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Glossary

Showing 921-930 out of 1156 Terms

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  • Pituitary gland

    pih-TOO-ih-TAYR-ee...

    A pea-sized organ attached to the part of the brain called the hypothalamus. It lies at the base of the brain above the back of the nose. The hypothalamus sends signals to the pituitary gland, which then makes hormones that control other glands and many of the body’s functions, including growth and fertility.

  • Plasma

    PLAZ-muh

    The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

  • Platelets

    PLAYT-let

    A tiny, disc-shaped piece of cell that is found in the blood and spleen. Platelets are pieces of very large cells in the bone marrow called megakaryocytes. They help form blood clots to slow or stop bleeding and to help wounds heal. Having too many or too few platelets or having platelets that don’t work as they should can cause problems. Checking the number of platelets in the blood may help diagnose certain diseases or conditions. Also called thrombocyte.

  • Pleural effusion

    (PLOOR-ul eh-FYOO-zhun)

    An abnormal collection of fluid between the thin layers of tissue (pleura) lining the lung and the wall of the chest cavity.

  • Pneumonia

    (noo-MOH-nyuh)

    A severe inflammation of the lungs in which the alveoli (tiny air sacs) are filled with fluid. This may cause a decrease in the amount of oxygen that blood can absorb from air breathed into the lung. Pneumonia is usually caused by infection but may also be caused by radiation therapy, allergy, or irritation of lung tissue by inhaled substances. It may involve part or all of the lungs.

  • Pneumothorax

    (NOO-moh-THOR-ax)

    An abnormal collection of air in the space between the thin layer of tissue that covers the lungs and the chest cavity. This can cause all or part of the lung to collapse. A pneumothorax may be caused by a chest injury, certain medical procedures, lung disease, or other damage to lung tissue. Sometimes the cause of a pneumothorax is not known. The most common symptoms are sudden chest pain and trouble breathing. Some types of pneumothorax may go away on their own, but others may be life threatening.

  • Polyp

    (PAH-lip)

    A growth that protrudes from a mucous membrane.

  • Polys

    The group of white cells that is important to your ability to resist bacterial infection. A ""poly"" count of less than 1,000 indicates less than normal protection and considerable risk of infection.

  • Pons

    ponz

    Part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain. It is part of the brainstem.

  • Port

    port

    A device used to draw blood and give treatments, including intravenous fluids, drugs, or blood transfusions. The port is placed under the skin, usually in the chest. It is attached to a catheter (a thin, flexible tube) that is guided (threaded) into a large vein above the right side of the heart called the superior vena cava. A port may stay in place for many weeks or months. A needle is inserted through the skin into the port to draw blood or give fluids. Also called port-a-cath.