Lecture 8: Development of the Brain Flashcards
(54 cards)
What induces the formation of the neural plate, neural groove, neural folds, and neural tube?
Notochord
As the neural folds migrate to the middle and zipper up and down you get the formation of a rostral neuropore and caudal neuropore, when do these close by?
Rostral neuropore: close by day 25
Caudal neuropore: close by day 27
Which 5 cells of the CNS arise from neuroectoderm?
1) Astrocytes: structural and support cells
2) Dendrites and Axons
3) Oligodendrocytes: myelinate axons in CNS
4) Ependyma cells
5) Epithelium of Choroid Plexus
Where are Microglial cells of the CNS derived from?
Mesoderm (mesenchyme)
Neural tube cranial to _______ somites becomes the brain?
4th
What are the 3 primary brain vesicles?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
What week does the forebrain and hindbrain divide and what are their divisions?
- 5th week
- Forebrain —> Telencephalon (cerebral hemisphere) and Diencephalon (thalamus, hypothalamus, and optic nerve)
- Hindbrain —> Metencephalon (pons/cerebellum) and Myelencephalon (medulla)
*The midbrain does NOT divide
The cervical flexure demarcates what?
Hindbrain from the spinal cord
The pontine flexure divides what?
Divides the hindbrain into Metencephalon (rostral) and Myelencephalon (caudal)
What 4 brain components arise from the Diencephalon?
1) Thalamus
2) Hypothalamus
3) Epithalamus
4) Eye (optic nerve)
What is Holoprosencephaly (HPE) and what other abnormalities is it commonly associated with?
- Incomplete separation of cerebral hemispheres
- Most associated w/ facial abnormalities due to reduction of FNP
Describe the embryological development of the Pituitary Gland; where does each lobe arise from?
- Upgrowth from roof of mouth (first arch ectoderm) forms Hypophysial diverticulum (Rathke’s pouch) = Anterior lobe
- Downgrowth from diencephalic floor (neuroectoderm) forms Neurohypophysial diverticulum = Posterior lobe
- Stalk of Rathke’s pouch regresses around week 6 and lobes fuse together
The spinal cord is formed by the neural tube caudal to the ______ pair of somites
4th
What is found in the Ventricular (zone 1), Intermediate (zone 2), and Marginal (zone 3) of the spinal cord?
1) Ventricular (Zone 1): neuroepithelial stem cells
2) Intermediate (Zone 2): neurons, astrocytes, microglia and/or glia
3) Marginal (Zone 3): oligodendrocytes, microglia, and axons that will eventually become myelinated (white matter)
Differentiation of the SC produces _____ walls, but _____ roof and floor plates
Thick walls, but thin roof and floor plates
The sulcus limitans is important for dividing?
- Alar plate (dorsal): sensory
- Basal plate (venral): motor
Where do the nucleus gracilis and nucleus cuneatus of the lower medulla develop from and what aspect of the medulla are they located on?
- In caudal Myelencephalon, neuroblasts in Alar plate from these nuclei
- Located on the Dorsal aspect of the medulla
What aspect of the medulla are the pyramids found on; which tract do they contain?
- Ventral aspect
- Contain CST
As the pontine flexure forms what affect does it have on the walls and roof plate of the medulla; what does it do to the alar and basal plates?
- Causes walls of medulla to move laterally
- Thins the roof plate
- Alar plates becomes lateral to the basal plates —> motor nuclei develop medially and sensory nuclei develop laterally
Cerebellum develops from what part of the alar plate and what must occur for its development?
- Dorsal parts of the Alar plates
- Rhombic lip (aka cerebral swelling) migrate and fuse midline
Which 4 nuclei develop from the basal plate of the Metencephalon?
1) Abducens nucleus
2) Facial motor nucleus
3) Trigeminal motor nucleus
4) Superior salivatory nucleus
Which CN’s are associated with GSE?
CN III, IV, VI, XII
Which CN’s are associated with GVE?
CN III, VII, IX, X
Which CN’s are associated with SVE; these innervate muscles derived from where?
CN V, VII, IX, X, XI
*Muscles derived from the pharyngeal arches
