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Endocrine glands release hormones into blood. Only target cells respond appropriately, so a hormone can circulate widely while producing specific effects. Hormonal responses are often slower and longer-lasting than nervous responses. Insulin from the pancreas lowers elevated blood glucose, including promoting glucose uptake and glycogen formation. Glucagon increases glucose availability when levels fall. Distinguish glycogen storage from glucagon, the hormone.
Video by Cognito. The video’s own board label is retained; follow the specification reference and scope notes on this lesson for assessed content.
Viewing focus: Compare endocrine and nervous communication
After watching, attempt these questions before opening the answers. You can also use the written lesson below.
After watching 1: Which organ makes urea from excess amino-acid breakdown?
Liver. The kidneys excrete urea but do not create it by that process.
After watching 2: Which hormone lowers blood glucose?
Insulin. It supports uptake and storage.
What you'll be able to do
Endocrine glands release hormones into blood. Only target cells respond appropriately, so a hormone can circulate widely while producing specific effects. Hormonal responses are often slower and longer-lasting than nervous responses. Insulin from the pancreas lowers elevated blood glucose, including promoting glucose uptake and glycogen formation. Glucagon increases glucose availability when levels fall. Distinguish glycogen storage from glucagon, the hormone.
The kidneys filter blood and selectively reabsorb useful substances and suitable amounts of water, producing urine containing wastes such as urea. Urea forms in the liver from excess amino-acid breakdown, not in the bladder. ADH influences water reabsorption, so higher ADH generally gives a smaller volume of more concentrated urine. Dialysis and transplantation have different benefits and limitations. Blood glucose, body temperature and water balance are separate regulated variables.
FSH, LH, oestrogen and progesterone coordinate the menstrual cycle, with feedback between glands and reproductive organs. Contraception can use hormonal control or physical barriers, with different benefits and limitations. Fertility treatment may stimulate egg maturation, and IVF fertilises eggs outside the body before embryo transfer. Plant hormones regulate growth and tropisms and have agricultural uses, such as rooting powders or controlled ripening. Explain each hormone’s target and effect rather than treating hormones as interchangeable signals.
Attempt these problems on paper before opening the worked reasoning. Explain your steps as well as giving a final answer.
Common mistakes to avoid
Key takeaways
Question 1: Why does high blood glucose trigger insulin?
This is negative feedback.
Check the assessed scope and practical or mathematical requirements.
An external explanation or interactive activity to use alongside the lesson. It may include extension material.
Close the notes and answer from memory. Revisit any explanation you cannot yet reconstruct.
Test yourself
Answer a few questions, then review anything you missed.
Start with the quiz above to check the key ideas. You can also choose another topic from the practice library.