An important, physiological aspect of most beings are the imuno-boosting nanoscopic robots. Nanoscopic robots act as a supplement to a species natural defenses, boosting the immune system as much as 300%. Any kind of DNA altering virus or cancer is halted before it can do any damage or spread, and body degradation is slowed as much as possible, allowing for long life. Depending on the species, other healing functions may be enhanced as well. Pain can be reduced and consciousness can be maintained even with immense physical damage (explaining why a being can be shot in the head and still keep going).
The nanoscopic robots are self-replicating and adaptive. They use materials from the host body to create new nanoscopic robots and decide what type of robot to create based on what is needed. So, a hardened combatant would have more tissue regeneration and blood clotting robots then a scientist and the scientist’s robots would probably focus on reducing body degradation due to aging.
Nanoscopic robots can travel from mother to child, so it is rare to have to have them injected into a new being. Foreign nanoscopic robots are introduced into a being usually from the use of a medical patch. Nanoscopic robots from a med patch mostly disappear, as they use themselves as material to repair the host. Occasionally, specialized nanoscopic robots are needed to combat specific poisons and viruses.
A very useful function that has been incorporated into these minute robots has nothing to do with keeping the host healthy - at least not directly. They can set up a tiny dampening field around their host that interferes with a transporter lock. The host can do this, simply by willing it, thus preventing him from being transported against his will. The host has to consciously think about this, though, so if he is unconscious he is out of luck.
Nanoscopic technology was first widely used when the Confederation was expanding into the galaxies during the galactic wars. Often, the technology was used as a bargaining chip when negotiating with new species. The offer of enhanced health and extended lifespan brought many races into the folds of the Confederation.