Chapter 3 Flashcards
(14 cards)
A major organ and other covering of the body, essential to life. its appendages—hair, nails and special glands. Function: body’s protector, its first line of defense again infection
Integumentary system
- Aids in excretion of waste products
- Has nerve endings that provide the brain with sensory information related to pain, heat and cold, touch, pressure, and vibration.
- Insulates body and protects from trauma through subcutaneous layer of fat
- Prevent excessive water loss (dehydration)
- Protects from pathogenic organisms and foreign substances; provides a natural barrier against infection
- Regulates temperature
- Synthesizes vitamin D
Functions of the skin
The outermost layer of the skin, is composed of stratified squamous epithelium. The cells are packed tightly and have no distinct blood supply. Divided into two layers or strata: an other, dead, cornified portion and a deep, living, cellular portion.
Epidermis
The inner layer of the epidermis, it is the only layer of the epidermis able to undergo cell division and reproduce. It receives its blood supply and nutrition from the underlying dermis through a process called diffusion. Provides a constant new supply of cells or upper layer and enables the skin to repair itself from injury.
Stratum germinativum
Outermost epidermal layer, they are flat and the cell struture is filled with a protein called keratin. The keratin makes te cells dry, tough and somewhat waterproof.
Stratum corneum
Highly specialized cells called melanocytes that give rise to pigment, a black or dark brown pigment occurring naturally in the hair, the skin, and the iris and choroid of the eye. It is responsible for skin color.
Melanin
Often called true skin, it is well supplied with blood vessels and nerves and contains glands and hair follicles. Composed of connecive tissue with cells scattered among collagen and elastic fibers.
Dermis
Finger-like projections that project into the lower epidermal layer.
Papillae
The layer of tissue directly beneath the dermis. Connects the skin the the muscle surface. Composed of adipose tissue and loose connective tissue. Functions: 1. Storing water and fat, 2. Insulating the body, 3. Protecting the organs lying beneath it, and 4. Providing a pathway for nerves and blood vessels.
Subcutaneous layer (superficial fascia)
Appendages of the skin. Are coiled, tubelike structures located in the dermal and subcutaneous layers. The tubes open into pores on the skin surface. Approximately 3 million sweat glands are located thoughout the integumentary system. These glands excrete sweat, which cools the body’s surface. Sweat is composed of water, salts, urea, uric acid, ammonia, sugar, lactic acid, and ascorbic acid
Sudoriferous (sweat) glands
Appendages of the skin. Are modified sudoriferous glands. They secrete a waxlike substance called cerumen and are located in the external ear canal. Cerumen is thought to protect the canal from foreign body invasion. However, too much cerumen, causing impaction in the ear canal, can cause difficulty with hearing and can make the ear canal a breeding ground for infection
Ceruminous gland
Appendages of the skin. Secrete sebum (an oily secretion) through the hair follicles distributed on the body. Their function is to lubricate the skin and hair that covers the body. Sebum also inhibits bacterial growth.
Sebaceous glands
Appendages of the skin. Composed of modified dead epidermal tissue, mainly keratin. Distributed all over the body in varying amounts. The root is enclosed in a follicle deep in the dermis. Shaft protrudes from the skin. Surrounding follicle is a band of muscle tissue called arrector pili (sensation of cold or fear causes these muscles to contract, making it stand upright and dimpling the skin surrounding it.
Hair
Appendages of the skin. Are composed mainly of keratin, but the keratin is more compressed. The base/root is made up of living cells and is covered mostly by the cuticle. Part of the root, the lunula is exposed and looks like a white crescent. The remainder is the body. It appears pick because of the blood vessels lying immediately beneath it.
Nail
