Table 3. Endothelial surface likened to tennis courts in medical literature.

NO	SOURCE	ANALOGY	AREA(m2)	REFERENCE
1	Harrison's Principles of Internal Medicine (19th Ed)	Endothelial cells line the surface of the entire circulatory tree, totalling 1–6 × 1013 cells, enough to cover a surface area equivalent to about six tennis courts.		24
2	Vascular Medicine: A Companion to Braunwald's Heart Disease	The endothelium serves as the innermost lining of all blood vessels. It is the largest organ in the body weighing approximately 1.0 to 1.8 kilograms, containing approximately 1 x 1013 cells, and representing a surface area roughly equivalent to 6 to 8 tennis courts.		32
3	Physical Activity and Cardiovascular Disease Prevention	The vascular endothelium of an average sized individual contains approximately 10,000,000,000,000 endothelial cells that weigh 1.5 kg and covers almost 700 m2, an area equivalent to six tennis courts	700	33
4	Body Renewal: The Lost Art of Self-Repair	Stretched out, your endothelia might cover a tennis court		34
5	The Metabolic Syndrome	In the adult human, it represents 1 per cent of body mass with a collective surface area of 350 m2 (Pries, Secomb and Gaehtgens, 2000), the equivalent of approximately one and a half tennis courts.	350	35
6	The Endothelium and Endothelin: Beyond Vascular Reactivity	The vessel wall is 5 times the size of the heart in mass and 6 times the size of a tennis court in area.		36
7	Endothelial dysfunction: a comprehensive appraisal	Although it is a monolayer that covers the inner surface of the entire vascular system, its total weight is more than a liver and has a mass equal to several hearts or, if it is extended, covers a various tennis courts surface area.		37
8	Does Endothelium Buffer Fat?	The interface between ECs and plasma is between 4000 and 7000 m2, equivalent to the surface of >20 tennis courts.	4000-7000	38
9	Obesity and risk of vascular disease: importance of endothelium-dependent vasoconstriction	Endothelial cells form the inner lining of arterial and venous blood vessels and lymphatic vessels which amount to approximately 1.5 kg in a person weighing 70 kg, covering an area ofapproximately four tennis courts		39
10	Textbook of Vascular Medicine	The average capillary density in the body is 600 vessels/mm3 tissue with around 1000m2 surface area available for exchange of materials, which is equivalent to the surface area of almost four tennis courts.	1000	40
11	Endothelial Mechanotransduction, Redox Signaling and the Regulation of Vascular Inflammatory Pathways	In an adult human, the surface area of the entire endothelium is 3,000 m2 which is equivalent to at least six tennis courts	3000	41
12	Holland-Frei Cancer Medicine	An angiogenic focus appears as only a tiny fraction or a small “hot spot” of proliferating and migrating endothelial cells that arise from a monolayer of resting endothelium of approximately 1000 m2, an area the size of a tennis court.	1000	42