Human Anatomy and Physiology

The smallest living unit of the body is the cell. It's so amazing, it deserves a lesson of its own. Even though almost all cells are microscopic, they're jam-packed with many different kinds of organelles and surrounded by complex membranes.

This lesson tackles the subject of heredity. It's probably the most technical of all the lessons because it explores genetics. You will learn how genes determine your physical and mental characteristics, and how your parents' genetic material determines these traits. Then you will meet a man who lived in the 1800's—Gregor Mendel, the Father of Genetics—because his insights paved the way for the modern understanding of heredity.

This lesson introduces the nervous system. You will learn how it's organized, its different jobs, and the structures that make thinking, feeling, and moving possible. You will also learn how the nervous system works when you think you're in danger or you've suddenly been affected by physical pain. You will use your chemistry knowledge in this chapter in looking at how nervous impulses are transmitted. Finally, you will learn about nervous system disorders—what causes them and their effects.

Human bones have several functions, and some aren't so obvious. For example, did you know that red blood cells are made in your bones? Or that bones store minerals that are essential for the function of your nerves and muscles? This lesson explores the structure and function of bones, different types of joints, and the amazing structure of your spinal column. You will learn about some common disorders of this system and what you can do to keep your bones strong.

Like the skeletal system, the muscular system is crucial for movement, but it has other functions, too. Muscles are also a lot more complicated than they appear. You will learn why even simple movements involve chemical reactions and a close coordination between this system and the nervous system. In the last chapter, you will learn about several common injuries to different parts of the muscular system.

This lesson focuses on the respiratory system in this lesson. As you're probably aware, it's the group of organs that allow you to get that crucial substance—oxygen—to all the cells in your body. But your respiratory system has some other functions that this lesson touches on. You will learn about the anatomy of your respiratory organs and which muscles are crucial for breathing. You will also become aware of the differences between ventilation, external respiration, internal respiration, and cellular respiration.

There's so much to learn about the circulatory system. This lesson explores the composition of blood, the various blood cells, and the different kinds of blood vessels in your body. Of course, the heart is a crucial part of the circulatory system, so you will learn about its chambers, valves, coronary vessels, and electrical system. You will learn how blood travels around the body and its important functions. You will finish this lesson knowing the importance of taking care of this organ system.

In this very interesting lesson, you will learn all about the disease-fighting ability of your body. The human body also has a system of vessels (similar to blood vessels) called the lymphatic system. You will learn about its disease-fighting role as well as some of its other functions. You will learn about some of the other organs in your body that are involved in the battle against disease. This lesson concludes with the different ways the body's disease-fighting ability can be compromised and why sometimes the body turns on its own cells.

This lesson takes a closer look at two different organ systems—the integumentary system (the skin) and the urinary system. Both of these systems work to get rid of waste products that would kill you if they were allowed to build up in your body. You will learn, too, how important these two systems are in maintaining homeostasis. People are often surprised to learn how complex even the skin can be. And the structures of the urinary system, particularly the kidneys, are quite amazing. At the end of this lesson, you will know all about kidney failure and the challenges of dialysis and kidney transplantation.

You might not think about food the same way after this lesson on the digestive system. This lesson explores all the different structures involved with converting food into the chemicals your body needs to grow, repair tissues, and carry on all the functions of life. When you finish this lesson, you will understand the value of eating a variety of foods, how good food choices will enhance your health, and about one of the most common kinds of cancer—colon cancer.

This course concludes with a lesson on the endocrine and reproductive systems. You will learn how the endocrine and nervous systems work together to regulate all of your body's functions. Finally, you will explore some specific endocrine glands, the hormones they produce, and how they influence each other.