Integumentary System

What is the largest organ system in the body by weight?

The integumentary system.

What are the 5 functions of the integumentary system?

Protection, thermoregulation, receiving environmental stimuli, excretion, and water balance.

What are the three primary layers of the integument?

Epidermis, dermis, and hypodermis.

What type of tissue is the epidermis?

Stratified squamous epithelium.

What type of tissue is the dermis?

Dense irregular connective tissue.

What type of tissue makes up the hypodermis?

Areolar (loose) connective tissue with adipose cells.

What is the epidermis composed of?

Keratinized stratified squamous epithelium.

What are the 4 cell types of the epidermis?

Keratinocytes, melanocytes, Merkel cells, and Langerhans' cells.

What is the main function of the outer portion of the epidermis?

Protection.

What do keratinocytes produce?

Keratin.

What do melanocytes produce?

Melanin.

What do Langerhans' cells do?

They are epidermal macrophages that help activate the immune system.

What are Merkel cells?

Touch receptors associated with sensory nerve endings.

What type of connective tissue makes up the dermis?

Dense irregular connective tissue.

What are the properties of the connective tissue in the dermis?

It is strong and flexible.

What cell types are found in the dermis?

Fibroblasts, macrophages, mast cells, and white blood cells.

What are the two layers of the dermis?

Papillary and reticular.

Where is the hypodermis located?

Deep to the skin.

What is the hypodermis composed of?

Areolar and adipose connective tissue.

What are the three pigments that contribute to skin color?

Melanin, carotene, and hemoglobin.

What is melanin?

A yellow to reddish-brown to black pigment responsible for dark skin colors.

What causes freckles and pigmented moles?

Local accumulations of melanin.

What is carotene?

A yellow to orange pigment.

Where is carotene most obvious?

The palms and soles of the feet.

What is hemoglobin's contribution to skin color?

It is a reddish pigment responsible for the pinkish hue of the skin.

Where are eccrine sudoriferous glands found?

Palms, soles of the feet, and forehead.

What type of sweat do eccrine glands produce?

Thin, non-odorous sweat.

Where are apocrine sudoriferous glands found?

Axillary and anogenital areas.

What type of sweat do apocrine glands produce?

Thicker, odorous sweat.

What are mammary glands?

Specialized sudoriferous glands that secrete milk.

What are ceruminous glands?

Modified apocrine glands in the external ear canal.

What do ceruminous glands secrete?

Cerumen.

What type of glands are sebaceous glands?

Simple alveolar glands.

Where are sebaceous glands found?

All over the body.

What do sebaceous glands secrete?

Sebum.

What is the function of sebum?

It softens the skin when stimulated by hormones.

What is hair?

Filamentous strands of dead keratinized cells produced by hair follicles.

What type of keratin does hair contain?

Hard keratin.

What are the three parts of a hair?

Medulla, cortex, and cuticle.

What is hair pigmented by?

Melanin from melanocytes at the base of the hair.

Where is hair NOT distributed?

Palms, soles, lips, nipples, and portions of the external genitalia.

Where are nails derived from?

The epidermis.

What is the function of nails?

Protect the tips of the fingers.

How fast do nails grow?

1 mm per week.

How are burns classified?

By degrees.

What does a first-degree burn damage?

The epidermis.

What does a first-degree burn look like?

Redness of the skin, like a mild sunburn.

What does a second-degree burn damage?

The epidermis and dermis.

What does a second-degree burn produce?

Wet blisters.

What can cause a second-degree burn?

Serious sunburn or steam burn.

What does a third-degree burn damage?

The epidermis, dermis, and hypodermis.

What is a major result of a third-degree burn?

Permanent scarring.

What is the Rule of Nines used for?

Estimating fluid loss in burn patients using the percentage of body surface burned.