development Flashcards
how do somatic + ANS nerves travel
somatic and sympathetic ANS nerves travel together
2 types of sympathetic ganglia
paravertebral = sympathetic chain T1 - L2 and prevertebral splanchnic nerve T5 to L2
3 ganglia in prevertebral splanchnic nerve? what spinal levels
T5 to L2. celiac, superior and inferior mesenteric ganglion
paravertebral preganglionic cell bodies: neurons at which levels? post ganglionics?
T1 to L2. but post ganglionic neurons project to entire body
white or grey ramus communicasns?
white = myelinated, preganglionic sympathetic. grey ramus = unmyelinated post synpatic
sympathetic NS: regardless of target, all begin?
the same: preganglionic short myelinated axons exit SC through ventral root and enter spinal nerve. exit spinal nerve via white ramus communicantes. enter sympathetic trunk/chain where post ganglionic neurons reside
3 options for sympathetic NS
synapse in sympathetic chain ganglion then return to spinal nerve. ascend/descend within chain then synapse within the chain and return to spinal nerve at that level. enter sympathetic chain, pass through w/o synapsing and form splanchnic nerve towards abdominal organs, synapse in prevertebral ganglion
sympathetic splanchnic: what levels
T5 to L2
parasympathetic: innervation
cranial nerves 3, 7, 9, 10 (vagus) for visceral organs of thorax + abdomen. sacral parasympathetics S2 - 4
5 steps for development of ANS
neuroblast formation. neuronal migration. differentiation. axon guidance. synpatogenesis.
CNS and PNS come from?
neurulation - neural tube = CNS = cranial nerves and preganglionic cell bodies. neural crest = PNS = post ganglionics
neurulation: steps involved and what 3 choices
notochord sends signals. neural plate then neural tube = CNS. some signal = neural crest = PNS. no signal = epidermis
somites
become other parts of body, but will give signals to migrating neural crest cells to turn into ANS, melanocytes, sensory neurons, etc.
what makes CNS + PNS (general)
tube = CNS. crest = PNS
what is derived from neural tube? what isn’t?
CNS and all preganglionic ANS neurons from neural tube. PNS and post ganglionic ANS neurons are from neural crest
preganglionic sympathetic and sacral parasympathetic derived from
cells in the intermediate grey matter of the spinal cord = neural tube
pre and post ganglionic sympathetic neurons: what lvels
pre = T1 - L2. post = C1 to Cx1
cranial sympathetic nerve levels
T1 - T5
post ganglionic parasympathetic development
from neural crest. migrate short distances
