STEPHEN PRICE Flashcards
difference between CNS and PNS?
CNS: brain and spinal cord
PNS: all nerves and ganglia outisde the brain and spinal cord
what do AFFERENT nerves do?
these carry info to CNS from the PNS
what do EFFERENT nerves do?
these carry info from CNS to the PNS
what are the 3 divisions of the sensory afferent?
- somatosensory
- viscerosensory
- special sensory
what are the division of the motor efferent nerves?
- somatomotor
- autonomic: parasympathetic, sympathetic and enteric
what does the somatosensory involve?
skeletal muscle and skin
what does the somatomotpr involve?
skeletal muscle that is voluntray
what does the autonomic nervous system involve?
smooth muscle
cardiac muscle
glandular and secretory tissue
these are all involuntary
what is the distribution of cell bodies within the gray matter?
same no of cell bodies from top to bottom
what is the distribution of cell bodies within the white matter?
- smaller as you go down to te cortex
- bigger as you go down to the cervical region
what is the route of sensory nerves?
from the spinal cord to the dorsal root ganglian
what is the route of motor nerves?
to the spinal cord coming out of the ventral root
which subdivision of the PNS does the basal ganglia belong to?
autonomic nervous system
what is an inductive process?
takes stem cells and lineage restrictions that give rise to a few types of cells, allowing differentiation
how does the brain of an embryo develop to form the CNS?
- begins as a hollow tube
- cerebral hemispheres outgrowths on either side from cranial end of tube
- sweeps over the surface hiding the central core of the developing brain
what is the sequence of development starting from a zygote?
zygote-blastula-gastrula-3 germ layer-larva
where are the embryonic stem cells derived from?
the larva stage where they can give rise to any type of cell
how does a cell become functional?
exits the cell cycle and differentiates
what are the 3 germ layers?
ectoderm
mesoderm
endoderm
explain what happens during neural induction during gastrulation?
the dorsal mesoderm migrates abteriorly under the dorsal ectoderm releasing signals to induce the nervous system
explain exp of hens and spermann?
- 2 different frog embryos
- the embryo of the unpigmented donor is transplanted to the pigmented recipient at the same stage of development
- a second nervous system arose
- the cells tell other cells to become the nervous system so induce the second nervous system in ventral ectoderm
what are the 3 events during neurulation?
- contact between notochord and future floor plate
- folding and delamination of neural crest cells
- coverage, notochord deataches, crest migrationa nd roof plate is formed
what are the 4 stages that pluripotent ectodermal cells have to pass to become neuronal precursor or progenitor cells and then neurons?
- competence- they need to receive the inductive signals and become proginetors
- specification- stay as progenitors or leave
- determination- enter neuronal differentiation pathways(their subtypes have been decided)
- differentiation- exit cell cyle and express neuronal genes
why are morphogens critical?
generates distinct neuronal subtypes in distinct positions in the dorso ventral axis of the neuronal tube
what are the 2 ways in which neuronal crest cells migrate?
- dorsolaterally into ectoderm and continue towards the midline
- ventralaterally through the anterior half of each sclerotome
what happens to neuronal crest cells that remain in the sclerotome
they become dorsal root ganglia BUT
some can continue to produce sympathetic ganglia and adrenal medulla (nerve clusters around the axon)
when does the migration of schwann cells stop?
when they come in contact with an axon
what do neurogulins do?
stimulates differentiation and proliferation of schwann cell PRECURSORS
also contribute to survival
each dorsal root ganglia is composed of 3 neuronal crest populations what are these:
- one from the opposite side of the anterior somite
- one from the adjacent side of the posterior somite
at specific regions of the trunk, neuronal crest cells produce?
- sympathetic ganglion cells
- epinepherin secreting cells of the adrenal medulla
