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Step 1 Endocrinology-First Aid 2017 > Physiology > Flashcards

Flashcards in Physiology Deck (195):
1

Where in the cell is preproinsulin made?

Rough ER

2

Where is proinsulin stored?

Secretory granules

3

Insulin receptors have what type of enzymatic activity?

Tyrosine kinase activity

4

What does binding of insulin induce?

Glucose uptake and gene transcription

5

What are the effects of insulin on glycogen?

Increased glycogen synthesis and storage

6

What are the effects of insulin on triglycerides?

Increased triglyceride synthesis

7

What are the effects of insulin on sodium?

Increased sodium retention in kidneys

8

What are the effects of insulin on protein?

Increased protein synthesis in muscle

9

What are the effects of insulin on potassium?

Increased cellular uptake of potassium

10

What are the effects of insulin on glucagon?

Decreased glucagon release

11

What are the effects of insulin on lipolysis?

Decreased lipolysis in adipose tissue

12

What are the effects of insulin on the fetus?

None, cannot cross the placenta

13

Which GLUT transporter is insulin dependent?

GLUT4

14

Where are GLUT4 transporters found in the body?

Skeletal and adipose tissue

15

What activity can increase expression of GLUT4 transporters?

Exercise

16

Where are GLUT1 transporters found in the body?

RBCs, brain, cornea, placenta

17

Which GLUT transporter is bidirectional?

GLUT2

18

Where are GLUT2 transporters found in the body?

B islet cells, liver, kidney, and small intestine

19

Where are GLUT3 transporters found in the body?

Brain and placenta

20

Where are GLUT5 transporters found in the body?

Spermatocytes and GI tract

21

Which GLUT transporter uptakes fructose

GLUT5

22

What molecule does the brain utilize for energy during starvation?

Ketones

23

What molecule does the brain normally use for energy?

Glucose

24

Why are RBCs only able to utilize glucose for energy?

They lack mitochondria for aerobic metabolism

25

What tissues are insulin-independent for glucose uptake?

Brain, RBCs, Intestine, Cornea, Kidney, Liver (BRICK L)

26

What is the major regulator of insulin release?

Glucose

27

What cell signaling molecule does insulin use in insulin-dependent glucose uptake?

Tyrosine kinase

28

What regulatory molecules are released after oral ingestion of glucose that stimulate insulin release?

Glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic peptide (GIP)

29

What is the effect of GLP-1 and GIP on beta cells?

Increased beta cell sensitivity to glucose

30

Stimulation of which adrenergic receptors decreases insulin release?

Alpha-2

31

Stimulation of which adrenergic receptors increase insulin release

Beta-2

32

What is the effect of glucose entering a pancreatic beta cell?

Increased ATP from glucose metabolism

33

What is the affect of increased ATP in a pancreatic beta cell?

Increased ATP closes potassium channel

34

What is the affect of closing the potassium channel in a pancreatic beta cell?

Depolarization of the membrane

35

What is the affect of depolarization of the membrane in a pancreatic beta cell?

Opens voltage-gated calcium channels

36

What is the affect of increased calcium in a pancreatic beta cell?

Exocytosis of insulin granules

37

What cells of the pancreas make glucagon?

Alpha cells

38

What causes secretion of glucagon?

Hypoglycemia

39

What inhibits glucagon release?

Insulin, hyperglycemia and somatostatin

40

Gluconeogenesis and glycogenolysis are mediated by what hormone?

Glucagon

41

What effect does cortisol have on glucagon?

Permissive effect allowing glycogenolysis

42

Increased ketone production is caused by what hormone?

Glucagon

43

What hypothalamic hormone is decreased with chronic steroid use?

CRH

44

What pituitary hormones are increased by CRH?

ACTH, MSH, and B-endorphin

45

What hypothalamic hormone decreases release of prolactin?

Dopamine

46

What is the effect of some antipsychotics on dopamine release?

Decreased dopamine release causing hyperprolactinemia which leads to galactorrhea and amenorrhea, osteoporosis and hypogonadism

47

Regulates release of GH from anterior pituitary

GHRH

48

Regulates release of FSH and LH from anterior pituitary

Pulsatile GnRH

49

What is the effect of tonic release of GnRH?

Suppresses HPG axis, decreased LH and FSH release

50

What is the effect of pulsatile release of GnRH?

Leads to puberty and fertility, increased LH and FSH release

51

What suppresses release of GnRH?

Hyperprolactinemia

52

What is the function of prolactin?

Decrease GnRH release, promote milk production, decrease ovulation in women and spermatogenesis in men

53

What are the affects of a pituitary prolactinoma?

Amenorrhea, galactorrhea, osteoporosis, and hypogonadism

54

What is the affect of somatostatin on GH and TSH

Decreases release of GH and TSH

55

What is the somatostatin analog?

Ocreotide

56

Prolactin release is stimulated by what hypothalamic hormone?

TRH

57

What is the function of TRH?

Increase release of TSH and prolactin

58

What pathologic conditions increase TRH?

Primary and secondary hypothyroidism

59

What is the effect of increased TRH secretion as seen in primary and secondary hypothyroidism?

Increased prolactin secretion causing galactorrhea

60

Where is prolactin secreted from?

Mainly anterior pituitary

61

Prolactin is structurally homologous to what other hormone?

Growth Hormone (GH)

62

What hypothalamic hormone is inhibited by prolactin?

GnRH

63

What dopamine agonist can be used to treat prolactinoma and inhibit prolactin secretion?

Bromocriptine

64

What is the effect of antipsychotics and estrogens on prolactin secretion?

Stimulate production via dopamine antagonistic effects

65

How does prolactin inhibit its own secretion?

Increases dopamine release

66

What are the effects on TRH by increasing plasma T3/T4?

Decreased TRH

67

What are the effects of pregnancy on prolactin release?

Increases estrogen which stimulates prolactin release

68

What are the effects of spermatogenesis and ovulation on prolactin release?

Increase FSH and LH which inhibit prolactin release

69

What is the effect of progesterone on prolactin release?

Inhibits prolactin release

70

What is the effect of nipple stimulation on prolactin release?

Increases prolactin release

71

What is the effect of a crying baby or sight of a baby on prolactin release?

Inhibits higher cortical centers which inhibit hypothalamic release of dopamine and stimulate TRH release causing prolactin secretion

72

What is the effect of GH on insulin?

Increases insulin resistance

73

What hormone is released by liver vi GH stimulation?

IGF-1

74

What type of release is seen in GH?

Pulsatile release

75

What is the effect of excess GH release?

Adults - Acromegaly
Children - Gigantism

76

What is the main cause of excess GH release?

Pituitary adenoma

77

What is the treatment for acromegaly or gigantism?

Ocreotide or surgery

78

What inhibits release of GH?

Glucose, somatostatin via negative feedback by somatomedin

79

When is secretion of GH seen?

Exercise, deep sleep, puberty and hypoglycemia

80

Sleep deprivation or starvation lead to a decrease of which appetite regulatory hormone?

Leptin

81

Sleep deprivation and Prader-Willi syndrome lead to an increase of which appetite regulatory hormone?

Ghrelin

82

Where is leptin made?

Adipose tissue

83

Where is ghrelin made?

Stomach

84

What area of the brain is affected by endocannabinoids?

Hypothalamus and nucleus accumbens

85

What hormone regulates serum osmolarity and blood pressure?

ADH

86

What ADH receptors regulate serum osmolarity?

V2 receptors

87

What ADH receptors regulate blood pressure?

V1 receptors

88

How is osmolarity via ADH regulated?

Insertion of aquaporin channels in in principal cells of renal collecting duct

89

What ADH levels are seen in central diabetes insipidus?

Decreased ADH levels

90

What ADH levels are seen in nephrogenic diabetes insipidus?

Normal or increased ADH levels

91

What type of mutation can cause nephrogenic DI?

V2 receptor mutation

92

What ADH analog is used to treat central DI and nocturnal enuresis?

Desmopressin acetate

93

What are the primary regulators of ADH?

Osmoreceptors in hypothalamus

94

What condition can cause release of ADH?

Hypovolemia

95

Which antifungal will inhibit cholesterol desmolase?

Ketoconazole

96

Ketoconazole will inhibit which cholesterol enzyme?

Cholesterol desmolase

97

What is the rate-limiting step of cholesterol synthesis?

StAR

98

What enzyme is responsible for the conversion of testosterone to DHT?

5-alpha-reductase

99

Which drug inhibits 5-alpha-reductase?

Finasteride

100

The hormonal breast cancer drug, exemestane, will inhibit which enzyme?

Aromatase

101

Which hormonal breast cancer drugs are known to inhibit aromatase?

Exemestane and anastrozole

102

What is the only steroid that is not protein bound and is water soluble since it is sulfated?

DHEA

103

What enzyme, responsible for aldosterone, is acted on by angiotensin II?

Aldosterone synthase

104

What enzyme in cholesterol synthesis is acted on by ACTH?

Cholesterol synthase

105

What are common findings in all congenital adrenal enzyme deficiencies?

Increased ACTH, enlarged adrenal glands, decreased cortisol and skin hyperpigmentation

106

Which enzyme deficiency leads to ambiguous genitalia and undescended testes in men and lack of 2ndary sexual development in girls?

17-a-hydroxylase

107

What potassium levels are seen in patient with decreased androstenedione and lack of 2ndary sexual development?

Hypokalemia

108

17-a-hydroxylase deficiency will result in what sex hormone levels?

Decreased

109

What hormones are produced in excess in 17-a-hydroxylase deficiency?

Mineralocorticoids

110

What is the most common congenital adrenal enzyme deficiency?

21-B-hydroxylase deficiency

111

What potassium levels are seen in 21-B-hydroxylase deficiency?

Hyperkalemia

112

21-B-hydroxylase deficiency results in what mineralocorticoid levels?

Decreased

113

Precocious puberty and salt wasting seen in infancy with decreased BP is seen in which congenital adrenal enzyme deficiency?

21-B-hydroxylase deficiency

114

What renin levels are seen in 21-B-hydroxylase deficiency?

Increased renin levels

115

Hypokalemia, increased sex hormones, high blood pressure and virilization is seen in what congenital adrenal enzyme deficiency?

11-B-hydroxylase

116

17-a-hydroxyprogesterone is increased in which congenital adrenal enzyme deficiency?

21-B-hydroxylase

117

What is the effect of Cortisol on hyperglycemia?

Increases gluconeogenesis and insulin resistance

118

What effects does cortisol have on wound healing?

Decreased inflammatory and immune response

119

What effects does cortisol have on TB and candidiasis?

Reactivation via blockage of IL-2 production

120

What effect does chronic stress have on cortisol?

Causes prolonged secretion

121

How does cortisol increase BP?

Upregulation of alpha-1 receptors on arterioles, increases sensitivity to NE and Epi and can bind to aldosterone receptors at high concentrations

122

What is the active form of calcium?

Ionized or free calcium

123

How is calcium found in the body?

Ionized (45%), bound to albumin (40%), and bound to anions (15%)

124

Cramps, pain, paresthesias, and carpopedal spasms are seen with what electrolyte imbalance?

Hypocalcemia

125

What causes increased binding of calcium to albumin

Increases in pH

126

What is the primary regulator of PTH

Ionized/free calcium

127

What effect do pH changes have on PTH secretion?

Can effect PTH levels based on pH

128

What effect do changes in albumin levels have on PTH secretion?

None

129

How does acidosis affect calcium levels?

Increases free calcium which decreases PTH levels

130

How does alkalosis affect calcium levels?

Decreases free calcium which increases PTH levels

131

D2 is obtained from what sources?

Ingestion of plants

132

D3 is obtained from what sources?

Sun exposure and ingestion of plants

133

Where in the body does vitamin D2 or D3 get converted to 25-OH?

Liver

134

Where in the body does vitamin 25-OH get converted to 1,25-(OH)2?

Kidneys

135

What is the active form of vitamin D?

1,25-(OH)2

136

What is the function of vitamin D?

Increase absorption of calcium and phosphate in gut and enhance bone mineralization

137

What increases production of 1,25-(OH)2?

Increased PTH and decreased calcium and phosphate

138

What does vitamin D deficiency cause in children?

Rickets

139

What does vitamin D deficiency cause in adults?

Osteomalacia

140

What is the inactive form of vitamin D?

24,25-(OH)2 D3

141

What is the function of PTH?

Increase calcium reabsorption and decrease phosphate reabsorption in the kidneys

142

What increases reabsorption of both calcium and phosphate from the gut?

1,25-(OH)2 D3

143

Where is parathyroid hormone secreted from?

Chief cells of he parathyroid

144

Where in the renal tubule is calcium reabsorbed?

Distal convoluted tubule

145

Where in the renal tubule is phosphate reabsorption blocked?

Proximal convoluted tubule

146

What is the function of PTH

Increase bone resorption of calcium and phosphate
Increase calcium reabsorption at DCT
Increase 1,25-(OH)2 D3 production
Decrease phosphate reabsorption at PCT

147

What is calcitrol?

1,25-(OH)2 D3, the active form of vitamin D

148

How does PTH effect serum calcium and phosphate levels?

Increases calcium and decreases phosphate

149

How does PTH effect urine calcium and phosphate levels?

Decreases calcium and increases phosphate

150

How does PTH effect urine cAMP levels?

Increases cAMP

151

What PTH like hormone ins commonly increased in malignancies like squamous cell carcinoma of the lung or renal cell carcinoma?

PTHrP

152

What is the effect of PTH on osteoblasts and osteocytes?

Stimulates RANK-L

153

What is the effect of RANK-L on osteoclast activity?

Binds to RANK receptor on osteoclast and increases calcium via bone resorption

154

What serum calcium, phosphate, and magnesium levels are seen with increased PTH

Decreased calcium, phosphate, and magnesium levels

155

What is the effect of markedly decreased magnesium levels on PTH?

Decreases PTH

156

What commonly causes decreases in magnesium levels?

Diarrhea, aminoglycosides, diuretics and alcohol abuse

157

Where is calcitonin secreted from?

Parafollicular cells (C cells) of the thyroid

158

What enzyme in the kidney is responsible for converting vitamin D into its active form?

1-alpha-hydroxylase

159

What serum calcium, phosphate, and magnesium levels cause PTH to be secreted?

Decreased levels

160

What effect does an increase in 1,25-(OH)2 D3 have on PTH?

Negative feedback, inhibits PTH

161

What effect does decreased phosphate have on 1-alpha-hydroxylase activity?

Increases activity to make 1,25-(OH)2 D3 which increases calcium and phosphate gut absorption and release from bone

162

What hormone opposes actions of PTH?

Calcitonin

163

What effect does calcitonin have on calcium?

Decreases bone resorption of calcium

164

What effect does increased serum calcium have on calcitonin?

Increases calcitonin secretion

165

Where is T3 formed mostly?

At target organs

166

What anterior pituitary hormone functions synergistically with T3/T4?

GH

167

What is the effect of T3 on the body?

Increased:
1. Bone growth and CNS maturation
2. B1-receptors in heart = increased CO, HR, SV, contractility
3. BMR via increased Na/K/ATPase activity
4. Glycogenolysis, gluconeogenesis and lipolysis

168

How do increased T3/T4 levels effect TRH?

Anterior pituitary - decreased sensitivity to TRH
Hypothalamus - decreased TRH release

169

How does TRH effect T3/T4?

TRH stimulates TSH release from pituitary which stimulates follicular cells in thyroid to release T3/T4

170

Effect where excess iodine temporarily inhibits thyroid peroxidase causing decreased iodine organification and production of T3/T4

Wolff-Chaikoff effect

171

What protein is responsible for binding most T3/T4 in blood?

Thyroxine-binging globulin (TBG)

172

Which form of T3/T4 is active form?

Unbound form

173

When are decreased TBG levels seen?

Liver disease and steroid use

174

When are increased TBG levels seen?

Pregnancy and OCP use

175

What sex hormone increases TBG?

Estrogen

176

What enzyme is responsible for the peripheral conversion of T4 to T3?

5'-deiodinase

177

What thyroid hormone is the major thyroid product?

T4

178

Which thyroid hormone has a greater affinity for the nuclear receptor in target tissues?

T3

179

Which enzyme is responsible for oxidation, organification of iodide and coupling of MIT and DIT?

Thyroid peroxidase

180

T4 is composed of what two molecules?

2 DIT molecules

181

T3 is composed of what two molecules

1 DIT + 1 MIT

182

Which drug inhibits both thyroid peroxidase and 5'-deiodinase?

Propylthiouracil (PTU)

183

Which drug inhibits only thyroid peroxidase?

Methimazole

184

What effect do glucocorticoids have on thyroid hormone production?

Inhibit peripheral conversion of T4 to T3

185

Which endocrine hormones are associated with cAMP?

FLAT ChAMP:
FSH, LH, ACTH, TSH, CRH, hCG, ADH, MSH, PTH
calcitonin, GHRH, glucagon, histamine

186

Which cAMP associated endocrine hormones have V2 receptor binding?

FSH, LH, ACTH, TSH, CRH, hCG, ADH

187

Which cAMP associated endocrine hormones have H2 receptor binding?

MSH, PTH, calcitonin, GHRH, glucagon, histamine

188

Which endocrine hormones are associated with cGMP?

BAD GraMPa (think vasodilators):
BNP, ANP, EDRF

189

Which endocrine hormones are associated with intracellular receptors?

PET CAT on TV:
Progesterone, Estrogen, Testosterone
Cortisol, Aldosterone, T3/T4, Vitamin D

190

Which endocrine hormones are associated with receptor tyrosine kinase?

MAP kinase pathway (think Growth Factors):
insulin, IGF-1, FGF-1, PDGF, EGF

191

Which endocrine hormones are associated with non-receptor tyrosine kinase?

JAK/STAT pathway (PIGGLET) acidophils and cytokines:
Prolactin, Immunomodulators, GH, G-CSF, Erythropoietin, Thrombopoietin

192

What binding hormone causes gynecomastia in men?

Increased sex-hormone binding globulin

193

What binding hormone causes hirsutism in women?

Decreased sex-hormone binding globulin

194

What hormone binds testosterone?

Sex-hormone binding globulin

195

What condition in women increases sex-hormone binding globulin?

OCPs and pregnancy