L12 Nervous system structure through development Flashcards
What are the 3 germ layers?
- Ectoderm
- Mesoderm
- Endoderm
What does the endoderm form?
Endoderm forms the internal organs (lining of viscera) and several glands
What does the mesoderm form?
Bones and muscles
What does the ectoderm form?
Skin and nervous system (neural plate too)
What is the neural plate?
The neural plate is a thickened region of the ectoderm (the outermost layer of cells in an embryo) that forms on the dorsal (back) side of the developing embryo
Explain the process of neurulation
The neural plate folds inward, forming the neural groove, and then the edges of the folds fuse to create the neural tube (CNS) or neural crest (PNS)
What neurons could form from the neural crest? (6)
Sensory neurons, dorsal root ganglion neuron, parasympathetic neurons, enteric neurons, schwann cells
Why are women advised to take Folic Acid when trying to conceive and durng pregnancy?
Folic acid supports normal and efficient cell division and growth required for the neural tube to form correctly and close properly
What is anencephaly?
Anencephaly is a severe birth defect that occurs when the neural tube fails to close properly at the **top (head) end ** during early embryonic development
Happens at the rostral (head) end
What is spina bifida?
Spina bifida is a birth defect that occurs when the neural tube fails to close along the spine
Happens at the caudal (tail) end
What does the rostral side of the neural tube differentiate into?
The 3 primary brain vesicles:
- Prosencephalon (Forebrain):
This is the most anterior vesicle.
- Mesencephalon (Midbrain):
This is the middle vesicle. - Rhombencephalon (Hindbrain):
This is the most posterior vesicle.
What are the secondary brain vesicles of the forebrain?
- Telencephalon
- Diencephalon
- Optic vesicles
What two secondary brain vesicles does the prosencephalon divide into during embryonic development?
Telencephalon
Diencephalon
What does the optic stalk and optic cup develop into?
Optic stalk = optic nerve
Optic cup = retina
Can you identify the key stages in the development of the nervous system? (4)
1) Neural plate formation - ectoderm thickens into plate
2) Neurulation - neural plate folds inward, creating neural groove + folds which eventually closes to form the neural tube
3) Neural tube differentiates into primary brain vesicles: prosencephalon, mesencephalon and rhombencephalon
4) Forebrain differentiates further into telencephalic vesicles, diencephalon and optic vesicles
What are the key functions of the midbrain?
- Motor control
- Vision processing
- Auditory processing
- Pain
What is the cerebellum’s primary role?
The cerebellum’s primary role is to coordinate voluntary movements, ensuring they are smooth and precise.
It receives input from sensory systems (eyes, ears, muscles, joints) and the cerebrum, and then fine-tunes motor commands
What is the cerebellum?
Part of the brain located at the back of the head. Represents 10% of the brain’s total volume, houses over 50% of the total number of brain’s neurons
What are the derivatives of the Telencephalon (forebrain)?
- Cerebral cortex
- Cerebral nuclei ( basal ganglia, amygdala, basal forebrain)
What are the derivatives of the Diencephalon (forebrain)?
- Thalamus
- Hypothalamus
- Retina
Where is the associated ventricular space for the Telencephalon?
Lateral ventricles
Where is the associated ventricular space for the Diencephalon?
Third ventricles
What are the adult brain derivatives for the Mesencephalon (midbrain)?
- Superior and inferior colliculi
- Red nucleus
- Substantia nigra
Where is the associated ventricular space for the midbrain?
Cerebral aqueduct
