Parts of a neurone
Axon -extensions of cytoplasm that transmit impulses away from cell body
to axon endings.
Dendrites - many thin extensions of cytoplasm that receive impulses from
other nerve cells and transmit impulses towards cell body.
Cellbody/centron- contains nucleus & groups of ribosomes in cytoplasm
that synthesise neurotransmitters.
Synaptic end bulb- swelling at end of axon in which neurotransmitters are
stored
Axon endings - secrete neurotransmitters by exocytosis is into synaptic
cleft.
Only in peripheral nervous system.
Schwann cells-surround peripheral neurones in vertebrates grow around
axon to form multi-layered myelin sheath.
Myelin sheath-formed as Schwann cells grow around axon in peripheral
neurones . provide electrical insulation to speed up nerve impulse.
Modes of Ranvier- intervals in myelin sheath between adjacent Schwann
cells.
Schwann
, Spinal cord
Long thin tubular bundle of nervous tissue & support cells
that extend from the brain.
Protected by the spinal column.
Most peripheral nerves originate from the spinal cord.
Its function is to transmit neural signals between brain and
rest of body, also contains neural circuits than can
independently control numerous reflexes.
Central grey matter contains Sensory fibres from the peripheral
mainly nerve cell bodies. nervous system enter the spinal cord
Surrounded by white matter on the dorsal root and the cell bodies
which consists of nerve fibres of the sensory fibres are found in the
surrounded by myelin sheath. dorsal root ganglia. Motor fibres
Spinal cord surrounded by leave via the ventral roots.
membranes called meninges.
Axon -extensions of cytoplasm that transmit impulses away from cell body
to axon endings.
Dendrites - many thin extensions of cytoplasm that receive impulses from
other nerve cells and transmit impulses towards cell body.
Cellbody/centron- contains nucleus & groups of ribosomes in cytoplasm
that synthesise neurotransmitters.
Synaptic end bulb- swelling at end of axon in which neurotransmitters are
stored
Axon endings - secrete neurotransmitters by exocytosis is into synaptic
cleft.
Only in peripheral nervous system.
Schwann cells-surround peripheral neurones in vertebrates grow around
axon to form multi-layered myelin sheath.
Myelin sheath-formed as Schwann cells grow around axon in peripheral
neurones . provide electrical insulation to speed up nerve impulse.
Modes of Ranvier- intervals in myelin sheath between adjacent Schwann
cells.
Schwann
, Spinal cord
Long thin tubular bundle of nervous tissue & support cells
that extend from the brain.
Protected by the spinal column.
Most peripheral nerves originate from the spinal cord.
Its function is to transmit neural signals between brain and
rest of body, also contains neural circuits than can
independently control numerous reflexes.
Central grey matter contains Sensory fibres from the peripheral
mainly nerve cell bodies. nervous system enter the spinal cord
Surrounded by white matter on the dorsal root and the cell bodies
which consists of nerve fibres of the sensory fibres are found in the
surrounded by myelin sheath. dorsal root ganglia. Motor fibres
Spinal cord surrounded by leave via the ventral roots.
membranes called meninges.
