ANATOMY OF THE NERVOUS SYSTEM: Central and Peripheral
THE NERVOUS SYSTEM
Is subdivided into the CNS and PNS
CNS: Brain and spinal cord (where integration occurs)
PNS: everything other than the brain and spinal cord
Functions of the NERVOUS SYSTEM:
1. Sensation
2. Integration
3. Response
A neuron:
- A cell body (SOMA) → carries out metabolic functions
- Dendrites → extensions which carry signals to cell body
- AXONS → SIGNALS carried away from cell body
All these cell bodies form the grey matter
Nerve FIBRES form the white matter
Bundles of cell bodies in the CNS is called a nucleus
IN THE PNS is called GANGLION
A nerve is a bundle of axons in the PNS
A tract is a bundle of axons in the CNS
PNS:
Subdivided into:
Somatic (sensory and movement)
Autonomic nervous system (ANS)
- Sympathetic → flight and Fight
- Parasympathetic → rest and digest
Enteric nervous system → found in the digestive tract responsible for autonomous functions
and operates INDEPENDENTLY to the brain and spinal cord.
CENTRAL NERVOUS SYSTEM:
, - Brain (cerebrum and cerebellum)
- Brainstem
- Spinal cord
The membranous covering of the CNS is called meninges:
o DURA matter: strong, thick and dense membrane composed of dense fibrous
tissue. Attached to bones of the skull on the outside
o ARACHNOID: Thin and fibrous tissue
o PIA: thin on the surface of the brain and spinal cord- fibrous tissue
The subarachnoid space (between PIA and Arachnoid) is filled with CSF which provides a
liquid cushion to the brain and spinal cord.
Haemorrhages can occur here due to aneurysms.
FALX CEREBRI:
The falx cerebri is the fold of dura between 2 hemispheres in longitudinal fissure.
- Provides support and reduces side movement of brain
The falx cerebelli projects between the hemispheres of the cerebellum
while the tentorium cerebelli separates the
cerebellum and the cerebrum.
The corpus callosum is found at the bottom of the longitudinal fissure; it
contains the largest amount of white matter tracts connecting the two hemispheres.
THE NERVOUS SYSTEM
Is subdivided into the CNS and PNS
CNS: Brain and spinal cord (where integration occurs)
PNS: everything other than the brain and spinal cord
Functions of the NERVOUS SYSTEM:
1. Sensation
2. Integration
3. Response
A neuron:
- A cell body (SOMA) → carries out metabolic functions
- Dendrites → extensions which carry signals to cell body
- AXONS → SIGNALS carried away from cell body
All these cell bodies form the grey matter
Nerve FIBRES form the white matter
Bundles of cell bodies in the CNS is called a nucleus
IN THE PNS is called GANGLION
A nerve is a bundle of axons in the PNS
A tract is a bundle of axons in the CNS
PNS:
Subdivided into:
Somatic (sensory and movement)
Autonomic nervous system (ANS)
- Sympathetic → flight and Fight
- Parasympathetic → rest and digest
Enteric nervous system → found in the digestive tract responsible for autonomous functions
and operates INDEPENDENTLY to the brain and spinal cord.
CENTRAL NERVOUS SYSTEM:
, - Brain (cerebrum and cerebellum)
- Brainstem
- Spinal cord
The membranous covering of the CNS is called meninges:
o DURA matter: strong, thick and dense membrane composed of dense fibrous
tissue. Attached to bones of the skull on the outside
o ARACHNOID: Thin and fibrous tissue
o PIA: thin on the surface of the brain and spinal cord- fibrous tissue
The subarachnoid space (between PIA and Arachnoid) is filled with CSF which provides a
liquid cushion to the brain and spinal cord.
Haemorrhages can occur here due to aneurysms.
FALX CEREBRI:
The falx cerebri is the fold of dura between 2 hemispheres in longitudinal fissure.
- Provides support and reduces side movement of brain
The falx cerebelli projects between the hemispheres of the cerebellum
while the tentorium cerebelli separates the
cerebellum and the cerebrum.
The corpus callosum is found at the bottom of the longitudinal fissure; it
contains the largest amount of white matter tracts connecting the two hemispheres.
