Brain Development Flashcards
Neural Tube Development
(Diagram)
Alar Lamina
Dorsal thickening from neuroepithelium which contain nerve cell bodies that will form processes that exit thickening into marginal layer of neural tube
Basal Lamina
Ventral thickening from neuroepithelium which contain nerve cell bodies that will form processes that exit thickening into marginal layer of neural tube
3 Main functional types of Neurons
- Motor (efferent): from basal lamina of neural tube
- Association (interneurones): from alar lamina of neural tube
- Sensory (afferent): from neural crest
** All 3 having different functions (functional types), they all have a different developmental origin within the developing NS
-basal lamina is the source of all efferent neurons
Motor Neurons
- Convey messages from the CNS to the periphery of the body. (i.e. to supply muscles with motor neurons taking impulses from CNS to different limbs of body).
- Efferent.
- Carrying impulses out of the CNS to the periphery of the body
Association or Interneurons
- Neurons like this connect or associate one point in the CNS with another point in the CNS, but they never leave the CNS unlike the motor neurons. Could be anything, one bit of spinal cord to another bit of spinal cord. Associated one point of CNS with another.
- By far the most numerous in the Nervous system!
Sensory (afferent) Neurons
- bring information in from the periphery of the body.
- From the skin to the CNS.
- Doing the opposite thing to efferent neurons in terms of signal transfer.
3 Vesicles of “3 vesicle stage of Brain”
- Forebrain
- Midbrain
- Hindbrain
- Development of Brain I
- Ventricles contain cerebrospinal fluid
- shows 3 obvious expansions of this cranial end of neural tube
- hindbrain becomes the part continuous with the rest of the neural tube and this leads to the formation of the spinal cord
“5 Vesicle Stage of Brain”
- Soon after 3 vesicle stage:
- Forebrain region forms a growth pouch-like on either side
- two expansions of forebrain vesicles
- becomes 5-vesicle stage due to added expansions
Brain Regions
Pontine Flexure
- Hindbrain elongates somewhat and tends to grow in length so much that to accommodate it has to be folded. Becomes V-shaped or U-shaped –> Pontine Flexure
Pons and Medulla Oblongata
- the Pontine Flexure:
allows for 2 different parts of the brain to develop from the hindbrain vesicle. More rostral part is the pons. And the most caudal part becomes continuous with the spinal cord and is called the medulla oblongata.
Formation is due to elongation of the hindbrain vesicle
Secondary Neural Structures to Adult Neural Structures
Parts of the Brain
(including all that composes forebrain, midbrain, and hindbrain)
Parts of the Telecephalon
- cerebral hemispheres (2)
- Largest parts of telencephalon. Form connections that join the left hemisphere with the right
- limbic system
- olfactory bulb
- interconnecting structures (commisures)