I always find it amazing that so many martial artists have so little knowledge (or even factually incorrect knowledge) about the human body. We often talk of martial arts as being precise and exact, and I do not think this is possible without knowing the weak points of the body. Guro Fred will contend, rightly so, that a lack of knowledge of the body not only keeps us from attaining our optimal state of health, but when fighting, ignorance makes a tough job even tougher.
Particularly for smaller artists or female artists, it is critical to master a few points that can be relied upon to bring an opponent down, especially when that opponent is likely to be bigger/stronger.
Although I post an acupuncture chart above, I do not think it is a requirement for every artist to know every point on every meridian. However, it is well worth knowing a few, and especially knowing the location and function of key organs of the body such as the liver, spleen, heart, and major arteries/veins and nerve clusters - this is useful to know where to attack, and also where to protect on your own body. Without such knowledge, martial arts becomes vulgar and coarse, based only on physical strength and lacking the grace of an "art" or the precision of a science.
Martial Arts can be summarized as "your strong points against your enemy's weak points".
That is not possible if you do not know where they are.
Take some time to study up on the basic target organs: liver, spleen, kidneys, heart. Also learn the difference between a choke (attacks the windpipe) and a strangle (attacks the carotid arteries). Work on understanding the key joints of the body: wrist, elbow, shoulder, ankle, knee, hip, neck. Be familiar with the spinal column and how it controls balance and power.
This knowledge will definitely take your training to the next level. See you in anatomy class!