ship between the appendix and INFLAMMATORY
BOWEL DISEASE(IBD) as well as the role of GALT
HYPERPLASIA(enlargement of the lymphoid tissue)
in APPENDICITIS. Because of its location and narrow
structure, the appendix is vulnerable to circum-
stances that cause it to become inflamed or
infected. Appendicitis is the most common health
condition involving the appendix.
For further discussion of the appendix within
the context of gastrointestinal structure and func-
tion, please see the overview section “The Gas-
trointestinal System.”
See also AGING, EFFECTS ON IMMUNE RESPONSE;
APPENDECTOMY; MUCOSA-ASSOCIATED LYMPHOID TISSUE
(MALT).
ascites The accumulation of fluid within the
peritoneal cavity. Ascites is an abnormal condition
that often accompanies chronic LIVERdisease such
as CIRRHOSIS and LIVER DISEASE OF ALCOHOLISM.
Ascites sometimes also develops with HEART FAIL-
URE, END-STAGE RENAL FAILURE(ESRF), OVARIAN CAN-
CER, and metastatic cancer that infiltrates
abdominal structures. Ascites typically causes little
discomfort. Paracentesis, in which the doctor uses
a needle and syringe to withdraw a sample of the
fluid, can help to diagnose the cause of the ascites.
The doctor also may use paracentesis to withdraw
large amounts of fluid to relieve the ascites. Other
treatments include a very low sodium diet and
diuretic medications to encourage the kidneys to
withdraw larger amounts of fluid from the blood.
Untreated or persistent ascites invites PERITONITIS, a
potentially life-threatening INFECTION.
See also HEPATITIS; PORTAL HYPERTENSION; STEATO-
HEPATITIS.16 The Gastrointestinal System