Organ Systems - Integumentary System, Organ, Circulatory System of Gastropods, Excretory System of Gastropods, Sulcus, Body Systems (Paperback)

Chapters: Integumentary System, Organ, Circulatory System of Gastropods, Excretory System of Gastropods, Sulcus, Body Systems. Source: Wikipedia. Pages: 25. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: The integumentary system (Etymology - Latin integumentum, from integere to cover; from in- + tegere to cover ) is the organ system that protects the body from damage, comprising the skin and its appendages (including hair, scales, feathers, and nails). The integumentary system has a variety of functions; it may serve to waterproof, cushion and protect the deeper tissues, excrete wastes, regulate temperature and is the attachment site for sensory receptors to detect pain, sensation, pressure and temperature. In humans the integumentary system additionally provides vitamin D synthesis. The integumentary system is the largest organ system. In humans, this system accounts for about 16 percent of total body weight and covers 1.5-2m of surface area. It distinguishes, separates, protects and informs the animal with regard to its surroundings. Small-bodied invertebrates of aquatic or continually moist habitats respire using the outer layer (integument). This gas exchange system, where gases simply diffuse into and out of the interstitial fluid, is called integumentary exchange. This is the top layer of skin made up of epithelial cells. It does not contain blood vessels. Its main function is protection, absorption of nutrients, and homeostasis. In structure, it consists of a keratinized stratified squamous epithelium comprising four types of cells: keratinocytes, melanocytes, Merkel cells, and Langerhans' cells. The major cell of the epidermis is the keratinocyte, which produces keratin. Keratin is a fibrous protein that aids in protection. Millions of dead keratinocytes rub off daily. The majority...More: http: //booksllc.net/?id=5966