The Integumentary System
Major roles of the Integumentary System protection maintenance of normal body temperature storage (of fat) synthesis (of vitamin D) excretion (of salts, water and wastes in sweat) sensory perception
The Skin: 3 Major layers
Did You Know?... At 8-10 pounds, the skin is bodies largest organ!
The Epidermis The epidermis is the outer layer of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the ______ at .05 mm and the thickest on ______ at 1.5 mm. Cells of the epidermis are constantly sloughing off and replacing themselves…
The Epidermis cont… 5 layers Cells are shaped like columns at the base and migrate upward, as dead cells are continuously sloughed off at the surface stratum corneum stratum licidum stratum granulosum stratum spinosum stratum basale
Which layer of the epidermis is this?
Specialized Epidermal Cells The melanocyte- produces pigment (melanin) The Langerhans' cell- frontline defense of the immune system in the skin
They aid in grasping objects, scratching, and protecting fingers and toes.
The Dermis This layer varies in thickness as well, depending on the area of the body. It is a mere 0.3 mm on the eyelid and 3.0 mm on your back. The dermis is composed of 3 types of tissue….
The Dermis cont… 2 types of tissue that are present throughout (not in layers). collagen elastic tissue
Dermis Tissue: Collagen Collagen is the most abundant and important structural protein in your body. It strengthens and supports many body tissues from the outside creating an “extracellular matrix.”
Dermis: Elastic tissue Elastic protein fibers made by cells called fibroblasts provide protection for tissues underneath the dermis as well as the pliability we associate with the skin.
Specialized Dermal Cells erector pili muscle cells support hair follicles. oil (sebaceous) glands, scent glands, and sweat glands are associated with the follicle. Blood vessels and nerves course through this layer. The nerves transmit sensations of pain, pressure itch, and temperature, and blood vessels facilitate gas exchange.
The Importance of Glands Sweat glands play an important role in keeping the body cool sebaceous glands secrete sebum which has waterproof and antimicrobial properties
What makes these hairs stand on end? Why?
Can you name structures 1-4?
Layer 3: The Subcutaneous Also referred to as the “hypodermis,” this layer of the skin is composed primarily of adipose tissue (fat). This layer plays a key role in insulating the body and regulating the temperature of the skin. The hypodermis can vary significantly in thickness and incorporates larger blood vessels and nerves.
Nails Your nails extend from the epidermis and contain a tough protein called keratin. They play an important role in grasping objects, scratching, and protecting fingers and toes.
Did you Know? Your fingernails grow about 5 times faster than your toenails!
Hair Also composed of the protein keratin hair acts as an effective insulator between you and the environment. hair follicles originate in the dermis.
Did You Know? Hair can grow as little as 0.1 inches per month or as fast as 0.5 inches per month depending on genetics and your diet.
Aging and the integumentary system Marked declines in: Cell division in stratum basale Melanocyte production Glandular activity Hair follicle function Elastic fiber function in dermis Blood supply to skin Rate of repair
Disorders of the skin Lesions and tumors infections (bacterial, viral, fungal, parasitic) inflammatory reactions and allergies Genetic diseases acne
Anatomy of a Pimple