The nervous system coordinates voluntary and involuntary actions and transmits signals
between different parts of the body. It includes all the neural tissues in the body.
Basic functional unit = neuron
Supporting cells = neuroglia = separate and protect neurons, provide supportive
framework (effective signal transmission)
• Define the central and peripheral nervous systems
CNS = brain + spinal cord = responsible for integrating, processing and coordinating
sensory data and motor commands from different parts of the body and the brain. Also
responsible for higher cognitive function.
PNS = all the neural tissues except the brain and spinal cord. It delivers sensory
information to the CNS and carries motor demands to the peripheral tissues and systems.
Functionally divided into afferent = sensory information towards CNS and efferent NS =
carries motor commands from CNS to muscles and glands.
PNS anatomical divisions:
- cranial nerves
- Spinal nerves.
PNS functional division:
- somatic = innervates muscoskeletal structures and sense organs of the skin, involved in
spinal reflexes, efferent functions under voluntary control
- Autonomic - innervates smooth muscles and glands, maintains homeostasis, not under
voluntary control
Further divide into following divisions:
Sympathetic, parasympathetic (resting) , enteric (located in GI tract)
• Identify the spinal cord, spinal nerves and peripheral nerves
Thoraco - lumbar outflow = autonomic nervous system
Sympathetic nerve fibers arise from thoracic and lumbar regions
Cranio-sacral outflow - parasympathetic nerves
Spinal cord is a tubular bundle of nervous tissues extending from the lowermost part of the
brainstem medulla oblongata. It passes down the vertebral canal and terminates as a
cone-shaped swelling = the conus medullaris.
Terminates at the level of L1-L2
The spinal nerves continue to branch out diagonally forming caudal equine.
A slender strand of fibrous tissue extends from the inferior tip of the spinal cord to attach to
the sacrum called the filum terminals.
The spinal cord and brain consists of two types of nervous tissue:
- grey matter = contains cell bodies, dendrites and proximal parts of axons of neurons,
inner part of spinal cord, H-shaped in cross-section,
> two posterior (dorsal horns) = receives sensory information
> two anterior (ventral) horns - cell bodies of motor neurons
Lateral horn is only present in thoracolumbar regions as these contain the cell bodies of
the sympathetic NS.
Amount of grey matter is the greatest in cervical and lumbar regions where sensory and
motor control of limbs is greatest giving rise to cervical and lumbar enlargements.
- White matter = contains an abundance of myelinated axons which run in tracts carrying
signals from one part of the CNS to another
Surrounds the grey matter, contains axons that course up and down the cord, bundles are
arranged in 3 pairs called columns (or funiculi) : posterior, lateral and anterior
Each column consists of subdivisions called tracts:
between different parts of the body. It includes all the neural tissues in the body.
Basic functional unit = neuron
Supporting cells = neuroglia = separate and protect neurons, provide supportive
framework (effective signal transmission)
• Define the central and peripheral nervous systems
CNS = brain + spinal cord = responsible for integrating, processing and coordinating
sensory data and motor commands from different parts of the body and the brain. Also
responsible for higher cognitive function.
PNS = all the neural tissues except the brain and spinal cord. It delivers sensory
information to the CNS and carries motor demands to the peripheral tissues and systems.
Functionally divided into afferent = sensory information towards CNS and efferent NS =
carries motor commands from CNS to muscles and glands.
PNS anatomical divisions:
- cranial nerves
- Spinal nerves.
PNS functional division:
- somatic = innervates muscoskeletal structures and sense organs of the skin, involved in
spinal reflexes, efferent functions under voluntary control
- Autonomic - innervates smooth muscles and glands, maintains homeostasis, not under
voluntary control
Further divide into following divisions:
Sympathetic, parasympathetic (resting) , enteric (located in GI tract)
• Identify the spinal cord, spinal nerves and peripheral nerves
Thoraco - lumbar outflow = autonomic nervous system
Sympathetic nerve fibers arise from thoracic and lumbar regions
Cranio-sacral outflow - parasympathetic nerves
Spinal cord is a tubular bundle of nervous tissues extending from the lowermost part of the
brainstem medulla oblongata. It passes down the vertebral canal and terminates as a
cone-shaped swelling = the conus medullaris.
Terminates at the level of L1-L2
The spinal nerves continue to branch out diagonally forming caudal equine.
A slender strand of fibrous tissue extends from the inferior tip of the spinal cord to attach to
the sacrum called the filum terminals.
The spinal cord and brain consists of two types of nervous tissue:
- grey matter = contains cell bodies, dendrites and proximal parts of axons of neurons,
inner part of spinal cord, H-shaped in cross-section,
> two posterior (dorsal horns) = receives sensory information
> two anterior (ventral) horns - cell bodies of motor neurons
Lateral horn is only present in thoracolumbar regions as these contain the cell bodies of
the sympathetic NS.
Amount of grey matter is the greatest in cervical and lumbar regions where sensory and
motor control of limbs is greatest giving rise to cervical and lumbar enlargements.
- White matter = contains an abundance of myelinated axons which run in tracts carrying
signals from one part of the CNS to another
Surrounds the grey matter, contains axons that course up and down the cord, bundles are
arranged in 3 pairs called columns (or funiculi) : posterior, lateral and anterior
Each column consists of subdivisions called tracts:
