The Peripheral Nervous System
Nervous Tissue
2 main types:
- Neurons – structural and functional unit of nervous
system.
o Rapid communication.
o Composed of a cell body with processes
(extensions) called dendrites and an axon.
o Dendrites carry impulses to the cell body.
o Axons carry impulses away from the cell body.
- Neuroglia – non-neuronal, excitable cells.
o Scaffolding.
Neuroglia
- Astrocytes – Blood brain barrier
- Microglia – phagocytosis
- Ependymal cells – fluid production
- Oligodendrocytes – myelin sheath in CNS
- Schwann cell – myelin sheath in PNS
- Satellite cells – support neuronal cell bodies in
ganglia in PNS
Nerve Structure
- Myelin sheath of varying thickness consists of phospholipid
membrane with constrictions at defined intervals (nodes of
Ranvier)
- Impulses leap from node to
node (saltatory
conduction) -> faster
- Myelin is formed by
Schwann cells (PNS) and
oligodendrocytes (CNS)
, The Nervous System
Autonomic Nervous System
- Can be divided into:
o Parasympathetic – anabolic, promote energy conservation
o Sympathetic – catabolic, mobilise body for fight or flight
- Nervous system can be divided into
o structural components → central and peripheral nervous system
o functional components → autonomic and somatic nervous system
Nervous Tissue
2 main types:
- Neurons – structural and functional unit of nervous
system.
o Rapid communication.
o Composed of a cell body with processes
(extensions) called dendrites and an axon.
o Dendrites carry impulses to the cell body.
o Axons carry impulses away from the cell body.
- Neuroglia – non-neuronal, excitable cells.
o Scaffolding.
Neuroglia
- Astrocytes – Blood brain barrier
- Microglia – phagocytosis
- Ependymal cells – fluid production
- Oligodendrocytes – myelin sheath in CNS
- Schwann cell – myelin sheath in PNS
- Satellite cells – support neuronal cell bodies in
ganglia in PNS
Nerve Structure
- Myelin sheath of varying thickness consists of phospholipid
membrane with constrictions at defined intervals (nodes of
Ranvier)
- Impulses leap from node to
node (saltatory
conduction) -> faster
- Myelin is formed by
Schwann cells (PNS) and
oligodendrocytes (CNS)
, The Nervous System
Autonomic Nervous System
- Can be divided into:
o Parasympathetic – anabolic, promote energy conservation
o Sympathetic – catabolic, mobilise body for fight or flight
- Nervous system can be divided into
o structural components → central and peripheral nervous system
o functional components → autonomic and somatic nervous system
