Human Skin, Free PDF Download

Lesson Objectives and Overview: Human Skin teaches students all about the largest organ in the human body. Students will discover some amazing facts about skin and its traits. They will be able to define the major parts of skin and list its functions. The lesson even includes an optional addition that provides students the opportunity to observe how skin reacts to different things, such as cold weather. This lesson is for students in 4th grade, 5th grade, and 6th grade.

Every lesson plan provides you with a classroom procedure page that outlines a step-by-step guide to follow. You do not have to follow the guide exactly. The guide helps you organize the lesson and details when to hand out worksheets. It also lists information in the yellow box that you might find useful. You will find the lesson objectives, state standards, and number of class sessions the lesson should take to complete in this area. In addition, it describes the supplies you will need and lists how you need to prepare beforehand.

The classroom procedure page has an “Options for Lesson” section that lists several suggestions for additional tasks. One idea is to assign a skin condition to each student to research and present to the class, such as melanoma. Another idea is to have students draw a birthmark that they would like to have. They could also make an enlarged drawing of skin with labels and other information about each part. You could invite a dermatologist to speak to your class and answer their questions about human skin. One more idea is for students to compare human skin to the skin of other animals. If it’s cold outside when you present this lesson, you could take students outside to observe their goosebumps up close with a magnifying glass.

The paragraph on the teacher notes page provides extra information or guidance for the lesson. It suggests teaching this lesson in conjunction with others that relate to the human body, such as our lesson on the integumentary system. You can use the blank lines on this page to write down thoughts and ideas you have as you prepare.

The Human Skin lesson plan contains five pages of content. The lesson first describes some facts about skin. Skin covers the entire human body. It is the body’s largest organ, and it covers and protects our muscles, bones, other organs, and everything else inside us. Without it, our bodies would fall apart. In addition, skin helps the body maintain its temperature and allows us to experience the sense of touch.

Human skin has three main layers, and those layers each have their own functions and parts. The outside layer is the epidermis, and its main function is to protect. This is the part of the skin that we can see. Cells grow deep within the layer. On the outside are flat, dead skin cells that you could easily rub right off. New cells come to the surface when those dead skin cells fall off. These new cells contain keratin, which makes the skin tough and waterproof. Other cells produce melanin, which is a pigment that darkens the skin and protects it from strong sunlight.

Most of the cells in the epidermis layer, roughly 95% of them, work to produce new cells. The remaining 5% of cells produce the melanin pigment. Students will discover that a person loses about 30,000 to 40,000 dead skin cells off the epidermis layer every minute of the day! That equates to about nine pounds of skin cells every year. While our skin protects our bodies, we do need to take care of it by wearing sunscreen and protective clothing when outside.

The middle layer, or layer beneath the epidermis, is the dermis. This layer is thicker and more elastic compared with the outside layer. It is home to glands, hair follicles, nerves, and blood vessels. There are two types of glands here: sebaceous and sweat. Sebaceous glands produce sebum, a type of oil that helps keep the skin soft and waterproof. Sweat glands produce moisture to cool us down when it gets too hot.

Hair follicles produce all the hair on our bodies. Up close, they look like tiny bulbs. Most of our hair is short and fine, and the only places without any hair are the palms of our hands and soles of our feet. And on our heads, we have about 100,000 hair follicles. The head is obviously one place where our hair is usually much thicker and longer.

The nerves and blood vessels in the dermis layer also have a role to play. The nerves are basically sensors that send messages to the brain. For example, they may tell the brain what the temperature is like. They also cause us to feel pain or allow us to know how hard something is pressing against our skin. In addition, nerves can inform us how smooth or rough an object is. The blood vessels, which are part of the circulatory system, carry oxygen and nutrients to our cells and carry away waste.

Finally, the hypodermis layer—also known as the subcutaneous layer—is the deepest. It consists mostly of fat, helps keep the body warm, and absorbs shocks. It also connects the skin to the tissues beneath it. Hair follicles start in this layer because this is where hair roots are. The hypodermis also has glands. These glands connect to each hair follicle and coat the hair with oil, which is what gives hair its shine.

The lesson provides a diagram that shows lots of other parts of the skin. Because of its setup, you could create a game in which students study the parts and then guess where they go on the diagram. You can cover up the parts and reveal them as students guess correctly.

Students will next learn about other important functions of skin, such as temperature control. Typically, a person’s body temperature stays around 98.6°F since these conditions allow the body and cells to remain healthy. The brain’s inner thermometer, called the hypothalamus, sends messages to the skin when temperatures change. The skin then responds in a certain way.

For example, if a person is outside on a hot day playing games at recess, their blood vessels receive a signal from the hypothalamus to release some of that heat. The sweat glands then release moisture through the skin’s pores into the air to cool down. The hotter our bodies are, the more moisture our sweat glands will release. When that moisture hits the air, it evaporates, leaving the body cooler.

Blood vessels also react when it gets really cold. When our bodies cool, blood vessels keep blood away from the skin’s surface to keep our bodies warm. As a result, we get goosebumps! The scientific name for this phenomenon is the pilomotor reflex. This reflex causes special tiny muscles called erector pili to pull on the hairs so they stand up straight.

Skin comes in differing thicknesses and forms. Most of our skin is about 2 millimeters thick. On the soles of the feet, however, it is much thicker because it gets rubbed a lot when we move around. And on our eyelids, the skin is only about half a millimeter thick. The skin on our knees and elbows has more elasticity and is looser so that it can more easily stretch when we move. Our palms are much firmer than the backs of our hands to make it easier to grasp things.

Because the skin protects us, we should do our best to protect it. Students will next learn about issues with the skin. Blisters, calluses, and corns often develop because of some type of overuse of or excessive rubbing in an area on the skin. Blisters are areas where watery liquid forms on the hands and feet due to rubbing and pressure. (You could ask students if they have ever gotten a blister, perhaps after playing a sport or running a lot.)

Calluses are areas of thick skin that result from excessive rubbing over a long period of time. The skin hardens from the pressure and thickens. Similar to a callus, a corn is an area of hard, thick skin that usually consists of a soft yellow ring of skin around a hard, gray center. These usually develop on top of or in between toes. They also form from repeated rubbing of the toes.

Other skin conditions include rashes, acne, psoriasis, and warts. There is also a skin cancer called melanoma. If skin becomes severely damaged, it may try to heal itself by forming scar tissue. This tissue is not the same as normal skin. It often appears discolored and lacks sweat glands and hair.

Apart from skin conditions, people are often born with what we call birthmarks. A birthmark can be present the day a person is born or show up soon after. Birthmarks are not a kind of illness and don’t usually cause any pain. One of the most common kinds is a hemangioma, a group of tiny blood vessels that grow bunched together in a specific area. The area appears red or purple. Nobody knows what causes the vessels to group together.

The Human Skin lesson plan includes three worksheets: an activity worksheet, a practice worksheet, and a homework assignment. Each one helps reinforce students’ grasp of the lesson material. Use the guide on the classroom procedure page to determine when to hand out each worksheet to the class.

The activity worksheet instructs students to work with a partner. However, you can also have students work alone or in groups if you prefer. There are two pages for the activity. Remind students to be careful during this portion as they will be using a sharp object. Students will take turns testing how a needle, cloth, and pencil eraser feel different parts of their hands and arms and compare them. Then they will use a magnifying glass to see their skin close up. They will observe the parts of their skin that have no hair and the parts that do have hair. Then they will draw pictures to represent what they observed.

For the practice worksheet, students will match definitions to the words they represent in the word bank. There are 15 total definitions. Then they will complete three questions in which they have to name layers of skin, parts of skin, and skin conditions.

There are two sections of the homework assignment. The first part requires students to label each part of the human skin. There is an image on the worksheet with the blank labels pointing to the proper part. A word bank contains each of the eight terms they will need. For the second part, students must match facts to the skin layer they represent: epidermis (E), dermis (D), hypodermis (H).

The last two pages of the PDF are answer keys for the practice and homework worksheets. Given the nature of these assignments, students responses should match those on the answer keys exactly. The correct answers are in red to make it easy to compare to students’ work. If you choose to administer the lesson pages to your students via PDF, you will need to save a new file that omits these pages. Otherwise, you can simply print out the applicable pages and keep these as reference for yourself when grading assignments.