Which terms refer to up and down, respectively?

The terms that refer to up and down are "superior" and "inferior." "Superior" indicates a position higher or above another part of the body, while "inferior" denotes a position lower or below another structure. For example, the head is considered superior to the neck, and the stomach is inferior to the heart.

On the other hand, "anterior" and "posterior" refer to the front and back of the body, respectively. "Dorsal" and "ventral" indicate the back (dorsal) and belly (ventral) surfaces, while "cranial" and "caudal" refer to directions toward the head (cranial) and toward the tail (caudal). While these terms are all important in anatomical language, when specifically describing vertical orientation, "superior" and "inferior" are the most appropriate terms.