 Dear students, in this topic we shall discuss the phenomena and mechanism of mechanoreception. Mechanoreception is the sensory detection of physical stimuli that cause, that have mechanical energy. For example, the stimuli of stretch, touch, pressure, sound and gravity. These mechanical stimuli cause physical changes in the receptor cell membrane. For example, deformation, bending, displacement, stretching, etc. Such processes or such deformations occur in the receptor cell membrane. The receptor cells involved in the reception of such physical stimuli are called mechanoreceptors. These mechanoreceptors consist of ion channel proteins. These ion channel proteins are linked to some type of external structures. For example, celia or sensory hairs are these are associated with some type of internal structure that can be stretched, that is the cytoskeleton. These mechanoreceptors can be highly sensitive. They can respond to a physical displacement of as little as 0.1 nanometer. Dear students, now we shall discuss the mechanism of mechanoreception. When an external structure physically bends or displaces, it generates tension that alters the permeability of ion channels present in the membrane. The change in ion channel permeability alters the membrane potential. Change in membrane potential results in either depolarization or hyperpolarization. Dear students, now we shall discuss the structure of mechanoreceptors. The simplest mechanoreceptors consist of undifferentiated nerve endings. These undifferentiated nerve endings are found in the connective tissues present in the skin. While the complex mechanoreceptors have accessory structures associated with these mechanoreceptors and these accessory structures can transfer mechanical energy to the receptive membrane that actually contains the mechanoreceptors. Dear students, we shall discuss different types of mechanoreceptors one by one. Here we shall discuss the mechanoreceptors for touch, pressure and vibration. Receptors for these senses are embedded in the skin. The gentle touch receptors are situated at the base of hairs. These receptors are called hair and organs. They respond to displacement of hairs, very little movement or very little displacement of hairs. Similarly, another type of touch receptors which are called misnurse corpuscles are found in the ridges of fingertips. These misnurse corpuscles have encapsulated nerve endings. Another type of receptor found in the skin is for the mechanoreception of pressure. These structures are these receptors are called pasinian corpuscles and they are situated deep in the skin. Sense of vibration ke liye skin me ek aur type ke receptors bhi pahe daate hain jine marcles disks kate hain. Now we shall discuss the stretch mechanoreceptors. These stretch mechanoreceptors are found in the muscles of arthropods and vertebrates. They have various types. Most common of the stretch receptors are called proprioceptors. These proprioceptors detect muscle movements. They consist of mechanically sensitive nerve endings associated with specialized muscle fibers. When a muscle is stretched, dendrites receive this stimulus. As a result, action potentials are triggered in the sensory neurons and transmitted to the spinal cord. Another type of mechanoreceptors are involved in the reception of sound and equilibrium. These receptors are found in the middle and inner ear of vertebrates. For both these senses, there is a basic pattern. In two senses ke liye, small particles or moving fluids. Cell surface structures ke deflection pahe daate hain. Yani yaha pe stretch nahi hogi. Balke ek fluid ya uske andar mojood, solid particles strike karte hain ek receptor surface ke saad aur as a result, deflection produce hoti hain. Jab deflection produce hoti hain, as a result, action potentials are generated.