Marieb Anatomy & Physiology 1 Chapter 5: Integumentary System

12th edition textbook

Integumentary system

The skin and its accessory structures, including hair, nails, sweat glands, sebaceous glands, and subcutaneous tissue.

Skin

Organ made of two main layers: the epidermis and dermis.

Epidermis

Outer protective layer of skin; made of epithelial tissue and has no blood vessels.

Dermis

Layer beneath the epidermis; makes up most of the skin and contains dense connective tissue and blood vessels.

Hypodermis

Layer beneath the skin made mostly of adipose and areolar connective tissue; also called subcutaneous tissue or superficial fascia.

Subcutaneous tissue

Another name for the hypodermis; anchors skin and provides insulation and shock absorption.

Superficial fascia

Another name for the hypodermis.

Keratinized stratified squamous epithelium

Tissue that makes up most of the epidermis.

Keratinocytes

Most common epidermal cells; produce keratin.

Keratin

Tough, protective protein produced by keratinocytes.

Melanocytes

Cells in the deepest epidermis that produce melanin.

Melanin

Pigment made by melanocytes that helps protect DNA from UV radiation.

Melanosomes

Packages containing melanin that are transferred from melanocytes to keratinocytes.

Dendritic cells

Immune cells in the epidermis that help defend against foreign material; also called Langerhans cells.

Langerhans cells

Another name for dendritic cells; immune cells of the epidermis.

Tactile epithelial cells

Touch receptor cells located at the epidermal-dermal junction; also called Merkel cells.

Merkel cells

Another name for tactile epithelial cells; involved in touch sensation.

Stratum basale

Deepest epidermal layer; contains mitotically active stem cells.

Stratum germinativum

Another name for the stratum basale.

Stratum spinosum

Epidermal layer above the basale; contains cells connected by desmosomes and pre-keratin filaments.

Stratum granulosum

Epidermal layer where keratinization begins.

Stratum lucidum

Clear layer found only in thick skin; contains dead, flattened keratinocytes.

Stratum corneum

Most superficial epidermal layer; contains many rows of dead, keratinized cells.

Keratinization

Process in which epidermal cells become filled with keratin and eventually die.

Keratohyaline granules

Granules in the stratum granulosum involved in forming keratin.

Lamellar granules

Granules that release a water-resistant glycolipid.

Desmosomes

Structures that hold epidermal cells together and help the skin resist tension.

Thick skin

Skin containing all five epidermal layers; found on palms, fingertips, and soles.

Thin skin

Skin containing four epidermal layers and no stratum lucidum.

Papillary dermis

Thin, superficial part of the dermis made mainly of areolar connective tissue.

Reticular dermis

Deeper part of the dermis made mainly of dense irregular connective tissue.

Dermal papillae

Projections of the dermis into the epidermis that may contain capillaries and sensory receptors.

Friction ridges

Ridges that improve grip, enhance touch, and create unique fingerprints.

Dermal vascular plexus

Network of blood vessels near the border of the dermis and subcutaneous tissue.

Cleavage lines

Lines showing the direction of collagen fibers in the skin; also called tension lines.

Tension lines

Another name for cleavage lines; cuts parallel to these lines usually heal better.

Flexure lines

Visible skin folds near joints where the dermis is tightly attached.

Tyrosine

Amino acid used to make melanin.

Tyrosinase

Enzyme involved in producing melanin from tyrosine.

Carotene

Yellow-orange pigment that accumulates especially in the stratum corneum and subcutaneous tissue.

Hemoglobin

Blood pigment that can give fair skin a pinkish color.

Cyanosis

Bluish skin color associated with low oxygenated hemoglobin.

Pallor

Pale skin that may occur with stress, low blood pressure, or anemia.

Blanching

Another term associated with paleness of the skin.

Erythema

Redness of the skin that may occur with fever, inflammation, allergy, or embarrassment.

Jaundice

Yellowing of the skin associated with liver disorders.

Ecchymosis

Skin discoloration caused by blood leaking into tissues; a bruise.

Hematoma

Collection of leaked blood in tissue that causes discoloration or swelling.

Hair

Structure made of dead, keratinized cells; also called pili.

Pili

Another name for hairs.

Hair root

Part of the hair located within the skin where keratinization is still occurring.

Hair shaft

Part of the hair above the skin where keratinization is complete.

Medulla

Central part of the hair shaft.

Cortex

Layer of the hair surrounding the medulla.

Cuticle

Outermost layer of the hair shaft made of overlapping cells.

Hard keratin

Tough keratin found in hair.

Sudoriferous glands

Sweat glands.

Eccrine sweat glands

Sweat glands important for temperature control; found throughout the body, especially palms, soles, and forehead.

Apocrine sweat glands

Sweat glands found mainly in the axillary and anogenital areas; usually empty into hair follicles.

Sebaceous glands

Oil glands that produce sebum; usually empty into hair follicles.

Sebum

Oily secretion that lubricates skin and hair, reduces water loss, and helps kill bacteria.

Merocrine secretion

Release of a gland product by exocytosis; used by eccrine and apocrine sweat glands.

Holocrine secretion

Release in which gland cells rupture; used by sebaceous glands.

Protection

Function of skin that provides chemical, physical, and biological barriers.

Acid mantle

Low-pH environment on the skin that helps prevent bacterial growth.

Defensins

Antimicrobial substances that help kill bacteria.

Body temperature regulation

Skin function involving sweating and changes in dermal blood vessel diameter.

Insensible perspiration

Water loss through the skin that occurs without noticeable sweating; about 500 mL per day.

Vasodilation

Widening of dermal blood vessels to help release heat.

Vasoconstriction

Narrowing of dermal blood vessels to reduce heat loss.

Cutaneous sensation

Ability of skin receptors to detect touch, pressure, pain, and other sensations.

Tactile corpuscles

Receptors that detect touch; also called Meissner corpuscles.

Meissner corpuscles

Another name for tactile corpuscles; detect touch.

Lamellar corpuscles

Receptors that detect deep pressure; also called Pacinian corpuscles.

Pacinian corpuscles

Another name for lamellar corpuscles; detect deep pressure.

Hair follicle receptors

Sensory receptors that detect movement of hairs.

Free nerve endings

Sensory receptors that can detect pain.

Metabolic functions

Skin functions that include vitamin D production and other chemical activities.

Vitamin D

Vitamin produced with help from the skin that is important for calcium absorption.

Blood reservoir

Function of the skin that allows it to hold up to about 5% of the body's total blood volume.

Excretion

Removal of small amounts of substances such as ammonia, urea, and uric acid through sweat.

Basal cell carcinoma

Most common and least malignant major skin cancer; begins in stratum basale cells.

Squamous cell carcinoma

One of the three major types of skin cancer listed in the chapter.

Melanoma

One of the three major types of skin cancer listed in the chapter.

Ultraviolet radiation

UV radiation that can damage skin and increase the risk of skin cancer.

First-degree burn

Burn involving only the epidermis; causes redness, swelling, and pain.

Second-degree burn

Burn involving the epidermis and upper dermis; may cause blisters.

Partial-thickness burn

Term used for first- and second-degree burns in the PowerPoint.

Third-degree burn

Full-thickness burn involving the entire thickness of the skin.