| annular scleritis | An often protracted inflammation of the anterior portion of the sclera, forming a ring around the corneoscleral limbus. (05 Mar 2000) |
|---|---|
| annular scotoma | A circular scotoma surrounding the centre of the field of vision. See: ring scotoma. (05 Mar 2000) |
| annular sphincter | A short thickening of circular muscular fibres, similar to a ring; a ring-shaped sphincter as opposed to a segmental sphincter. (05 Mar 2000) |
| annular staphyloma | A staphyloma extending around the periphery of the cornea. (05 Mar 2000) |
| annular stop | <microscopy> The opaque ring-shaped stop with a small central opening usually placed in the objective back focal plane to provide dispersion staining. (05 Aug 1998) |
| annular stricture | A ringlike constriction encircling the wall of a canal. (05 Mar 2000) |
| annular synechia | Adhesion of the entire pupillary margin of the iris to the capsule of the lens. (05 Mar 2000) |
| annular syphilid | Cutaneous lesions of secondary syphilis in which the papules form annular lesions with raised papular borders and clear central portions. (05 Mar 2000) |
| Gerlach's annular tendon | fibrocartilaginous ring of tympanic membrane |
| absolute system of units | A system based on absolute units accepted as being fundamental (length, mass, time) and from which other units (force, energy or work, power) are derived; such system's in common use are the foot-pound-second, centimeter-gram-second, and meter-kilogram-second system's. (05 Mar 2000) |
| absorbent system | <anatomy> The tissues and organs (including the bone marrow, spleen, thymus and lymph nodes) that produce and store cells that fight infection and the network of vessels that carry lymph. (12 May 1997) |
| alimentary system | The organs that are responsible for getting food into and out of the body and for making use of food to keep the body healthy. These include the mouth, oesophagus, stomach, liver, gallbladder, pancreas, small intestine, colon, and rectum. (12 Dec 1998) |
| anterolateral system | A composite bundle of fibres, located in the ventrolateral part of the lateral funiculus, containing spinothalamic, spinohypothalamic, spinoreticular, and spinomesencephalic (spinotectal, spinal to periaqueductal grey, etc.) fibres; occupies the combined areas of the spinal white matter historically divided into anterior and lateral spinothalamic tracts; located in white matter ventral to the denticulate ligament, hence the anatomical basis for the anterolateral cordotomy; concerned with the transmission of nociceptive and thermal information and with crude (nondiscriminative) touch. (05 Mar 2000) |
| anti-allergic and respiratory system agents | A collective term for drugs used to treat allergic reactions as well as those drugs that produce an effect on the respiratory system. (12 Dec 1998) |
| arch-loop-whorl system | See: Galton's system of classification of fingerprints. (05 Mar 2000) |