Table 2. Gastrointestinal surface area likened to tennis courts in medical literature.

NO	SOURCE	ANALOGY	AREA(m2)	REFERENCE
1	Vander’s Human Physiology: The Mechanisms Of Body Function, Thirteenth Edition	The human small intestine’s total surface area is about 250 to 300 square meters, roughly the area of a tennis court.	250-300	8
2	Textbook Of Medical Physiology	Thus, the combination of the folds of Kerckring, the villi, and the microvilli increases the total absorptive area of the mucosa perhaps 1000-fold, making a tremendous total area of 250 or more square meters for the entire small intestine—about the surface area of a tennis court.	>250	23
3	Harrison's Principles of Internal Medicine (19th Ed)	The functional surface area of the small intestine is somewhat greater than that of a doubles tennis court		24
4	Medical Physiology: A Cellular and Molecular Approach	The total surface area of the human small intestine is ~200 m2, or the surface area of a doubles tennis court	200	25
5	Cellular and Molecular Immunology E-Book	First, the combined mucosa of the small and large bowel has a total surface area of more than 200 m2 (the size of a tennis court), made up mostly of small intestinal villi and microvilli.	200	26
6	Avery's Diseases of the Newborn E-Book	The fully developed gastrointestinal (GI) tract reaches a total length of approximately 20 to 30 feet (Hounnou et al, 2002) and has a mucosal surface area of 300 to 400 m2 (DeWitt and Kudsk, 1999), which is equivalent to the size of a singles tennis court.	300-400	27
7	Intestinal crosstalk – a new paradigm for understanding the gut as the “motor” of critical illness	The mucosal surface of the gut represents the largest body surface in contact with the outside world (approximately 300 m2, roughly the area of a tennis court).	300	28
8	Oxygen in the regulation of intestinal epithelial transport	When one considers that the intestinal epithelium covers an area equivalent to a tennis court and that it must actively pull 9 l of fluid and approximately 1 kg of nutrients from the lumen each day, one can get an appreciation of the energy requirement for the Na+/K+-ATPase to perform its functions		29