There are ten organ systems in your body that each have different functions, and they all must work together to keep you alive and healthy. In this lesson, you'll learn about each of these body systems, both what they do and which organs they contain.
Cardiovascular & Endocrine
Your body is an amazing machine, with many systems and organs that must all work together to keep you healthy. Let's look at the body systems in detail, examine their functions, and learn which organs are in each.
The cardiovascular system is responsible for circulating blood throughout your body. The most important organ in the cardiovascular system is the heart. Your heart contracts about once a second for your entire life, and you can't live more than a few minutes if it stops working properly. In addition to the heart, the cardiovascular system contains blood vessels like arteries, capillaries, and veins. Arteries carry blood away from your heart to the tissues of your body. They connect to tiny capillaries where oxygen and other gases are exchanged with the surrounding tissues. Then, the blood travels back to your heart through veins.
The endocrine system produces hormones that regulate everything from growth to blood pressure. There are many glands in the endocrine system, but some of the most important are the pituitary gland, pineal gland, pancreas, thyroid, parathyroid, adrenal glands, hypothalamus, and the sex hormone glands (testes in males and ovaries in females). Each of these secretes different hormones that affect how your body functions.
Integumentary & Musculoskeletal
The integumentary system contains the largest organ in your whole body, which makes up about 15% of your body weight. It covers and protects all your other organs and tissues, plays a critical role in regulating your temperature, produces vitamin D, and allows you to feel heat, cold, pressure, and pain. What are we talking about? Your skin! Your skin, hair, and nails are all part of the integumentary system.
The musculoskeletal system is made up of two major types of tissue: muscle and bone. Together, they provide support and structure to the other body tissues and organs and give you the ability to move. Muscles are attached to bones by bands of connective tissue called tendons, and bones are attached to other bones by similar tissues called ligaments. Tendons and ligaments, along with the cartilage that is found in joints, are also part of the musculoskeletal system.
Lymphatic & Nervous
The lymphatic system contains many small vessels that circulate a clear fluid called lymph around your body. It's important in carrying water out of your tissues to prevent swelling and also plays a vital role in your immune system. Attached to the lymphatic vessels are many lymph nodes that are full of white blood cells that fight infections. If an infection is detected by the lymph nodes, they immediately begin to activate lots of white blood cells that produce antibodies to fight infections. This is why your lymph nodes tend to swell when you're sick. This is a normal and important part of fighting off infection.
The nervous system uses electrical impulses to receive sensory information and control movement. The largest organ of the nervous system is the brain. Your brain is the control center for your whole body. You use it to make decisions, store memories, and coordinate sensory and motor impulses that allow you to experience the world and control your movements. The spinal cord is attached to the brain. Together, the brain and spinal cord make up the central nervous system.
There are many nerves attached to the spinal cord and brain that go to and from every part of your body. All of these together are called the peripheral nervous system.
Digestive & Urinary
The digestive system is responsible for taking in and processing food. It starts with your mouth, where your tongue, teeth, and salivary glands begin to break down food. Then, as you swallow, the food moves through your esophagus and into your stomach where it's mixed with acids that break it down even more. Next, it moves into your small intestine, where nutrients are absorbed. Did you know that your small intestine is about 20 feet long? That's more than three people standing on top of each other!
Whatever indigestible matter remains at the end of the small intestine passes into the much shorter large intestine. There, water is returned back to your body and the waste products from digestion are passed out of the body through the rectum. Other digestive system organs that produce and store enzymes to help with the digestive process are the liver, pancreas, and gallbladder.
The urinary system contains two kidneys, the bladder, the urethra, and ureters, which connect the kidneys to the bladder. The kidneys filter your blood to remove wastes, regulate the amount of water in your body and your blood pressure, and control the electrolyte levels in your blood. They produce urine, which then passes through the ureters to be stored in the bladder. Urine passes out of your body through another narrow tube called the urethra.
Respiratory & Reproductive
The respiratory system is responsible for taking in oxygen and excreting carbon dioxide. This is really important because without a steady supply of oxygen, your cells will quickly die. The main organs of the respiratory system are the lungs. When you inhale, air enters your mouth and nose and travels down the trachea to the bronchi that go into each lung, and then into smaller bronchioles that take oxygenated air deep into the lungs. In small air sacks called alveoli, blood cells excrete carbon dioxide into the lungs and pick up oxygen. Then, when you exhale, the air travels back up the trachea and out your mouth.
The reproductive system is what allows humans to reproduce. In both males and females, it contains sex organs which produce hormones and create the sperm and egg cells that must combine to start a new life. In males, the two most important organs are the testes, which secrete hormones and produce sperm cells, and the penis. The female reproductive system is a little more complicated because it has to not only create egg cells, but also nurture and protect a growing fetus before birth. In females, important organs of the reproductive system include the ovaries, uterus, and vagina.
Your body contains ten organ systems that must all work together to keep you healthy. The cardiovascular system is responsible for circulating blood throughout your body. The endocrine system produces hormones. The integumentary system contains the largest organ in your whole body (your skin) and covers and protects all the other organs and tissues. The musculoskeletal system is made up muscle and bone, which provide your body with support, structure, and the ability to move.
The lymphatic system is an important part of your immune system, and contains many small vessels that circulate lymph around your body and lymph nodes full of white blood cells. The nervous system uses electrical impulses to receive sensory information and control all your muscles. The digestive system is responsible for taking in and processing food. The urinary system contains the two kidneys, the bladder, the urethra, and the ureters and is responsible for filtering your blood to remove wastes. The respiratory system is responsible for taking in oxygen and excreting carbon dioxide. The reproductive system is what allows humans to reproduce and is different in males and females.