-
CNS appears at the beginning of the 3rd week as the
neural plate
-
The neural plates lateral edges soon elevate to form the
neural folds 
-
The wall of neural groove is lined with a thick
Pseudostratified epithelium
-
Once the neural tube closes, neuroepithelial (inner wall of the neural groove) cells begin to give rise to the
Primitive nerve cells, or neuroblasts
-
The wall of neural groove is lined with a thick pseudostratified epithelium called
neuroepithelial cells, or neuroepithelium
-
Nerve cells in the spinal cords are derived from
neuroblasts (primitive nerve cells)
-
Once neuroblasts form, they lose their ability to
Divide
-
Axons of neurons in the basal plate break through the marginal layer and become the
Ventral root of the spinal nerve 
-
Schwann cells do what
Myelinate the peripheral nerve, beginning at month 4 of fetal life
-
Nerve fibers in CNS do not become myelinated until the
First year of postnatal life.
-
Glial cells in CNS (except microglia) are derived from
Gliablasts
-
Microgila are derived from the
Bone marrow (mesenchyme)
-
Glial cells in PNS such as Schwann cells, sensory ganglia, and sensory fibers are derived from
The neural crest cells
-
The cephalic end of the neural tube
shows three dilations called
Primary brain vesicles
-
The lumen of the spinal cord is continuous with that of the
Brain vesicles
-
Rhombencephalon/Hindbrain consists of
myelencephalon
-
The myelencephalon is,
the most caudal of the brain vesicles
-
Myelencephalon gives rise to the
medulla
-
Metencephalon form the
cerebellum and the pons
-
Mesencephalon gives rise to the
Midbrain
-
The Superior colliculus receive direct input from the
eye
-
Inferior colliculus receives information from the
ear
-
Inferior colliculus functions as a relay station en route to the
thalamus
-
The Prosencephalon is more commonly known in a developed brain as the
Forebrain
-
Telencephalon gives rise to the
Cerebral hemispheres
-
Diencephalon gives rise to what structures
- Optic cup and stalk, part of pituitary gland, Thalamus, hypothalamus, and pineal
- gland
-
The most caudal part of the roof
plate develops into the
pineal gland
-
Pituitary gland has what two origins
- 1. ectodermal outpocketing of the stomadeum known as Rathke’s pouch
- 2. A downward extension of the diencephalon, the infundibulum
-
Pharyngeal hypophysis
is a small portion of Rathke’s pouch persists in the roof of the pharynx (defect)
-
Craniopharyngiomas may cause
hydrocephalus and pituitary disfunction
-
Spina bifida is a
general term for a Neural Tube Defect affecting the spinal region. It consists of a splitting of the vertebral arches.
-
Most defects of the spinal cord result from
abnormal closure of the neural folds in weeks 3 and 4 of development.
-
Anencephaly
- failure of the cephalic part of the neural tube to
- close. As a result, the vault of the skull does not form, and the malformed brain tissue degenerates.
-
Many defects of the CNS may occur without
much external manifestation
-
The leading cause of mental
retardation is
maternal alcohol abuse
-
I (Olfactory) and II (Optic) nerves arise from the
brainstem
-
III (Oculomotor) arises
outside the hindbrain
-
Development from IV to XII nerves,
arises from in the hindbrain.
-
Segmentation patterns in the brain and mesoderm appear by
the 25th day of development
-
The hindbrain is divided into eight rhobomeres
(r1-r8), and these structures give rise to
The cranial motor nerves.
-
In the hindbrain, proliferation centers in the neuroepithelium establish eight distinct regions called
rhombomeres
-
Cranial nerve sensory ganglia are outside of the brain and they originate from
- ectodermal placodes (ectodermal thinkenings) and
- neural crest cells
-
Epibranchial placodes contribute to ganglia for nerves of the
pharyngeal arches (V, VII, IX, and X)
-
Parasympathetic ganglia are derived from
neural crest cells
-
Parasympathetic ganglia and their fibers are carried by
Cranial Nerves III, VII, IX, and X.
-
Sympathetic nervous system originate from the
neural crest of the thoracic region
-
Adrenal gland arises from
- Cortex is derived from mesoderm
- Medulla is derived from neural crest
-
Postganglionic fibers for the parasympathetic nervous system arise from
ganglia derived from neural crest cells
-
Congenital megacolon (Hirschsprung Disease) Results from a failure of
- parasympathetic ganglia to form in the wall
- of part or all of the colon and rectum because the neural crest cells fail to migrate.
-
Where do the nueral crest cells originate from
As the neural folds elevate and fuse, cells along the lateral border dissociate from neighboring cells.
-
Neural Crest cells undergo what unique transition
Epithelial to Mesenchymal transformation
-
Migration of the neural cells is determined by what two properties
Intrinsic and extrinsic
-
How is migration of the neural cells regulated
High levels of chrondroitin sulfate
-
When do the neural cells begin to migrate
Around the third week of development
-
What are the two hypothesis's of how the cells are differentiated
Determined by the environment, and they are already programmed. Both have been shown to effect the development
-
What are some of the structures that are derived from the neural crest cells
- Connective tissue
- Bones of the face and skull
- Cranial nerve ganglia
- Dermis on face
- Dorsal root ganglia
- Adrenal medulla
- Glial cells
- Forebrain
- Melanocytes
- Smooth muscle cells
-
Neural Cranial cells are the only cells that will develop into
Cartilage
-
Neural crest cells are not irreversibly fixed to
differentiate to a specific path
-
NC cells to from the trunk region will become
Sympathetic Neurons and will produce norepinephrine (Dorsal root ganglia)
-
NC cells to from the cranial region will become
Parasympathetic neurons and will produce acetocholine
-
The factors that the neural crest cells are exposed to determines
Their fate
-
What are the three regions of neural crest cells
- Cranial
- Circumpharyngeal
- Trunk
-
What are the two sub portions of the circumpharyngeal area
Vagal and sacral cardiac
-
The trunk area of the neural crest cells are located
From the 6th somite to the most caudal somites
-
Trunk cells that travel ventrally will differentiate into
Adrenal medulla and sympathetic nervous system
-
What portion of the neural creat do the melanocytes derive from
The cells that migrate dorsalaterally from the trunk
-
The neural cells that form the parasympathetic innervation to the gut come from
Circumpharyngeal vagal area (somite 1-7) and sacral area (Past somite 28)
-
Cardiac Neural Crest cells arise from where
Somite 5
-
DiGeorge Syndrome is the reduced function of the thymus, thyroid, and parathroid, as well as heart abnormalities. Defects in what crest site would cause this
Disturbance in the cardiac crest of the circumpharyngeal area
-
The cranial neural crest cells do not express
HOX genes
-
Some of the cells in the R3 and R5 region do what under the presence of BMP4
Undergo Apoptosis
-
What regions of the cranial portion of the neural crest will make up cranial sensory ganglia 5,7,9,10
-
What bones of the skull arise from neural crest cells
- The blue ones
-
Cleft palets and lips are from a defect in what developing cells
Neural crest cells
|
|
