Nervous system structure through development Flashcards
What is derived from the ectoderm?
Skin and nervous system
What is the neural plate?
Part of the ectoderm which becomes the nervous system
What happens in neurulation?
- Neural plate folds to form neural groove and folds
- Further folding results in formation of neural tube and neural crest
Which sections of the nervous system form from the neural tube? (2)
- CNS
- Ventricular system
Which sections of the nervous system form from the neural crest? (1)
PNS
What is the CNS and ventricular system derived from?
Neural groove
What is the PNS derived from?
Neural crest
What are somatic motor neurons?
Neurons that innervate muscles (muscle comes from the somites)
How does closing of the neural tube happen?
Starts centrally and zips up and down from the middle
What is anencephaly?
Failure to close the neural tube at the top
What are the consequences of anencephaly?
Fatal
What is spina bifida?
Failure to close the neural tube at the bottom
Why are pregnant women advised to take folic acid in early pregnancy?
Reduces the chance of neural tube defects by 90%
How does folic acid prevent neural tube defects?
Influences DNA synthesis
What are the 3 primary brain vesicles which differentiate?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
What are the 3 secondary brain vesicles of the forebrain?
- Telencephalic vesicles
- Diencephalon
- Optic vesicles
What do the telencephalic vesicles become?
Cerebral hemispheres
What do the optic vesicles become?
Optic stalk and optic cup
What does the optic cup become?
Retina
What does the optic stalk become?
Optic nerve
What are the key stages in development of the nervous system? (2)
- Neurulation
- Differentiation
What happens during forebrain differentiation?
- Olfactory bulbs develop at the front of the cerebral cortex
- Ventricles start to develop
- Grey matter and white matter differentiate
What does grey matter contain?
Neuronal cell bodies
What does white matter contain?
Myelinated axons
What does the basal telencephalon contain?
Basal nuclei
What develops from the diencephalon? (2)
- Thalamus
- Hypothalamus
What are the types of white matter tracks in the forebrain? (2)
- Corpus callosum
- Internal capsule
What is the corpus callosum?
White matter track which carries information from one side of the brain to the other
What is the internal capsule?
Carries information between the cerebral cortex and the thalamus/midbrain/pons/medulla etc.
What are the sections of the midbrain? (3)
- Tectum (dorsal)
- Tegmentum (ventral)
- Cerebral aqueduct
What is the midbrain involved in? (4)
- Visual processing
- Auditory processing
- Voluntary movement
- Pain control
What structures make up the hindbrain? (3)
- Pons
- Medulla
- Cerebellum
What do the rhombic lips become?
Cerebellum
What happens in hindbrain differentiation? (4)
- Rhombic lips form cerebellum
- Fourth ventricle forms
- Pons forms
- Medulla and medullary pyramids form
What are medullary pyramids?
White matter structures
What are the main outer structures of the cerebellum? (3)
- Two hemispheres
- Vermis
- Folia
What are folia?
Folds which increase the surface area of the cerebellum to allow it to have more neurons
What are the main inner structures of the cerebellum (3)
- Cerebellar cortex
- White matter
- Deep cerebellar nuclei (grey matter)
What are the pontine nuclei?
Nuclei in the pons involved in motor control
What are the functions of the cerebellum?
Coordination of movement, balance and posture
How is information processed in the cerebellum?
- Information from cerebral cortex feeds into pontine nuclei via internal capsule
- Pontine nuclei project into cerebellar cortex
- Purkinje cells integrate information and send back out via deep cerebellar nuclei
What proportion of CNS neurons are in the cerebellum?
50%
What proportion of CNS volume is the cerebellum?
10%
