Receptors - specialized cells or sensory organs that receive information from the environment.
Receptor - generally a structure that has the ability to:
specific recognition of stimulation of a physicochemical nature;
eliciting a response to stimulation, directly or through other structures.
Due to the nature of the stimulus or stimulation, the receptors are divided into:
chemoreceptors - receptors that distinguish between chemicals; the term is sometimes used in relation to:
proteins: taste and smell receptors - receptor proteins of taste buds and olfactory neurons of the olfactory epithelium (olfactory receptors);
cells: taste neurons, olfactory neurons;
organs: taste buds, olfactory epithelium);
thermoreceptors - receptors that react to temperature or its change;
nociceptors - pain sensation receptors;
mechanoreceptors - receptors for mechanical sensations, such as touch (Vater-Pacini lamellar body) or sound (the cochlear organ of the inner ear uses mechanoreceptors to transform sound into nerve signals);
vibroreceptors - receptors for short vibrations caused by surface tremors;
photoreceptors - light receptors (proteins: opsins, rhodopsin; cells: suppositories, rods; organs: eye);
magnetoreceptors - receptors for the intensity and direction of the magnetic field;
electroreceptors - receptors for the intensity and direction of the electric field;
osmoreceptors - osmotic pressure receptors;
proprioreceptors - movement, position and balance receptors;
baroreceptors (presoreceptors) - pressure receptors;
Statoreceptors, static receptors - inform the central nervous system about the position of the body and its movements. Some receptors may also respond to stimuli other than those appropriate to their function. For example, human nociceptors and thermoreceptors respond to capsaicin in hot-tasting varieties of peppers (Capsicum sp.), And cold receptors are activated with menthol.
Cholinergic receptors (parasympathetic system):
Nicotine (N) - the agonist is nicotine;
Nicotine neural (Nn);
Muscle nicotine (Nm);
Muscarine (M) - The agonist is muscarine. There are 5 types of M1-M5:
M1 - learning and memory;
M2 - heart;
M3 - smooth muscles.
Classification of receptors
due to the location:
exteroreceptors - outside the body;
interoreceptors - inside the body; are divided by location:
proprioreceptors (proprioceptors) - the motor organ (articular, muscular) - informs about the position of the body and its parts in relation to each other (kinesthesia);
interoreceptors (enteroceptors) - internal organs - inform about the condition of individual organs, blood pressure;
angioreceptors - inform about the state of the environment in the vessels.
exteroreceptors are divided according to the contact with the stimulus:
telereceptors, distance receptors - at a certain distance from the outer surface of the body (e.g. photoreceptors - eyesight, chemoreceptors - smell, organs of hearing and balance);
contactoreceptors, contact receptors - are in direct contact with the stimulus (e.g. touch, pain, taste, temperature);
deep sensation receptors (proprioreceptors).
mechanism of action of capsaicin