Respuesta :
Answer:
Explanation
The Axon or nerve fibre is a long, thin projection of the neuron or nerve cells that sends signals in the form of electrical impulses from the cell body (soma) to the synaptic terminals. The axons are of two types: myelinated and unmyelinated. The unmyelinated axons lack myelin sheaths which make the transmission of electrical impulses slower while the myelinated axons transmit electrical impulses faster.
Answer:
: carries information toward other neurons.
Explanation:
Structure
This Axon or nerve fibre is a long protrusion of the cytoplasm from the cell body. This cytoplasm are refereed to as Axoplasm, and they are bounded by membrane called Axolema. Layers of fats deposits, protein and water called myelin sheath are deposited in concentric rings around the axon by a process called myelination.
This grouped axon into two types. Axons with myelin are said to be myelinated axons. Their origin depends on the location. Myelin sheath of the peripheral nervous system are formed by Schwann's cells. The latter are bounded by Neurilemma which is nucleated .They formed the outermost layer of axon in contact with extracellular environments. while oligodendrites forms the myelin sheath of central nervous system.
The layers of myelin are interrupted at intervals by Nodes of Ranvier along the axon.These nodes has concentration of sodium and potassium channels. Axons without myelin deposits are said to be unmyelinated. Their axopalsm are covered by Axolema.
Length of axon varies from location of neurons,and functions of neuron. The longest axon are present in the sciatic nerve which travels from the Sacral plexus at the hip to the lower ribs. The largest axons are found in the Betz cells. while the smallest axons are located in the interneurons,
Function
The basic function of the axon is related to its function.
The general function of Myelin sheath is to maintain the integrity of the action potential been transmitted, and insulation of the electrical impulses in the axon from other neuron
The mechanisms involved the axonlema conduct of electrical impulses as action potential along the axon length. The interruption at nodes of Ranvier makes the action potential to 'jump' in a type of electrical transmission called saltatory conduction, which increases the speed of conduction in a neuron. Unmyelinated neuron lacks Nodes of Ranvier, and therefore conducted action potential slowly.
