Chapter 6 Integumentary System

Chapter 6 Integumentary System

Mrs. Clark

​Cutaneous Membrane

• ​The integumentary system includes the skin and all of its appendages (hair, nails, and skin glands). It consists of two layers: epidermis and dermis.

• The epidermis is the outermost layer. It consists of stratified squamous epithelial tissue; it also contains no blood vessels.

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​Cutaneous Membrane

• ​The dermis has an abundance of blood vessels plus sweat glands, sebaceous glands, nerve endings, and hair follicles. Papillae extend upward from dermis, where it interlocks with downward waves projecting from the bottom of the epidermis.

  The hypodermis is made of areolar and adipose tissue; it binds skin to underlying tissue.

Multiple Choice

Which is not a layer of the skin

• Epidermis

• Dermis

• Hypodermis

• h

Multiple Choice

The epidermis is made of ___________ tissue.

• Simple Squamous Epithelium

• Stratified squamous epithelium

• Areolar

• Adipose

​Layers of Epidermis

• ​The innermost layer of the epidermis is the stratum basale (basal layer or stratum germinativum). It consists of a layer of columnar stem cells that continually undergo mitosis to produce new skin cells.

• ​The new skin cells push older cells upward. As the cells are pushed upward, they stop dividing and produce keratin, which replaces the cytoplasm and nucleus in each cell. In the process, the cells flatten and die. 

​Layers of Epidermis

• ​By the time the cells reach the outermost layer (the stratum corneum), all that is left is their keratin. Called keratinocytes, these cells replace the dead cells that flake away with daily wear. 

• ​The stratum corneum consists of up to 30 layers of dead, flat, keratin-coated cells. This makes the skin’s surface durable and resistant to abrasions. It also forms an effective barrier, preventing water from entering the body from the outside whereas still allowing for evaporation.

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Multiple Choice

The innermost layer of the epidermis

• Stratum basal

• Stratum corneum

• keratinoc

Multiple Choice

This substance makes us waterproof

• carotene

• keratin

• sebum

• adipose

​Skin Color

• Melanocytes produce melanin.

• Melanin protects the nucleus from ultraviolet (U V) exposure.

• The amount and type of melanin determines skin color.

• There are two types of melanin: pheomelanin (a reddish color) and eumelanin (a brown-black color).

Multiple Choice

Dark brown to black skin is produced by  what pigment?

• pheomelanin

• eumelanin

• carotene

• keratin

​Melanocytes

• ​Produce melanin and release it between cells.

• ​Keratinocytes bring the melanin into the cells.

• ​Melanin forms a cap over the cell's nucleus to protect it from harmful UV rays.

• ​Prolonged exposure to sunlight stimulates production of more melanin darkening the skin.

Multiple Choice

What part of the cell does the melanin protect?

• cytoplasm

• nucleus

• Cell membrane

• ribosomes

​Cyanosis - caused by lack of oxygen in blood

​Jaundice - decreased liver function

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• Various disorders can produce abnormal changes in skin color, such as cyanosis, jaundice, bronzing, albinism, erythema, pallor, and hematoma.

  (page 91)

​Bronzing - deficiency of adrenal hormones. Addison's disease

​Albinism genetic lack of pigment

​Erythema - increased blood flow to the skin's surface

​Palor - decreased blood flow

Multiple Choice

A genetic lack of pigment

• albinism

• palor

• erythema

• cyanosis

Multiple Choice

A person with a chronic lung disease may have this condition

• erythema

• jaundice

• Bronzing

• cyanosis

​Functions of the Skin

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• Protection

• Barrier

• Vitamin D production

• Sensory perception

• Thermoregulation

(See page 92)

Multiple Choice

Keeping the body from absorbing excess water when swimming is an example of this function of the skin.

• protection

• barrier

• thermoregulation

​Hair

• ​​The hair shaft extends above the skin’s surface. 

• ​Each hair lies within a sheath of epidermis called a hair follicle. Hair follicles have a rich nerve and blood supply.

  Buried in the dermis is the hair bulb or root; this is the lowest part of the hair and is where growth occurs. 

​Hair

• ​​At the base of the hair is a cluster of connective tissue and blood vessels (called the papilla) that nourishes each hair. 

  Attached to each hair follicle is a small bundle of smooth muscle called the arrector pili muscle. Cold temperatures, or emotions such as fear, cause the muscle to contract. When it does, the hair becomes more upright, sometimes called “standing on end.”

Multiple Choice

The lowest part of the hair where growth occurs.

• Shaft

• follicle

• bulb

• papilla

Multiple Choice

This can cause the hair to "stand on end" when you are cold or frightened.

• shaft

• papilla

• arrector pili

• follicle

​Nails

• ​Nails consist of densely packed, heavily keratinized epithelial cells. 

• The nail body is the visible part of the nail; the cuticle is a fold of skin surrounding the nail body; the lunula is a crescent-shaped white area at the base of the nail.

• The nail bed is a layer of epithelium under the nail; it normally appears pink because of the rich blood supply in the area.

• The nail root is the proximal end of the nail (hidden underneath overlying tissue).

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​Nails

• Nails grow as newly keratinized cells are added to the nail root from the nail matrix. As the new cells are added, the nail is pushed forward. 

• Various disorders can cause changes in nails, including clubbing, cyanosis, flattened or concave nail beds, dark lines beneath nail, white nails, yellowish nails, pale nail beds.

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Multiple Choice

The crescent shaped white area on the nail.

• cuticle

• lunula

• nail bed

• nail root

Multiple Choice

The fold of skin surrounding the nail body.

• cuticle

• lunula

• nail bed

• nail root

​Sweat Glands

• ​There are two types of sweat glands: eccrine glands and apocrine glands.

• ​Eccrine glands contain a duct that leads from the secretory portion to the skin’s surface.

• They produce sweat, which contains potassium, ammonia, lactic acid, uric acid, and other wastes. Sweat plays a chief role in helping the body maintain a constant core temperature and also helps the body eliminate wastes. 

  Eccrine glands are widespread throughout the body and are especially abundant on the palms, soles, forehead, and upper torso.

​Sweat Glands

• ​Apocrine glands contain a duct that leads to a hair follicle; these are scent glands that respond to stress and sexual stimulation. Sweat produced by apocrine glands does not have a strong odor unless it accumulates on the skin; when this occurs, bacteria begins to degrade substances in the sweat, resulting in body odor.

  Apocrine glands begin to function at puberty; they are located mainly in the axillary and anogenital (groin) regions.

​Sebaceous Glands

• Other glands called sebaceous glands open into a hair follicle; they secrete an oily substance called sebum, which helps keep the skin and hair from drying out and becoming brittle. Sebum has a mild antibacterial and antifungal effect.

  Sebum production increases during adolescence. When excess sebum accumulates in the gland ducts, pimples and blackheads can form. 

Multiple Choice

Which gland produces an oily substance?

• Eccrine

• apocrine

• sebaceous

Multiple Choice

Which type of sweat gland doesn't function till puberty

• eccrine

• apocrine

• sebaceous

Multiple Choice

This gland helps the body maintain a constant core temperature.

• eccrine

• apocrine

• sebaceous