Capillaries are microscopic vessels where food and gases are exchanged with cells of the body.
Cell waste products, such as carbon dioxide, are carried away by the circulatory system.
When the coronary arteries, which supply blood to the heart, become clogged with fat, it is more difficult for blood to nourish heart muscles. When blood flow to the heart is cut off or greatly reduced, a heart attack might occur, damaging the heart.
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.
Arteries carry oxygen-rich blood away from the heart. Veins carry oxygen-depleted blood back to the heart.
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.
The large intestine absorbs water, salt, vitamins, and other materials.
The pancreas, liver, and gall bladder play key roles in digestion.
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 urinary system, also called the excretory system, is a group of organs that work together to remove liquid waste containing a compound called urea.
The bladder stores urine, which leaves the bladder via a narrow tube called the urethra.
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.
Diabetes is a condition in which the hormone insulin isn't released in sufficient amounts, or at all. Insulin is produced by cells in the pancreas and regulates levels of sugar in the blood.
The endocrine system in the body's regulator. It is composed of tissues and organs throughout the body that secrete hormones.
Glands are specific structures that make and release hormones. An example is the thyroid gland, which releases hormones that control the rate of metabolism in the body.
Glands, such as those in the neck, are specific structures that make and release hormones.