General Body

An Overview of the Human Body

The human body is made up of several types of systems that work together to help your body function correctly. Here, we’ll cover the main six.

Skeletal system:

• This includes all of your bones and joints. The skeletal system helps give your body structure, lets you move, and keeps your internal organs safe. Humans have 206 bones.

Muscular system:

• Your muscles help you move. You have more than 600 muscles, and they do everything from pump blood to help you lift weights. Some of your muscles are voluntary muscles; you need to think about moving these. Others, like your heart, don’t require any thinking.
• There are three types of muscles: smooth, cardiac, and skeletal. Smooth muscles work behind the scenes. For example, they work in the digestive system, allowing your food to go through your stomach. The cardiac muscle pumps blood throughout your body. Finally, skeletal muscles are voluntary. You control what they can do.

Nervous system:

• This is the body’s communication system. Your brain dictates how your body functions, and your nervous system relays this to the rest of your body.
• The nervous system tells your brain what is happening in the rest of your body. For example, if you touch something hot, your nervous system communicates this to the brain, which then tells your body what to do.
• The autonomic nervous system controls the body’s automatic functions, such as breathing, sweating, and digesting.
• The sympathetic nervous system deals with stress by telling the body to produce adrenaline. This is called the flight-or-fight response.
• The parasympathetic nervous system tells your body to rest. It slows your heart rate, helps you digest food, and assists in conserving energy.

Circulatory system:

• Your heart, blood vessels, and blood make up the cardiovascular system.
• Blood from the heart delivers nutrients and oxygen to your body and helps fight disease.

Digestive system:

• This system includes everything that helps you process food and drinks.
• It begins with your mouth, followed by your throat, liver, gallbladder, stomach, pancreas, small and large intestines, appendix, and anus.
• Each of these body parts includes other parts that help transport your food, preserve nutrients, and expel waste.

Respiratory System:

• This system houses the lungs, which inhale oxygen and exhale carbon dioxide. The trachea (or windpipe) filters the air and sends it to the bronchi (two tubes that lead to each lung).
• Oxygen fills the 600 million alveoli that are inside the lungs, and transports the oxygen to your bloodstream.

Other systems include integumentary (skin, hair, and nails), immune, reproductive, endocrine, and urinary systems.