Endocrine System

1. Endocrine System Chapter 10

2. Regulating Body Function • Working closely with your nervous system is theendocrine system, a chemical communication system that regulate many body functions.

3. Exocrine vs Endocrine Exocrine Glands Endocrine • secrete their products into ducts that empty onto a surface or into a cavity. • Ex: Sweat glands and salivary glands • Ductless glands. • They secrete chemicals (hormones) into intracellular spaces. not

4. Regulating Body Function • A gland is a group of cells, or an organ, that secretes a chemical substance. • The endocrine glands secrete chemicals called hormones directly into the bloodstream. • The blood carries the hormones directly to the tissue they are targeted to affect. • Some hormones are produced continuously, while others are produced only at certain times.

5. Regulation of Hormone Secretion Negative Feedback Positive Feedback • Homeostatic control mechanism that reverses what is happening in the body • More common than positive feedback. • Ex: Insulin, Body Temperature, Blood Pressure • Amplifies changes rather than reverses them. • Ex: Labor – amplified contractions.

6. Mechanisms of Hormone Action Nonsteroid Hormones Steroid Hormones • Second messenger mechanism: nonsteroid hormones serve as 1st messenger between gland and cells; Another molecule will then act as a 2nd messenger providing communication within the target cell • Lipid-soluble • Can pass through cell membrane of target cell • Bind with receptors on the nucleus and act on DNA

7. Meet the Glands Endocrine System

8. Pituitary • The pituitary gland at the base of the brain is a gland that signals other endocrine glands to produce hormones when needed. • It is also known as the “Master Gland” and is located at the base of the brain. • It secretes several hormones. • These regulate the thyroid gland, adrenal glands, and kidneys- plus your growth and development. It produces growth hormones.

9. Pituitary Anterior Posterior • TSH • Thyroid stimulating • ACTH • Adrenocorticotropic • FSH • Follicle-stimulating • LH • luteinizing • GH • growth • Prolactin • ADH • Anti-duretic • Oxytocin

10. Hypothalamus • The hypothalamus is a vital neuroendocrine and autonomic control center beneath the thalamus. • Secretes: • Releasing hormones • Anterior pituitary • Inhibiting hormones • Posterior pituitary

11. Parathyroid • The parathyroid glands direct the distribution of certain minerals in your body. • Increase Ca+ in blood • Secretes • Parathyroid hormone or PTH

12. Pancreas • The pancreas is part of two body systems- the digestive system and the endocrine system. • It is located behind the stomach and supplies the small intestine with digestive juice. • It produces insulin and contains small clusters of cells called the islets of Langerhans, which control blood sugar levels. • It produces insulin.

13. Pancreas

14. Thymus • The thymus gland is located in the mediastinum. • It is a vital part of the body’s immune system. • Produces thymosin

15. Pineal Gland • The pineal gland is located in the third ventricle of the brain. • It produces melantonin.

16. Thyroid • The thyroid gland is located where the larynx and trachea meet. • It regulates the chemical reactions of nutrients in the cells. • It produces thyroxine.

17. Adrenal • The adrenal glands are located on your kidneys. • They secrete hormones that help the body maintain its levels of sodium and water, aid the digestive process, and control your body’s response to emergencies. • It produces adrenaline.

18. Adrenal

19. The Body’s Response to Stress • When your brain recognizes a stressful situation, your adrenal glands responds by releasing the hormone adrenaline. This hormone prepares your body to respond to stress.

20. Reproductive • During adolescence, the endocrine system plays an important role in growth and development.

21. Ovaries • The ovaries are the female reproductive glands. • They control the development of secondary sex characteristics during adolescence. • It produces estrogen.

22. Placenta • The placenta anchors the developing fetus to the uterus and provides a “bridge” for the the exchange of nutrients and waste products between the mother and the developing baby.

23. Testes • The testes are the male reproductive glands. • They control the development of secondary sex characteristics during adolescence. • It produces testosterone.

24. Problems or Abnormalities Endocrine System

25. Secretions of Hormones Hyposecretion Hypersecretion • Production of too little hormone by a diseased gland • Production of too much hormone by a diseased gland

26. Diabetes • Diabetes mellitus is a disease that may be caused by inadequate insulin production by the pancreas. • Symptoms include: • lack of energy • weight loss • extreme thirst • frequent urination

27. THYROID HYPOTHRYOIDISM HYPERTHYROIDISM • Underactive thyroid gland can cause a dull facial expression, hoarse voice, facial puffiness, coarse, dry skin and hair, and weight gain. • Goiter- caused by low dietary iodine intake • Cretinsim- when hyposecretion occurs in infants/toddlers • Overactive thyroid gland produces symptoms that may include protrusion of eyeballs, warm, moist skin, trembling hands, nervousness, increased sweating, disturbed sleep, and weight loss.

28. Growth Hormone hyposecretion hypersecretion • Dwarfisim • Gigantism • Acromegaly results when GH is secreted too much after adolescents.

29. Parathyroid • Parathyroid hormone (PTH) and vitamin D help manage calcium balance in the body • Calcium is important to many body functions, including: • Bone formation • Hormone release • Muscle contraction • Nerve and brain function

30. Parathyroid and Nerve Cells

31. Parathyroid hypersecretion hyposecretion • Results inhypercalcemia • Causes several abdominal, muscle, kidney and psychological symptoms • Results in hypocalcemia • Symptoms include: • Petechiae (red spots on skin) • Strong muscle contractions of the hand (cramping) • Life threatening • ECG changes