Hormones

Hormones are chemical substances which are produced in one part of an organism which have effect on another part. Below are the main hormones:

Plant hormones

• Natural growth hormone, auxin is responsible for phototropism.
• Plant hormones are also used artificially for rooting.
• Rooting powder is put onto cuttings to make them root quicker.

Animal hormones

• Produced in endocrine glands which pass hormones directly into the blood where they are distributed to different parts of the body.
• The Pancreas produces insulin.

Adrenal glands

• Situated at the top of the kidneys.
• Produces adrenaline, the hormone produced when you are scared or excited.
• Adrenaline stimulates faster breathing, increased heart rate, more glucose and widening of blood vessels so more oxygen can be transported to the parts of the body that need it

Reproductive organs

• Produce sex hormones.
• Oestrogen from the ovary to cause secondary sexual characteristics and menstrual cycle.
• Testosterone from testes causes male secondary sexual characteristics.