Cytology: the study of the internal structure of individual cells, the smallest units of life. Histology: examines tissues, groups of cells that work together to perform specific functions. Homeostasis: the maintenance of a relatively constant internal environment suitable for the survival of body cells and tissues. Gross anatomy: the study of the structural features of the human body without the aid of a microscope. Developmental anatomy: examines the changes in form that occur between conception and physical maturity. Comparative anatomy: considers the similarities and relationships in anatomical organization of different animals. Cartilage vessels moving in, needs blood vasculature which allows transport of chemicals and minerals (ossification); initiates at the primary ossification site. Epiphyseal plates (growth plates) are ossified by the time we are 20. Lipophobic needs plasma membrane to get to target cells. Ability of the cell to respond to autocrine hormones. Target cell can control how many receptors are there for hormone to bind onto.