CNS development
- Develops from hollow tube
- Rostral end becomes enlarged - brain
- Forebrain (telencephalon + diencephalon)
- Midbrain (mesencephalon)
- Hindbrain (metencephalon/pons + myelencephalon/medulla). Cerebellum is outgrowth
- Caudal end remains as spinal cord
Telencephalon (2 parts)
Cerebrum, basal ganglia
Cerebrum
- Most of brain
- Highest level of processing, motor activity, sensory perception, consciousness
- Outer layer is cerebral cortex - grey matter (cell bodies, dendrites, synapses)
- Inner layer is white matter (myelinated axons)
Basal ganglia
movement control
Diencephalon (2 parts)
thalamus, hypothlamus
thalamus
processes info going to cerebrum
hypothalamus
role in regulation of autonomic body functions
brainstem (3 parts)
Midbrain
Hindbrain: pons and medulla
- Contain white matter tracts
- nuclei of cranial nerves
Reticular formation + its 3 functions
Central core of brainstem
1. ascending: arousal and consciousness
2. descending: muscle tone (gamma-MN)
3. Respiratory and cardiovascular centres (medulla)
Ventricular system
Carries CSF
- Right and left lateral ventricles
- 3rd ventricle (in diencephalon, between thalami)
- cerebral aqueduct, 4th ventricle (between dorsal pons and cerebellum)
CSF
- Prod by choroid plexus (in ventricles)
- Leaves ventricular system via apertures b/w cerebellum and medulla
- Fills space surrounding entire CNS
Pia mater
innermost layer on surface of CNS
arachnoid membrane
fits loosely over surface
- Space between arachnoid membr and pia mater: subarachnoid space, CSF
- Rich blood supply
- CSF reabsorbed into veins
Dura mater
outermost layer - thick, tough, protective
CSF functions
Buoyant - protects against forces distorting brain (ex. gravity)
Excretion of waste byproducts from neurons and glia
Transport of hormones
