Hair & Nails

Hair

Hair originates from the base of the downward extension of living epithelial cells into the dermis that is called the hair follicle. The hair shaft is the part of the hair that is exposed on the skin's surface. The hair root is the remaining follicle beneath the skin. The hair bulb is the bulge at the base of the hair root surrounding the papilla. The hair matric is a layer of basal cells that make up the hair bulb.

Nails

Nails are a specialized structure of the epidermis that occurs at the tips of our fingers and toes. A diagram of a nail is pictured below:

Sweat (Sudoriferous) Glands

Two types:

1. Eccrine (merocrine) sweat glands

- Present throughout skin surface

- Help regulate body temperature through evaporation

- Controlled by the sympathetic division of the autonomic nervous system

2. Apocrine glands

- Associated with hair follicles, are larger, and lie deeper in the dermis

- Release a thicker fluid due to a high concentration of fatty acids

- Responsible for body odor and do not begin to function until puberty

- Are stimulated during emotional stress and sexual excitement

Sebaceous Glands

- Oil glands found all over the body which generate and excrete a mixture of lipids, called sebum, onto the hair and skin surface for lubrication

- Antibacterial and prevent water loss in low-humidity environments (not a problem here in VB)

24) INTEGUMENTARY SYSTEM OF HOMEOSTASIS

The integumentary system is active in wound repair and scarring. Burns are a special kind of wound that affect much of the integumentary system and will be discussed in detail.

Keloid- A raised or hypertrophic scar that results when scarring continues after a wound is healed

Burns- Wounds that result when skin is exposed to intense heat, radiation, electrical current, or caustic chemicals

1. First degree burns- Only the epidermis is damaged

2. Second degree burns- Destroy the epidermis and extend into the dermis, resulting in painful blistering

3. Third degree burns- Penetrate the full thickness of the skin, including the subcutaneous layer (hypodermis)

4. *Fourth degree burns- Affect the underlying muscle and bone, and always require emergency trauma care

Thus concludes my 16 hours of capacity building before the real fun begins.

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