2-D Neurulation and Somite Development Flashcards
What are the major events of neurulation
the notochord causes the epiblast to thicken and the neural plates fold
The process of neurulation dervies what adult structures?
the developing neural tube will ultimately form the neurons fo the central nervous system while the neural crest cells will develop into the PNS
Cell located a the crest of the neural folds will form the:
neural crest cells
Nerual folds come together together at the midline and gradually fuse resulting in a
neural tube
Open ends of the nerual tube are called
neuropores
Cranial expansion of the neural tube becomes
the prosencephalon, the mesencephalon and the rhombencephalon
What is the adult fate of neural crest cells?
neural crest cells segment and migrate extensively forming neurons in both sensory and motor ganglia, melanoblasts, adrenal medulla, pia mater, arachnoic and cephalic an brachial arch structures
Depending on how far neural crest cells migrate, what do they become?
- Epithelial cells of the neural tube divide and migrate out of the CNS to become neuroglia (satellite cells in ganglia and schwann cells that protect small axons), 2. Migrate a short distance: dorsal root sensory ganglion, 3. Further: sympathetic neurons either as chain ganglion or pre-aortic ganglion, 4. Farthest ventrally: enter the wall of the gut to form neurons of the parasympathetic terminal ganglia
What is the alar plate?
the dorsal part lateral to the the neural tube include dorsal neuroblasts the form interneurons for sensory signalling
What is the basal plate?
the neural tube cells that migrate lateral to the ventral part of the neural tube form motor neurons
Name cell bodies that are devied form the neural tube
viscero and somatomotor
Name cells that are nerual crest-derived
DRG, chain ganglia
How does neuralation affect eh overall form of the body?
changes it form a two dimensional disc to 3-D tube with obvious cranial/caudal and dorsal/ventral axes
Mesoderm laterla to the notochord and neural tube condenses to form what three tissues?
paraxial, intermediate and lateral
What do the paraxial, intermediate and lateral plates give rise to?
paraxial makes up the somite giving rise to muscle, bone and dermis; intermediate gives rise to organs of urogenital system; lateral palte gives rise to the body cavities
Somites have 3 morphologically and developmentally distinct portions called:
sclerotome, mytome and dermatome
Describe how the sclerotomes develop.
sclerome migrates ventromedially to form the vertebral body and paired processes that grow dorsally from the body, later dorals migration forms aroudn the notocord forming the vertebra and the annulus fibrosis; some continue onto be come ribs. The notocord incorporates into the vertebral colum by serving as the nucleus pulposus
What part of the vertebral column is not part of the ectoderm
intervertebral discs, the nucleus pulposus
Describe the development of the myotome
forms almost all the skeletal msucle, with the epimere forming paravertebral, extensor muscles and the ventral hypomere forms the body wall and limb mucles
What innervates the hypo and epimere respectively?
the ventral and dorsal rami respectively
Describe the development of the dermatome
dermatome spread out under the ectoderm to form the dermis and subcutaneous tissue in an organized and semental way
Define dermatome
an area of skin innervated by a single spinal nerve (alt. the portion of the somite that forms the dermis
Name the cranial enlargements in the neural tube
prosencephalon, mesencephalon and rhombencephalon
In the trunk neural crest cells form the dorsal root ganglion, in the head they form…
four pairs of sensory ganglia known as the trigeminal, facial, glossopharyngeal and vagal ganglia
Mammary glands, retina , lens, outer tympanic membrane and sensory of epithelia of the olfactory and auditory are from what embryonic tissue?
ectoderm
Embryonic tissue that forms the epithelium of the auditory tube and middle ear cavity as well as the hymns and epithelium of the bladder
endoderm
What is the name of the tissue that precedes the celomic sacs?
lateral plate
What becomes of the intermediate mesoderm
kidney and gonads
What structure becomes skeletal muscle
epimere and hypo mere from the myotome somite (paraxial mesoderm)
What tissue does the epithelium of lung and urinary systems develop from?
grow of the gut tube (endoderm)
