Integumentary System
* The integumentary system is the largest is the largest organ system accounting for about 16% of the total body weight.
* The integumentary system consists mainly of the skin and its soft derivatives like sweat glands, sebaceous glands and mammary derivatives like hair and nails.
* The skin is made up of two layers – epidermis and dermis.
* The epidermis consists of five sub – layers, namely stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum and tratum germinativum.
* The dermis contain several structures like blood vessels, lymph capillaries fibres, nerves fibres, sebaceous or oil and sweat glands, and hair follicles.
Skin as Sense Organ
* The presence of widely distributed free nerve endings in the dermis makes the skin the largest sense organ.
* There are different nerve endings or receptor cells or receptor corpuscles for various sensations.
* The tactile receptors respond to touch, pressure and vibrations, the thermoreceptors to temperature, and the nociceptors respond to pain.
* There are six types of tactile receptors – Nerve Ending, Root Hair Plexus, Merkel’s discs, Meissners corpuscles, Pacinian corpuscles, and Ruffini corpuscles.
* Skin receptors are also called cutaneous receptors.
* The intensity of feeling a stimulus depends on the area of your skin.
* The brain analyses and processes the stimulus, and the body reacts accordingly.