1. Endocrine System

2. Introduction The nervous system and the endocrine system coordinate functions of all body systems

3. Introduction Nervous system controls body actions via nerve impulses

4. Introduction Endocrine system controls body activities by releasing hormones

5. Introduction Two kinds of glands 1.Exocrine 2.Endocrine

6. Introduction Exocrine – secrete their products into ducts Example: salivary and sweat glands

7. Introduction Endocrine – secrete hormones into blood

8. Introduction Endocrine glands; 1.Pituitary 2.Thyroid 3.Parathyroid 4.Adrenal 5.Pineal

10. Introduction The pancreas has exocrine and endocrine functions

11. Introduction Stomach, intestines, and kidneys also produce hormones

12. Hormone Receptors Although travel in blood throughout the body, they affect only specific cells

13. Hormone Receptors Hormones bind to receptors on target cells

14. Hormone Receptors Down Regulation – When a hormone is present in excess, a decrease in the number of receptors may occur

15. Hormone Receptors Up Regulation – When a hormone is deficient, an increase in the number of receptors may occur

16. Hormones Two main types; 1.Circulating 2.Local

17. Circulating Hormones Hormones that travel in blood and act on distant target cells

18. Local Hormones Hormones that act locally without first entering the blood stream

19. Local Hormones Two types; 1.Paracrine 2.Autocrine

20. Local Hormones Paracrine – act on neighboring cells

21. Local Hormones Autocrine – act on the same cell that secreted them

22. Hormone Chemistry Some are lipid soluble and others are water soluble

23. Lipid-soluble hormones Include; Steroids, thyroid hormones, and nitric oxide

24. Water-soluble hormones Include; Peptides, proteins, and glycoproteins

25. Hormone Transport Water-soluble hormones travel free in plasma

26. Hormone Transport Lipid soluble hormones bind to transport proteins to be carried in blood

27. Action of Lipid Soluble Hormones 1. Hormone binds to and activates receptors within cells

29. Action of Lipid Soluble Hormones 2. The activated receptors alter gene expression, which results in the formation of new proteins

31. Action of Lipid Soluble Hormones 3. The new proteins alter the cells activity

33. Action of Water Soluble Hormones 1. The hormone binds to the membrane receptor

35. Action of Water Soluble Hormones 2. The activated receptor activates a membrane G-protein which turns on adenylate cyclase

37. Action of Water Soluble Hormones 3. Adenylate cyclase converts ATP into cyclic AMP which activates protein kinases.

39. Action of Water Soluble Hormones 4. Protein kinases phophorylate enzymes, which either become more or less active than the nonphosphorylated form

41. Hormonal interactions The responsiveness of a target cell to a hormone depends on; 1.Hormone’s concentration 2.Number of receptors 3.Influences exerted by other hormones

42. Hormonal interactions Three types; 1.Permissive 2.Synergistic 3.Antagonist

43. Hormonal Interactions 1.Permissive – one hormone required to act before another can be effective

44. Hormonal Interactions 2. Synergistic – Two hormone produce an effect that is greater than the sum of individual effects

45. Hormonal Interactions 3. Antagonistic – When hormones oppose each other

46. Control of Hormone Secretions Controlled by; 1.Nervous system 2.Chemical changes in blood 3.Other hormones 4.Negative feedback 5.Positive feed back

47. Control of Hormone Secretions Negative feedback – High levels of one substance may feed back and lower the secretion of the other substance

48. Control of Hormone Secretions Positive feedback – high levels of one substance may feedback and increase the secretion of the other substance

49. Pituitary Gland Hypophysis

51. Pituitary Gland Located in the sella turcica of the sphenoid bone

52. Pituitary Gland 1.Anterior pituitary (adenohypophysis) 2.Posterior pituitary (neurohypohysis)

54. Anterior Pituitary Hormones of the A.P. are controlled by hormones produced by the hypothalamus

55. Anterior Pituitary Hormones 1.Human growth hormone (hGH) 2.Thyroid-stimulating hormone (TSH) 3.Follicle-stimulating hormone (FSH) 4.Luteinizing hormone (LH) 5.Prolactin (PRL) 6.Adrenocorticotropic hormone (ACTH) 7.Melanocyte-stimulating hormone (MSH)

56. Anterior Pituitary Hormones travel from the hypothalamus to the A.P. via a vascular network called the hypophyseal-portal system

57. Anterior Pituitary hGH – essential for normal body growth responsible for growth spurt during puberty inhibits cell glucose uptake

58. Anterior Pituitary Controlled by Growth hormone-releasing hormone (GHRH)

59. Dwarfism Deficiency in hGH

60. Gigantism Excess hGH in kids

61. Acromegaly Excess hGH in adults

62. Anterior Pituitary TSH causes thyroid to secrete thyroid hormone

63. Anterior Pituitary TSH Controlled by TRH (thyrotropin releasing hormone)

64. Anterior Pituitary TSH High levels of thryoid hormone feed back and inhibit TSH secretion

65. Anterior Pituitary TSH Low levels of thyroid hormone cause TSH levels to go up

66. Anterior Pituitary FSH In females, FSH initiates follicle development and secretion of estrogens in the ovaries

67. Anterior Pituitary FSH In males, FSH stimulates sperm production in the testes

68. Anterior Pituitary FSH – Controlled by Gonadotropic- releasing hormone (GnRH)

69. Anterior Pituitary LH In females, LH stimulates secretion of estrogen by ovarian cells to result in ovulation

70. Anterior Pituitary LH In males, LH stimulates the interstitial cells of the testes to secrete testosterone

71. Anterior Pituitary LH – controlled by GnRH

72. Anterior Pituitary PRL High levels of progesterone, estrogen and prolactin during pregnancy promotes breast growth

73. Anterior Pituitary PRL Estrogen blocks the milk-secreting action of PRL

74. Anterior Pituitary PRL During labor, the estrogen-secreting placenta is delivered. After that, PRL causes the breasts to secrete milk.

75. Anterior Pituitary PRL Suckling promotes PRL secretion

76. Anterior Pituitary Controlled by Prolactin–releasing hormone (PRH)

77. Anterior Pituitary ACTH controls the production and secretion of glucocorticoids (cortisol) by the cortex of the adrenal medulla

78. Anterior Pituitary ACTH Stress stimulates ACTH release, which in turn stimulates cortisol release.

79. Anterior Pituitary Controlled by Corticotropin-releasing hormone (CRH)

80. Anterior Pituitary MSH increases skin pigmentation

81. Anterior Pituitary Controlled by CRH

82. Posterior Pituitary Does not synthesize hormones

83. Posterior Pituitary It does store and release oxytocin (OT) and antidiuretic hormone (ADH)

84. Posterior Pituitary These hormones are made by the hypothalamus and stored in the P.P.

85. Posterior Pituitary The neural connection between the hypothalamus and the P.P. is via the hypothalmohypophyseal tract

87. Posterior Pituitary OT stimulates contraction of the uterus during labor

88. Posterior Pituitary OT Stimulates ejection of milk from the breasts

89. Posterior Pituitary OT As uterine contractions and cervical dilation increase during labor, they have positive feedback on the P.P. and increases OT secretion.

90. Posterior Pituitary OT stimulated by suckling

91. Posterior Pituitary ADH Stimulates water reabsorption by the kidneys

92. Posterior Pituitary ADH effect of ADH is to decrease urine volume and conserve body water

93. Posterior Pituitary ADH controlled by osmotic pressure of the blood, which is monitored by the hypothalamus

94. Posterior Pituitary ADH Dehydration stimulates ADH secretion

95. Posterior Pituitary ADH Alchohol inhibits ADH secretion, increasing the urine output

96. Diabetes Insipidus Due to lack of ADH secretion or when the kidneys are resistant to ADH

97. Thyroid Located below the larynx and has r. and l. lateral lobes

99. Thyroid consists of thryoid follicles

101. Thyroid Follicular cells secrete thyroxine (T4) and triiodothyronine (T3)

103. Thyroid Parafollicular cells secrete calcitonin (CT)

105. Thyroid Hormones Increases metabolism

106. Thyroid Hormones Crucial for brain development

107. Thyroid Hormones Up regulates beta receptors in the heart

108. Thyroid Hormones Important for growth and skeletal maturation

109. Thyroid Hormones Crucial for G.I. motility

110. Thyroid If you produce excess thyroid hormone, it feeds back and inhibits TSH secretion

111. Thyroid If the thyroid hormone levels decline, there is less negative feedback on the pituitary

112. Calcitonin Reduces blood calcium levels

113. Parathyroid Parathyroid Glands are embedded on the posterior surfaces of the lateral lobes of the thyroid

115. Parathyroid Produces parathyroid hormone (PTH)

116. Parathyroid PTH increases blood calcium levels and decreases blood phosphate levels

117. Parathyroid PTH secretion controlled by blood calcium and phosphate levels directly via negative feedback loops

118. Adrenal Glands  Located superior to the kidneys

120. Adrenal Glands  Consists of an outer cortex and an inner medulla

122. Adrenal Cortex  Divided into three zones

123. Adrenal Cortex 1. Zona glomerulosa (outer zone) – secretes mineralcorticoids (aldosterone)

124. Adrenal Cortex  Aldosterone decreases potassium levels and increases sodium levels

125. Adrenal Cortex  Aldosterone is stimulated by Angiotensin II

127. Adrenal Cortex 2. Zona fasciculata (middle zone) – secretes glucocorticoids (cortisol)

128. Adrenal Cortex  Cortisol increases blood glucose levels by suppressing insulin and via gluconeogenesis

129. Adrenal Cortex  Cortisol is an immunosuppressant

130. Adrenal Cortex  Cortisol raises blood pressure

131. Adrenal Cortex  Cortisol controlled by CRH and ACTH

133. Adrenal Cortex 3. Zona reticularis (inner zone) – secretes androgens (testosterone)

135. Adrenal Medulla  Secretes epinephrine and norepinephrine

136. Pancreas Endocrine and exocrine gland

138. Pancreas Located posterior and slightly inferior to the stomach

139. Pancreas Its exocrine secretions are drained by the pancreatic duct into the duodenum

141. Pancreas Contains over a million islets of langerhans

143. Pancreas It mainly consists of clusters of cells (acini) These are enzyme-producing exocrine cells

144. Pancreas Four types of cells in the Pancreatic Islets

145. Pancreas 1. Alpha cells secrete glucagon which increases blood glucose levels

146. Pancreas Beta cells secrete insulin which decreases blood glucose levels

147. Pancreas Delta cells secrete somatostatin, which acts as a paracrine and inhibits the secretion of insulin and glucagon

148. Pancreas F-cells secretes pancreatic polypeptide, which regulates release of pancreatic digestive enzymes

149. Pancreas Glucagon and insulin are controlled by negative feedback

150. Pancreas/Negative Feedback Glucagon is released during fasting or hypoglycemia

151. Pancreas/Negative Feedback Glucagon promotes glycogenolysis and gluconeogenesis

152. Pancreas Insulin is secreted after meals

153. Pancreas Insulin increases glucose uptake by muscle and fat cells

154. Pancreas Insulin stimulates glycogenesis

155. Pancreas Insulin stimulates lipogenesis

156. Pancreas Insulin increases amino acid uptake into cells and increases protein synthesis

157. Pancreas Insulin inhibits lipolysis

158. Diabetes Mellitus Type I – It is caused by an autoimmune destruction of beta cells

159. Diabetes Mellitus Type II – Due to obesity. As obesity progresses, they develop insulin resistance

160. Ovaries Lie in pelvic cavity and produce sex hormones (estrogens and progesterone)

161. Ovaries These hormones responsible for; 1. Development and maintenance of female sexual characterisics

162. Ovaries 2. Reproductive cycle

163. Ovaries 3. Pregnancy

164. Ovaries 4. Lactation

165. Testes Lie inside the scrotum and produce testosterone

166. Testes Testosterone related to the development and maintenance of male sexual characteristics

167. Pineal Gland Attached to the roof of the third ventricle

168. Pineal Gland Secretes melatonin

169. Seasonal Affective Disorder SAD Due to over-production of melatonin

170. Thymus Secretes several hormones related to immunity

172. Thymus Thymosin (hormone) – promote maturation of T cells (white blood cell involved in immunity)