What is Chemoreceptor?-Definition, Structure, Types and Functions

The receptors which respond to changes in chemicals are called chemoreceptors. Chemoreception is a direct sense in those molecules. It acts specifically to stimulate a response. Chemoreception is the oldest and most universal sense in the animal kingdom.

What is Chemoreceptor?

A chemoreceptor, also known as a chemosensor, is a specialized sensory receptor that converts chemicals (endogenous or inducible) into biological signals. If the chemoreceptor is a neuron, the signal can be in the form of an action potential; if the chemoreceptor is a specialized cell (such as a neuron), it can activate a neurotransmitter of a nerve fiber.

Chemoreceptors are specialized cells that detect chemicals in the body. Chemoreceptors are found throughout the body, from the nose to the brain. The main function of these receptors is to sense chemical changes in the blood. This information helps regulate hunger and satiety.

Structure Of Chemoreceptors

Chemoreceptors are proteins or protein complexes that bind molecules that can be detected at a distance, usually at low concentrations (smell) or at close and usually higher concentrations (taste), each of which is Airborne organisms are both volatile and non-volatile stages.

The chemoreceptor cells are surrounded by supporting structures that form the most visible part of the chemosensory organ. Support structures are often formed as epidermal specializations. These specialized structures are;

• Pegs (Sensilla Basiconica)

• Hairs (Sensilla Chaetica)

• Plates

• Pits (Sensilla Coeloconica)

Chemoreceptors In Invertebrates

Here are examples of chemoreceptors in some invertebrates;

Chemoreceptors in Protozoa:

They have a chemical sense. They respond with avoidance behavior. They avoid acid, alkali, and arid salt stimuli. Specific chemicals attract predatory ciliates to their prey.

(B) Chemoreceptors In Aquatic Invertebrates

The chemoreceptors of many aquatic invertebrates are found in pits or depressions. Water with the specific chemical can circulate through it.

(c) Chemoreceptors in Arthropods:

The chemoreceptors are present on the antennae in arthropods. These are also present in mouthparts, and legs. They are present in the form of hollow hairs. These hairs are called sensilla. Sensilla contain chemosensory neurons.

The nature of chemical receptors is linked to their lifestyles. Some animals are used to perform tasks, such as humidity detection, pH assessment, prey tracking, food recognition, and mate locating. So their chemoreceptors detect these chemicals. For example, a female silk moth secretes bombykol as a sex attractant.

The male silk moths can detect bombykol in one trillion molecules. Its receptors are present on the antennae. A male moth can find a female from several miles downwind at night.

Types Of Chemoreceptors

There are two types of chemoreceptors;

Peripheral Chemoreceptors

It is present in the aortic and carotid bodies. It gets activated in response to changes in the partial pressure of oxygen.

Central Chemoreceptors

The central chemoreceptors are present in the medulla oblongata. They respond to changes in oxygen, and carbon dioxide tension in the blood or the cerebrospinal fluid.

Functions Of Chemoreceptors

It performs following functions;

• Central chemoreceptors detect changes in ) hydrogen ion concentration in cerebrospinal fluid. (CSF)

• It helps to regulate the depth and rhythm of breathi.ng.

• Chemoreceptors respond to changes in levels of oxygen, carbon dioxide, and pH.