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Drugs and diseases reference index

Drugs and diseases reference index
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Medical Dictionary Definitions A-Z List

Medical Dictionary Definitions A - Z - «S»:

  1. Sinus headache Sinus headache
    Sinus headache: A headache caused by pressure within the sinus cavities of the head, usually in connection with infection of the sinuses. Signs and symptoms of sinus headache include pain and tenderness in the sinus area, discharge from the nose, and sometimes swelling of the face. Vascular hea...
  2. Sinus node Sinus node
    Sinus node: The sinus node is one of the major elements in the cardiac conduction system, the system that controls the heart rate. This stunningly designed system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood. Th...
  3. Sinus rhythm Sinus rhythm
    Sinus rhythm: The normal regular rhythm of the heart set by the natural pacemaker of the heart called the sinoatrial (or sinus) node. It is located in the wall of the right atrium (the right upper chamber of the heart). Normal cardiac impulses start there and are transmitted to the atria and down to...
  4. Sinus tachycardia Sinus tachycardia
    Sinus tachycardia: A fast heartbeat (tachycardia) because of rapid firing of the sinoatrial (sinus) node. The sinoatrial (or sinus) node is the natural pacemaker of the heart. It is located in the wall of the right atrium (the right upper chamber of the heart). Normal cardiac impulses start there...
  5. Sinus, cavernous Sinus, cavernous
    Sinus, cavernous: A large channel of venous blood creating a "sinus" cavity bordered by the sphenoid bone and the temporal bone of the skull. The cavernous sinus is an important structure because of its location and its contents which include the third cranial (oculomotor) nerve, the fourth cranial ...
  6. Sinus, ethmoid Sinus, ethmoid
    Sinus, ethmoid: See: Ethmoid sinus....
  7. Sinusitis Sinusitis
    Sinusitis: Sinusitis is inflammation of the lining membrane of any of the hollow areas (sinuses) of the bone of the skull around the nose. The sinuses are directly connected to the nasal cavities. Picture of the anatomy of the sinuses Picture of the detail of the sinuses ...
  8. Sinusitus headache Sinusitus headache
    Sinusitis headache: Headache that occurs in association with infection or inflammation of the paranasal sinuses, the air cavities within the passages of the nose. Common symptoms of sinus infection are headache, facial tenderness or pain, and fever. Other possible symptoms include cloudy, discol...
  9. Sir Charles Bell Sir Charles Bell
    Sir Charles Bell: See: Bell, Charles....
  10. siRNA siRNA
    siRNA: Abbreviation for small inhibitory RNA, a short sequence of RNA which can be used to silence gene expression....
  11. Sirolimus Sirolimus
    Sirolimus: A naturally occurring substance discovered in a soil sample from Easter Island. Sirolimus was initially thought to hold promise as an antifungal antibiotic but this idea was dropped when sirolimus was unexpectedly found to have immunosuppressive activity. The US Food and Drug Administrat...
  12. Sitophilus granarius Sitophilus granarius
    Sitophilus granarius: See: Granary weevil....
  13. Sitosterolemia Sitosterolemia
    Sitosterolemia: A genetic disease involving lipids (fats) in which there is excessive intestinal absorption of dietary sterols and impaired clearance of these sterols from the liver into the bile. These sterols include cholesterol and the plant sterol sitosterol (from which comes the name of the di...
  14. Situational syncope Situational syncope
    Situational syncope: The temporary loss of consciousness in a particular kind of situation. The situations that trigger this reaction are diverse, and include having blood drawn, straining while urinating or defecating, and coughing. It can also be due to the emotional stress, fear, or pain. Wh...
  15. Situs inversus totalis Situs inversus totalis
    Situs inversus totalis: A condition in which there is complete right to left reversal (transposition) of the thoracic and abdominal organs. For example, the heart is not in its usual position in the left chest but is in the right chest. (This is position of the heart is referred to as dextrocardi...