Embryology II Flashcards
What neural elements are derived from neural crest?
dorsal root ganglia, sympathetic chain ganglia, sympathetic (prevertebral) ganglia, eneteric and parasympathetic ganglia, parasympathetic ganglia of CN III, VII, IX, and X, sensory ganglia of CN V, VII, VIII, IX, X
What are non-neuronal derivatives of neural crest?
schwann cells, melanocytes, pia and arachnoid of meninges, satellite cells of peripheral ganglia, chromaffin cells of adreenal medulla, ciliary and pupillary muscles, cartilage of pharyngeal arches.
What are placodes?
specialized epithelial cells that develop in the head region and join with neural crest cells to for ganglia of CN V, VII, VIII, IX, X
What are the structures of the developing spinal cord?
basal plates: anterior masses that will form motor structures
alar plates: posterior cell masses that will form sensory structures
intermediate zone: in the interface btw the basal and alar plates.
sulcus limitans that seprates the alar and basal plates
What is the developmental basis for referred pain?
mising of somatosensory and visceral afferents in the alar plate.
How is the spinal cord segmented in early development, and what role does this play later on/what are implications?
somites divide into sclerotomes (form vetebrae), dermatomes, and myotomes. spinal nerves are the joining of the sensory and motor roots at the intervertebral foramen. since vertebrae develop between spinal nerves, they are intersegmental: caudal sclerotome plus cranial sclerotome= 1 myotome/dermatomes
Where does the spinal cord end in the adult?
1st lumbar vertebrae
From what brain parts are the medulla, pons, and midbrain derived?
medulla from the myelencephalon
pons from the metencephalon
midbrain from the mesencephalon
How does the fourth ventricle form? What are the implications for the basal and alar plates?
central canal of the medulla opens.to form the 4th ventricle. alar plate moves to a position dorsal-lateral to the basal plate. they remain divided by the sulcus limitans in the brain stem.
What do alar plate derivatives do? Basal plate derivatives?
Alar plate derivatives do sensory
basal plate derivatives do motor
What are 4 cranial nerve alar plate derivatives in the brainstem?
spinal trigeminal nucleus (descending trigeminal nucleus)
main sensory nucleus of the trigemnal
solitary nucleus
vestibular and cochlear nuclei
What are the alar plate derivatives in the brain stem that don’t involve cranial nerves?
inferior olivary complex, basilar pontine nuclei, substantia nigra
What is the difference in location and function btw the descending trigeminal nuclei and the main sensory trigeminal nuclei?
descending starts in the mid pons and goes down to the spinal cord-medullary junction,while main nucleus stays in the mid pons. descending does protopathic and main sensory does epicritic
Where is the solitary nucleus?
caudal pons and into the entire medulla
What basal plate nuclei are found in the midbrain? (3)
trochlear, oculomotor. Edinger-Westphal
