Chapter 1 Notes: Structural Organization, Organ Systems, Metabolism, and Feedback

Levels of Structural Organization

  • The body is organized in six distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.
  • This framework moves from small-scale components to the whole living organism.
  • Common levels (from simplest to most complex):
    • Chemical level
    • Cellular level
    • Tissue level
    • Organ level
    • Organ system level
    • Organism level

Organ Systems of the Human Body

  • Organ systems are groups of organs that work together to perform related functions.

  • Principle: Organs that work together are grouped into organ systems.

  • Integumentary System

    • Components: Hair, Skin, Nails
    • Functions: Encloses internal body structures; site of many sensory receptors

  • Skeletal System

    • Components: Bones, Joints, Cartilage
    • Functions: Supports the body; enables movement (with muscular system)

  • Muscular System

    • Components: Muscles
    • Functions: Enables movement (with skeletal system); helps maintain body temperature

  • Endocrine System

    • Major glands listed: Pituitary gland, Thyroid gland, Pancreas, Adrenal glands, Ovaries, Testes
    • Functions: Secretes hormones; regulates bodily processes

  • Nervous System

    • Major components: Brain, Spinal cord, Peripheral nerves
    • Functions: Detects and processes sensory information; activates bodily responses

  • Cardiovascular System

    • Major components: Heart, Blood vessels
    • Functions: Delivers oxygen and nutrients to tissues; Equalizes temperature in the body

Metabolism

  • Metabolism comprises both anabolic and catabolic reactions.
  • Anabolic reactions are building reactions and they consume energy.
  • Catabolic reactions break materials down and release energy.
  • Overall metabolism includes both anabolic and catabolic processes.

Negative Feedback Systems

  • In a negative feedback system, a stimulus (a deviation from a set point) is resisted through a physiological process that returns the body to homeostasis.
  • A negative feedback system has five basic parts.
  • An example: Body temperature is regulated by negative feedback.

Positive Feedback Loop

  • A positive feedback loop drives a change in the body's status rather than returning to homeostasis.
  • Example: Normal childbirth is driven by a positive feedback loop.