In this preview of TCM Foundations 1, Bill Schoenbart L.Ac, DAOM touches on the role of what are known as the vital substances in Chinese medical physiology, such as qi, blood, body fluids, shen, and jing essence. This class specifically focuses on jing essence, which is responsible for growth, reproduction, and development. Deficiency in jing essence can lead to various health issues such as stunted growth, infertility, and osteoporosis.