Question

3. Describe the general morphological structure of a typical neuron and describe each structure in terms of location within the cell and its function to the cell. (5 points)

Answer 1

Neuron is the basic unit of central and peripheral nervous system. It is a specialised cells that transfer chemical and electrical signal between surrounding neurons and muscles cells.

Sturcture of a neuron:

The neuron is atypical to a normal cells, having few processes. In addition to all the cell component of a cell like nucleus and mitochondria and ribosome, it conatins few unique structure for transferring electrical and chemical signals.

1. Cell body:

It is the central portaion of the cell containing all the organelles like endoplasmic reticulum, Golgi body, mitochondria and nucleus and is round shaped.

2. Dendrites:

these are the branch like structures projections from the cell body. There is absence of any kind of covering on the dendrite and a main dentrite can branch away into few, which are known as dendritic spine. The main function of dendrites is to receive the electrical signal and transfer the same to the cell body.

3. Axon:

It is a single tube like structure projecting from the cell body opposite to the surface of origin of dendrites. It carries the signal from cell body to the dendrites of next neuron or to the muscle cells. There are branching at the terminal of an axon along with nobs, which store the neurotransmitter.
the junction of cell body and axon is known as axon hillock. There are presence of Nissl granules in the axon hillock which are actually rough endoplasmic reticulum.

4. Myelin sheath:

some axons are covered by a lipid rich substance to insulate them. This is known as myelin sheath. The myelin helps in rapid transfer of electrical potential along the axon of neuron. It is actually formed by glial cells, which are non-neuronal in origin.

5. Nodes of Ranvier:

there are periodic gaps in myelin sheath where the electrical signal is actually "jumps" to get transferred to the end of the axon.

6. Schwann cell:

It is also called neurilemma cell and any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons.
SCHWANN CELL GRANULES CELL BODY RANVIER'S NODE -AXON CELL Boy GRANULES NISSL 1. I S MYELIN Axon HILLOCK UL → MITOCHONDRIA DEN DRON ofoSYNAPTIC KNOB AXON TERMINAL