Question

Receptors for taste, smell and for blood oxygen are called as
A. Mechanoreceptors
B. Nociceptors
C. Chemoreceptors
D. Thigmoreceptors

Answer 1

Hint:- A receptor is a specialized cell or a group of specialized cells which have the ability to respond to a stimulus. The stimulus such as light, heat, touch or chemicals are sensed by receptor cells. Receptors are molecules of protein which have specificity for certain molecules called ligands and bind with them to produce a series of reactions. Our sense organs like eyes, ear, tongue, nose and skin are
profound examples of sensory receptors.

Complete step-by-step solution:-
Receptors are found either on the cell surface (i.e., cell-surface receptors) or inside the target cells (i.e. internal receptors). In the biological system, the action of receptors includes the relay of signal, amplification and then integration. Sensory receptors lie in close proximity to neurons. On receiving a stimulus, the energy is first converted into electric signals which are then relayed across neurons to the Central Nervous System or brain.
Chemoreceptors create a response to chemical stimuli. They are responsible for sensing taste and smell. Our tongue possesses taste buds which are embedded in the epithelium and open in our mouth through a taste pore. They have gustatory receptors which occur in a group of 50-150. They help to sense taste. The nasal cavity and its roof is lined with olfactory epithelium which possess millions of olfactory receptors each connected to olfactory neurons. Olfactory receptors help to detect smell.
The brain responds by directing the effector tissue which in turn directs the motor neurons to send response signals. Therefore, chemoreceptors are responsible for sensing taste, smell and also oxygen in blood.
So, the correct answer is (C), Chemoreceptors.

Note:- Electrical changes in receptor cells initiate an action potential across a neuron. Each receptor cell is made up of only one type of receptor protein. An organism’s response to chemicals is highly affected by the concentration level of the chemical.