I'm hearing time and time again that with a self-defense handgun load, shot placement is more important that how big the bullet is, or how fast it moves. I remember seeing a video where a Navy SEAL was talking about their equipment, and that their sidearm is a 9mm, and how the round gets made fun of. He went on to say that his enemies won't be making fun of it when they've got two in their heart, and one in their brain. I admit I know very little about human anatomy. I don't know how the body will be affected by a hit to a given spot. Are there any resources that summarize things like this? Obviously, taking a shot to the brain or heart will quickly remove the threat, but are there any other areas?