Higher Tier: thyroxine feedback and adrenaline response
| English | Français |
|---|---|
| adrenaline/əˈdrenəlɪn/ | adrenaline |
| thyroxine/ˈθaɪrəksaɪn/ | thyroxine |
What would explain this observation?
- Higher Tier: A rapid stress response and continuing metabolic regulation have different purposes. Identify the gland, hormone and effect before drawing a feedback loop.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Adrenaline 肾上腺素 is released by adrenal glands in fear or stress. It increases heart rate and boosts oxygen and glucose delivery to brain and muscles, preparing for fight-or-flight. Thyroxine 甲状腺素 is released by the thyroid and stimulates basal metabolic rate, supporting growth and development. Thyroxine levels are controlled by negative feedback.
- thyroxine: A thyroid hormone stimulating basal metabolic rate and supporting growth/development; adrenaline: An adrenal hormone supporting the fight-or-flight response.
Which hormone is associated with stimulating basal metabolic rate?
A supplied thyroxine control diagram may show low thyroxine stimulating pituitary signalling to the thyroid, followed by thyroxine release. Raised thyroxine then reduces the stimulating signal. Explain how that opposes the initial fall. Do not assign the same negative-feedback sequence to every adrenaline event merely because both substances are hormones.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- A supplied thyroxine control diagram may show low thyroxine stimulating pituitary signalling to the thyroid, followed by thyroxine release. Raised thyroxine then reduces the stimulating signal. Explain how that opposes the initial fall. Do not assign the same negative-feedback sequence to every adrenaline event merely because both substances are hormones.
- Compare fictional gland–hormone–effect diagrams and labelled time records. State which change is the stimulus and how the response changes the regulated variable. School tasks must not provoke fear, distress or dangerous exertion, administer hormones or interpret classmates’ health. Use supplied data to analyse mechanisms and model boundaries.
Which two habits make the investigation or model in this case more defensible?
Compare fictional gland–hormone–effect diagrams and labelled time records. State which change is the stimulus and how the response changes the regulated variable. School tasks must not provoke fear, distress or dangerous exertion, administer hormones or interpret classmates’ health. Use supplied data to analyse mechanisms and model boundaries.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: a fictional resting energy-use model rises from 80 to 92 relative units. Increase = 12 units, or 15% of the starting value. This illustrates interpreting a stated metabolic response, not measuring a hormone level or diagnosing a thyroid condition. Hormone concentration requires its own units and evidence.
A fictional metabolic measure rises from 100 to 120 units. Calculate percentage increase. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
A fictional metabolic measure rises from 100 to 120 units. Calculate percentage increase.
The result is 20 %. Known: a fictional resting energy-use model rises from 80 to 92 relative units. Increase = 12 units, or 15% of the starting value. This illustrates interpreting a stated metabolic response, not measuring a hormone level or diagnosing a thyroid condition. Hormone concentration requires its own units and evidence.
Check the conclusion and its limits
- Adrenal glands and thyroid are different glands. Basal metabolic rate concerns resting metabolic activity rather than only visible movement. Negative feedback reduces a disturbance; an arrow labelled inhibition needs an explanation of what is inhibited and why.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
The thyroid and adrenal glands are the same gland. This claim is false: Adrenal glands and thyroid are different glands. Basal metabolic rate concerns resting metabolic activity rather than only visible movement. Negative feedback reduces a disturbance; an arrow labelled inhibition needs an explanation of what is inhibited and why.
Higher Tier: thyroxine feedback and adrenaline response: A supplied thyroxine control diagram may show low thyroxine stimulating pituitary signalling to the thyroid, followed by thyroxine release. Raised thyroxine then reduces the stimulating signal. Explain how that opposes the initial fall. Do not assign the same negative-feedback sequence to every adrenaline event merely because both substances are hormones.
The thyroid and adrenal glands are the same gland.
Adrenal glands and thyroid are different glands. Basal metabolic rate concerns resting metabolic activity rather than only visible movement. Negative feedback reduces a disturbance; an arrow labelled inhibition needs an explanation of what is inhibited and why.
A thyroid hormone stimulating basal metabolic rate and supporting growth/development: write the technical term.
thyroxine means A thyroid hormone stimulating basal metabolic rate and supporting growth/development.