Intro + spina bifida

Question 1

What are the 3 components of the Brainstem?

Answer 1

1. Midbrain
2. Pons
3. Medulla

Question 2

What is the CNS made up of?

Answer 2

1. Cerebrum (2 cerebral hemispheres)
2. Diencephalon
3. Brainstem
4. Cerebellum
5. Spinal cord

Question 3

what is the PNS made up of?

Answer 3

nerve axons & ganglion (contain cell bodies/soma)
cranial nerves (12 pairs) and spinal nerves (31 pairs)

Question 4

What is columnar organization?

Answer 4

Columnar organization refers to collections of neuron cell bodies (gray matter) with similar organization and function located through multiple levels of the spinal cord and brainstem

Question 5

What is the difference between convergence and divergence?

Answer 5

Convergence (input) is where hundreds of billions of neurons come together and converge with one
neuron
- Ex. affert info from MSK system and input from brain
- ex. neural input to sensory assoc areas in cerebral cortex, where info from hearing, vision, touch is integrated

divergence (output) is where one neuron synapses and provide input to several neurons
- Ex. signaling of info from a pinprick

Question 6

What makes up white matter?

Answer 6

axons

Question 7

What makes up gray matter?

Answer 7

neuron cell bodies

PNS: ganglia
CNS: nuclei
CNS but surface of brain: cortex

Question 8

Bundles of while matter could be called:

Answer 8

tract
lemniscus
fasciculus
column
peduncle

Question 9

What germ layer is the nervous system developed from?

Answer 9

ECTOderm
(outer cell layer of the embryo)

Question 10

What does the neural tube develop into?

Answer 10

Spinal cord and brain (CNS)

Question 11

What does the neural crest develop into?

Answer 11

PNS

Question 12

Summarize normal brain development

Answer 12

Telencephalon –> cerebral hemispheres, basal ganglia
Diencephelon –> thalamus & hypothalamus
Mesencephalon –> midbrain
Metencephalon –> pons & cerebellum
Myelencephalon –> medulla

Question 13

Compare and contrast spina bifida occulata and spina bifida cystica

Answer 13

spina bifida occulata
- defect confied to vertebral arches
- meninges DONT extend through the defect (no protrusion)
-Usu produces no clincal sxs
- tuft of hair on overlying skin

spina bifida cystica
- meninges (w or w/o spinal cord) protrude through vertebral arch defect to dorm cyst-like sac (filled w/ CSF)

Question 14

What is meningomyelocele?

Answer 14

meningomyelocele (open spinal bifida) is spina bifida cystica where both the meninges AND spinal cord protrude through the vertebral arch defect

-neuro deficits manifest inf to level of cyst
-ex. with lumbosacral involvement –> saddle anesthesia, paralysis of bladder and anal sphincters, partial or complete paralysis of skeletal mm of legs

Question 15

what is Arnold-Chiari malformation/cerebellomedullary defect?

Answer 15

-Congenital
-Medulla & post-cerebellum are elongated and extend into foramen magnum
-Often no clinical sxs
- If severe, –> hydrocephalus
- Common sxs: respiratory problems, difficulty in swallowing, diminished gag reflex, noisy breathing, laryngeal stridor

Question 16

What is anencephaly?

Answer 16

• rostral neuropore fails to close
• Most anencephalic fetuses (65%) die in utero….and virtually all by end of first postnatal week

Question 17

What is spina bifida?

Answer 17

-neural tube defect
-birth defect that occurs when spine and psinal cord dont form properly
-portion of neural tube doesnt close or dev properly
-results in defects in spinal cord and/or bones of spine

Question 18

What is meningocele?

Answer 18

the meninges protrude through the vertebral arch defect (but not the spinal cord)

Nerve damage is uncommon

Question 19

What is the most severe type of spina bifida?

Answer 19

myelomeningocele