Integumentary System

Integumentary System Made up of skin, hair, and nails Acts as primary defense of immune system Helps body maintain healthy internal environment

Integumentary System Skin Largest organ in the human body! Protects by keeping moisture in and foreign particles out of body Nerve endings throughout your skin allow you to feel what’s around you and react Helps regulate body temperature (homeostasis) Helps rid waste – 2 major layers thick Epidermis and Dermis

Integumentary System Epidermis Composed of Epithelial tissue Most epidermal cells are dead and filled with proteins called Keratin Keratin is a protein that allows cells to be durable and tough

Skin Layers Epidermis Stratum Corneum (horny) Stratum Lucidum (clear) Stratum Granulosum (granular) Stratum Spinosum (spiny) Stratum Basale (basal)

Integumentary System Dermis Lies underneath epidermis Mostly connective tissue Contains fibers made of collagen These fibers provide strength to the tissue and allow skin to bend and twist without tearing

Integumentary System Dermis Layers of the Dermis Papillary layer – Fingerlike projections – loose connective tissue Reticular layer – irregular connective tissue – dense connective tissue

Integumentary System Skin Color Determined by darkening chemical in skin called melanin Increase in melanin = darker skin color Decrease in melanin = lighter skin color

Integumentary System Skin Color Melanin is found in upper layer of epidermis of skin Absorbs much of harmful radiation from sun to decrease DNA damage that can lead to cancers.

Integumentary System Hair Formed at bottom of tiny sac called hair follicle Hair grows as new cells are created in hair follicle Old cells get pushed upward

Integumentary System Hair The only living cells in a hair are in the hair folicle Hair protects skin from UV Radiation and helps keep particles out of body Eyelashes, nose/ear hair, pubic hair, armpit hair etc… Color comes from melanin – like skin color

Integumentary System Hair Hair regulates body temperature by contraction of tiny muscles attached to the hair follicle. When these muscles contract they cause the follicle to push upward toward the epidermis and create “goose bumps” If the follicle contains a hair the hair will stand up This will cause the warm air to be trapped between the hair and the body and thus keeping the body warmer – Acts like a sweater

Integumentary System Nail Protect tips of fingers and toes so as to remain soft and sensitive yet tough Form from nail roots under skin at base and sides of nails As new cells form, nail grows outward

Integumentary System Nail Parts Free edge Body Root Lunula Nail folds Eponychium Cuticle Nail bed Nail matrix

Integumentary System Sweat glands Sudoriferous – Dermis layer Small organs in the skin that produce sweat Salty liquid that flows to surface of skin As sweat evaoorates, skin is cooled Aid in removing several types of waste chemicals from bloodstream

Integumentary System oil glands Sebaceous glands – Dermis layer Release oil that keeps hair flexible and helps keep epidermis waterproof/water resistant