| A | B |
|---|
| asymmetrical | irregular shape |
| radial symmetry | can be divided along any plane to produce two halves which look alike |
| bilateral symmetry | can be divided only one way to produce mirror image halves |
| anterior end | front end |
| posterior end | back end |
| dorsal side | upper side |
| ventral side | lower side |
| anterior | head region |
| posterior | tail region |
| dorsal | back on top |
| ventral | abdomen on bottom |
| medial | close to middle |
| lateral | close to side or movement away from middle |
| distal | away from the main part |
| proximal | close to the main part |
| oral | end with the mouth |
| aboral | opposite end of the mouth |
| cephalic | toward the head |
| caudal | toward the tail |
| ectoderm | becomes the nervous system, epidermis of skin, pituitary, and lens of eye |
| misoderm | becomes muscles, skeleton, notochord, circulatory system, kidney, and reproductive system |
| endoderm | becomes the lining of the digestive tract, liver, pancreas, epithelial lining of the lungs, and many endocrine glands |
| acoelomates | contain no body cavity |
| pseudocoelomates | contain a partial body cavity |
| coelomates | contain a true body cavity |
| cephalization | concentration of sense organs and developed nervous system |
| symmetry | refers to balance in body portions |
