Medical Dictionary

Health Glossary

Demystifying medical language. Browse or search for clear, human-centered explanations of common medical terms.

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Bilirubin

A yellow substance produced when red blood cells break down. High bilirubin levels can cause jaundice. Related:

Biopsy

A medical procedure where a small sample of tissue is removed and examined to help diagnose disease. Biopsies are commonly…

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Blackhead (Open Comedone)

A blackhead is an open comedone in which the blocked hair follicle remains open at the skin’s surface. The dark…

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Blood Pressure

The force of blood pushing against the walls of blood vessels. Blood pressure that stays too high over time is…

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Blood Sugar

The amount of glucose present in the blood. The body uses glucose for energy, but blood sugar that stays too…

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Blood Vessel

A blood vessel is a tube that carries blood throughout the body. Blood vessels transport oxygen, nutrients, hormones, immune cells,…

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Body Mass Index (BMI)

A measurement that compares weight to height. BMI is sometimes used to estimate whether a person may be underweight, overweight,…

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Bronchitis

Inflammation of the airways that carry air to the lungs. Bronchitis often causes: Related:

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Cancer

A disease where abnormal cells grow uncontrollably and may spread to other parts of the body. There are many different…

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Capillary

A capillary is the smallest type of blood vessel in the body. Capillaries connect arteries to veins and allow oxygen,…

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Carbohydrate

A major nutrient that provides energy for the body. Common carbohydrate sources include: Related:

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Cardiovascular Disease

A group of diseases affecting the heart and blood vessels. Examples include: Related:

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Cardiovascular Disease

Diseases affecting the heart and blood vessels. Examples include: Related:

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Cardiovascular System

The body system made up of the heart and blood vessels. It is responsible for: Related:

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Cell

A cell is the smallest structural and functional unit of a living organism. Every part of the human body is…

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Central Nervous System

The part of the nervous system made up of the brain and spinal cord. It controls: Related:

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Chemotherapy

A type of treatment that uses medicines to destroy or slow the growth of cancer cells. Chemotherapy may also affect…

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Chills

A sensation of coldness often accompanied by shivering. Chills commonly occur with: Related:

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Cholesterol

A fatty substance found in the blood. The body needs some cholesterol, but very high levels can increase the risk…

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Chronic

A condition that lasts for a long time, often months or years. Chronic illnesses may require ongoing treatment, monitoring, or…

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Circulation

The movement of blood throughout the body. Circulation helps deliver: It also helps remove waste products. Related:

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Circulation

The movement of blood through the body. Good circulation helps deliver: to body tissues and organs. Related:

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Collagen

Collagen is the body’s most abundant structural protein and provides strength and support to many tissues. Collagen is found in…

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Comedone

A comedone is a blocked hair follicle caused by a buildup of sebum and dead skin cells. Comedones are the…

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