(spor″ŏ-zō′īt″) An elongated sickle-shaped immature malarial parasite that develops from a sporoblast within the malarial oocyst. Upon bursting of the oocyst within a mosquito, sporozoites are released into the body cavity and make their way to the salivary gland. They are introduced into human blood by a mosquito and almost immediately enter liver cells, where they go through two schizogonic divisions and then reenter the bloodstream and infect erythrocytes.
[ME. sporten, to divert] Mutation.
(spor-ū-lā′shŭn) [L. sporula, little spore] 1. The production of spores, a method of reproduction in fungi, mosses, and ferns. 2. Bacterial production of spores, resistant forms that can withstand extremes of heat and cold, and dehydration.
(spot) 1. A small surface area differing in appearance from its surroundings. SYN: macula. 2. Randomly collected, as in a urine specimen.
ash-leaf s. White macules found on the trunk and extremities of persons with tuberous sclerosis.
Bitot s. SEE: Bitot spots.
blind s. 1. Physiological scotoma situated 15° to the outside of the visual fixation point; the point where the optic nerve enters the eye (optic disk), a region devoid of rods and cones. SEE: scotoma. 2. In psychiatry, the inability of a person to have insight into his or her own personality.
blood s. A dried specimen of blood placed on filter paper, used for laboratory analysis, as for congenital metabolic diseases.
Brushfield s. SEE: Brushfield spot.
cherry-red s. A red spot visible on the retina of children with sphingolipid disorders, such as Niemann-Pick disease or Tay-Sachs disease. SYN: Tay s.
cold s. An area on a nuclear medicine scan in which no radioactive tracer is taken up, indicative of nonfunctioning tissue in a gland or other structure.
cotton-wool s. A tiny white infarct with soft or blurred borders in the retina, and present in hypertension, diabetes mellitus, bacterial endocarditis, and other diseases. SYN: soft exudate.
focal s. The area on the x-ray tube target that is bombarded with electrons to produce x-radiation.
Fordyce s. SEE: Fordyce disease.
genital s. The area on the nasal mucosa that tends to bleed during menstruation. SEE: vicarious menstruation.
hematocystic s. Any of the focal red marks seen on esophageal varices. They consist of aneurysms of the wall of the dilated blood vessel. Their ...