Test 4 Unit Review

Function of Skin

Acts as a barrier against microorganisms, UV radiation, chemicals, and physical injury; regulates temperature; provides sensation; offers immune defense; facilitates excretion; synthesizes vitamin D.

Synthesis of Vitamin D

The skin produces vitamin D when exposed to UVB sunlight, crucial for calcium absorption and bone health.

Thick vs Thin Skin

Thick skin, found on palms and soles, has a thicker epidermis and lacks hair follicles; thin skin covers most of the body, is more delicate, and contains hair follicles and oil glands.

Epidermis

The outermost layer of skin made of keratinized stratified squamous epithelium, providing a barrier and lacking blood vessels.

Keratinization

The process where keratinocytes move from the deeper epidermis to the surface, becoming hardened and waterproof.

Types of Melanin

Eumelanin (brown/black pigment) provides more UV protection; Pheomelanin (reddish/yellow pigment) provides less UV protection.

Sweat Glands

Eccrine glands secrete watery sweat for temperature regulation; apocrine glands secrete thicker sweat activated during puberty.

Sebaceous Glands

Glands that secrete sebum to lubricate the skin and hair, found throughout the body except for palms and soles.

Arrector Pili Muscle

A small muscle attached to hair follicles that contracts in response to cold or fear, causing goosebumps.

Heat Loss Mechanisms

Radiation, conduction, convection, and evaporation are methods by which the body loses heat.

Hypothalamus

The control center for body temperature, detecting changes and activating responses like sweating or shivering.

Skin Color Determinants

Skin color is determined by melanin production, genetics, sun exposure, and conditions like hyperpigmentation and jaundice.

Skin Cancer Types

Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) are common, while Melanoma is the most deadly, originating from melanocytes.

Heat Exhaustion vs Heat Stroke

Heat exhaustion causes dizziness and sweating; heat stroke is more severe, with a body temp over 104°F requiring immediate treatment.

Burn Grades

First-degree burns affect only the outer skin; second-degree burns cause blisters; third-degree burns damage all layers and may need grafts.

Vitamin A

Supports skin cell turnover, reduces wrinkles, and treats acne.

Vitamin E

Acts as an antioxidant, improving moisture retention and protecting skin from free radicals.

Vitamin C

A powerful antioxidant that boosts collagen production, brightens skin, and protects against UV damage.

Vitamin K

Helps with skin healing, reduces bruising, and minimizes dark circles.

Hypodermis

The deepest layer composed of fat and connective tissue, providing insulation and connecting skin to muscles and bones.

Muscle Function

The Arrector Pili Muscle contracts to create goosebumps for insulation.

Nail Color Indicators

Normal nails should be pink; blue nails indicate poor oxygenation; yellow nails are often linked to respiratory issues.