بسم الله الرحمن الرحيم
السلام عليكم ورحمة الله و بركاته …
أما بعد …
هذا موضوع متواضع أتمنى أن ينال على إعجابكم .
Accessory Organs Of The Skin )) ))

A. Hair Follicles :
1. hair can be found in nearly all regions of the skin .
2. each hair develops from epidermal cells at the base of a tubelike hair follicle .
3. as new cells are formed , old cells are pushed outward and become keratinized , forming the hair shaft .
4. a bundle of smooth muscle cells , called the arrector pili muscle , is attached to each hair follicle .
5. hair color is determined by genetics :
melanin from melanocytes is responsible for most hair colors but red hair also contains the pigment trichosiderin .
B. Sebaceous Glands :
1. sedaceous glands ( holocrine glands ) are usually associated with hair follicles .
2. they secrete sebum , which helps keep the and hair soft , moisturized , and waterproof .
C. Nails :
1. nails are protective coverings over the ends of fingers and toes .
2. keratinized epidermal cells produce nails .
3. nails consist of stratified squamous epithelial cells overlying the nail bad , with the lunula as the most actively growing region of the nail root .
4. as new cells are produced , older ones are pushed
outward and become keratinized .
5. the keratin of nails is harder than that produced by the skins epidermal calls .
D. Sweat Glands :
1. sweat glands ( sudoriferous glands ) are either eccrine , which respond to body temperature , or apocrine , which respond to emotional stress .
2. each sweat gland is a coiled tube .
3. sweat is primarily water but also contains salts products salts and waste products .
4. modified sweat glands , celled eruminous glands ,
secrete wax in the ear canal .
5. mammary glands , another modified type of sweat glands , secrete milk .