Encyclopedia of Health and Medicine

kernicterus 67
from high levels of BILIRUBIN in the BLOOD. As well,
the URINE may be dark brown or tea-colored and
the stools pale, indicating a high concentration of
BILE pigments dissolved in the urine and a lack of
bile entering the intestinal tract. Intense itching
(PRURITIS) often accompanies jaundice, the skin’s
reaction to the irritation of the bilirubin deposits.
Bilirubin is a byproduct of the destruction of erythrocytes
(red blood cells). The SPLEEN performs
this destruction to rid the body of old erythrocytes
that no longer function properly. The liver incorporates
bilirubin into bile, which it then secretes
into the gastrointestinal tract to aid in digestion as
well as to excrete the excess as waste.
Jaundice indicates liver disease or GALLBLADDER
DISEASE that interferes with this bilirubin handling,
either in the breakdown stage (liver) or the elimination
stage (GALLBLADDER). In most people the
jaundice goes away with treatment of the underlying
condition. Newborns commonly develop a
form of jaundice not related to liver dysfunction
called NEONATAL JAUNDICE or physiologic jaundice.
See also CHOLESTASIS; CIRRHOSIS; HEPATITIS.
jejunum The middle segment of the SMALL INTES-
TINE, between the ILEUM and the DUODENUM. The
jejunum is six to eight feet long and handles
absorption of carbohydrates and proteins, as well
as vitamins such as VITAMIN K and minerals such as
iron. The jejunum’s tissue composition and excellent
blood supply allow it to be the source of tissue
grafts for reconstruction of the pharynx and upper
ESOPHAGUS after radical surgery to treat laryngeal
CANCER (cancer of the THROAT). Health conditions
that can involve the jejunum include INFLAMMA-
TORY BOWEL DISEASE (IBD), CELIAC DISEASE, and MAL-
ABSORPTION disorders.
For further discussion of the jejunum and the
small intestine within the context of gastrointestinal
structure and function, please see the
overview section “The Gastrointestinal System.”
See also BOWEL ATRESIA; SHORT BOWEL SYNDROME.
kernicterus
See NEONATAL JAUNDICE.