Hormonal Co-ordination in Animals and Plants
Reception, Response and Co-ordination · Hormonal Co-ordination
Syllabus tag: KCSE | Biology | Form 4 | Topic 3 Reception, Response and Co-ordination
Lesson objectives
By the end of this topic, you should be able to:
- Define a hormone and compare nervous with hormonal co-ordination.
- State the endocrine glands, their hormones and effects.
- Explain the effects of hormone over- and under-secretion.
- Describe plant hormones and tropisms, and their applications.
Summary
A hormone is a chemical messenger made by an endocrine gland, carried in the blood, and acting on distant target organs. Hormonal co-ordination is slower but longer-lasting than nervous co-ordination. In plants, auxins control growth responses called tropisms, which are directional growth movements towards or away from a stimulus.