The endocrine system maintains homeostasis through chemical messengers called hormones. The hypothalamus controls the endocrine system and pituitary gland. The pituitary gland regulates other endocrine glands and releases hormones in response to signals from the hypothalamus. Major endocrine glands include the thyroid, parathyroid, adrenal, pancreas, ovaries/testes, which regulate processes like metabolism, growth and development, and reproduction.

2. Amino acid

4. Control center of all autonomic regulatory activities of the body

5. Main function of the hypothalamus is homeostasis

7. Stimulates the release of hormones

11. Sella turcica– saddle-shaped depression of the sphenoid bone where lies the pituitary gland

12. A short stalk, the infundibulum, and a vascular network connect the pituitary gland to the hypothalamus.

14. The cells are organized in clumps and cords separated by fenestrated sinusoidal capillaries.

15. Regulates other endocrine glands and some non-endocrine tissues

16. 3 derivatives of Rathke’s pouch:

17. Pars distalis (distal lobe)

18. Pars intermedia (intermediate lobe)

20. Presence of highly branched glial cells called pituicytes that resemble astrocytes and are the most abundant cell type in the posterior pituitary; serves a supporting role in the CNS

21. NOT an endocrine gland; stores and releases secretory products from the hypothalamus

22. 3 components:

23. Neural lobe (Pars nervosa, Infundbular process)

24. Pituitary stalk (Infundibular stem)

26. Consists of two lateral lobes united by an isthmus

28. Composed of reticular fibers and network of capillaries

30. a. Follicular cells

31. Also called Principal cells

32. Most numerous cell type

33. Cuboidal in shape with spherical nucleus

35. Larger than follicular cells

36. Can occur either alone or in clumps

38. Responsible for growth,cell differentiation and control of the basal metabolic rate and oxygen consumption in cells

39. Affect protein, lipid, and carbohydrate metabolism

40. Calcitonin

41. Lower blood calcium levels through inhibition of bone resorption

43. Usually embedded in the thyroid capsule

44. Derived from the pharyngeal pouches

46. Found singly or in small groups

49. Occupy 15% of the cortex

50. Immediately beneath the capsule

51. Columnar or pyramidal cells

52. Arranged in closely packed, rounded, arched cords, or small clumps

53. Secrete hormone mineralocorticoid - aldosterone

54. Zona Fasciculata

55. Occupy 65% of the cortex

56. Intermediate zone

57. Polyhedral, often binucleated cells with lipid droplets in their cytoplasm

58. Cells are also called spongyocytes due to vacuolization

59. Arranged in one or two – cell thick straight cords

60. Secrete hormone glucocorticoid - cortisol

61. Zona Reticularis

62. Occupy 7% of the cortex

63. Innermost layer – lies between zona fasciculata and medulla

64. Smaller cells disposed in irregular cords forming an anastomosing network

65. Presence of lipofuscin pigment granules – large and numerous

66. Irregularly shaped cells with pyknotic nuclei – suggesting cell death

67. Arranged in cords or clumps

69. Composed of polyhedral cells

70. Arranged in cords or clumps, supported by reticular fiber network

71. Composed of chromaffin cells

72. Secretes catecholamines – Epinephrine and Norepinephrine

74. Release neurotransmitter into systemic circulation for systemic effects on multiple organs

75. Contains NE and E cells

76. E cells

77. Characterized by containing small granules

78. Store epinephrine

79. NE cells

80. Characterized by larger granules

81. Contains dense cores giving an appearance of eccentric “bulls - eyes”

82. More intense chromaffin reaction

84. Under the covered surface is the tunica albuginea made of dense irregular connective tissue and responsible for whitish color of ovary

85. Below that tunica albuginea is the cortex of the ovary where there is predominance of ovarian follicles

86. Deep in the cortex is highly vascularized connective tissue core of ovary, medulla

88. In addition, produced by the corpus luteum, placenta, liver, breasts and adrenal glands in smaller quantities

89. Essential to the menstrual cycle

90. Prepares uterus for pregnancy

91. Enriching and thickening of endometrium

92. Contributes to the development of secondary characteristics

93. Breasts, widened pelvis, increased body fat in buttocks, thigh and hip region

94. Less facial hair and smoother skin

96. For fertility and pregnancy

97. Prepare the endometrium for implantation of fertilized egg and its development

98. Maintain the uterus throughout pregnancy

100. The nucleus as the germinal vesicle and the nucleolus as the germinal spot

101. The human ovum is surrounded by a number of egg envelopes:

102. Vitelline membrane

103. A thin, inner transparent layer secreted by the ovum itself

104. Zona pellucid

105. A thick middle layer which is transparent and non - cellular

106. Corona radiate

107. An outer, thicker coat formed of radially elongated follicular cells.

109. Maturation of sex organs (part. Penis)

110. Formation of scrotum in the fetus

111. Deepening of voice (sec. sex charac.)

113. A pine cone shaped gland

114. Produces several important hormones including melatonin

115. Melatonin influences sexual development and sleep-wake cycles

116. Composed of cells called pinealocytes and cells of the nervous system called glial cells

117. Connects the endocrine system with the nervous system in that it converts nerve signals from the sympathetic system of the peripheral nervous system into hormone signals

118. Also contains sand - well - brain sand or corpora arenacea

119. Calcium-containing concretions in the pineal parenchyma

120. Increase in size and number with age

121. Radio opaque

122. Provide a good midline-marker

123. 2 cell types

124. Pinealocytes

125. 95% of the cells

126. Large, light and round nuclei

127. Secretions: cocktail substances

128. May decrease secretory activity in most other endocrine glands

129. May delay puberty through antigonadotrophic effects

130. Astrocytes

131. Glial cells

132. Dark, elongated nuclei

133. Interstitial cells

134. Greater number in the stalk of the gland

135. Nuclei are elongated

136. Stain more deeply than those of the pinealocytes

137. Resemble the astrocytes of the brain in having long-cell process and an abundance of intermediate filaments throughout the cytoplasm

138. The most prominent secretory product of the pineal body is melatonin

140. Regulation of endocrine functions

141. Conversion of nervous system signals to endocrine signals

142. Causes feeling of sleepiness

144. Surrounding the pineal body

146. Lymphocytes that have passed through the thymus are transformed into T cells.

148. Activates the immune system by activating the T-Cells (T-Killer Cells; T-Helper Cells; T-Memory Cells)

149. T – Lymphocytes

150. The thymus consists of lobules full of T-lymphocytes (white blood cells associated with antibody production).

152. From G cells

153. Secretion of gastric acid by parietal cells

155. From S cells

156. Secretion of bicarbonate from liver, pancreas and duodenal Brunner’s gland

157. Enhances effects of CCK

158. Stops production of gastric juice

159. Cholecystokenin

160. From I cells

161. Release of digestive enzyme from pancreas

162. Release bile from gallbladderLIVER<br />Thrombopoietin<br />From hepatocytes<br />Stimulates megakaryocytes to produce platelets<br />Insulin Like Growth Factor (IGF)<br />From hepatocytes<br />Insulin like effects<br />Regulate cell growth and development<br />Angiotensinogen and Angiotensin<br />From hepatocytes<br />Vasoconstriction<br />Release of aldosterone from adrenal cortex dipsogen <br />PANCREAS<br />Glucagon<br />From α islet cells<br />Glycogenolysis and gluconeogenesis in liver<br />Increases blood glucose level<br />Insulin<br />From β islet cells<br />Intake of glucose<br />Glycogenesis and glycolysis<br />Lipid synthesis<br />Somatostatin<br />From δ islet cells<br />Inhibit release of insulin<br />Inhibit release of glucagon<br />Suppress the exocrine secretory action of pancreas<br />