A young red blood cell that usually remains in the bone marrow with only a few venturing out into the circulating blood. The number of reticulocytes in blood rises when red cell production is unusually vigorous, as after a major bleeding episode or after the bone marrow has been suppressed and is regenerating, or when there is unusually rapid red blood cell destruction as in cases of hemolytic anemia. The reticulocyte is so named because it has a fine reticulum representing ribosomal remains.
- Reticulocyte count
The number of reticulocytes (young red blood cells) circulating in blood, usually less than 1 percent of the total number of red blood cells. Elevation of the reticulocyte count above 1 percent (reticulocytosis) is a sign of rapid red blood cell production.
An elevation in the number of reticulocytes (young red blood cells) in blood, a sign of unusually rapid red blood cell production. The number of reticulocytes is normally less than 1% of the total number of the red blood cells. A higher proportion (above 1%) constitutes reticulocytosis.
The retina is the nerve layer that lines the back of the eye, senses light, and creates impulses that travel through the optic nerve to the brain. There is a small area, called the macula, in the retina that contains special light-sensitive cells. The macula allows us to see fine details clearly. The eye has […]
- Retinal artery, central
The blood vessel that carries blood into the eye and supplies nutrition to the retina. The counterpart to the central retinal artery is the central retinal vein, the vessel that carries blood away from the retina.
- Retinal detachment
A separation of the retina from its connection at the back of the eye. The separation usually results from a tear (that is, a rent or rip, not a tear drop) in the retina, which often occurs when the vitreous gel pulls loose or separates from its attachment to the retina. Once the retina has […]