from high levels of BILIRUBINin the BLOOD. As well,
the URINEmay be dark brown or tea-colored and
the stools pale, indicating a high concentration of
BILEpigments 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 ery-
throcytes (red blood cells). The SPLEENperforms
this destruction to rid the body of old erythrocytes
that no longer function properly. The liver incor-
porates 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
DISEASEthat interferes with this bilirubin handling,
either in the breakdown stage (liver) or the elimi-
nation stage (GALLBLADDER). In most people the
jaundice goes away with treatment of the under-
lying condition. Newborns commonly develop a
form of jaundice not related to liver dysfunction
called NEONATAL JAUNDICEor physiologic jaundice.
See also CHOLESTASIS; CIRRHOSIS; HEPATITIS.jejunum The middle segment of the SMALL INTES-
TINE, between the ILEUMand the DUODENUM. The
jejunum is six to eight feet long and handles
absorption of carbohydrates and proteins, as well
as vitamins such as VITAMIN Kand minerals such as
iron. The jejunum’s tissue composition and excel-
lent blood supply allow it to be the source of tissue
grafts for reconstruction of the pharynx and upper
ESOPHAGUSafter 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-
ABSORPTIONdisorders.
For further discussion of the jejunum and the
small intestine within the context of gastrointesti-
nal structure and function, please see the
overview section “The Gastrointestinal System.”
See also BOWEL ATRESIA; SHORT BOWEL SYNDROME.kernicterus See NEONATAL JAUNDICE.kernicterus 67