Atherosclerosis is a condition in which fatty substances are deposited on the inner walls of arteries. It is often the cause of heart attacks.
Oxygen-rich blood is circulated throughout the body.
Heartburn is caused by the back flow of acidic stomach contents into the esophagus. It is also called acid reflux.
The two kidneys in the body monitor levels of salt and water concentrations. Waste material, including excess water, is filtered out of the blood by kidneys in the form of urine.
Food travels down the esophagus into the stomach through a series of involuntary muscular contractions called peristalsis.
Salt, water, and excess materials are excreted from the body by sweat glands, which are located in the skin and excrete waste through tiny openings in the skin called pores.
The central nervous system includes the brain, which is protected by the skull, and the spinal cord, which is protected by vertebrae, making up the backbone.
A concussion is an injury to the brain that can be caused by a hard hit to the head or violent shaking of the brain.
The endocrine system in the body's regulator. It is composed of tissues and organs throughout the body that secrete hormones.
A nerve cell, also called a neuron, is the primary cellular building block in the nervous system.
There are two main sections of the nervous system - the central nervous system and the peripheral nervous system - which work together.
The peripheral nervous system contains nerves that form a network throughout the body that directs voluntary and involuntary activities. The spinal cord connects the brain to nerves throughout the body.
The peripheral nervous system consists of all the body's nerves located outside of the spinal cord and brain.
The skull protects the brain.
The breast bone and ribs protect the lungs and heart.
Cartilage is found at the end of bones and joints. It enables the ends of bones to move smoothly against each other.
A joint is the place where two bones come together. The knee is an example of a hinge joint.
Some bones produce red blood cells.
This moving arm depicts skeletal muscle, or voluntary muscles, which move when we want them to move. Skeletal muscles usually work in pairs, meaning that when one contracts the other relaxes.
Sprains occur when ligaments at a joint are stressed or torn.