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Accessory Structures of the Skin (a.k.a. Skin Appendages)

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Presentation on theme: "Accessory Structures of the Skin (a.k.a. Skin Appendages)"— Presentation transcript:

1 Accessory Structures of the Skin (a.k.a. Skin Appendages)
Hair Nails Glands

2 3 Protective Functions of Hair
Protection for the head Shields the eyes Helps to keep foreign particles out of the respiratory tract Protects against bumps? Another function of hair: insulation

3 Hair

4 Hair

5 Parts of a Hair Hair root is enclosed in the hair follicle
Hair shaft is the part of the hair that projects from the surface of the skin Growth zone of follicle is called the Hair bulb matrix Most of the shaft is dead keratinized material Papilla of the hair is projection of connective tissue that contains blood vessels

6 Hair

7 Internal Structure of Hair
Medulla (central core of hair shaft)) Cortex (second layer) Melanocytes = pigment-producing cells Produce varying amounts and colors of pigment - Cuticle of the hair is the outermost layer; Contains the most keratin Wears away at end = “split ends”

8 Around the Hair Small bands of smooth muscle muscle cells called arrector pili muscles connect to each side of the hair follicle to the cells of the dermis. When they contract we get “goosebumps”

9 Nails

10 Nails A nail is a scale-like modification of the epidermis
Like claws or hooves

11 Nails

12 Structure of a Nail Free edge is that part of the nail that extends out from the epidermis Nail body or plate is the visible part of the nail that is attached to the epidermis Nail root is the part that is embedded inside the epidermis of the skin

13 Structure of a Nail Skin fold that is thick at the base of the nail is the cuticle. The thickened – proximal area of the stratum basale of the epidermis is the *Nail matrix which is responsible for nail growth As nails are produced by this matrix, they become heavily keratinized

14 Structure of a Nail Like hairs, nails are mostly dead keratin
Nails are transparent, but look pink due to the blood supply of the underlying dermis The white crescent of the nail, which falls over the nail matrix is called the lunula

15 Glands

16 Glands Glands of the SKIN - Cutaneous glands are all exocrine glands, which means they have ducts to release their secretions. Two major types in the skin: Sebaceous glands = oil glands Sudoriferous glands = sweat glands

17 Sebaceous Glands

18 Sebaceous Glands = OIL Glands
Found all over the skin except for the palms of the hands and the soles of the feet Ducts mostly empty into a hair follicle sebum is a lubricant; mixture of oily substances that keeps skin soft

19 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

20 Sudoriferous Glands = SWEAT Glands
Have own ducts to surface PORES of the skin. These glands can be  eccrine glands which are far more numerous and found all over the body  Apocrine sweat glands are mostly in axillary and genital areas of the body

21 Glands

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