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1. NEURON PRESENTED BY: Ms. SUKHRAJ KAUR M.Sc. NURSING (PEDIATRICS) ASHOKA INSTITUTE OF NURSING, PATIALA

2. NEURON Neurons are the cells considered to be the structural and functional unit of the nervous system. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. An important part of the function of neurons is in their structure, or shape.

3. 4 PARTS OF THE NEURON Cell body Dendrites Axon Axon terminal

4. Cell Body The main portion of the neuron is called cell body. In the center of the cell body is the nucleus of the cell, where the chromosomes that contain all of the genetic material are stored.

5. Conti .. This is also the part of the cell that creates mRNA for cell replication. The cell body relays the information down to the axon

6. DENDRITES Dendrites are branch-like structures extending away from the cell body, and their job is to receive messages from other neurons and allow those messages to travel to the cell body. Dendrites are specialized to receive signals from neighboring neurons and carry them back to the cell body

7. AXON It is a tube-like structure that carries an electrical impulse from the cell body to the structures at opposite end of the neuron i.e axon terminals, which can then pass the impulse to another neuron.

8. Conti.. Myelin sheath is also present around the axons is called as myelinated nerve fibers. This myelin sheath further consist of protein- lipid complex called as schwann cells. There is a short gap between the two segments of axon is the Nodes of Ranvier where the signals get recharged

9. AXON TERMINAL An Axon terminal is the very end of a branch of nerve axon. Axon Terminal is the last step for the relay of information inside the neuron.

10. -Electrical Communication -Chemical Communication How do Neurons Communicate?

11. THE ELECTRICAL PART Action potential is an electrical current sent down the axon. The activity within the neurons is electrical. This current causes the neuron to “ fire ”

12. CONTI.. Action potentials travel down the axon like a wave of energy

13. Synaptic transmission The Synapse is the space Or synaptic gap between neurons Information must be transmitted across the synapse to other neurons via the neurotransmitters . This is an electrochemical process

14. Let’s Review!

15. Neurotransmitters Neurotransmitters are chemical substances that reside in the axon terminals They communicate to other neurons by binding to receptors on neighboring neurons

16. Chemical Communication The communication between neurons is chemical

17. TYPES OF NEURONS There are many neurons in the nervous system—a number in the trillions. They can be classified as: Depending upon the number of poles Unipolar Neurons Bipolar Neurons Multipolar Neurons

18. Conti.. Depending upon the functions Motor neurons Sensory neurons

19. Depending upon the number of poles

20. Conti.. Unipolar Neurons These neurons have a single pole, from which the both axon and dendrites arise. True unipolar are present only in embryonic stage in human being.

21. Conti.. Bipolar Neurons These neurons have two poles, one for axon & other for dendrite. Bipolor neurons are found in the vestibular, cochlear ganglia, in the nasal olfactory epithelium & bipolar cells in the retina of the eye.

22. Conti.. Multipolar Neurons These have many poles. One of the pole gives rise to axon and all other to dendrites. In CNS most of the neurons are multipolar.

23. Depending upon the functions Motor neurons These are also known as efferent nerve cells. These carry impulses from CNS to the effector organ like muscles, glands, blood vessels. These neurons have very long axon and short dendrites.

24. Conti.. Sensory neurons These are also known as afferent nerve cells. These carry impulses from effector to the CNS. These neurons have very short axon and long dendrites.