Acne – clogged pores in the skin.. Bacteria – germs. Contracts – gets smaller. Dermis – the inner layer of the skin. Epidermis – the outer layer of the skin. Hair Follicles – tiny pits where the hair grows. Keratin – tough protein found in skin, nails and hair. Melanin – substance that gives your skin color. Oil glands – organs in the skin that makes sebum or greasy fluid. Pores – small openings on the surface of the skin. Sebum – greasy or oily fluid made by oil glands. Sensory nerves – nerves that feel heat, cold, pain, and pressure. Shivering – contracting of the muscles to help warm the body. Skin – largest organ in the body. Sweat glands – organs in the skin that get rid of water in the body. Things you will learn in this unit: Why acne happens What causes people to have different colored skin and freckles How our skin controls our body temperature Have you ever….. had a pimple? gotten sweaty when exercising? had goose bumps?
What are the five senses?
We use our five senses all the time. The senses are touch, sight, hearing, smell, and taste. Without our senses, life would be much less enjoyable. Food would not have flavor without taste and smell. Without our sense of touch, sandpaper would feel the same as rabbit fur. We wouldn’t be able to hear a baby giggle, a bird sing, or the siren of an ambulance without our sense of hearing. If we could not see, we wouldn’t know how many different colors there are in the world around us. In the next several lessons, you will learn about each of the five senses, starting with the sense of touch.
The body’s largest organ
Your sense of touch happens through the largest organ of the body, the skin. Your skin can identify four different feelings: heat, cold, pain, and pressure. In addition to the sense of touch, your skin does many other important things. It helps control your body temperature. The skin also acts like a sandwich bag. It keeps harmful substances like bacteria and dirt on the outside, away from your internal organs and fluids. The skin has two layers. The outer layer is the epidermis. The epidermis is made up of dead cells and keratin. Keratin is a tough protein found in skin, nails, and hair. The hardened cells of the epidermis overlap to form a tough, strong waterproof covering. These cells are easily knocked off when touched. This is why skin can look dry. The inner layer, the dermis, is the living section of the skin. The living cells in the dermis are always dividing in order to replace the dead cells in the epidermis. New cells push the older cells upward. By the time they reach the surface, these older cells are dead and pressed into a flat shape. Together, the dermis and the epidermis are the only as thick as this line: _______ .
Skin structures
The dermis contains many other structures. This layer has blood vessels, hair follicles, sweat glands, and fatty tissue. In the dermis are the endings of sensory nerves that allow us to feel heat, cold, pain, and pressure. Across the top of the epidermis are a series of small openings. These pores allow sweat and sebum to leave the skin. Hair grows from hair follicles or tiny pits in the skin. Only the hair in the dermis is alive. The hairs we see are the shafts or remains of dead hair cells. Each hair follicle has a tiny muscle that contracts, or gets smaller, when you feel cold or when you experience emotions such as fear. The follicles also have sweat glands that produce an oily fluid called sebum. Sebum keeps the hair shafts and skin soft.
Clean skin, oil, and acne
The skin needs to be kept clean. Washing every day with soap and water removes dirt, dust, sweat, and extra sebum. Good hygiene keeps your skin, and your body, in a healthier state. But it won’t always keep you from getting acne. During puberty, the oil glands may go into overdrive and produce too much sebum. This is a common problem for teenagers and some adults. When the skins pores get blocked with this excess oil, they form plugs that keep oil from getting to the skin’s surface. This causes a skin condition called acne. Acne happens when germs, or bacteria, growing in clogged pores cause an infection producing swelling and redness. There are different kinds of acne. A basic clogged pore is a pimple. A whitehead is a plugged hair follicle that keeps its infection under the skin, but makes a white bump appear in the skin’s surface. A blackhead is a plugged hair follicle that moves its infection up to the skin’s surface, where it makes a black bump appear. Its black color is caused by too many dark-colored skin cells, not by dirt.
Skin color
There is a colored substance in skin called melanin. Melanin contains grains of brownish-black pigment that give skin its color. Skin with little melanin is very pale. More melanin in the skin gives a person a very dark skin. Freckles are caused by an uneven distribution of melanin. In light-skinned people, more melanin forms when they are out in the sun. Being in the sun over time increases the production of melanin. This change in skin is commonly called tanning. Additional melanin also causes more freckles for people who are already freckled.
Temperature control
Your skin helps you maintain a constant body temperature. When you are hot, blood vessels near the skin widen and carry warm blood to the surface. That way, air touching your skin can cool the blood. Another way your body cools itself is through sweating. When the temperature of your skin increases, sweat glands produce sweat. Sweat is water with salt dissolved in it. As the sweat evaporates, your body cools. With over 3 million sweat glands, the body is very good at cooling from within. When we are cold, our blood vessels contract, or get smaller. This moves the bloodstream farther away from the skin’s surface and helps hold the heat. Muscles around the hair follicles also contract, causing tiny bumps on the skin called goose bumps. These contracted muscles make the hairs stand upright, trapping air to help keep your body warm. Shivering is another way your body produces heat. When you shiver your skeletal muscles contract, and this helps you warm up.
Answer these questions as you read the chapter.
Name the five senses that the part of the body responsible.
How is the skin like a sandwich bag?
What are the two layers of skin?
What forms the epidermis?
What is keratin?
Where in your body can you find keratin?
Why does skin often look dry (or ashy)?
Where is the dermis?
How is the dermis different from the epidermis?
What skin structures are found in the dermis?
What skin structure allows you to feel?
How do sweat and sebum leave the skin?
Is the hair we actually see on our skin dead or alive?
What happens to your skin and hair when you are cold?
What is sebum?
What is the function of sebum?
Why do you get acne?
How is acne formed?
What is the difference in a pimple, a whitehead and a blackhead?
Why are people all different colors?
How does the skin regulate or control body temperature?
How many sweat glands does your body have?
What happens to our blood vessels when you are cold?
How does shivering warm you up?
Connect the subject (or first part of the sentence) with the predicate (the second part of the sentence) to make a true statement. Write the new complete sentence. The skin is caused by melanin Keratin is the largest organ in the body Sweat glands is the dermis Sweating feel hot, cold, pain, and pressure Sensory nerves is caused by clogged pores The outer layer of the skin make sebum Oil glands forms a tough, waterproof covering The inner layer of the skin is the epidermis Acne helps control body temperature Skin color help get rid of water from the body
Underline the word or words that are different in each sentence. In each pair of sentences, cross out the false sentence. 1a. Shivering helps keep the body warm. b. Shivering helps keep the body cool. 2a. Sweat leaves the body through hair follicles. b. Sweat leaves the body through pores. 3a. The skin is the largest organ of the body. b. The brain is the largest organ in the body. 4a. Oil glands make sebum. b. Oil glands make sweat. 5a. The outer layer of the skin is the epidermis. b. The outer layer of the skin is the dermis. 6a. Melanin causes skin color. b. Keratin causes skin color. 7a. The hairs we see on our arms are live hair cells. b. The hairs we see on our arms are dead hair cells. 8a. The dermis contains blood vessels and other skin structures. b. The epidermis contains blood vessels and other skin structures. 9a. Pores allow sweat and sebum to leave the skin. b. Sensory nerves allow sweat and sebum to leave the skin. 10a. Sebum is sweat. b. Sebum is an oily or greasy fluid. 1la. Freckles are caused by melanin. b. Freckles are caused by sebum. 12a. As sweat evaporates, your body is cooled. b. As sebum evaporates, your body is cooled.
Label the parts: dermis epidermis sweat glands hair follicle oil glands hair pore In your own words, explain to me why you should take care of your skin and how you should take care of your skin.