Integumentary System

Integumentary System TABLE OF CONTENTS Lessons 1. Integumentary System Go 2. Diseases and Disorders Go TABLE OF CONTENTS

Lesson 1– Integumentary System It performs these functions: Protects body Maintains body temperature Eliminates waste Helps respond to touch sensations Absorbs substances Helps produce vitamin D Integumentary System The integumentary system refers to the skin that covers the body. The skin is the largest organ of the body. It performs these functions: Protects the body by screening the sun’s ultraviolet rays and keeping out pathogens Maintains proper body temperature Eliminates waste through perspiration Helps respond to touch sensations through the nerves in the skin Absorbs certain substances, including some medications Helps produce vitamin D using sunlight Temporarily stores fat, glucose, water, vitamins, and salts

Lesson 1– Layers of Skin Epidermis Dermis Hypodermis Layers of Skin The skin consists of three basic layers: the epidermis (outermost), dermis (middle), and hypodermis (innermost). The epidermis contains no blood vessels or nerve cells. It is made up of five smaller layers. The cells of the outermost layer, the stratum corneum, are continually shed and replaced with new cells from the innermost layer, the stratum germinativum. The dermis is also called the corium, or “true skin.” This layer is made of elastic connective tissue. It contains blood vessels, lymph vessels, nerves, involuntary muscle, sweat and oil glands, and hair follicles. Patterns of ridges are formed between the top of the dermis and the epidermis that create unique fingerprints and footprints for each person. The hypodermis is the innermost layer of skin. This layer is made of elastic and fibrous connective tissue as well as fatty tissue. It connects the skin to underlying muscles and protects body organs.

Lesson 1– Pigmentation Skin color is inherited Melanin Carotene A person’s basic skin color is inherited. It is determined by pigments in the epidermis. Melanin is a brownish-black pigment that can result in a black, brown, or yellow tint to the skin. This pigment can absorb ultraviolet light to tan the skin, and small concentrations of it form freckles. Carotene is a yellowish-red pigment that also influences the color of the skin.

Lesson 1– Glands of the Skin Sudoriferous glands Sebaceous glands Glands of the Skin The integumentary system has two main types of glands, sudoriferous and sebaceous. Sudoriferous glands are known as sweat glands. From their coiled bases, tubes extend through the dermis and form pores on the surface of the skin. Perspiration excreted through these pores eliminates excess water, heat, and a small amount of waste and salts. Sebaceous glands are oil glands that usually open onto hair follicles. They produce sebum, which is an oil that keeps the skin and hair soft and pliable. It also acts as a barrier against bacteria and fungi to help prevent infections.

Lesson 1– Hair and Nails Hair helps protect the body Root Shaft Nails protect the fingers and toes from injury Hair and Nails Hair and nails are two other parts of the integumentary system. Hair helps protect the body and is present on all surfaces except the palms of the hands and the soles of the feet. Each hair has two parts, a root and a shaft The root grows beneath the skin surface in a tube called a follicle. The shaft protrudes from the skin and is visible. Nails protect the fingers and toes from injury. They are made of dead epithelial cells packed closely together in a dense surface. They are formed in the nail bed. As long as the nail bed is not damaged, a nail will always grow, even if one has been lost.

Lesson 2– Abnormal Pigmentation Albinos Abnormal colors of the skin can indicate disease: Erythema Jaundice Cyanosis Chronic poisoning Abnormal Pigmentation Some people are born with an abnormal condition in which the skin has no pigment. These people are known as albinos. Their skin has a pinkish tint, and their hair is pale yellow or white. Their eyes are red and very sensitive to light. Abnormal colors of the skin can indicate disease. Erythema is a reddish color of the skin that can be caused by burns or by blood clogging in the vessels. Jaundice is a yellow color of the skin that can indicate liver or gallbladder disease or other diseases where red blood cells are destroyed. Cyanosis is a bluish color of the skin that is caused by a lack of oxygen. Chronic poisoning may cause the skin to look gray or brown.

Lesson 2– Skin Eruptions Macule Papule Vesicle Pustule Crust Wheal Ulcer Skin Eruptions Skin eruptions are also known as lesions, and they may also indicate disease. Common skin eruptions include the following ones: Macule: Flat, discolored spot on the skin; such as a freckle Papule: Raised, solid area less than 1 cm in diameter Vesicle: Raised, fluid-filled sac; such as a blister Pustule: Pus-filled, raised sac; such as acne Crust: Dry pus or blood covering an injury; such as a scab Wheal: Itchy, raised area with an irregular shape; such as a hive Ulcer: Open sore with deep loss of skin surface

Lesson 2– Diseases and Disorders of the Integumentary System Acne Vulgaris Contact Dermatitis Eczema Psoriasis Diseases and Disorders of the Integumentary System Acne vulgaris is a chronic disorder of the sebaceous glands. It usually occurs at adolescence. The exact cause is not known, but it is most likely caused by too much sebum being produced. Excess oil, dirt, or bacteria may block openings to the sebaceous glands or hair follicles. As a result, skin eruptions on the face and upper back may occur. Treatment may involve a special skin washing routine, topical ointments, antibiotics, and exposure to ultraviolet light. Heavy creams and makeup should be avoided. Contact dermatitis is an inflammation of the skin that can be caused by anything that irritates the skin. It is often an allergic reaction to pollen, detergents, cosmetics, or even food. Symptoms include redness, itching, swelling, and blisters. Treatment involves removing the irritant that is causing the problem. After the area is washed, topical ointments may also be applied. Eczema is chronic, noncontagious inflammation of the skin. Diet, soaps, cosmetics, medications, and stress can all cause eczema. Symptoms include dry, red, itchy, and scaly skin. Treatment involves removing the irritant and applying topical medications containing hydrocortisone. Psoriasis is a chronic skin disorder in which too many epidermal cells are produced in the body. The exact cause is not known, but the disorder may be triggered by stress. Symptoms include dry red patches covered with silvery-white scales on the trunk, arms, hands, legs, and scalp. Treatment may relieve symptoms, but there is no cure. Treatment involves topical ointments, removal of scales, and exposure to ultraviolet light.