Organism level systems

The nervous system allows us to react to our surroundings very quickly and to coordinate our behavior. It comprises millions of neurones and electrical impulses pass along them very quickly.

The endocrine system secretes hormones into the bloodstream from glands throughout the body. Hormones produce an effect on specific target organs in the body.

Hormones control important processes like germination, flower opening, dropping leaves, phototropism and geotropism. We use plant hormones in weedkillers, and to make seedless fruit and root cuttings.

Homeostasis is the regulation of conditions in the body such as temperature, water content and carbon dioxide levels. Diabetes is a condition where the body cannot regulate its blood glucose levels.

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.