 Dear students, in this topic we shall discuss what are sensory modalities and various types of receptors which receive these sensory modalities. Dear students, the sensory modalities are the types of sensory information that we can distinguish or perceive. They are commonly known as senses. Receptors may be external or internal depending on the source of stimulus. The sensory modalities are perceived through specific receptors. These receptors are located in sense organs or they are scattered in various parts of the body. Dear students, first we shall discuss the external sensory modalities. There are five major external sensory modalities of humans which we call senses, five major senses, that is, sense of vision, sense of hearing, sense of touch, sense of taste and sense of smell. The sense of vision is perceived through eyes. These eyes have photoreceptors. Sense of hearing is perceived through ears which have mechanoreceptors. Sense of touch is perceived through skin which has misnourished carpacels. Sense of taste is perceived through taste buds in the tongue which have gastatory receptors. The sense of smell is perceived through nasal cavity that has olfactory receptors. Dear students, now we shall discuss the internal sensory modalities. The internal sensory modalities are perceived through intraceptive receptors. These intraceptive receptors respond to the stimuli or signals from within the body. We shall take few examples or types of intraceptive receptors. The first example is of vestibular system. The receptors of vestibular system respond and monitor orientation of the body. Body's direction and angles and balance are receptors in the vestibular system to monitor. Thermoreceptors are second type. Thermoreceptors are scattered on the skin. They keep track of thermal changes or thermal state of the body. Chemoreceptors which detect chemical changes in the body. Another type of intraceptive receptors is the proprioceptors. These proprioceptors are located in the movable joints. They monitor the position of muscles and joints. Then another type is nociceptors, which are distributed evenly in the skin and deeper parts of the body. They perceive the sensation of pain. To perceive the sensation of pressure, there are pasenian carpacels which are situated deep in the skin. The intraceptive receptors and these sensations are very important because they communicate information to the brain about the internal conditions of the body through the pathways which are not brought into consciousness. They play a crucial role in providing information to the brain about the state of the body and its position in space. Just imagine that we walk using our joints and muscles and they are being used in balance. Just imagine that if we have to give orders to our joints, bones, and muscles to think about which angle we are going to go, whether we are straight or not, then the walk becomes so difficult. Non-human animals have sensory modalities. In addition to such modalities that we have discussed and are present in men, special modalities have distance thermoreception, electroreception, and magnoreception. The distance thermoreception is the detection of heat energy emitted from a distance. It is perceived through special pit organs which are found in some snakes. Snakes use this sense to detect their prey from a distance due to temperature difference. Mammals and other animals have a different body temperature of a few degree centigrade, and snakes perceive this difference from a distance because of their pit organs. Mammal detection is the detection of low-frequency electric signals. This sense is found in some electric fishes and they use this sense to communicate with one another in murky waters. Dear students, In order to perceive the magnetic field of the earth, birds have special magno-receptors which provide sense of direction during the navigation of the sky. These receptors are usually found in migratory birds.