介绍

  • Cells → Tissues → Organs → Systems
  • Tissues
    • epithelial tissue
    • muscle tissue
    • nerve tissue
    • connective tissue
  • About 60% of the adult human body is fluid
    • intracellular fluid
      • 2/3 of this fluid is inside the cells
    • extracellular fluid
      • 1/3 is outside the cells
      • namely the internal environment
  • Homeostasis内稳态
    • maintenance of a nearly constant internal environment
    • (pH, temp., osmotic pressure, ions and etc.)
  • Regulation of body functions
    • Neural regulation
      • the nervous system regulates body functions via the reflex
      • Fast and quick
      • A reflex arc includes sensors, afferent nerves, nerve centers, efferent nerves and effectors
    • Humoral regulation
      • the endocrine system secretes hormones to regulate body functions
      • Slow but durable
    • Auto-regulation
      • cells, tissues, organs regulate themselves without the participation of the nervous/endocrine system. Small scale.
  • cybernetics控制论
    • negative feedback
    • positive feedback