Integumentary System

List at least three situations in which dogs pant. How do humans respond to those same situations? Why do you think dogs pant? Do you know of any other animals that pant?

Functions of Skin Your skin, hair, and nails make up your integumentary system. Skin protects you by keeping water in your body and foreign particles out of your body. Nerve endings in your skin let you feel things around you. Skin helps regulate your body temperature. Skin also helps get rid of waste chemicals.

Layers of Skin Epidermis The epidermis is the outermost layer of skin. Most cells in the epidermis are dead. Dermis The thicker layer of skin that lies beneath the epidermis is the dermis. Subcutaneous Tissue A fatty layer beneath the dermis

blood vessels - Tubes that carry blood as it circulates. Arteries bring oxygenated blood from the heart and lungs; veins return oxygen-depleted blood back to the heart and lungs. hair follicle - a tube-shaped sheath that surrounds the part of the hair that is under the skin. It is located in the epidermis and the dermis. The hair is nourished by the follicle at its base (this is also where the hair grows).

hair shaft - The part of the hair that is above the skin. hair erector muscle - a muscle is connected to each hair follicle and the skin - it contracts (in response to cold, fear, etc.), resulting in an erect hair and a "goosebump" on the skin. melanocyte - a cell in the epidermis that produces melanin (a dark-colored pigment that protects the skin from sunlight).

Pacinian corpuscle - nerve receptors that respond to pressure and vibration; they are oval capsules of sensory nerve fibers located in the subcutaneous fatty tissue sebaceous gland - a small, sack-shaped gland that releases oily (fatty) liquids onto the hair follicle (the oil lubricated and softens the skin). These glands are located in the dermis, usually next to hair follicles.

sweat gland - (also called sudoriferous gland) a tube-shaped gland that produces perspiration (sweat). The gland is located in the epidermis; it releases sweat onto the skin.

Hair A hair forms at the bottom of a tiny sac called a hair follicle. Composed of a protein called keratin and pigments which give it color Helps protect skin from ultraviolet light Helps regulate body temperature in most mammals.

Animation!!

Nails A nail grows from living cells in the nail root at the base of the nail. Nails are also made of keratin Nails protect the tips of your fingers and toes.

Skin Injuries Skin is often damaged, but fortunately can repair itself. However, damage to the genetic material in skin cells can cause skin cancer.

Diseases/Disorders Alopecia Areata Non-contagious autoimmune disorder Immune system attacks the hair follicles Hair is lost in some or all regions of the body Treatments: medication or surgery (hair transplant)

Psoriasis Chronic, non-contagious, autoimmune disease Red and scaly patches or lesions can be observed on the skin Skin grows excessively, causing it to appear white and scaly Treatment: medications to prevent excess skin growth

Warts Tiny, round, rough tumor Found typically on the hands and feet Caused by the human papilloma virus Can be contagious, and spreads from one person to another via contact Usually disappear after a few months Can also be removed

Dermatitis Inflammation of the skin Different types of dermatitis Can have different causes Starts out as an itchy rash Spreads to increase with redness and swelling Not life-threatening or contagious

Athletes Foot Fungal infection Causes scaling, flaking and itching of various areas of the skin Transmitted mostly in moist areas where people walk barefoot Usually affects the feet Treatment: creams or sprays to kill fungus