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## Integumentary System ### Absorption - The skin can absorb certain chemicals and drugs like estrogen and nicotine. - **Transdermal administration** is when drugs are administered through the skin using an adhesive patch. - The patch keeps the drug in contact with the skin surface. - Drugs are a...

## Integumentary System ### Absorption - The skin can absorb certain chemicals and drugs like estrogen and nicotine. - **Transdermal administration** is when drugs are administered through the skin using an adhesive patch. - The patch keeps the drug in contact with the skin surface. - Drugs are absorbed into blood vessels in the dermis. ### Temperature Regulation - Body temperature is influenced by capillary networks and sweat glands in the dermis. - **Vasoconstriction** is when blood vessels narrow, reducing blood flow to the periphery of the body. - Vasoconstriction conserves heat. - **Vasodilation** is when blood vessels widen, increasing blood flow to the periphery of the body. - Vasodilation releases excess heat. ### Immune Function - **Epidermal dendritic cells** play an important role in initiating an immune response against pathogens that have penetrated the skin. - These cells and dendritic cells of the dermis also attack epidermal cancer cells. ### Sensory Reception - The skin contains a vast number of sensory nerve endings that detect stimuli such as touch and pressure. - There are seven major types of sensory receptors in the skin. - They detect, distinguish, and interpret stimuli of our external environment. ### What Did You Learn? 1. How does the skin produce vitamin D? 2. Is the skin entirely waterproof? Explain how the skin dissipates excess heat?