Skin Hypodermis Skin Color Skin Function

Subcutaneous or Hypodermis Not part of the skin Between dermis and tissues below

Rich in Adipose tissue (subcutaneous fat) Subcutaneous injections

Skin Color Determined by amount of 1. Melanin 2. Carotene 3. Hemoglobin at surface

1. Melanin Dark Brown pigment Produced by Melanocytes – Stratum Basale – Tyrosine → Melanin Enzyme Tyrosinase

Melanin Decreased Tyrosinase – Graying of Hair – White skin of elderly

Melanin Absence of Tyrosinase – Albinism (recessive)

Melanin Absence of Tyrosinase – Albinism

Melanin Melanocytes can group together – Results in ….

Melanin Freckles

Amount of Melanin Controlled by – Genes – Environment UV radiation

2. Carotene Yellow-orange pigment Found in food products

3. Hemoglobin Red Tint – Vessels dilate at surface - Embarrassment (nerves)

Skin Functions 1. Protection – Microorganism barrier – Water loss (keratin) – Chemicals (keratin)

Skin Functions – Physical damage (collagen fibers and desmosomes) – UV damage (melanin)

Skin Functions 2. Sensory – Pressure, touch, pain, and temperature

Skin Functions 3. Excretion – Salts and wastes (urea)

Skin Functions 4. Vitamin D production – UV light reaction –Important for calcium absorption in bones

Skin Functions 5. Immunity – Macrophages in tissue

Skin Functions 6. Temperature regulation – Release Heat Vasodilatation – Increase blood flow to dermis

Skin Functions 6. Temperature regulation – Conserve Heat Vasoconstriction – Decrease blood flow to dermis