1. - Responses in the Human –Endocrine System

2.  Define the term: hormone.  Outline what the Endocrine System is  Compare action, distinguishing between exocrine & endocrine glands.  Comparison endocrine action with nerve action  Location of the main glands in the endocrine system and know which hormones they release

3. Glands Glands are parts of the body that secrete substances. There are two types: 1.Exocrine glands 2.Endocrine glands

4.  Exocrine glands have ducts (tubes) to release their products into e.g. salivary glands, tear glands, sweat glands, mammary glands etc Exocrine glands

5. The endocrine glands are ductless glands. They release their products (hormones) straight into the tissue fluid, where they pass into the blood.  Endocrine Glands

6. Hormones  Hormones are chemical ‘messengers’, produced in specialised glands, and transported in the blood to a particular area where they have their specific effect.

7.  The endocrine glands interact with the nervous system to provide the communication, co-ordination and control within the body.

8.  The action of hormones is slower and more general than nerve action and they control mainly long-term changes such as growth, metabolism and sexual maturity.  On passing through the liver, the hormones are broken down and excreted by the kidneys.

9. EndocrineNervous Cells where message starts Message Carried by Message sent from Message received by Transmission time Effects Duration

10. Comparison of the endocrine and nervous systems - 1 Target organReceived by BloodCarried by GlandCells where message starts Cells throughout the body Message sent to Chemical (Hormone) Message Endocrine

11. Comparison of the endocrine and nervous systems - 1 EndocrineNervous Cells where message starts GlandSense receptor MessageChemical (Hormone) Electrical(Impulse) Carried byBloodNerve cell Message sent toCells throughout the body A specific cell or tissue Received byTarget organEffector (muscle or gland)

12. long-lasting (hours) Duration Can be widespreadEffects Usually slowSpeed of transmission Endocrine Comparison of the endocrine and nervous systems -- 2

13. EndocrineNervous Speed of transmission Usually slowRapid EffectsCan be widespreadLocalised usually Durationlong-lasting (hours) Usually brief (seconds) Comparison of the endocrine and nervous systems -- 2

14. Which body system?

15.  Define the term: hormone.  Outline what the Endocrine System is  Compare action, distinguishing between exocrine & endocrine glands.  Tell the difference between nervous and endocrine system

16. Today’s objectives  State the location of the principal glands in the human.  Outline for each gland, one hormone & its function.

17. ENDOCRINE GLANDS

19. Hypothalamus It releases hormones to control the pituitary gland Example: Growth hormone releasing factor – stimulates the production of growth hormone from the pituitary gland.

20.  The pituitary is often called the ‘master gland’, as many of its hormones trigger other glands to release theirs.  Example of hormone released here: Growth hormone – causes body to build proteins and so leads to growth

21. Gigantism

22. Dwarfism

23.  The thyroid gland, in the neck, produces thyroxine, which controls the rate of reactions in the body (our metabolism) Thyroid gland

24. Parathyroid  The parathyroid produces parathyroid hormone, which increases blood calcium levels.

25.  Is an endocrine and exocrine gland.  The Islets of Langerhans is the endocrine portion  It produces the hormone insulin, which stimulates cells to absorb glucose from the blood, and store it as glycogen. The pancreas  The exocrine portion produces enzymes for digestion.

26.  The adrenal gland produces adrenaline, which helps the body cope with emergencies —the ‘flight or fight’ hormone. Adrenal glands

27.  The ovary produces oestrogen to prepare the female for pregnancy. The ovaries

28.  The testes produce testosterone which triggers sperm production and secondary sexual characterisitics in the male. Testes

30. Name that gland

31. Match hormones to glands

32. LEARNING CHECK Name the main endocrine glands in the body. Name one hormone produced by each gland. Give one function for each hormone. Why is the pituitary often called the “master gland”? Where would you find the Islets of Langerhans?

33. Endocrine glands can sometimes malfunction  Low levels of thyroxine reduce the rate of metabolism.  Taking the hormone in tablet form once a day can solve the problem – hormone supplement THYROID gland:  Excess thyroxine can greatly increase metabolic rate.  Treatment is often by removal of part of the gland. DISORDERS of the Endocrine System

34. Cretinism Too little thyroid hormone

35. Graves disease – too much thyroid hormone

36. Common hormone supplements - examples In some people, the pancreas cannot produce insulin, which results in diabetes Regular daily injections of insulin are required to treat diabetes– hormone supplement.

37.  In oral contraceptives, oestrogen and progesterone are taken to prevent ovulation and therefore pregnancy Hormone supplements

38. Feedback mechanism for hormone control Often the level of a hormone in the blood controls the production of another HIGHER LEVEL ONLY

39. Check your learning..  Explain 1 Hormone giving a description of its deficiency symptoms, excess symptoms & corrective measures  Name 2 examples of hormone supplements & their use.  Describe the feedback mechanism for a named hormone