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Jo Cameron, a lady who has a rare genetic mutation, makes her feel virtually no pain. She never feels anxious or afraid in a painful situation. Her condition was discovered when she had surgery on her hand; doctors found out that she didn't need painkillers after surgery; so, what do you think about her condition? Why does it happen to her? The part of our body which make all of us sense pain is not functioning in her body. Do you know what that part is responsible for sensing the pain?

Picture explaining the pain knowing neurons

They are called pain receptors. They are a type of sensory neuron with specialised nerve terminals found throughout the body, including the skin, deep tissues (such as muscles and joints), and most visceral organs.

Similar to pain receptors, there are many other receptors, which can be found throughout our body. These receptors help us see, smell, taste, hear, sense the touch, sense the temperatures etc.
Receptors are specialised tips of the nerve cells that detect information around our external environment by means of a stimulus and create a impulse into the nervous system, which results in the nervous system to take actions.

These receptors are situated in the sense organs such as eyes, nose, tongue, ears and skin.
The receptors are the specialised ends of a nerve cell or a group of nerve cells that collect information about environmental changes in stimuli.

 Sensory neurons, a type of nerve cell, transmit information from the receptors to the brain. Sensation refers to the impulses that flow from the receptor to the brain through the sensory neuron. This feeling is analysed and interpreted as perception in the brain. Motor neurons are a type of nerve cell that transmits information from the brain to the effector organ. Muscles and glands are the primary effectors, producing appropriate reactions.

The action of sensory and motor neuron
Pathway of nerve impulses
The information is received via chemical reaction at the dendritic tip of a nerve cell, which results in an electrical impulse.
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This electrical impulse travels from the dendrite to the cell body and at the axon terminals.
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The electrical impulse at the axon's end triggers the release of chemicals.
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These chemicals cross the synapse and initiate a similar electrical impulse in the following neuron's dendrite.
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Finally, a similar synapse permits such impulses to be delivered from neurons to other cells like glands and muscle cells.

In the above flowchart the pathway of nerve impulse while sensing an information is given. At the very first step, it is mentioned that information is received via chemical reaction at the dendritic tip of a nerve cell. The information is passed via the dendritic tip of nerve cell, also called as receptors.

Chemical synapse

Animals receive external information through a specialised system or organ known as the sense organs or receptors organ. Human beings have five different sensory organs. The following is a list of them.

Five senses concepts with human organs

 Location of the receptor Name of Receptor Stimulus Eyes Photo receptor Light Ears Phono receptor Sound Nose Olfactory receptors Smell Tongue Gustatory receptors Taste Skin Tango receptor Thermo receptor Touch Heat/cold All over the body Algesireceptors Pain Internal ear Statoreceptors Acceleration/gravity All over the body Nociceptors Pain

The video explaining the types of receptors and sensory receptors
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