BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Serotonin receptors are widely expressed within the GI tract, and five of the seven known families, 5-HT1, 5-HT2, 5-HT3, 5-HT4, and 5-HT7 receptors, are expressed in the gut and can affect gut functions151 (Fig. 3).

Detailed explanation-2: -It is recognised that the enteric nervous system (ENS) has a unique ability to mediate reflex activity independently of input from the brain or spinal cord. 1–4 This ability implies that the ENS contains sensory receptors, primary aVerent neurones, interneurones, and motor neurones.

Detailed explanation-3: -The walls of the alimentary canal contain a variety of sensors that help regulate digestive functions. These include mechanoreceptors, chemoreceptors, and osmoreceptors, which are capable of detecting mechanical, chemical, and osmotic stimuli, respectively.

Detailed explanation-4: -Muscarinic receptors are divided into five main subtypes M1, M2, M3, M4, and M5. [4] While each subtype exists within the central nervous system, they are encoded by separate genes and localized to different tissue types.