Neuron Anatomy & Physiology

1. Presented by- Shruti Richa
Assistant Professor
Central Institute of Pharmacy

3.  Neurons are the basic unit of the nervous system.
All cells of the nervous system are comprised of
neurons. The nervous system helps us to sense and
respond to our environment.
 Neurons pass messages to each other using a special
type of electrical signal. Some of these signals bring
information to the brain from outside of the body,
such as the things we can see, hear, and smell.
Other signals are instructions for our organs, glands
and muscles.
 So, the neurons (or nerve cells) are specialized cells
that transmit and receive electrical signals in the
body.

4.  Neurons are composed of three main parts:
dendrites, a cell body, and an axon.
 Neurons receive their signals from the
neighbouring neurons through their dendrites.
From there, the signal travels to the main cell body,
known as the soma. Next, the signal leaves the
soma and travels down the axon to the synapse.
 Dendrites Cell body (soma) Axon
Synapse

5.  It means tree like or branches like.
 It receives the signals and forwards it to the cell
body.

6. The cell body is called as perikaryon since its nucleus is
always found at periphery. It has following components:
 Nucleus - It contains genetic material (chromosomes)
including information for cell development and synthesises
proteins, necessary for cell maintenance and survival. It is
covered by a membrane.
 Nucleolus - It produces ribosomes necessary for
translation of genetic information into proteins.
 Nissl Bodies - It is the groups of ribosomes used for
protein synthesis.

7.  Endoplasmic reticulum (ER) - The system of
tubes for transport of materials within cytoplasm. It
has ribosomes (rough ER) or no ribosomes (smooth
ER). With ribosomes, the ER is important for
protein synthesis.
 Golgi Apparatus - The membrane-bound structure
important in packaging proteins.
 Microfilaments/Neurotubules - The system to
transport materials within a neuron and may be used
for structural support as well.
 Mitochondria - It produces energy to fuel cellular
activities.

8.  Axons are the structure found on a single axis. It is
cylindrical in shape.
 They are also called as nerve fibres.
 It varies in length (can be over 1 meter long).
 The longest axon is called the dorsal root
ganglion (DRG), from the skin to the brain.
 Most axons are covered by a white, waxy substance
called myelin sheath.
 This coating insulates nerves and increases the speed at
which impulses travel.
 Myelin is created by Schwann cells in the peripheral
nervous system and oligodendrocytes in the CNS.

9.  There are some structures related to axon:
1. Axon hillock: The cell body and axon where
joins, they form a triangle like structure. It is called
as axon hillock.
2. Axon collateral: When an axon joins with the
axon of another axons, then this is called as axon
collateral.
3. Initial segment: It is the point where axon gets
started.
4. Trigger zone: The space between axon hillock
and initial segment is termed as trigger zone.
 There are small gaps in the myelin coating, called
nodes of Ranvier. The action potential jumps
from gap to gap, allowing the signal to move much
quicker.

11.  1. Dendrites: It receive electrical impulses from
neighboring neurons.
 2. Soma: The cell body which contains most of the
cell’s organelles.
 3. Nucleus: It contains the cell’s DNA.
 4. Axon: It transfers electrical impulse signals from the
cell body to the synapse.
 5. Myelin sheaths: It Cover the axon and work like
insulation to help keep electrical signals inside the cell,
which allows them to move more quickly.
 6. Synapses: It Sends electrical impulses to neighboring
neurons.

12.  So, it is the complexity of neuronal networks that
gives us our personalities and our consciousness.
 They are responsible for the most basic of actions,
and the most intricate. From automatic reflex
actions to deep thoughts.

14.  https://www.khanacademy.org/science/high-
school-biology/hs-human-body-systems/hs-the-
nervous-and-endocrine-systems/v/anatomy-of-a-
neuron
 https://www.thoughtco.com/neurons-373486
 https://askabiologist.asu.edu/sites/default/files/resour
ces/coloring_pages/pdf/aab_neuron_anatomy_activi
ty_0.pdf
 https://faculty.washington.edu/chudler/cells.html
 https://www.medicalnewstoday.com/articles/32028
9.php#carry_message