Ch. 5 Integumentary System

What are the 3 parts of the integumentary system?

Skin, hair, and nails, along with associated glands and sensory receptors.

What are the main functions of the integumentary system?

Protection, temperature regulation, sensation, vitamin D production, and preventing water loss.

What are the 3 layers associated with the skin?

Epidermis, dermis, and hypodermis (subcutaneous layer).

Which layers are considered the actual skin?

Epidermis and dermis.

What is the hypodermis?

The layer beneath the skin that contains connective tissue and adipose tissue; it is not technically part of the skin.

What is the epidermis?

The outermost layer of the skin, made of keratinized stratified squamous epithelium.

What is the dermis?

The layer beneath the epidermis that contains connective tissue, blood vessels, nerves, hair follicles, and glands.

What is the main function of the epidermis?

Protection and prevention of water loss.

What is the main function of the dermis?

Provides strength, elasticity, nourishment, sensation, and support for skin structures.

What are the 5 epidermal layers from deep to superficial?

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.

Which epidermal layer is found only in thick skin?

Stratum lucidum.

Where is thick skin found?

Palms of the hands and soles of the feet.

Where is thin skin found?

Most of the body.

What is the outermost epidermal layer?

Stratum corneum.

What is the deepest epidermal layer?

Stratum basale.

What happens in the stratum basale?

New epidermal cells are produced through cell division.

What is keratin?

A strong, protective protein found in the epidermis, hair, and nails.

What is keratinization?

The process in which epidermal cells fill with keratin, die, and become part of the protective surface.

What are melanocytes?

Cells that produce the pigment melanin.

What is melanin?

A pigment that contributes to skin, hair, and eye color and helps protect cells from UV radiation.

What determines differences in skin color?

The amount and type of melanin produced, how it is distributed, and how it is broken down.

What is the hair follicle?

A tube-like structure in the skin from which hair grows.

Where does hair growth begin?

In the hair bulb, where cells divide and form the hair.

What is the hair shaft?

The part of the hair that extends above the skin surface.

What is the hair root?

The part of the hair located below the skin surface.

What is the hair papilla?

Connective tissue at the base of the hair bulb that contains blood vessels supplying nutrients.

What is the arrector pili muscle?

A small smooth muscle attached to a hair follicle that contracts to make hair stand up.

What causes goosebumps?

Contraction of the arrector pili muscles.

What are nails made primarily of?

Hard keratin.

What is the nail matrix?

The growth region where new nail cells are produced.

What are sebaceous glands?

Glands that produce sebum, an oily substance that lubricates and helps waterproof skin and hair.

What is sebum?

An oily secretion that helps keep skin and hair from drying out.

What are eccrine sweat glands?

Sweat glands that release watery sweat onto the skin surface, helping regulate body temperature.

What are apocrine sweat glands?

Sweat glands found mainly in the armpits and groin that become active around puberty.

Why can apocrine sweat develop body odor?

Bacteria on the skin break down substances in the secretion.

How does sweating help maintain homeostasis?

Evaporation of sweat removes heat from the body.

What happens to skin as it ages?

It generally becomes thinner, less elastic, and slower to repair.

What are the main skin receptors responsible for?

Detecting sensations such as touch, pressure, vibration, pain, and temperature.

What is the difference between thick and thin skin?

Thick skin has five epidermal layers, including stratum lucidum, and lacks hair follicles; thin skin lacks stratum lucidum and contains hair follicles.