TEAS® Science Study Guide
Integumentary System
The integumentary system — skin, hair, and nails — protects the body, regulates temperature, and provides sensation.
Functions — barrier against pathogens and water loss, temperature regulation, sensation (touch, pressure, pain, temperature), vitamin D synthesis, and excretion of small amounts of waste through sweat.
Three layers
- Epidermis — The outer layer. No blood vessels. Contains melanin, the pigment that gives skin its color and protects against UV radiation.
- Dermis — The middle layer. Contains blood vessels, nerve endings, hair follicles, and sweat and oil glands. This is the layer that does most of the work.
- Hypodermis (subcutaneous layer) — The deepest layer. Mostly fat; insulates and cushions.
Temperature regulation
- Too hot → blood vessels dilate (bringing heat to the surface) and sweat glands release sweat, which cools by evaporation.
- Too cold → blood vessels constrict (conserving heat) and muscles shiver to generate heat.
This is another example of homeostasis.
Terms to know
- Epidermis — Outermost skin layer.
- Dermis — Middle layer; holds blood vessels, nerves, and glands.
- Melanin — Pigment that protects against UV light.
- Vasodilation — Widening of blood vessels to release heat. Vasoconstriction — Narrowing to conserve it.
What the TEAS asks most
- Which layer contains blood vessels and nerve endings? Dermis.
- Which is the outermost layer? Epidermis.
- How does the body cool itself? Vasodilation and sweating.
- Which vitamin does the skin synthesize? Vitamin D.