Neurons or nerve cells are the basic structural and functional units of nervous system. Neuron does everything including information processing, receiving, and sending throughout the body in the form of neurotransmitters. The whole nervous system is made of these neurons or nerve cells. Hence, understanding anatomical structure and function of neurons or nerve cells is really essential.
Meaning and examples of neurons or nerve cells
Neurons or nerve cells are fundamental units of nervous system specialized in transmitting electrical impulses and chemical signals throughout the body. It does so by using different components of neurons like dendrons, axons, cell body.
For layman’s term, neurons are basic units of nervous system that send information between neurons in the form of chemical signals. Such chemical signals are called neurotransmitters.
What does neurotransmitters mean?
Neurotransmitters are chemicals that are used to transmit between gap of two neurons or synapse. Because, it is necessary to cross electric signals from one neurons to another. And, there is a gap between two neurons. Therefore, chemicals called neurotransmitters are used to transmit electric signals across the gap or synapse.
On the basis of structure of the neurons, they are classified as unipolar, pseudounipolar, bi-polar, and multipolar neurons. But on the basis of function, neurons or nerve cells are classified as sensory, motor, interneurons.
Understanding anatomical structure and function of neurons or nerve cells
As I mentioned that neurons or nerve cells are basic functional unit of neurons system. There are various types of neurons based on anatomical structure and function of neurons or nerve cells.
Structure and function of Cell body or cyton
Structurally, neuron has cell body or cyton, dendron, and axon. Each of these components play different functions to pass information through body.
The cell body or cyton has a nucleus with Nucleolus and neuroplasm. Cyton plays vital role in the synthesis of enzymes needed for the formation of neurotransmitters. A clear film of cytoplasm surrounds the nucleus around which there are neurofibrils.
Neurofibrils do the job in transmission of nerves. Neurofibrils is a threadlike delicate structure. It transmits electric signals or impulse. It extends from dendrite to the axon.
Nissl’s granules is a neuron cell organelle Or substances found in the cell body. It does the job of protein synthesis. After protein synthesis, it transport it to the cell body for smooth functioning.
Simple definitions of Neuroplasm, Neucleolus, neurofibrils, Nissl’s granules in neurons
Neurofibrils are up to 2 μm in diameter in size. It is present in the cyton or cell body. It carries electric signals from dendron to the axons. Simply, it is extended from dendrite to axon. In other words, carries electric impulse from dendrite to axon. In appearance, it is thread like delicate structure.
Next, the cyton or cell body or soma has abundant nutrient rich cyto-plasm with nucleus. Cytoplasm in the neuron body is called neuroplasm. Neuroplasm includes Nissl’s granules. It is substance does the job of protein synthesis. Neuroplasm also has other cell organelles like mitochondria, golgi bodies, ribosomes etc.
Finally, neucleolus is present in oval shaped nucleus of neuron. It is production site of ribosomes. And it is made of DNA, Protein & RNA. Ribosome in neuron does the job of protein production. So, it has great role in the functioning of neuron.
Nucleus in the cyton or soma is a oval shaped structure surrounded by cytoplasm or neuroplasm. Simply, it regulates cell. It contains DNA to produce ribosomes. And, as I mentioned that ribosomes does the job of protein production.
Describing structure and functions of dendron and axon in neurons
Dendron Or dendrite is a branched tree like structure arises out of neuron body having 5 to 7 in numbers. It receives the electro-chemical impulses from other axon terminus of neurons and sends to the cell body or cyton. Importantly, Nissl’s granules and neurofibrils both are present at the base of dendron as they pass message towards the cyton.
Axon is a branchless, long nerve fibre of neurons arises from cyton or cell body. It’s main function is to carry the messages away from the cell body or cyton with a bundle of neurofibrils.
Explaining function of Synapse or gap between two neurons
It is a junction between two neurons. And, it is a site where chemical signals are sent between dendrite and axon terminus. They present present at the tips of dendrites. In other words, the interconnection between two neurons is called synapse. Such synapse may be axo-dendronic, axo-axonic, axo-somatic, or dendro-dendronic.
What are the types of neurons or nerve cells
On the basis of structure of neurons, nerve cells are classified as: unipolar, pseudounipolar, bi-polar, and multipolar neurons. Besides, on the basis of function, neurons or nerve cells are classified as sensory, motor, interneurons.
Unipolar neurons or nerve cells
Neurons in invertebrates are called unipolar neurons. In this neurons, there is single extension from cell body or cyton upto the axon. Unipolar neurons are absent in human body.
B-ipolar neurons or nerve cells
While in bi-polar neurons, there are two distinct structures extended from cell body or cyton. Examples of structures are axon and dendrite. Nerves in the ear, eye, and nasal cavity are known as bi-polar neurons. These are not common like others.
Multipolar neurons or nerve cells
Finally, multipolar neurons are the neurons which are present in the human being, especially in the central nervous system, peripheral nervous system and autonomic nervous system.
In this neurons, there are multiple structures extend from the cell of the body or cyton. It has single axon but multiple dendrites.
Now let’s understand the types of neurons on the basis of function they do. They are sensory neurons, motor neurons, and interneuron cells.
Difference between sensory, motor and interneuron cells
When you experience effective stimuli, it provides sensory input to activate sensory neurons so that these cells pass information to the nervous system throughout body. The sensory inputs may be anything in the external environment like physical or chemical.
For example, if you experience hot or cold, it is termed as physical sensory inputs. Whereas, if you experience taste or smell, it becomes chemical sensory inputs.
Motor neurons — lower and upper motor neurons
Second, motor neurons are neurons locates in spinal cord of central nervous system. Motor neurons connect with muscular system and organs for ensure movement as per commond. Technically, there are two types of motor neurons. One is lower motor neurons that connect with spinal cord to muscles; whereas, motor neurons that connect brain to the spinal cord becomes upper motor neurons.
Finally, it is interneurons which links sensory neurons with motor neurons. It is also important to interconnection between two neurons. This is all about the anatomical structure and function of neurons or nerve cells.
Circulatory system of human body