Neuroanatomy

Question 1

Neurulation

Answer 1

Neural plate differentiation and formation of neural tube. Takes one week

Question 2

what signaling factor that differentiates the ventral axis of the neural tube

Answer 2

sonic hedgehog (Shh) from notochord

Question 3

what is the signaling factor that differentiates the dorsal axis of the neural tube

Answer 3

bone morphogenic protein (BMP) from ectoderm

Question 4

primary neurulation

Answer 4

ectoderm forming neural tube

Question 5

secondary neurulation

Answer 5

• mesoderm forming neural tube
• local differentiation of cells
• starts at the caudal eminence

Question 6

when/ what does primary and secondary neuruation fuse together

Answer 6

• occurs at day 40
• forms neural canal
• sacral part of S1 came from secondary neurulation

Question 7

type of closure for neural tube maturation

Answer 7

non-sequential closure

Question 8

when does neural tube closure begin

Answer 8

day 19-21

Question 9

what is the sequence of neural tube maturation/ closure

Answer 9

1- brain stem & upper sc
2-3 head
4- neck
5- sacral sc & secondary neurulation

Question 10

when does neural tube maturation end

Answer 10

rostr al- 23rd day

caudal- 28th day

Question 11

what does incomplete closure of caudal neuropore cause

Answer 11

spina bifida

Question 12

anacephaly

Answer 12

• lack of skull & cerebrum
• only have a brainstem
• failure of wave 2 closure
• remains open & doesn’t develop into brain
• lethal

Question 13

spina bifida

Answer 13

• incomplete formation of sc
• vertebrae open & unfused
• different degrees of severity
• spina bifida occulta (mild)
• spina bifida meningocele (moderate)
• spina bifida myelomeningocele (severe)

Question 14

most mild form of spina bifida

Answer 14

spina bifida occulta

Question 15

moderate form of spina bifida

Answer 15

spina bifida meningocele

Question 16

most severe form of spina bifida

Answer 16

spina bifida myelomeningocele

Question 17

how is spina bifida prevented

Answer 17

folate

Question 18

components of hindbrain

Answer 18

• medulla (myelencephalon)

- pons (metencephalon)

Question 19

component of midbrain

Answer 19

mesencephalon

Question 20

components of diencephalon

Answer 20

• thalamus
• hypothalamus
• epithalamus

Question 21

components of telencephalon

Answer 21

cerebral hemispheres

Question 22

neural tube derivatives

Answer 22

• hindbrain
• midbrain
• diencephalon
• telencephalon
• sc
• ventricular system

Question 23

what special sense is an extension of brain and arises from the neural tube

Answer 23

eyes

Question 24

cephalic flexure

Answer 24

• optical axes perpendicular to vertebral column
• creates cranial base flexion: bends brain forward to ‘adapt’ to sanding upright & accounts for forward projection of eyes

Question 25

pontine flexure

Answer 25

-area of 4th ventricle

Question 26

where does the cerebellum derive from

Answer 26

pontine flexure/ pons

Question 27

neurons

Answer 27

• nerves in CNS
• cell body, dendrites, axons
• all differ in size, shapes, purpose

Question 28

types of glial cells

Answer 28

outnumber neurons 10:1

• oligodendrocytes
• astrocytes
• microglia
• ependymal cells (line fluid cavities)

Question 29

oligodendrocytes

Answer 29

-1 cell myleninates parts of many different axons

Question 30

unmyleninated CNS axons

Answer 30

DO NOT have any glial cells around them

Question 31

unmyleniated PNS axons

Answer 31

surrounded by single layer of Schwann cell membrane

Question 32

schwann cells in PNS

Answer 32

one schwann cell mylenates one axon and leaps to the next oney

Question 33

protoplasmic & fibrous astrocytes

Answer 33

• modulate synaptic transmission: connects to synapses to regulate neural activity
• release transmitters, nutrients, gf, cytokines
• pickup excess K+, transmitters & metabolic waste
• regulates bf via connections to bv
• astrocyte detects neuronal activity and adjusts bf via v.c constricting/ v. dilating bv as needed (basis of functional MRI)

Question 34

what does brain tissue destruction cause

Answer 34

fibrous astrocytic scar

Question 35

how do glial cells (astrocytes) enhance neuronal function

Answer 35

by releasing glial-transmitters aka glutamate

Question 36

what is blood brain barrier (BBB) formed by

Answer 36

-capillary endothelial cells (w/ tight junctions– 20x more than non-CNS capillaries)
-basement membrane
-astrocyte feet- metabolically
maintain endothelial junction
-all allow restrictions on whatever is allowed through
-what is released passed the BBB is highly regulated

Question 37

what locations do not have a BBB

Answer 37

• hypothalamus
• area postrema
• preiventricular region
• capillaries allow entry of larger molecules
• hormones contact hypothalamic cell receptors

Question 38

where do digested poisons stimulate

Answer 38

areas postrema’s pathway to vomiting center

Question 39

what is transported through the BBB

Answer 39

• aqueous compounds restricted via tight junctions
• allow lipophilic structures and drugs via transcellular passage
• transporter to allow glucose, aa, purine bases, nucleosides, choline
• specific receptor mediated endocytosis of certain hproteins like insulin & transferrin

Question 40

microglia

Answer 40

• phagocytic cells eat debris
• secrete cytokines during inflammation
• induce long-term changes in CNS like sensitization/pain
• from bone marrow to monocytes to micorglia