Ch15 Development and Aging Pt1 Flashcards
When does nervous system development begin?
18 days after fertilization (gestation)
What are the 4 stages of nervous system development?
Neural plate, neural groove, neural tube, and neural crest
What forms the basic structure of the nervous system?
Embryonic neural tube and neural crest
The neural tube forms what?
The brain and spinal cord
The neural crest forms what?
The autonomic and sensory ganglia as well as the adrenal medulla
Where does the neural tube first develop?
In the lower cervical region
Where does the neural tube first “zip up”?
In a cranial direction
Where does the neural tube end up closing?
Caudally, towards the sacrum
By when does the neural tube close?
By 24 days gestation
The neural tube defect, anencephaly, is caused by what?
Incomplete closure of the cranial end of the neural tube. The forebrain typically fails to develop
The neural tube defect, spina bifida, is caused by what?
Incomplete closure of the caudal (sacral) end of the neural tube
What happens in spina bifida?
Meninges protrude out of the back
Meningocele, a type of spina bifida, results in what?
An incomplete vertebral arch but the spinal cord remains in place
Myelomeningocele, a type of spina bifida, results in what?
Portions of the spinal cord bulge into the sac of meninges
What are some effects of having spina bifida?
Paralysis, sensory loss of extremities, loss of bowel and bladder control
Where does the brain develop from?
The cranial end of the neural tube
What are the structures of the forebrain?
Cerebral cortex, subcortical nuclei, thalamus, and hypothalamus
What are the structures of the hindbrain?
Pons, cerebellum, and medulla oblongata
The forebrain undergoes tremendous growth, whereas the midbrain and hindbrain remain relatively small. True or false
True
What do neural crest cells form?
The autonomic nervous system, somatosensory neurons and receptors, and part of the adrenal gland (adrenal medulla)
Where are neural crest cells found?
They migrate throughout the body
Basic organizational structure of the nervous system is in place by how many weeks of gestation?
12
Neurons continue to divide to compose how many neurons?
100 billion
What are the 3 processes involved in nervous system development?
Migration, differentiation, and myelination
