Healthy Skin - Textbook PDF

Healthy Skin MAIN IDEA​ ​The skin is an organ with several important functions​. When you think of an organ, you might think of a body part such as your heart or your stomach. You might overlook your body’s largest organ, which is not found beneath your skin—it is your skin! The average person’s sk...

Healthy Skin MAIN IDEA​ ​The skin is an organ with several important functions​. When you think of an organ, you might think of a body part such as your heart or your stomach. You might overlook your body’s largest organ, which is not found beneath your skin—it is your skin! The average person’s skin has a surface area of 2 square meters and weighs about 3 kilograms. Your skin has many jobs. It acts as a waterproof shield that defends against germs and keeps them from getting into your body. Your skin helps maintain your body temperature. When you sweat, your skin gets rid of water and salts and cools your body. Your skin allows you to feel and sense pressure, temperature, and pain. Your skin also uses energy from sunlight to make vitamin D, which helps keep bones and teeth healthy. The skin is composed of three main layers. The epidermis is the outermost layer of the skin. The palms of your hands and the soles of your feet are where the epidermis is thickest on your body. This outer layer of skin is at its thinnest where it covers the outside of your eyelids. The dermis is underneath the epidermis. The dermis contains nerve endings, blood vessels, and oil and sweat glands. The dermis is the part of your skin that enables your sense of touch. This layer is also the part of your skin that helps keep you cool by getting rid of waste when you sweat. The innermost layer of skin, the subcutaneous layer​,​ connects your skin to muscle and bone. The subcutaneous layer is also the part of the skin that holds the roots of your hair follicles. The figure in the Lesson Resources panel shows the structure of the skin. READING CHECK List​ What are the three layers of the skin? Caring for Your Skin MAIN IDEA​ ​You can take several steps to help keep your skin healthy​. Keeping your skin healthy can help you feel, look, and smell good. Having healthy skin is also an important part of your overall physical health. Try these tips for taking care of your skin: Bathe or shower every day. Use soap to wash away dirt, sweat, oils, and bacteria that collect on your skin. If you have dry or delicate skin, you may find it helpful to moisturize it with lotion. Dry or cracked skin can itch or become irritated. Limit the amount of time you spend in the sun, especially between the hours of 10:00 a.m. and 4:00 p.m. This is when the sun’s UV rays are strongest and most direct. Whenever you do spend time in the sun, wear protective clothing and apply sunscreen with a sun protection factor (SPF) of 15 or higher. Reapply sunscreen about every two hours and after swimming. Avoid tanning beds, which can be harmful or damaging to the skin in ways similar to exposure to the sun. Avoid tattoos and piercings. Permanent body decoration can put you and your skin at risk for disease and scarring. You will see advertisements for many types of skin care products. Your family and friends may make recommendations. Entire store aisles are filled with various cleansers, lotions, creams, and other items that promise to make your skin healthier and look better. You may be tempted to try many of these products. You may find some that work as promised, while others appear to have no effect. However, remember to use your skills as a wise consumer. You can make informed choices about the types of products to buy and use on your skin. Skin Problems Did you ever wake up, look in the mirror and see a huge pimple? One skin problem experienced by many teens and some adults is acne​. ​The openings of hair follicles onto the skin are called pores. Bacteria gather in the clogged pores, making them swell up. The figure in the Lesson Resources panel shows how acne forms. If you get acne, avoid picking it or trying to pop the pimple. In fact, try not to touch your skin at all. Instead, wash the area with a mild soap and warm water. Be gentle, and don’t scrub too hard. Washing helps remove the dirt, oil, sweat, or makeup that can cause pores to clog. Over-the-counter acne medications can often help clear up breakouts. You will find many different acne medications on the market. Keep in mind the guidelines for being a good comparison shopper you learned in the previous lesson. If you have a bad case of acne, you may need to see a dermatologist​. Viruses can also affect the skin. Cold sores and warts are both caused by viruses. Both can be treated but are contagious. Contagious means the virus can be spread to others. A person with a wart or cold sore should avoid skin contact with others. Washing the hands thoroughly and often is also important. READING CHECK Describe​ How can bacteria and viruses affect the skin? Body Piercing and Tattooing For some adults, piercings or tattoos are ways to express themselves. However, unlike different clothes or hair styles, body piercings and tattoos are permanent. Both carry potential health risks because they break the physical barrier of the skin. This can allow germs to enter the body. Germs that are passed along by tattoo or piercing needles can cause infection. If the needles used for tattooing are not sterile, they can spread bacteria and viruses. Piercings can also spread disease and cause scarring. An oral piercing can damage your mouth and teeth. A tattoo or piercing may also impact your social health. They can limit future opportunities and relationships. Additionally, many states in the U.S. have limits on the age at which a person can get a tattoo or body piercing. In many states, teens under the age of 18 need parental approval to get a tattoo or body piercing. This typically also applies ear piercings. Sun Damage Factors in the environment can affect your personal health. For example, the sun gives off ultraviolet (UV) rays​. Sunburn happens when UV rays damage skin cells. You might think soaking up lots of UV rays will give you a healthy-looking tan. In reality, a tan indicates that skin damage has occurred. One way that the result of tanning will show up on your skin is through wrinkles, or premature aging of the skin. Even worse, too much time in the sun increases the risk of skin cancer. You can protect yourself from UV rays by limiting sun exposure and using sunscreen. Check the weather forecast for the UV Index. This is a scale that categorizes levels of UV radiation reaching Earth's surface. The figure in the Lesson Resources panel shows the UV Index. Special cells in the epidermis make melanin​.​ Darker skin has more melanin than paler skin. Melanin can block some, but not all, UV rays from reaching the lower layers of skin. What about indoor tanning beds? Many people use these devices to stay tan year round. However, tanning beds also emit UV rays. They can damage the skin, lead to skin cancer, and injure the eyes and immune system. Some people choose spray tans to make the skin look darker. Spray tans are safer than being exposed to UV rays through direct sunlight or tanning bed. However, a spray tan does not offer any additional protection from the sun's UV rays. Healthy Hair MAIN IDEA​ ​Hair grows from follicles in the dermis and is made of keratin​. You might spend a lot of time and money to make your hair look thick or to keep it from getting frizzy. The roots of hairs are in the dermis of your scalp. The scalp is the skin beneath the hair on your head. Hair grows from hair follicles in the dermis. As new hair cells are formed, old ones are forced out. Your hair contains a protein called keratin, the same substance that forms fingernails and toenails. Keratin is the substance that gives hair strength and allows it to bend and blow in the wind without breaking. The part of the hair that you can see is the shaft. The shape of the hair shafts determines whether your hair is wavy, curly, or straight. The figure in the Lesson Resources panel shows these three types of hair. As is the case with living skin, hair gets its color from the pigment melanin. The color of your hair is determined by heredity. You inherited genes from your parents that determined your hair color. Hair ​and​ Scalp Problems Two conditions that can affect the health of your hair are dry or oily scalp. Either problem can be corrected by choosing the right shampoo. Read the label carefully. Different products are made for dry, oily, and normal hair. Chlorine in swimming pools can dry out your hair and even cause it to change color. Special shampoos can remove chlorine. Another common scalp problem is dandruff​.​ Symptoms of dandruff include itchy scalp and flaking of the scalp. Dandruff can be caused by dry skin or certain skin diseases. Washing your hair regularly will help control itching of the scalp and flakes of dandruff. If regular hair washing does not work, using a special medicated shampoo can also help control and prevent dandruff. Sometimes, an itchy scalp is caused by head lice. Lice are tiny insects that live in hair and on the scalp and feed on human blood. Having lice is not an indication that a person is unclean. However, lice spread easily from one person to another. To help prevent lice from spreading, avoid sharing hats, combs, and brushes. If you get head lice, use a medicated shampoo that is developed for treating lice. You will also need to wash all your bedding, towels, combs, brushes, and clothing. Since lice spread easily, everyone else in your home will need to take these same steps. Caring for Your Hair Keep your hair healthy by washing it regularly with a gentle shampoo and using conditioner if needed. Keep in mind that when shopping for shampoos and conditioners, you will find many different types and brands on store shelves. Use the comparison shopping skills you have learned to choose the hair care products that are best for you. If possible, let your hair dry naturally. If you use a blow dryer, use low heat. Styling irons and high heat from hair dryers can make hair dry, brittle, and faded. Brushing or combing your hair helps you improve your appearance. It also helps keep your hair healthy and whole. Brushing and combing removes dirt from your hair and scalp in between shampooing. It also helps spread natural scalp oils down along the hair shaft. The natural oils produced in the scalp help keep your hair strong and in good condition. READING CHECK Describe​ What are two problems that can affect the scalp and hair?