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Ward- dev CN I & II
Question | Answer |
---|---|
Neurulation | The ECTODERM of the trilaminar embryo folds via neural folds about the neural groove. This forms the Neural tube and the neural crest cells. |
Structures from Neural Tube | it gives rise to entire CNS (spinal cord, brainstem, brain). |
Structures from Neural Crest cells | Migrate all over body to become: 1.Melanocytes. 2.Oligodendrocytes (CNS) and Schwann cells (PNS). 3.Nerve satellite cells. 4.ALL GANGLIA (posterior root ganglia, parasymp ganglia, symp ganglia). 5.Bones and cartilages of face and neck. |
Mesenchyme surrounding the neural tube becomes? | Meninges |
Alar and Basal Plates | The multiplying nerve cells near the center of the neural tube as it thickens. ALAR: posterior horn (sensory). BASAL: anterior horn (motor, sends axons to myotomes). |
Origin of Macroglial cells | Ventricular zone of the neural tube. |
Marginal zone of the neural tube forms? | White matter tracts (axons) in the spinal cord. |
Development of the brain and brainstem begins with what 3 primary vesicles? | 1.Prosencephalon (Forebrain). 2.Mesencephalon (midbrain). 3.Rhombencephalon Hindbrain). |
Cervical flexture | Found between the spinal cord and Rhombencephalon region during development. |
Cephalic flexture | found between Rhombencephalon and mesencephalon regions during development. |
5 Secondary vesicles during CNS development | Prosencephalon divids into (Telencephlon and diencephalon), mesencephalon (stays the same), Rhombencephalon (divides into Metencephalon and myelencephalon) |
After the formation of the 5 secondary vesicles from the primary 3 vesicles, where are the flextures | 1.cervical flexture (b/w spinal cord and myelencephalon). 2.Pontine flexture (b/w myelencephalon and metencephalon). 3.Cephalic flexture (in the middle of mesencephalon) |
Adult derivative of the Telencephalon | WALLS: Cerebral hemispheres. CAVITIES: lateral ventricles (seperated by the septum pellucidum). |
Adult derivative of the Diencephalon | WALLS: thalamus, hypothalamus, pineal gland. CAVITIES: third ventricle |
Adult derivative of the Mesencephalon | WALLS: Midbrain. CAVITIES: Aqueduct |
Adult derivative of the Metecephalon | WALLS: Pons and Cerebellum. CAVITIES: 4th ventricle |
Adult derivative of the Myelencephalon | WALLS: Medulla. CAVITIES: 4th ventricle |
Which secondary vesicle grows the most | Telencephalon. Neurons of the cerebral cortex enlarge as they proliferate. Grows from the inside out. |
Lobes formed from the Telencephalon | 1.Frontal. 2.Insular (gets overgrown by the frontal lobe). 3.Parietal. 4.Temporal. 5.Occipital. |
Formation of CN I | extension of the frontal lobe forming the olfactory tract. From the superior nasal cavity: axons pass through the cribriform plate to synapse with neurons in the olfactory bulb. |
retina of the eye is a direct extension of what? | Diencephalon which makes it part of the CNS. |
formation of the lens | derived from an invagination of epidermal tissue as the retinal cups around the epidermal layer |
Pathways of R and L optic N | Retina sends axons thru R and L optic N. they reach the optic chiasm where axons swap and head towards the thalamic nuclei. From the thalamus they move to the occipital lobe |
Flow of CSF thru ventricles | Lateral > 3rd > cerebral aqueduct > 4th > subarachnoid spcae |
Hydrocephalus | Stenosis of the Cerebral aqueduct (mesencephalon) will cause a back up of CSF in the 3rd and lateral ventricles. |
Holoprosencephaly | Failure of cerebral hemispheres and lateral ventricles to seperate. **Forms a semilobar or alobar cerebral cortex and will lead to facial development defects |
Failure of the Cranial Neuropore to close on time | disrupts occipital bone formation and causes herniation |
Neuropore defects: Posterior fontanelle of cranium | 1.Meningocele (protruding dura and subarachnoid space). 2.Meningohyrdocephalocele (protrusion of occipital lobe) |
Neuropore defects: Foramen Magnum | 1.Meningoencephalocele (protrusion of cerebellum) |