Lecture 3 Flashcards
When is the pre-embryonic stage?
0-14 days
When is the embryonic stage?
Day 15 to 8 weeks
When does the fetal stage happen?
End of 8 weeks to birth
What stage does myelination begin?
Fetal stage
What forms the nervous system in the embryonic stage
Ectoderm
When does the neural tube develop?
Day 18 to day 26
(or day 21 depending on where in the slide you look, it folds over and forms on day 21)
The neural plate forms ________ from the ectoderm, and edges of plate fold. Folds grow together at day ____ forming the neural tube
Longitudinally
Day 21
The open ends of the neural tube is called the
Neuropores
The neural tube closes first in the ____ region
Cervical
The superior Neuropore closes day ____whereas inferior neuropore closes on day ___
Day 27 for superior
Day 30 for interior
Definition of myotomes:
All muscles that receive innervation from specific spinal level
The inner layer of the Neural tube becomes _____
Whereas the outer layer becomes ______
Inner layer: Grey matter
Outer layer: White matter w/ axon and glial cells
What is the definition of a dermatome?
All skin innervated by that level of the spinal cord.
What do the neural crests form?
Peripheral sensory neuron
Autonomic neurons
Endocrine organs
Somites first appear in what area? (Frontal, Temporal, Parietal, Or Occipital)
Occipital region first, then caudally
The anteromedial part of the somite goes where
Scleroderm and then the vertebrae and skull
Remember:
Anteromedial part of somite > sclerotome > vertebrae and skull
Posteromedial > muscles of myotome
Lateral > dermatome becomes dermis
The posteromedial part of the somite goes where
Muscles of that myotome
Remember:
Anteromedial part of somite > sclerotome > vertebrae and skull
Posteromedial > muscles of myotome
Lateral > dermatome becomes dermis
The lateral part of the somite goes where
Dermatome
Remember:
Anteromedial part of somite > sclerotome > vertebrae and skull
Posteromedial > muscles of myotome
Lateral > dermatome becomes dermis
What is the connection of Pia, arachnoid, and dura mater from spinal cord to end of coccyx
Filum terminale
The spinal cord stops growing around what age?
Age 4/5
The vertebral column stops growing at what age
16-18
What is the end of the spinal cord called?
Conus Medullaris
When does brain development begin?
Day 28
Brain Development begins after the closure of the..
Superior neuropore
What are the parts of the hindbrain
Medulla, pons, cerebellum w/ the central canal (4th ventricle)
The posterior forebrain forms the…
Diencephalon including hypothalamus and thalamus
The anterior forebrain forms what?
Telencephalon which becomes cerebral hemispheres
The midbrain’s central canal forms the…
Cerebral aqueduct connecting the 3rd and 4th canals
The _____ hemispheric areas do not grow as much as others
The edges of the lateral sulcus cover the _____
Lateral
Insula
How do neurons travel to their final destination?
Send extension to brain surface and pull self along
OR
Climbing along glial cells before reaching center of brain
How do neurons differentiate?
Differentiate based on where the cells end up, function is determined by location, not predetermined
Several neurons may go to a single muscle cell during development but…
Only 1 goes to the adult muscle cell
Myelination of long axons begin at ____ month of fetal stage, and finishes at ____ years
4th month of fetal stage
3rd year after birth
Anencephaly
Undeveloped brain or incomplete skull
Arnold Chiari malformation
Lower part of the brain pushed down into spinal canal
Think of arnold from Hey Arnold, the lower part of his brain has definitely been pushed into the spinal canal
Tethered cord syndrome
Tissue attachments that limit movement of spinal cord
Spina bifida
Condition that effects the spine where neural tube does not close
Symmetric tonic neck reflex
During neck extension the arms will perform flexion and the legs will perform flexion. (Crawling position)
During neck flexion the arms will perform abduction and the legs will go to neutral (laying down position)
What cognitive abilities decline with age
Working/ long term memory
Visuospatial memories
Verbal fluency
What cognitive functions seem to be preserved with age?
Vocabulary
Comprehension
Remember: Dr. De Silva’s story about her mom having great vocabulary
What percent of motor neurons die in healthy order adults
25%
As a result of aging, myelin can become fragmented, which will undermine white matter. Where is this particularly present?
In the frontal and temporal lobes
Mild cognitive impairment
*no impairment to QOL
Memory loss with or without cognitive involvement
May be able to do most ADLs, but some issues could be present
90% develop Alzheimer’s within 5 years
What part of the neural tube becomes the motor plate which then innervates myotomes?
The ventral inner layer
remember ventral horn -> motor. The neural tube is basically just an early spinal cord
What part of the neural tube becomes the interneurons
The inner dorsal layer
What part of the neural tube divides into dorsal and ventral? (Inner or outer)
Inner
The outer layer becomes the white matter of the spinal cord, the inner layer divides into dorsal and ventral parts of the gray matter)
A neural crest forms a peripheral sensory neuron which extends 2 processes, where do these go?
One goes to the spinal cord
One goes to the dermal part of a somite, forming a dermatome
Where are the cell bodies of peripheral sensory neurons found?
Outside of the spinal cord, inside of the dorsal root ganglion
Motor roots of the spinal cord are myelinated at _____ of age, but nerves from the cortex to motor neurons are not myelinated until ____ of age
1 month
2 years
Remember you cannot become a terrible 2 until you have myelinated motor neurons!
The somites become the…
Dermatome/myotome/sclerotome(makes skeletal tissue)
Initially the embryonic disc only has 2 layers, called the….
Endoderm and ectoderm
Mesoderm forms later
