Knowledge Organiser
This topic summary covers Knowledge Organiser within Hormones & Behaviour for GCSE Biology. Topic 8: Hormones & Behaviour It is section 8 of 9 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 9
Practice
15 questions
Recall
20 flashcards
Knowledge Organiser
Key Terms
- Adrenaline: Fight-or-flight hormone; from adrenal glands
- Thyroxine: Metabolic rate hormone; from thyroid gland
- Adrenal glands: Above kidneys; activated by nervous system
- Thyroid gland: In neck; controlled by TSH from pituitary
- Metabolic rate: Speed of chemical reactions in cells
- Negative feedback: Response opposes the original change
- TSH: Thyroid-stimulating hormone from pituitary
Must-Know Facts
- Adrenaline: increases heart rate, breathing rate, blood glucose; diverts blood to muscles
- Thyroxine: controls basal metabolic rate
- Thyroxine negative feedback: low thyroxine → more TSH → more thyroxine
- Hormonal response is slower but longer-lasting than nervous response
- Hypothyroidism = too little thyroxine → slow metabolism, weight gain, tiredness, feeling cold
- Adrenaline triggers glycogen breakdown in liver → raises blood glucose
- Both nervous and hormonal systems involved in fight-or-flight
Common Mistakes
- Describing adrenaline effects without naming the gland: Always state "adrenaline released from the adrenal glands" — answers without the specific hormone and gland named score no marks.
- Stating adrenaline effects without linking to a reason: For each effect, add "so that..." — e.g., "heart rate increases so that more oxygenated blood reaches muscles for aerobic respiration." This converts a 1-mark description into a 2-mark explanation.
- Incomplete thyroxine negative feedback loops: The full loop must include every step: low thyroxine level detected by pituitary → pituitary releases more TSH → thyroid gland stimulated → more thyroxine produced → high thyroxine level inhibits TSH release from the pituitary → thyroxine returns to normal. The closing step — high thyroxine inhibits the pituitary — is the mark that confirms understanding of negative feedback; simply saying the pituitary "reduces" TSH is too vague.
- Saying hormones travel along neurones: Hormones travel dissolved in blood plasma, not along nerves — this is why hormonal responses are slower but longer-lasting than nervous responses.
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Practice Questions for Hormones & Behaviour
Which response does adrenaline prepare the body for?
State two effects of adrenaline on the body during a fight-or-flight response.
Quick Recall Flashcards
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