Analyze Feedback and Stability Examples - Biology

1. Identify the feedback type: rising thyroid hormone levels inhibit TRH and TSH release.

   Negative feedback. Thyroid hormone inhibits its own production.

2. Which option best indicates positive feedback from a graph trend after a disturbance?

   The variable moves farther from the original level over time. Shows amplification away from baseline.

3. Which hormone primarily raises blood calcium levels when they are low?

   PTH (parathyroid hormone). Increases calcium release from bones and absorption.

4. Identify the feedback type: blood pH drops, breathing increases, pH returns toward normal.

   Negative feedback. Breathing counteracts pH changes.

5. Identify the feedback type: blood pressure rises, baroreceptors signal, heart rate decreases.

   Negative feedback. Heart rate decreases to counter high pressure.

6. Identify the feedback type: blood glucose falls, glucagon increases, blood glucose rises.

   Negative feedback. Glucagon counteracts low glucose levels.

7. Which option best identifies the sequence in a homeostatic loop?

   Stimulus → receptor → control center → effector → response. The standard homeostatic pathway.

8. Which pancreatic cells secrete insulin when blood glucose is high?

   Beta cells. Release insulin when glucose is elevated.

9. Identify the feedback type: high blood osmolarity triggers thirst, drinking lowers osmolarity.

   Negative feedback. Drinking counteracts high blood concentration.

10. Identify the feedback type: low blood calcium triggers PTH, blood calcium increases.

    Negative feedback. PTH counteracts low calcium levels.

11. What is the control center's role in a feedback loop?

    Compares to set point and sends commands to effectors. Processes information and directs response.

12. What hormone increases water reabsorption in kidney collecting ducts?

    ADH (antidiuretic hormone). Promotes water retention in kidneys.

13. Which feedback type most commonly maintains internal stability: negative or positive?

    Negative feedback. Counteracts changes for stability.

14. Identify the feedback type: body temperature drops, shivering increases, temperature rises.

    Negative feedback. Shivering counteracts falling temperature.

15. What is the primary effect of ADH on urine volume?

    Decreases urine volume. Less water lost means less urine.

16. Which feedback type is most associated with childbirth and blood clotting?

    Positive feedback. Both involve amplification to completion.

17. What receptors detect stretch changes in blood vessels for blood pressure regulation?

    Baroreceptors. Detect pressure changes in vessel walls.

18. Identify the feedback type: blood glucose rises, insulin increases, blood glucose falls.

    Negative feedback. Insulin counteracts high glucose levels.

19. Identify the effector: glucagon signals a tissue to break down glycogen to glucose.

    Liver cells. Primary glucose release site for glucagon.

20. Which option best indicates negative feedback from a graph trend after a disturbance?

    The variable returns toward the original level over time. Shows correction back toward baseline.

21. Which hormone primarily lowers blood calcium levels when they are high?

    Calcitonin. Promotes calcium storage in bones.

22. What brain region commonly acts as the control center for human thermoregulation?

    Hypothalamus. Brain's thermostat for temperature control.

23. What is positive feedback in homeostasis?

    A response that amplifies a change, driving a process to completion. Reinforces changes to drive completion.

24. What term describes a normal range around a set point in homeostasis?

    Normal range. Acceptable variation around the set point.

25. Identify the effector: insulin signals a tissue to store glucose as glycogen.

    Liver cells. Primary glucose storage site for insulin.

26. Which option best distinguishes feedback from feedforward control?

    Feedback responds after change; feedforward anticipates change. Feedback reacts; feedforward predicts.

27. What is the main purpose of negative feedback in physiology?

    Stabilize internal conditions by counteracting deviations. Reverses changes to maintain balance.

28. What term describes the target value a homeostatic system maintains?

    Set point. The ideal value maintained by homeostasis.

29. Identify the feedback type: rising blood calcium triggers calcitonin, blood calcium decreases.

    Negative feedback. Calcitonin counteracts high calcium levels.

30. What is the main effect of insulin on blood glucose?

    Lowers blood glucose by promoting cellular uptake and storage. Promotes glucose uptake and storage.

31. What is the effector's role in a feedback loop?

    Carries out the response that changes the variable. Executes the corrective action.

32. Identify the feedback type: uterine contractions trigger oxytocin, contractions intensify.

    Positive feedback. Oxytocin amplifies contractions progressively.

33. Identify the feedback type: cold causes vasoconstriction, reducing heat loss and warming.

    Negative feedback. Vasoconstriction counteracts cooling.

34. Identify the feedback type: dehydration increases ADH, kidneys conserve water, dehydration decreases.

    Negative feedback. ADH counteracts dehydration by conserving water.

35. What is negative feedback in homeostasis?

    A response that reverses a change to restore a set point. Counteracts changes to maintain stability.

36. Identify the effector in thermoregulation when you shiver to warm up.

    Skeletal muscles. Contract to generate heat through movement.

37. What term describes a change that pushes a system away from a set point?

    Stimulus. A change that disrupts equilibrium.

38. Which pancreatic cells secrete glucagon when blood glucose is low?

    Alpha cells. Release glucagon when glucose is low.

39. Which variable is directly regulated by ventilation to help control blood pH?

    Blood $CO_2$ level. Ventilation controls $CO_2$ to maintain pH.

40. Identify the effector in thermoregulation when you sweat to cool down.

    Sweat glands. Produces sweat to cool the body.

41. Which gland releases TSH in the thyroid regulation pathway?

    Anterior pituitary. Releases TSH to stimulate thyroid gland.

42. What is the receptor's role in a feedback loop?

    Detects a change and sends information to the control center. Monitors and communicates changes.

43. What term describes keeping internal conditions within narrow limits despite external change?

    Homeostasis. Maintaining stable internal environment.

44. Identify the feedback type: blood $CO_2$ rises, breathing rate increases, blood $CO_2$ falls.

    Negative feedback. Breathing increases to remove excess $CO_2$.

45. Identify the feedback type: overheating causes vasodilation, increasing heat loss and cooling.

    Negative feedback. Vasodilation counteracts overheating.

46. What is the general relationship between $CO_2$ and blood acidity?

    Higher $CO_2$ increases acidity (lowers pH). $CO_2$ forms carbonic acid in blood.

47. What is the overall outcome of positive feedback during blood clotting?

    Rapid clot formation until the break in the vessel is sealed. Amplification continues until vessel is sealed.

48. Identify the feedback type: body temperature rises, sweating increases, temperature falls.

    Negative feedback. Sweating counteracts rising temperature.

49. Identify the feedback type: platelets release chemicals that attract more platelets to a wound.

    Positive feedback. Platelet aggregation amplifies itself.

50. What is the main effect of glucagon on blood glucose?

    Raises blood glucose by promoting glycogen breakdown in liver. Stimulates glucose release from storage.

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