Medical Dictionary

Health Glossary

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

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Hypertension

A condition where blood pressure stays too high over time. Hypertension often causes no symptoms early on but can damage:…

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Hypodermis (Subcutaneous Tissue)

The hypodermis, also called the subcutaneous tissue, is the deepest layer beneath the skin. It consists mainly of fat (adipose…

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ICU (Intensive Care Unit)

A specialized hospital unit for patients who are critically ill and require close monitoring and advanced medical support. Patients in…

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Illness

A state of poor physical or mental health. Illness may be: Related:

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Immune System

The body’s defense system against infections and harmful substances. The immune system helps recognize and fight disease-causing organisms. Related:

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Immune System

The body’s defense system against infections and harmful substances. It includes: Related:

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Immunity

The body’s ability to protect itself against infections and disease. Immunity may develop through: A weakened immune system can increase…

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Incubation Period

The time between exposure to an infection and the appearance of symptoms. Different diseases have different incubation periods. Related:

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Infection

A condition where harmful microorganisms enter the body and multiply. Infections may be caused by: Symptoms vary depending on the…

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Inflammation

Inflammation is the body’s natural response to injury, infection, or irritation. It helps the immune system repair damaged tissues and…

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Influenza

A contagious viral infection that mainly affects the respiratory system. Commonly called “the flu.” It may cause: Related:

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Insulin

A hormone that helps move glucose from the blood into cells for energy. Problems with insulin are central to diabetes.…

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Intestines

Long tube-like organs in the digestive system that help absorb nutrients and remove waste. The intestines include: Related:

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Iron Deficiency

A condition where the body does not have enough iron. Iron is important for: Common effects include: Related:

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Jaundice

Yellow discoloration of the skin or eyes caused by high levels of bilirubin in the body. Jaundice may occur in:…

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Keratin

Keratin is a tough structural protein that helps protect the skin, hair, and nails. Keratin gives strength to the outer…

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Keratinocyte

A keratinocyte is the main type of cell found in the epidermis. Keratinocytes produce keratin and form the protective outer…

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Kidney Failure

A condition where the kidneys stop working properly and cannot effectively remove waste and excess fluid from the body. Kidney…

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Lesion

A lesion is any area of tissue that has been damaged or has changed from its normal appearance. Lesions may…

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Leukemia

A cancer that affects blood-forming tissues, especially white blood cells. It begins mainly in: Related:

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Liver

A large organ that helps: The liver plays a major role in metabolism and detoxification. Related:

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Loss of Consciousness

A temporary or prolonged inability to respond or remain awake. Possible causes include: Related:

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Lungs

The main organs responsible for breathing and oxygen exchange. The lungs help: Related:

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Lupus

A long-term autoimmune disease in which the immune system attacks healthy body tissues. Lupus may affect: Related:

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