Lesson · S.1.8

The integumentary system

How skin, hair, and nails protect the body, sense the environment, and help hold internal temperature steady, plus the layer names the TEAS expects you to know.

ObjectiveS.1.8Read2 minExam weightHuman Anatomy and Physiology ≈ 41% of Science

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What you will be able to do

Name the three layers of skin and a structure or function found in each.
Explain how vasodilation and vasoconstriction regulate body temperature.
List the integumentary system's roles beyond protection, including waste excretion and vitamin D synthesis.

What the lesson concludes

Three layers, outer to inner: epidermis, dermis, hypodermis.
The epidermis surface is dead cells, which is what makes it waterproof, not the dermis.
Nerve endings for touch, temperature, and pain sit in the dermis, not the epidermis.
Vasodilation brings blood near the surface to cool the body, vasoconstriction pulls it away to conserve heat, a detail the TEAS likes to test.
Skin also excretes waste and synthesises vitamin D, alongside its main job of protection.