There are four main tissue types that make up the human body: epithelial tissue which covers surfaces, connective tissue which binds parts together, nervous tissue which receives and directs messages, and muscle tissue which controls movement. The human body maintains homeostasis through feedback inhibition loops that regulate internal conditions like temperature and chemical levels despite external changes. Cells make up tissues, tissues make up organs, and organs work together in organ systems to keep the human body functioning as a whole.