Motor Neurone

• Transport nervous impulse from a sensory neurone or relay in CNS (brain or spinal cord) to an effector such as muscle or gland
• Motor neurone has a cell body at end, located in CNS, cell body contains nucleus, cytoplasm with all cell organelles including ribosome clusters for protein synthesis
• Dendrites are thin cytoplasmic processes extending from cell body; transmit impulse to it, an axon is a longer cytoplasmic process, extends from cell body and transmits impulses away
• Axon is filled with axoplasm with many microtubules but no ribosomes, can be very long (cell body in low spinal cord could reach toe end, up to 1m long), also has terminal branches (end in synaptic bulbs)
• Synaptic bulbs have many mitochondria and vesicles containing neurotransmitter molecules; these pass impulse to effector cells, cause an effector cell response (e.g. muscle contraction or gland secretion)
• Myelinated motor neurone has myelin sheath made of Schwann cells around the axon, gaps between Schwann cells are called node of Ranvier