Tags & Description
Nerve fibers
________ within peripheral nerves may be classified as afferent (sensory) or efferent (motor) and as somatic (innervating skin and skeletal muscle) or visceral (innervating vessels and viscera)
Meningocoele
________- protrusion of the meninges through an opening in the vertebral arches to form a cyst beneath the skin.
Meningomyelocoele
________- like menigocoele but both the meninges and the spinal cord protrude.
Neuroblast
________- immature neurons which become the structural and functional cells of the central nervous system; a neuron would only persist if a functional synapse is formed; classification:
Spongioblast
________- develop into the connective tissue of the CNS called neuroglia.
Somatopleure
________ (somatic mesoderm + ectoderm) that forms body wall is distinguished from that forming fetal membranes (chorion and amnion)
Myeloschisis
________- cleft in the neural tube cause by failure of this part to close during neurulation.
Splanchnopleure
________ (splanchnic mesoderm + endoderm) merges bilaterally to form gut and mesentery, differentiated from extra- embryonic yolk sac (and allantois)
Notochord
________- gives rise to the nucleus pulposus, a gel- like substance surrounded by annulus fibrosus found between vertebrae.
Sclerotome
________ (ventromedial region) gives rise to vertebrae, ribs, and endochondral bones at the base of the skull.
Mesoderm blocks
________ located just lateral to the notochord, which induced somite development.
Ventricles
________- spaces wherein CSF- secreting choroid plexuses are found.
neural tube
The early embryo is flat, but the vertebrate body plan features a cylindrical theme- various cylindrical structures (derivatives of the gut, ________, notochord, etc .)
Rostral
________ to the notochord, mesenchyme forms less- developed somites, called somitomeres; these migrate into pharyngeal arches and form muscles of the jaw, face, pharynx, & larynx.
Meninges
________- covering of the CNS; composed of pia mater, arachnoid, and dura mater; derived from neural crest cells.
Spinal cord
________- from the posterior portion of the neural tube (where there is an underlying notochord)
Myotome
________ (intermediate region) gives rise to skeletal muscles of the body.
tube
The ________- shaped embryo undergoes three flexures that make it C- shaped.
D Diplomyelia
________- 2 spinal cords develop beside each other usually in one set or meninges and in one vertebral canal.
Hydranencephaly
________- thin- walled and greatly enlarged lateral ventricle filled with CSF.
A Hypoplasia
________ (aplasia)- reduced or absence of development of one or more segments of the spinal cord.
Myotomes of somitomeres
________ migrate to pharyngeal arches to provide skeletal musculature.
mesenchyme
Head (occipital) somites develop from proliferation of local ________ lateral to the cranial end of the notochord.
Dermatome
________ (lateral region) gives rise to the dermis of skin.
C Syringomyelia
________- abnormal cavitation of the spinal cord.
Myelodysplasia
________- a general term for a malformation of the spinal cord.
Hydrocephalus
________- accumulation of the excessive amount of cerebrospinal fluid in the cranial cavity.
gray matter
Inverted arrangement of white and ________ is brought about by unequal growth of the basal and alar regions of the brain vesicles.
pharynx
The ________ (foregut) develops five bilateral diverticula that internally demarcate the pharyngeal arches.
cylindrical head process
The ________ elongates by additional growth from its base (located in front of the primitive node)
Cerebellar hypoplasia
________ and atrophy- failure of the cerebellum to develop due to destruction of the cerebellar cortex.
Cerebellar abiotrophy
________- premature degeneration of Purkinje cell layer of the cerebellar cortex.
head process
As the ________ elongates upward & forward, a subcephalic pocket (space) is formed ventral to the ________, between the ________ and extra- embryonic tissue.
anterior half dozen
The elongation incorporates the most ________ somites into the future head.
excess accumulation of CSF
B. Hydromyelia- dilation of the central canal due to ________.
Pontine flexure A slight dorsal
________ bending in the rhombencephalon.
visceral efferent
The ________ (autonomic) pathway involves two neurons: 1] a preganglionic neuron that originates in the CNS and 2] a postganglionic neuron l__ocated entirely in the PNS__.
Neuroblast
immature neurons which become the structural and functional cells of the central nervous system; a neuron would only persist if a functional synapse is formed; classification
Spongioblast
develop into the connective tissue of the CNS called neuroglia
Primary
prosencephalon, mesencephalon, rhombencephalon
Secondary
telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
Spinal cord
from the posterior portion of the neural tube (where there is an underlying notochord)
Meninges
covering of the CNS; composed of pia mater, arachnoid, and dura mater; derived from neural crest cells
Notochord
gives rise to the nucleus pulposus, a gel-like substance surrounded by annulus fibrosus found between vertebrae
Ventricles
spaces wherein CSF-secreting choroid plexuses are found
The visceral efferent (autonomic) pathway involves two neurons
1] a preganglionic neuron that originates in the CNS and 2] a postganglionic neuron l__ocated entirely in the PNS__
The bilateral margins of this pocket are lateral body folds
which constitute the continuity between the elevated embryo and the relatively flat extra-embryonic tissue
Cerebellar hypoplasia and atrophy
failure of the cerebellum to develop due to destruction of the cerebellar cortex
Cerebellar abiotrophy
premature degeneration of Purkinje cell layer of the cerebellar cortex
Hydrocephalus
accumulation of the excessive amount of cerebrospinal fluid in the cranial cavity
Hydranencephaly
thin-walled and greatly enlarged lateral ventricle filled with CSF
Myelodysplasia
a general term for a malformation of the spinal cord
a. Hypoplasia (aplasia)
reduced or absence of development of one or more segments of the spinal cord
b. Hydromyelia
dilation of the central canal due to excess accumulation of CSF
c. Syringomyelia
abnormal cavitation of the spinal cord
d. Diplomyelia
2 spinal cords develop beside each other usually in one set or meninges and in one vertebral canal
e. Diastematomyelia
2 spinal cords develop with a partition between them
Myeloschisis
cleft in the neural tube cause by failure of this part to close during neurulation
Meningocoele
protrusion of the meninges through an opening in the vertebral arches to form a cyst beneath the skin
Meningomyelocoele
like menigocoele but both the meninges and the spinal cord protrude