Lecture 2 Flashcards
Name the three parts of the embryonic brain.
prosencephalon, mesencephalon and rhombencephalon
During gastrulation chemical signals released from the _____ near the mesoderm cause the ectoderm to thicken and for the neural plate
notochord
Shortly after the neural plate plate begins to fold inward to form the neural groove, fold cells migrate to form _____ _____ cells
neural crest
These areas of specialized cells in and around the early neural tube “tell” other cells what to become in the spinal cord and brainstem. (3)
roof plate cells, floor plate cells and notochord
Common disorder that results from improper folding of the neural folds to form the neural tube during neurulation.
spina bifida
What is the difference between primary and secondary neurulation regarding its location.
primary neuralation occurs in the more cranial sections of the posterior midline while secondary neurulation occurs at the S2 spinal levels and below
What is the difference between primary and secondary neurulation regarding the embryonic tissues involved.
primary neurulation is derived in ectoderm while secondary neurualtion is derive in loose mesoderm that becomes mesenchymal to epithelia transition tissue as it converts to neural epithelium which further cavities to form the neural tube
Name the three layers of neural tissue from the lumen moving exteriorly
ventricular/ germinal/ matrix zone containing stem cells and neuroblasts; mantle which contains the neurons and glia that become grey matter; marginal zone which contains the axons that become white matter
The neural lumen becomes what in adults?
ventricles
Name adult derivatives of the neural crest cells.
neurons and glia of the cranial glia, cartilage, bone and connective tissue in the head, sympathy-adreenal cells, sensory neurons and glia and pigment cells
What cells do the autonomic and sensory lineage of neural crest cells become (both traveling medial to the somite)?
postganglionic cells (adrenergic and cholinergic neurons) and sensory neurons respectively … along each path they encounter signaling molecule that “tell them” what to become
During development of the neural tube, the tube becomes segmented (neuromeres) and _____ in each segment encode transcription factors that tell the cells what to become.
(HOX) genes
Name the 5 transitional subdivisions of the embryonic brain.
telecephalon (prosencephalon), diencephalon (prosencephalon), mesencephalon (mesencephalon), mentencephalon (rhombeencephalon), mylencephalon (rhombencephalon)
What is the adult derivative of the telecephalon?
cerebrum which surrounds the lateral ventricles
What is the adult derivative of the diencephalon?
thalamus, hypothalamus and retina surrounds the 3rd ventricle
What is the adult derivative of the mesencephalon
midbrain, surrounds the cerebral aqueduct
What is the adult derivative of the mentencephalon?
middle brainstem: pons and cerebellum (surrounds the 4th ventricle)
What is the adult derivative of the mylencephalon
the medulla surrounds the outlet to the central canal
Name 2 other structure that are associated with the development of the cerebrum (also made from telecephalon)
(cortex), insula, basal ganglia, corpus callosum (connects hemispheres) occurs due to an immense growth of cells , including the tethering of the cortex (insula) which rests right on the basal ganglia
Why are the lateral ventricles so oddly shaped?
as the cerebral cortex enlarges lateral it also rotates causing the C shape of the ventricles
How is chord plexus form (hint describe two structure that come together)
pia mater abuts the ependymal cells of the ventricles and the blood vessels of the subarachnoid space are pushed up agains the ependymal cells, in this way CSF is derived from fluid leaking from vessels that is conditioned by ependymal cells
Ependymal cells are linked together by ___ ____
tight junctions
Describe how uncontrolled blood flow can lead to cerebral palsy in premature infants
premature infants cannot regulate blood flow well and vessels can rupture near a lateral ventricle because the germinal matrix zones around the ventricles becomes very vascularized. Bleeding can damage the motor cortex axons that run down to the body.
What specialized structures signal to the spinal cord regions what type of cell they should become?
the notochord, floor plate and specialized roof plate cause functional subdivisions of cells into alar and basal plates
What separates the subdivisions of the alar and basal plates?
sulcus limitans
In which region of the spinal cord do interneurons form?
in mostly in the alar plate
The alar plate becomes which two functional divisions of the CNS
general somatosensory and general viserosensory
The basal plate becomes which two divisions of the CNS
viseromotor and somatomotor
What is the significance of the pontine flexure
because of the bending of this region in the brainstem, the brainstem splits down the middle partially which causes the sensory portions to be more lateral to the motor portions in the medulla (located between the mentencephalon and myelencephalon)
Name special senses in the head that require special innervation
branchiomoter to muscles derived form the branchial arches, somatosensory in the ears, viscerosensory from tastebud and olfactory receptors
Migration of alar plate cells around the 4th ventricle forms the ___ ___ . Cells in posterior to this area become the _______.
rhombic lip; cerebellum
Describe the movement of sclerotome that causes the development of the vertebrae
sclerotome cells migrate to surround the notochord and then later migrate up around the spinal cord with the sclerotome forming the annulus fibrosis of the disc and most of the vertebrae
In the head some neural crest cells migrate into the __ ___ that form the facial bones.
branchial arches
In the head sclerotome par of the somite form the ____ .
skull
Midline evagination in the forebrain floor forms the ____ pituitary
posterior
Midline caudal roof of the forebrain becomes the _____ gland
pineal
The notochord lumen or neuroceoel becomes what in the adult?
ventricular system
