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Accessory Structures of the Skin (a.k.a. Skin Appendages). Hair Nails Glands. You’ve seen this before!. Hair. Parts of a Hair. Root (beneath the skin) Follicle (around the root) Shaft (keratinized) Hair bulb matrix (growth zone) Papilla (projection of connective tissue). Hair.
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Accessory Structures of the Skin(a.k.a. Skin Appendages) Hair Nails Glands
Parts of a Hair • Root (beneath the skin) • Follicle (around the root) • Shaft (keratinized) • Hair bulb matrix (growth zone) • Papilla (projection of connective tissue)
Internal Structure of Hair • Internal structure of hair: • Medulla (core) • Cortex • Cuticle • Melanocytes = pigment-producing cells • Produce varying amounts and colors of pigment • Located in the cortex of the hair
Around the Hair • Non-striatedarrectorpili muscles in the dermis connect to each side of the follicle • Sebaceous gland leads into the follicle
Nails • A nail is a scale-like modification of the epidermis • Like claws or hooves • Nails are transparent, but look pink due to the blood supply of the underlying dermis
Nail Diagrams cuticle free edge nail body lunula lateral nail fold proximal nail fold nail body nail root nail bed nail matrix cuticle epidermis dermis bone hyponychium
Glands • Cutaneous glands are all exocrine glands, which means they have ducts to release their secretions. • Two major types in the skin: 1) Sebaceous glands = oil glands 2) Sudoriferous glands = sweat glands
Sebaceous Glands • Found all over the skin except for the palms of the hands and the soles of the feet • Ducts mostly empty into hair follicles • Produce sebum = mixture of oily substances and fragmented cells • Lubricant
Sebaceous Glands • Acne is an active infection of the sebaceous glands • Results in “pimples” or bumps on the skin • Caused by overproduction of oil, which blocks pores
Sudoriferous Glands • Ducts lead to pores on surface of skin • Sweat = water plus salts, vitamin C, wastes, lactic acid • Functions: • To excrete waste • To inhibit growth of bacteria (sweat is acidic!) • To regulate body temperature