Essentials of Human Anatomy & Physiology - Skin and Body Membranes

Flashcards covering the structure, function, and components of the skin and body membranes.

Body Membranes

Cover body surfaces, line body cavities, and form protective sheets around organs. Classified according to tissue types.

Epithelial Membranes

Simple organs that cover and line membranes, containing both an epithelial tissue layer and a connective tissue layer.

Cutaneous Membrane

The skin; a dry, outermost protective boundary consisting of the epidermis (keratinized stratified squamous epithelium) and dermis (dense connective tissue).

Mucous Membranes (Mucosae)

Moist membranes that line body cavities open to the exterior, adapted for absorption or secretion, and consist of epithelium and loose connective tissue (lamina propria).

Serous Membranes (Serosae)

Line compartments in the ventral body cavity that are closed to the exterior, occurring in pairs separated by serous fluid; consist of simple squamous epithelium and areolar connective tissue.

Peritoneum

Specific serous membrane that covers organs in the abdominal cavity.

Pleurae

Specific serous membrane that surrounds the lungs.

Pericardia

Specific serous membrane that surrounds the heart.

Synovial Membranes

Connective tissue membranes that line fibrous capsules surrounding joints, bursae, and tendon sheaths, secreting a lubricating fluid.

Integumentary System

Consists of the skin (cutaneous membrane) and skin appendages (sweat glands, oil glands, hair, nails).

Functions of the Integumentary System

Insulates, cushions, and protects the body from mechanical, chemical, thermal damage, UV radiation, microbes, and water loss; regulates heat loss; acts as an excretory system; synthesizes vitamin D.

Epidermis

The outer layer of the skin, composed of stratified squamous epithelium containing keratinocytes.

Keratin

A fibrous protein produced by keratinocytes that makes the epidermis tough.

Strata of the Epidermis

From deepest to most superficial: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.

Stratum Basale

Deepest layer of the epidermis where cells undergo mitosis.

Stratum Corneum

Outermost layer of the epidermis, composed of shingle-like dead cells filled with keratin.

Melanin

A pigment produced by melanocytes in the stratum basale, providing skin color (yellow to brown to black).

Dermis

The connective tissue layer underlying the epidermis, containing the papillary and reticular regions.

Papillary Layer

The upper dermal region containing dermal papillae which house capillary loops and receptors.

Reticular Layer

The deepest skin layer, composed of dense irregular connective tissue, blood vessels, sweat/oil glands and deep pressure receptors.

Sebaceous Glands

Exocrine glands located all over the skin (except palms and soles) that produce sebum (oil).

Sudoriferous Glands

Sweat glands widely distributed in the skin; includes Eccrine and Apocrine glands.

Eccrine Glands

Sudoriferous glands located all over the body that open via ducts to pores on the skin, producing acidic sweat for temperature regulation.

Apocrine Glands

Sudoriferous glands that empty into hair follicles in the armpit and genitals, releasing sweat containing fatty acids and proteins.

Hair Follicle

An inner epithelial root sheath and an outer fibrous sheath; dermal region provides a blood supply to the hair bulb.

Arrector Pili Muscle

Connects to the hair follicle to pull hairs upright when we are cold or frightened.

Nails

Heavily keratinized, scalelike modifications of the epidermis; growth occurs from the nail matrix of nail bed.