A Guide to Health and the Human Body
Human anatomy involves how the human body is designed, including organs, muscles, bones, and systems that work together to keep the body functioning and healthy. As you learn about your body and how it works, you'll learn all about all of these systems, such as the circulatory, endocrine, digestive, and respiratory systems. Different organs belong to different systems, and each system depends on the others for overall health; if one system breaks down, the other systems don't function like they should. Stay healthy and strong by taking good care of your body.
Your heart and circulatory system make up the cardiovascular system, also called the circulatory system. The heart pumps blood throughout your body so the organs, tissues, and cells have oxygen and nutrients to function. Then, the blood goes back to the heart by way of the lungs, where it gets infused with fresh oxygen so it can be pumped back out through the body again. This amazing network of arteries, veins, arterioles, capillaries, and venules would stretch out over about 60,000 miles if they were positioned end-to-end.
Digestive and Excretory Systems
The digestive and excretory systems work together to take in food, convert it to energy, absorb nutrients, and eliminate wastes that the body doesn't need. Digestion starts in the mouth as you eat food. After chewing, food moves through the esophagus and into the stomach for digestion. The small intestine takes care of chemical digestion, and nutrients are absorbed here. In the large intestine, water is removed, and the waste material that's left eventually is passed out of the body through the rectum.
Your endocrine system includes a network of glands that make hormones that regulate body functions such as metabolism, reproduction, and sleep. Some major organs assist with hormone function, including the heart, liver, and kidneys. As glands make hormones, they travel through the bloodstream to different tissues. One part of this system is your pancreas, a gland that makes insulin, which helps control your blood sugar levels. Your thyroid is also a part of the endocrine system; it's a gland that produces hormones that regulate your heart rate and metabolism.
Integumentary and Exocrine Systems
The integumentary system includes your skin, hair, and nails as well as the tissues and glands below your skin. The main function of the integumentary system is to protect the tissues underneath. The exocrine system includes glands that make and secrete substances that protect or lubricate. Sweat and saliva are examples of substances produced by the exocrine system.
Lymphatic and Immune Systems
Your lymphatic system is a network of organs, cells, and vessels that move excess fluids to your bloodstream and filter pathogens from your blood. You have between 500 and 600 lymph nodes in your body; these are small organs shaped like beans through which lymph, or lymphatic fluid, travels. Your immune system includes cells and organs that are responsible for destroying pathogens that can make you sick. This happens either by blocking the pathogens or by sending special cells designed to fight and destroy them.
Muscular and Skeletal Systems
Your muscles and bones work together to make up the musculoskeletal system, which makes it possible for you to move. Bones, cartilage, and ligaments are part of the skeletal system, providing support and storing minerals the body needs. And some cells inside bones are immune cells that help keep you healthy. Bones meet at joints, which give you range of motion. Tendons attach muscles to bones, ligaments attach bones to bones, and muscles contract, and all of these factors work together to allow you to move your body. Muscles also support soft tissue and help you maintain positions.
The nervous system is a complicated network of nerves and cells that help your body parts communicate with each other, carrying messages from your brain and spinal cord to the rest of your body and back. The nervous system is divided into the central and peripheral nervous systems. The central nervous system consists of the brain and spinal cord. The peripheral nervous system consists of the somatic and autonomic nervous systems, which manage pain messages and control of organs.
The urinary system might also be referred to as the renal system. Your kidneys make urine by filtering out waste products and excess water from your blood. Urine moves through the kidneys and into the bladder. Once the bladder is full, it empties through the urethra to eliminate the waste from the body. The urinary system is crucial for maintaining the proper balance of water and chemicals in the body.
The body's reproductive system includes both external and internal organs that are designed to create new life. Males and females have different reproductive organs that work together. The male reproductive system produces sperm, and the female reproductive system produces eggs that must be fertilized by sperm to produce a new life. If fertilization occurs and the egg implants in the lining of the female uterus, it can grow into a fetus that will eventually be born as a new baby.
The respiratory system takes in oxygen and eliminates carbon dioxide. The lungs are the main organ of the respiratory system, and they work with the circulatory system to oxygenate blood. The diaphragm sits just under the lungs and helps to control breathing. The lungs are involved with inhaling oxygen-filled air and exhaling carbon dioxide, which is a waste product for the body.
- How the Body Works
- Bones and the Human Skeleton
- Eating for Strong Bones
- Tissues of Life
- Map of the Human Heart
- Digestive System Facts
- The Endocrine System
- 11 Surprising Facts About the Endocrine System
- Immune and Lymphatic Systems: Anatomy and Information
- The Brain 101
- The Child's Brain
- Anatomy of the Respiratory System
- Respiration and Your Health
- Skin: It's All Over You!
- Human Body Systems
- The Human Body
- 15 Facts About the Human Body
- Healthy Skin Matters
- Human Anatomy and Physiology: Meet the Heart
- The Heart Crossword
- Connecting Human Biology and Life Choices