Integumentary system

Largest organ of the human body

Skin (integument)

Three main layers of the skin

Epidermis, dermis, hypodermis (subcutaneous layer)

Primary function of the epidermis

Protection from environmental damage and waterproof barrier

Layer of the epidermis containing dead, flattened cells

Stratum corneum

Pigment that gives skin its color

Melanin

Cells that produce melanin

Melanocytes

Function of the dermis

Supports and nourishes the epidermis; contains blood vessels, nerves, and glands

Two types of glands found in the skin

Sweat glands (sudoriferous) and sebaceous (oil) glands

Role of sweat glands

Help regulate body temperature through evaporation

Function of sebaceous glands

Secrete sebum to lubricate and waterproof the skin and hair

Composition of the hypodermis

Mostly adipose (fat) tissue and connective tissue

Functions of the integumentary system

Protection, temperature regulation, sensation, excretion, and vitamin D synthesis

Two types of body membranes associated with the integumentary system

Cutaneous membrane and mucous membrane

Cutaneous membrane

The skin; composed of epidermis and dermis

Mucous membrane

Membrane that lines body cavities open to the outside, secretes mucus

Serous membrane

Membrane that lines body cavities closed to the outside, secretes serous fluid

Function of serous fluid

Reduces friction between organs and body cavity walls

Difference between thick and thin skin

Thick skin has a thicker epidermis with a distinct stratum lucidum; found on palms and soles. Thin skin covers the rest of the body.

Role of keratin in the skin

A protein that waterproofs and protects skin cells

Type of cells that make up the majority of the epidermis

Keratinocytes

Cause of a suntan

Exposure to UV radiation increases melanin production by melanocytes

Function of Langerhans cells

Immune cells that help protect the skin from pathogens

Layer of skin that contains blood vessels

Dermis

Primary function of the hypodermis

Insulation, energy storage, and cushioning

Psoriasis

A chronic autoimmune disease causing rapid skin cell production and scaling

Pigment responsible for red coloration in blood vessels under the skin

Carotene (yellow-orange) and hemoglobin (red)