Development of nervous system Flashcards
What embryonic event takes place during the third week of embryogenesis.
Gastrulation- bilaminar becomes trilaminar
Cells of the epiblast that remain in place form the _________-
ectoderm
Some of the cells of the epiblast invaginate and form the ____________.
primitive streak
some of the cells of the epiblast detach from the epiblast and form the ________
mesoderm.
SOme of the cells detach from the epiblast and move deeper and begin replacing hypoblast cells forming _________.
endoderm
3 structures involved in development of nervous system
Notochord first
Neural tube
Neural crest
The central nervous system develops from the primitive __________.
ectoderm
The first step of the neural system development is the formation of the ___________.
neural PLATE
Neural plate becomes ____________.
Neural groove
Around week 3 the neural groove begins to close to form the neural tube.
Neural tube
The ________________ segments of the spinal cord and their corresponding dorsal and ventral roots are formed by secondary neurulation.
sacral and coccygeal
The caudal eminence joins the ___________, and its cavity becomes continuous with the neural canal.
neural tube
The peripheral nervous system develops from cells of the_________.
neural crest
During 4th week the central canal rostrally gives rise to the 3 primary brain vesicles, which are what?
prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
During 5th week the 3 primary brain vesicles divide into _____ secondary brain vesicles.
five
The optic cup and nerves bulge from the _________ to form the eye
diencephalon
Anterior horn motor neurons innervate skeletal muscle and are classified as __________.
Somatic efferent (SE)
The lateral horn motor neurons project to autonomic ganglia and are classified as ______________.
Visceral efferent (VE)
________ are paired blocks of paraxial mesoderm
Somites
Somites separate and form three main tomes? what are they and what do they develop into.
Dermatome= skin
Scleratome =vertebrae
Myotome= muscles
Within brainstem, where do sensory and motor fibers go?
sensory stay dorsolaterally
motor stay ventrallaterally
The cerebellum arises from the rostral part of the ___________.
Rhombic lip
True/False: the cerebral cortex is formed in a sequence called the “inside-out pattern of development.”
True
How do neurons find their targets?
They secrete attractant molecules, called trophic factors or signpost molecules.
Neuronal growth cones send out small extensions called what?
filipodia
The sensory neurons of dorsal root ganglia are derived from ________.
neural crest cells
The anterior neuropore fails to close, stops formation of fetus brain formation, death is inevitable.
Anencephaly
What is a failure of the back of the skull to close?
cranhioshisis not as important below: meningocele- cyst has meninges meningoencepalocele- meninges plus brain meningohydroencephalocele- meninges plus brain and part of ventricular system
What is myeloschisis, a defect in closure of posterior neuropore. always involves a failure of vertebral arches to close.
Spina bifida
True/False: spina bifida is not preventable.
False, preventable!
What should you do to prevent spina bifida?
supplement with folic acid, reduces incidence of neural tube defects.
What is failure of migration of parasympathetic ganglion cells from the neural crest? Missing plexus of meissner and Auerbach. Leads to severe constipation
Hirschprung disease
Failure of the 2 cerebral hemispheres to separate?
Prosencephalization
What does a small eye opening, smooth philtrum, and thin upper lip a clue for?
Fetal alcohol syndrome
What is the congenital nervous system defects of fetal exposure to common infectious disease?
TORCH Toxoplasmosis Other agents Rubella Cytomegalovirus Herpes simplex virus. HIV infection.
Zika virus has been associated with a striking increase in the number of reported cases of _________ in newborns.
Microcephaly
