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Homeostasis and Feedback Systems in Anatomy & Physiology

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Terms in this set (20)

  • What is the definition of homeostasis according to Cannon (1932)?

    "The constant conditions which are maintained in the body ... which may vary, but which [are] relatively constant."

  • What is the modern definition of homeostasis?

    The condition in which the body's internal environment remains relatively constant within certain physiological limits.

  • What are the two main components of the internal environment in homeostasis?

    1. Extracellular fluid (e.g. plasma)
    2. Cytoplasm

  • What are the characteristics of a steady state maintained by homeostatic mechanisms?

    Open, dynamic, and living system.

  • What are the characteristics of equilibrium in contrast to steady state?

    Closed, static, and non-living system (e.g. sealed beaker of water).

  • What are the six components of a feedback system that maintains homeostasis?

    1. Sensor detects changes
    2. Circuit carries signals
    3. Effector produces effect
    4. Response from effector
    5. Feedback detected by sensor
    6. Shut-off when normalized

  • What role do receptors play in living feedback systems?

    Receptors detect stimuli and transduce signals; they also act as shut-off devices.

  • What are examples of effectors in living feedback systems?

    Glands and muscles that produce secretion or contraction.

  • How does the human body regulate cold temperature through effectors?

    Shivering, piloerection, peripheral vasoconstriction, and increased thyroid hormone.

  • How does the human body regulate hot temperature through effectors?

    Sweat glands activation, peripheral vasodilation, and decreased thyroid hormone.

  • What is the difference between negative and positive feedback systems?

    Negative feedback reverses the stimulus and stabilizes; positive feedback enhances the stimulus and is destabilizing.

  • Why is negative feedback the most common type of feedback system?

    Because it stabilizes physiological variables and maintains homeostasis.

  • What is an example of a positive feedback system?

    Self-reinforcing loops like the cartoon example where a stimulus causes a response that increases the stimulus.

  • What is the role of the control center in homeostasis?

    It receives input information, processes it, and sends output information to effectors.

  • What is the function of the effector in a feedback system?

    Produces a response that affects the variable to restore homeostasis.

  • What is the role of the receptor (sensor) in homeostasis?

    Detects changes in the variable and sends information to the control center.

  • What is the variable in homeostasis?

    The physiological factor or condition being regulated (e.g. temperature, pH).

  • What is the difference between steady state and equilibrium in physiological terms?

    Steady state requires energy and is dynamic; equilibrium is static and requires no energy.

  • What body systems are involved in maintaining homeostasis?

    Integumentary, endocrine, lymphatic, skeletal, muscular, cardiovascular, respiratory, nervous, digestive, and urinary systems.

  • What is the significance of feedback in homeostasis?

    Feedback allows the body to detect changes and adjust responses to maintain internal stability.