9. Development of the Nervous System Flashcards
Gastrulation occurs during week 3 and a primitive streak forms with a primitive node, groove, and pit along with the notochordal process. What does this become? (2)
Template for formation of vertebral column
Induce formation of the neural plate
Neurulation begins day 22-23 and notochord release sonic hedge hog which induces formation of neural plate (ectoderm), including?
Neural groove, folds, and NEURAL TUBE (primary neurulation)
As primary neurulation continues, the rostral and caudal neuropore form and fuse at what times?
Rostral at day 25
Caudal at day 28
Closure forms definitive neural tube
Secondary neurulation occurs days 20-42, and is when the caudal eminence fuses with ________ to form what?
Caudal neuropore to make sacral/coccyx regions
What will the neural tube/primary neurulation produce?
From brain to lumbar spinal cord
The neural tube from neuroectoderm forms many things, including neurons, astrocytes, oligodendrocytes and ependymal cells/epithelium of choroid plexus. What is the only cell of the nervous system not made from this?
microglial cells, which is phagocytic and is made from mesoderm and derived from monocytes/mesenchymal cell
The brain forms from the neural tube caudal to the fourth somite (mesoderm). What are the three primary brain vesicles?
Prosencephalon- forebrain
Mesencephalon - midbrain
Rhombencephalon - hindbrain
During the 5th week, the prosencephalon and rhombencephalon (fore/hindbrain) will divide into?
Fore: telencephalong and diencephalon
Hind: metencephalon and myelencephalon
The cervical flexure divides the hindbrain from the spinal cord, what does the pontine flexure divide?
the hindbrain into caudal myelencephalon and rostral metencephalon
What does the cephalic flexure bend between?
midbrain and forebrain
The basal ganglion and cortical structure inside is developing between what weeks?
6 to 32
What forms the following: cerebral cortex, subcortical white matter (internal capsule), olfactory bulb and tract, basal ganglia, amygdala, and hippocampus?
telencephalon
What forms the following: thalamus, hypothalamus, epithalamus, subthalamic nucleus and eyes (optic nerve)?
diencephalon
What forms the following: cerebral peduncles, superior and inferior collilculus, and CN II?
Mesencephalon/Midbrain
What forms the following: cerebellum and pons?
metencephalon
What forms the following: medulla oblongata, olive, pyramid?
myelencephalon
What results from incomplete separation of cerebral hemispheres, associated with facial abnormalities, reduction of FNP (frontonasal prominence) and hypotelorism (eyes close together)?
holoprosencepahly (HPE)
What are the three main causes of holoprosencephaly?
genetic AND environmental factors
maternal diabetes
teratogens (alcohol)
What are some of the common clinic features of HPE? 6
microcephalu, micropthalmia, cleft palate/lip, intellextual disability, epilepsy and hydrocephalus
The pituitary gland is formed from first arch of surface ectoderm from the roof of the mouth. Which contributes to what part?
anterior lobe known as rathke’s pouch (hypophysial diverticulum)
The posterior lobe of the pituitary gland is from neuroectoderm and is from the diencephalic floor. How do anterior and posterior meet?
Rathke’s pouch migrates up and fuses with neurohypophysial diverticulum, stalk of rathke’s pouch degrades
The neural tube caudal to 4ths somite will form the neural/central canal as well as the sulcus limitans which separates what?
alar plate from basal plate
What do the alar and basal plate form?
alar: dorsal horn/sensory neurons in CNS
Basal: motor neurons to skeletal M, presynpatic autonomics
The neural/central canal has three different zones, ventricular (directly around canal), intermediate and marginal. What are the main contents of each?
Ventricular Zone: Stem cell, ependymal, choroid plexus cell
intermediate: neurons, glioblast, astrocyte (gray matt)
Marginal: Oligodendrocyte
Sulcus limitans separates alar and basal plate, at the pontine flexure, it pushes what?
the alar laterl and basal plate medial
*this is why GVE/GSE/SVE are medial and GVA/SVA/SSA/GSA (sensory) are lateral