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Chapter 1_A&P I_Basic Concepts - slideshow 2

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Terms in this set (21)

  • What is homeostasis?

    Homeostasis is the maintenance of a stable internal environment within a narrow, normal range close to a set point despite changing external conditions.

  • Name four major core concepts in physiology.

    1. Homeostasis and feedback loops
    2. Structure and function are complementary
    3. Gradients drive physiological processes
    4. Cell-cell communication is crucial

  • What variables does the human body keep relatively constant through homeostasis?

    Body temperature (~37°C), blood glucose (70–120 mg/dL), water and electrolytes (Na⁺, K⁺, fluid), blood pH (~7.4), oxygen and carbon dioxide levels, and blood pressure (~120/80 mmHg).

  • What is a feedback loop in physiology?

    A control mechanism where a change in a variable causes a physiological response that feeds back to adjust that variable.

  • Describe a negative feedback loop.

    A process where changes in a variable trigger responses that oppose the change and return the variable to its normal range, shutting off once balance is restored.

  • What are the four parts of a homeostatic control system?

    Stimulus, receptor, control center (input), and effector (output) which together regulate a physiological variable.

  • Give an example of a negative feedback loop controlling body temperature.

    When body temperature drops, receptors detect the change, the control center signals effectors like skeletal muscles to shiver, producing heat and raising temperature back to normal.

  • What is a positive feedback loop?

    A process where a physiological change is amplified by reinforcing itself, causing rapid change until the loop is shut off.

  • Give an example of a positive feedback loop in the human body.

    During labor, stretching of the cervix causes oxytocin release, which increases uterine contractions, further stretching the cervix until delivery occurs.

  • How does blood clotting demonstrate positive feedback?

    Platelets release signals that recruit more platelets, amplifying clot formation until the vessel is sealed.

  • What is the relationship between positive and negative feedback loops?

    Positive feedback loops often occur within larger negative feedback loops to amplify a response temporarily before returning to homeostasis.

  • List four common myths about homeostasis and feedback.

    1. Negative feedback is bad and positive feedback is good.
    2. Homeostasis means no internal change.
    3. Feedback loops are simply on/off switches.
    4. Any variable can be perfectly controlled.

  • Explain the core principle of structure and function.

    Organs, tissues, and cells are organized to reflect their specific functions; form and function are complementary and shaped by evolution.

  • What is a physiological gradient?

    A difference in concentration, pressure, or temperature between two connected areas that stores energy to drive physiological processes.

  • How do gradients drive physiological processes?

    Stored energy in gradients is used to perform work, such as diffusion of gases or movement of fluids across membranes.

  • Why is cell-cell communication important?

    Cells coordinate actions through chemical or electrical signals to maintain homeostasis and function properly.

  • Name the four categories of chemical cell-cell communication.

    Endocrine, paracrine, autocrine, and juxtacrine signaling.

  • What is endocrine signaling?

    Cells release hormones into the bloodstream to affect distant target cells.

  • What is paracrine signaling?

    Cells release signals that affect nearby cells in the local environment.

  • What is autocrine signaling?

    Cells release signals that act on themselves.

  • What is juxtacrine signaling?

    Direct cell-to-cell communication through physical contact.