REGULATION THE ENDOCRINE SYSTEM

1. REGULATION THE ENDOCRINE SYSTEM • Body System which regulates: • overall metabolism • homeostasis • growth • reproduction

2. ENDOCRINE GLANDS • Ductless organs that secrete hormones directly into the bloodstream to be transported to other parts of the body

3. HORMONES • Chemical messengers that cause a change in target tissues activity • Examples: Insulin (protein-type) Testosterone (steroid)

4. Hormones • Hyposecretion- a deficiency of a hormone • Hypersecretion- an excess of a hormone

5. Target Tissues • Tissue that is affected by a particular hormone • Different than the secreting gland

6. DYNAMIC EQUILIBRIUM • Steady State • Constant small corrections that normally occur to keep an organism’s internal environment within limits needed for survival (stable) • HOMEOSTASIS

7. Feedback Mechanism • Cycle in which output of a system “feeds back” • Either modifies or reinforces the action of the system • Feedback responses can be simple or complex

8. Positive Feedback • Change in environment prompts a response • Response leads to greater change and greater response • Reinforces • Labor and childbirth is an example

9. Negative Feedback • Change prompts signal which leads to a decrease or stop of original response- opposes • Most common • Keeps levels constant • Maintains Homeostasis

10. FEEDBACK

11. Negative Feedback • Examples: • Regulating human body temperature

12. Negative Feedback • Regulates blood glucose levels Sugar level high neg feedback Pancreas low blood sugar Secretes insulin product decreases insulin Blood sugar drops

13. Pituitary Gland • Is sometimes called “The Master Gland” because it controls the other endocrine glands • It is located at the base of the brain

14. Pituitary Hormones • Thyroid Stimulating Hormone (TSH) • Causes the thyroid gland to release it’s hormone (thyroxine)

15. Pituitary Hormones • Follicle Stimulating Hormone (FSH) • Causes human egg cells to develop in the ovaries and influences other reproductive hormones

16. Pituitary Hormones • Growth Hormone (GH) • Causes bones to grow normally during childhood

17. Pituitary Hormones • Adrenocorticotropic Hormone (ACTH) • Stimulates the production and release of hormones from the adrenal glands

18. Thyroid Gland • The thyroid gland is H shaped and is located in the neck around the trachea • It produces thyroxine that regulates the rate of body metabolism and is necessary for normal mental and physical development • Contains Iodine

19. Parathyroid glands • The parathyroid glands are located within the thyroid gland • They produce the hormone parathormone which controls the levels of calcium and phosphorus

20. The adrenal glands are located at the top of the kidneys and produce the hormones adrenaline and cortisol Cortisol regulates sugar metabolism, water balance and helps to maintain blood pressure Adrenaline increases sugar levels in the blood, increases heart and breathing rates to get body ready for “fight or flight” Adrenal glands

21. Pancreas • The pancreas has cells called the islets of langerhans • These cells produce the hormones insulin and glucagon

22. Insulin lowers blood glucose levels by increasing the movement of glucose into the body cells • Within the cells of the liver insulin promotes the change of glucose to glycogen (a polysaccharide)

23. Pancreas • Glucagon raises blood glucose levels by promoting the change of glycogen in the liver back to glucose

24. Gonads – Sex Glands • The testes are located in the male scrotum and produce the hormone testosterone • Testosterone promotes the development of secondary sex characteristics in males (deep voice, facial and body hair, and the male body form)

25. Gonads – Sex Glands • The ovaries are located in the lower abdomen of females and produce the hormones estrogen and progesterone

26. Estrogen stimulates the development of the female reproductive system and the female secondary sex characteristics (development of breasts, broadening of hips and with progesterone, regulation of the menstrual cycle)

27. Malfunctions of the Endocrine System • Thyroid- Hyperthyroidism • Hypersecretion of thyroxine = increased metabolism, nervousness, irritability, sleeplessness and weight loss • May produce a goiter, an enlargement of the thyroid gland (which may be caused by lack of iodine in the diet)

28. Thyroid- Hypothyroidism • Hyposecretion of thyroxine in infancy may cause cretinism (child will be mentally retarded and a dwarf) • In adults sluggishness and weight gain due to decrease in metabolism

29. Pituitary • Hypersecretion of GH in children leads to gigantism where the individual is abnormally tall but in proportion • In adults acromegaly – large hands, feet and facial features

30. Pituitary • Hyposecretion of GH leads to dwarfism where the individual is small but normally proportioned

31. Pancreas • Hypersecretion of insulin can lead to diabetic shock because blood glucose levels fall dangerously low • Convulsions, unconsciousness and death may result

32. Pancreas • Hyposecretion of insulin causes diabetes • The glucose does not move into the cells and the blood glucose level rises • High blood glucose levels can damage organs and tissues • Insulin injections are given to control the blood glucose levels