What are the main routes of entry for skin absorption?

What are the main routes of entry for skin absorption?

• A. Nails, calluses, scars, and pores
• B. Hair shafts, sweat glands, and pores
• C. Nerves, blood vessels, muscles, and ligaments
• D. Hair follicles, sebaceous, sweat glands, and cuts

Answer: (D)

Skin absorption occurs mainly through appendageal pathways and through breaks in the skin. Hair follicles provide channels that bypass much of the outer protective layer, and the associated sebaceous glands open into these same areas, giving chemicals easier access to deeper skin layers. Sweat glands also supply ducts that reach the surface, creating another route for substances to move inward. When skin is cut or damaged, open entry points appear, allowing substances to reach underlying tissues quickly. Other options involve structures that aren’t primary routes for absorbing chemicals through intact skin. Nails are keratin-based barriers on the surface and don’t act as entry points. Hair shafts themselves are dead keratin and not typical paths for absorption. Internal structures like nerves, blood vessels, muscles, and ligaments sit below the skin and aren’t routes through the outer barrier. Scars can alter barrier properties but aren’t the main entry pathways in normal conditions. So, the main routes are through hair follicles, sebaceous glands, sweat glands, and cuts.

Skin absorption occurs mainly through appendageal pathways and through breaks in the skin. Hair follicles provide channels that bypass much of the outer protective layer, and the associated sebaceous glands open into these same areas, giving chemicals easier access to deeper skin layers. Sweat glands also supply ducts that reach the surface, creating another route for substances to move inward. When skin is cut or damaged, open entry points appear, allowing substances to reach underlying tissues quickly.

Other options involve structures that aren’t primary routes for absorbing chemicals through intact skin. Nails are keratin-based barriers on the surface and don’t act as entry points. Hair shafts themselves are dead keratin and not typical paths for absorption. Internal structures like nerves, blood vessels, muscles, and ligaments sit below the skin and aren’t routes through the outer barrier. Scars can alter barrier properties but aren’t the main entry pathways in normal conditions.

So, the main routes are through hair follicles, sebaceous glands, sweat glands, and cuts.