) of the ectoderm of the stomodeum (primordial oral cavity) that develops during week three
• Connection to the oral cavity degenerates during week six
• Hormones produced in the pars distalis or anterior lobe

Question 43

Neurohypophysis

Answer 43

-Arises from the neuroectoderm of the diencephalon
•Infundibulum: down growth of the neuroectoderm of the diencephalon
• Nerve fibers from the hypothalamus grow into the infundibulum- hormones are produced in the hypothalamus and travel to the pars nervosa via axons