1. Topic 6.6 Hormones & Homeostasis

2. The Endocrine System Hormones are chemical messengers secreted directly into the blood. They are carried to the target tissues (the place of intended action). The action of the hormone changes the condition of the tissue. Change monitored through feedback. negative or positive feedback. 1 2 4 3 5 8 6 7 Endocrine glands: 1.Pineal glandPineal gland 2.Pituitary glandPituitary gland 3.Thyroid glandThyroid gland 4.ThymusThymus 1.Adrenal glandAdrenal gland 2.PancreasPancreas 3.Ovary (female)Ovary (female) 4.Testes (male)Testes (male)

3. Hormone Where Produced Target cell Action Produced Insulin β cells of pancreas Skeletal muscle, liver cells Stimulates uptake of glucose from the blood and conversion to glycogen Glucagon α cells of pancreas Liver cells Break down glycogen into glucose so it can be released into the blood ThyroxinThyroid gland All cells of the body but main are brain, liver & muscle Regulates the metabolic rate & regulates body temperature LeptinAdipose tissuehypothalamus Inhibits appetite Melatonin Pineal gland But secretion is controlled by the SCN (Suprachiasmatic Nuclei) of the hypothalamus Brain cells Control of circadian rhythms (more melatonin secreted at night, in winter, & children leading to more sleep)

4. Maintaining the internal environment (blood & tissue fluids) of the body within safe limits