Chapter 8 Development of Nervous System Flashcards
when is the pre-embryonic stage
conception to 2nd week
steps of pre embryonic stage
cell, division, cluster of cell, and the inner cell mass gets suspended in the inner ring of cells
when is the embryonic stage
2nd to 8th week
what happens in the embryonic stage
organs are formed
what do the ectoderm, mesoderm, and endoderm become
ectoderm becomes sensory organs, epidermis, and sensory system
mesoderm becomes muscle skin and skeleton, excretatory and circulatory system
endoderm becomes gut, liver, pancreas and respiratory
when is the fetal stage
8th week to birth
what occurs in fetal stage
migration of skin, bone, and muscles away from neural tube out to developing body
top of neural tube (head) swells up as number of cells in head multiply exponentially
the body then develops dragging nervous tissue with it, heads explodes as the tissue develops in it
When is Neural Tube Formation
Day 18-26
neural plate?
part of ectoderm that becomes part of nervous system
the flat plates start to roll up like a cannoli
middle light purple is the neural tube and the dark is the nervous system tissue that gets placed right next door to tube
where is the superior neuropore
part that closes up and your brain forms around it
where is the inferior neuropore
closes at caudal end, closes spinal cord to coccyx
when the tube is rolled up, the nervous system cells form
concentric circles
inner gray of circle:
mantle layer that contains bodies of neurons (motor)
marginal layer (white)
protects axons of mantle layer and is cells of myelin sheath… schawnn and oligodendrocytes
what is the neural crest
cluster of cell bodies not in spinal cord… located in dorsal root of cord
dark is:
pseudounipolar cuz they’re peripheral
light is
multipolar in spinal cord and brain
somite
pieces of body… 31 balls of silly putt form on either side of neural tube
3 divisions of somite
schlerotome, myotome, and dermatome
schlerotome
makes bones of our body
myotome
piece of somite that makes muscles
dermatome
makes skin
muscles bone and skin all grab onto what
an axon and as they go to their developed position they drag the axons with them
in the neural tube, anterior is
motor
where is the association plate formed
dorsal
dorsal contains
cells OF sensory function
cells of peripheral somatosensory are located
in the dorsal root
definition of dermatome
all skin innervated by one of the 31 spinal nerves
dermatome is what section of the somite
embryonic
blue and red started as light purple and had gray and white ring…
blue and red started as light purple and had gray and white ring… blue is PART OF sensory but NOT somatosensory red little dots are motor neurons
at C3, the C3 somite is associated with…
C3 neural tube
schleratome starts growing out and creates an arm but grows out full length. who is the leader
C7 drags the neural tube with it
what is myotome
piece of somite that becomes muscle cell. all muscles that receive innervation from one spinal nerve
what section of somite is the myotome
embryonic
every other muscle gets innervation from at least
two spinal nerves
every muscles started out developmentally as at least ____ somites on the ____ and ____ somites on the ____
two on the left and two on the right
spinal nerve injuries will
weaken
peripheral nerve injuries will
paralyze
at the 3rd month, spinal cord is as long as
the spinal column
at birth, the spinal cord is
located at L3
as an adult the caudal end of spinal cord is
located at L1
forebrain
all structures rostral to midbrain
midbrain
own piece developmentally, fully formed divides the two
hindbrain:
pons, medulla, and cerebellum. helps control autonomic function, grossly move due to cerebeullum. this is primitive/reptilic
migration of the mantle layer cells
neural tube=gray is inside, brain and gray matter proliferate and fill up the space
how do the mantle layer cells move from inside to out?
astrocytes (structure to move)
batman or scaffold
primal development cells are alike but
differentiate when they get to where they’re going
frontal and parietal start the same but take on roles when they get to where they need to go
