anus The opening through which the body
passes solid waste (feces), below the final segment
of the COLONand the terminus of the gastrointesti-
nal system. The anal sphincter is a ring of MUSCLE
that contracts to contain fecal matter and relaxes
to expel it. Learning to control the contraction and
relaxation of the anal sphincter begins to take
place at age two or three; most children master
this control by age four or five. NERVOUS SYSTEM
damage, such as with PARKINSON’S DISEASE and
sometimes as a consequence of aging, can cause
loss of anal sphincter control with resulting FECAL
INCONTINENCE.
For further discussion of the anus within the
context of gastrointestinal structure and function,
please see the overview section “The Gastrointesti-
nal System.”
See also ANAL ATRESIA; ANAL FISSURE; RECTUM;
SPINAL CORD INJURY; STROKE; TRAUMATIC BRAIN INJURY
(TBI).appendectomy A surgical OPERATION to remove
an inflamed or infected APPENDIX. The conven-
tional open procedure involves making an incision
two to three inches long in the lower right
abdomen. Open appendectomy typically requires
two or three days of hospitalization and four to six
weeks for full recovery. A laparoscopy appendec-
tomy requires a shorter hospital stay and is a more
rapid recovery. For a laparoscopic appendectomy,
the surgeon makes four or five small incisions
(about^1 ⁄ 2 inch in length). Through one of the inci-
sions the surgeon inserts the laparoscope, a flexi-
ble lighted tube. Through the other incisions the14 The Gastrointestinal System
COMMON ANTIEMETIC MEDICATIONSActive Ingredient Representative Products Availability
bismuth subsalicylate Pepto-Bismol over the counter
buclizine Bucladin-S requires a doctor’s prescription
cyclizine Marezine requires a doctor’s prescription
dimenhydrinate Dramamine over the counter
diphenhydramine Benadryl over the counter
dolasetron Anzemet requires a doctor’s prescription
granisetron Kytril requires a doctor’s prescription
meclizine Antivert, Bonine over the counter (prescription strength also
available)
metoclopramide Reglan requires a doctor’s prescription
ondansetron Zofran requires a doctor’s prescription
prochlorperazine Compazine requires a doctor’s prescription
promethazine Phenergan requires a doctor’s prescription
scopolamine transdermal Transderm-V requires a doctor’s prescription
trimethobenzamide Tigan requires a doctor’s prescription