NEURONS

NEURONS

Neurons, also known as nerve cells specialized in sending and receiving signals from the brain. While neurons have a lot in common with other types of cells, they’re structurally and functionally unique.

➡️ The cell body which is Also known as the soma. The cell body is the neuron’s core. The cell body carries genetic information, maintains the neuron’s structure, and provides energy to drive activities.

➡️ Axon

An axon is a long, tail-like structure which joins the cell body at a specialized junction called the axon hillock. Many axons are insulated with a fatty substance called myelin. Myelin helps axons to conduct an electrical signal. Neurons generally have one main axon.

➡️ Dendrites

Dendrites are fibrous roots that branch out from the cell body. Like antennae, dendrites receive and process signals from the axons of other neurons. Neurons can have more than one set of dendrites, known as dendritic trees. How many they have generally depends on their role.

➡️ Myelin Sheaths  

Most long nerve fibers are covered with a whitish, fatty material called myelin (mi′e˘-lin), which has a waxy appearance. Myelin protects and insulates the fibers and increases the transmission rate of nerve impulses.

➡️Terminal end of axons 

At the end of an axon, there is a so-called axon terminal that is button-like which contains neurotransmitters and is responsible for providing synapse between neurons

➡️ Chemical synapses

In a chemical synapse, action potentials affect other neurons via a gap between neurons called a synapse. Synapses consist of a presynaptic ending, a synaptic cleft, and a postsynaptic ending.

When an action potential is generated, it’s carried along the axon to a presynaptic ending. This triggers the release of chemical messengers called neurotransmitters. These molecules cross the synaptic cleft and bind to receptors in the postsynaptic ending of a dendrite.

Neurotransmitters can excite the postsynaptic neuron, causing it to generate an action potential of its own. Alternatively, they can inhibit the postsynaptic neuron, in which case it doesn’t generate an action potential. 

➡️ Electrical synapses

Electrical synapses can only excite. They occur when two neurons are connected via a gap junction. This gap is much smaller than a synapse, and includes ion channels which facilitate the direct transmission of a positive electrical signal. As a result, electrical synapses are much faster than chemical synapses. However, the signal diminishes from one neuron to the next, making them less effective at transmitting.