Wk.2 L1 - Brain Development - Setting Up Foundations

Question 1

LO

Answer 1

1. Describe the overall functional organisation of the nervous system, including the major subdivisions of the CNS and PNS and their broad functions
2. State the major cells of the nervous system, be aware of their approximate numbers/ proportions
3. Describe the formation and differentiation of the neural tube and the relationship of the embryonic brain regions to the main divisions of the mature CNS

Question 2

Nervous System

Answer 2

CNS:
- Brain and Spinal cord

PNS:
- Conncets CNS to sensory organs, skin and muscle etc.
Sensory: Afferent
- Special sensory oragsns, skin, muscles

Motor: Efferent
- Somatic motor (skeletal muscle)
- Autonomic (smooth muscle, glands, enteric)

Question 3

Organisation of CNS

Answer 3

BRAIN:
Cerebrum:
- Cortex (perception, decision, memory voluntary motor)
- Basal Ganglia (Motivation and movement)
- Anygdala (fear and emotion)

Diencephalon:
- Thalamus
- Hypothalamus

Midbrain (Mesencephalon):
- Colliculi (visual and auditory reflexes)
- Substantia Nigra ( parkinsons disease cells degenerate here)

Brainstem:
- Pons (Motor & sensory to upper head and face)
- Cerebellum (coordination and movement)
- Medulla (breathing and HR)

SPINAL CORD:
- Motor and sensory to body

VENTRICLE:
- Hollow centre of tube filled with cerebrospinal fluid

Question 4

Trilaminar Embryo: 18 Days

Answer 4

3 main germ layers are set up
- Ectoderm (skin) - dorsal side
- Endoderm (viscera)
- Mesoderm (muscles, vessels, CT)

Neural plate has also formed on ventral side
- Nueral folds start to form
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Question 5

Folding of the neural tube

Answer 5

Ventral to the midline of the neural plate is the Notocord formed from the mesoderm

Neural folds create hinges pushing the neural plate down
- The neural fold regions then pinch in to form the neural tube
- Once Neural folds meet, the cells migrate inside as neural crest cells

Neural tube = CNS
Neural crest cells = PNS
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