Editing Tendon (section)

=== Tenocytes ===
The [[tenocytes]] produce the collagen molecules, which aggregate end-to-end and side-to-side to produce collagen fibrils. Fibril bundles are organized to form fibres with the elongated tenocytes closely packed between them. There is a three-dimensional network of cell processes associated with collagen in the tendon. The cells communicate with each other through [[gap junctions]], and this signalling gives them the ability to detect and respond to mechanical loading.<ref>{{cite journal | vauthors = McNeilly CM, Banes AJ, Benjamin M, Ralphs JR | title = Tendon cells in vivo form a three dimensional network of cell processes linked by gap junctions | journal = Journal of Anatomy | volume = 189 | issue = Pt 3 | pages = 593–600 | date = December 1996 | pmid = 8982835 | pmc = 1167702 }}</ref> These communications happen by two proteins essentially: [[GJA1|connexin 43]], present where the cells processes meet and in cell bodies [[GJB1|connexin 32]], present only where the processes meet.<ref name="Benjamin_1997">{{cite journal | vauthors = Benjamin M, Ralphs JR | title = Tendons and ligaments--an overview | journal = Histology and Histopathology | volume = 12 | issue = 4 | pages = 1135–1144 | date = October 1997 | pmid = 9302572 | doi = 10.14670/HH-12.1135 | doi-broken-date = 1 November 2024 | url = https://www.hh.um.es/pdf/Vol_12/12_4/Tendons%20and%20ligaments%20-%20an%20overview.pdf }}</ref>

Blood vessels may be visualized within the endotendon running parallel to collagen fibres, with occasional branching transverse [[anastomosis|anastomoses]].

The internal tendon bulk is thought to contain no nerve fibres, but the epitenon and paratenon contain nerve endings, while [[Golgi tendon organs]] are present at the [[myotendinous junction]] between tendon and muscle.

Tendon length varies in all major groups and from person to person. Tendon length is, in practice, the deciding factor regarding actual and potential muscle size. For example, all other relevant biological factors being equal, a man with a shorter tendons and a longer biceps muscle will have greater potential for muscle mass than a man with a longer tendon and a shorter muscle. Successful [[Bodybuilding|bodybuilders]] will generally have shorter tendons. Conversely, in sports requiring athletes to excel in actions such as running or jumping, it is beneficial to have longer than average [[Achilles tendon]] and a shorter [[calf muscle]].<ref>{{cite web|title=Having a short Achilles tendon may be an athlete's Achilles heel | work = Sports Injury Bulletin |url=http://www.sportsinjurybulletin.com/archive/achilles-tendon.html|access-date=2007-10-26|archive-date=2007-10-21|archive-url=https://web.archive.org/web/20071021223203/http://www.sportsinjurybulletin.com/archive/achilles-tendon.html|url-status=dead}}</ref>

Tendon length is determined by genetic predisposition, and has not been shown to either increase or decrease in response to environment, unlike muscles, which can be shortened by trauma, use imbalances and a lack of recovery and stretching.<ref>{{cite journal | vauthors = Young M | title = A review on postural realignment and its muscular and neural components. | journal = British Journal of Sports Medicine | date = 2002 | volume = 9 | issue = 12 | pages = 51–76 |url=http://www.elitetrack.com/article_files/posture.pdf |access-date=2010-06-23 |archive-date=2019-04-06 |archive-url=https://web.archive.org/web/20190406231332/http://www.elitetrack.com/article_files/posture.pdf |url-status=dead }}</ref> In addition tendons allow muscles to be at an optimal distance from the site where they actively engage in movement, passing through regions where space is premium, like the [[carpal tunnel]].<ref name="Benjamin_1997" />