Physiology Flashcards
1
Q
Where in the cell is preproinsulin made?
A
Rough ER
2
Q
Where is proinsulin stored?
A
Secretory granules
3
Q
What conditions increase insulin and C-peptide?
A
Insulinoma an sulfonylurea use
4
Q
Insulin and C-peptide are secreted in what amounts in relation to each other?
A
Equally
5
Q
Insulin receptors have what type of enzymatic activity?
A
Tyrosine kinase activity
6
Q
What does binding of insulin induce?
A
Glucose uptake and gene transcription
7
Q
What are the effects of insulin on skeletal muscle and adipose tissue?
A
Increased glucose transport into those tissues
8
Q
What are the effects of insulin on glycogen?
A
Increased glycogen synthesis and storage
9
Q
What are the effects of insulin on triglycerides?
A
Increased triglyceride synthesis
10
Q
What are the effects of insulin on sodium?
A
Increased sodium retention in kidneys
11
Q
What are the effects of insulin on protein?
A
Increased protein synthesis in muscle
12
Q
What are the effects of insulin on potassium?
A
Increased cellular uptake of potassium
13
Q
What are the effects of insulin on glucagon?
A
Decreased glucagon release
14
Q
What are the effects of insulin on lipolysis?
A
Decreased lipolysis in adipose tissue
15
Q
What are the effects of insulin on the fetus?
A
None, cannot cross the placenta
16
Q
Which GLUT transporter is insulin dependent?
A
GLUT4
17
Q
Where are GLUT4 transporters found in the body?
A
Skeletal and adipose tissue
18
Q
What activity can increase expression of GLUT4 transporters?
A
Exercise
19
Q
What GLUT transporters are insulin independent?
A
GLUT1, GLUT 2, GLUT3, GLUT5
20
Q
Where are GLUT1 transporters found in the body?
A
RBCs, brain, cornea, placenta
21
Q
Which GLUT transporter is bidirectional?
A
GLUT2
22
Q
Where are GLUT2 transporters found in the body?
A
B islet cells, liver, kidney, and small intestine
23
Q
Where are GLUT3 transporters found in the body?
A
Brain and placenta
24
Q
Where are GLUT5 transporters found in the body?
A
Spermatocytes and GI tract
25
Which GLUT transporter uptakes fructose
GLUT5
26
What molecule does the brain utilize for energy during starvation?
Ketones
27
What molecule does the brain normally use for energy?
Glucose
28
Why are RBCs only able to utilize glucose for energy?
They lack mitochondria for aerobic metabolism
29
What tissues are insulin-independent for glucose uptake?
Brain, RBCs, Intestine, Cornea, Kidney, Liver (BRICK L)
30
What is the major regulator of insulin release?
Glucose
31
What cell signaling molecule does insulin use in insulin-dependent glucose uptake?
Tyrosine kinase
32
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)
33
What is the effect of GLP-1 and GIP on beta cells?
Increased beta cell sensitivity to glucose
34
Stimulation of which adrenergic receptors decreases insulin release?
Alpha-2
35
Stimulation of which adrenergic receptors increase insulin release
Beta-2
36
What is the effect of glucose entering a pancreatic beta cell?
Increased ATP from glucose metabolism
37
What is the affect of increased ATP in a pancreatic beta cell?
Increased ATP closes potassium channel
38
What is the affect of closing the potassium channel in a pancreatic beta cell?
Depolarization of the membrane
39
What is the affect of depolarization of the membrane in a pancreatic beta cell?
Opens voltage-gated calcium channels
40
What is the affect of increased calcium in a pancreatic beta cell?
Exocytosis of insulin granules
41
What cells of the pancreas make glucagon?
Alpha cells
42
What causes secretion of glucagon?
Hypoglycemia
43
What inhibits glucagon release?
Insulin, hyperglycemia and somatostatin
44
Gluconeogenesis and glycogenolysis are mediated by what hormone?
Glucagon
45
What effect does cortisol have on glucagon?
Permissive effect allowing glycogenolysis
46
Increased ketone production is caused by what hormone?
Glucagon
47
What hypothalamic hormone is decreased with chronic steroid use?
CRH
48
What pituitary hormones are increased by CRH?
ACTH, MSH, and B-endorphin
49
What hypothalamic hormone decreases release of prolactin?
Dopamine
50
What is the effect of some antipsychotics on dopamine release?
Decreased dopamine release causing hyperprolactinemia which leads to galactorrhea and amenorrhea, osteoporosis and hypogonadism
51
Regulates release of GH from anterior pituitary
GHRH
52
Regulates release of FSH and LH from anterior pituitary
Pulsatile GnRH
53
What is the effect of tonic release of GnRH?
Suppresses HPG axis, decreased LH and FSH release
54
What is the effect of pulsatile release of GnRH?
Leads to puberty and fertility, increased LH and FSH release
55
What suppresses release of GnRH?
Hyperprolactinemia
56
What is the function of prolactin?
Decrease GnRH release, promote milk production, decrease ovulation in women and spermatogenesis in men
57
What are the affects of a pituitary prolactinoma?
Amenorrhea, galactorrhea, osteoporosis, and hypogonadism
58
What is the affect of somatostatin on GH and TSH
Decreases release of GH and TSH
59
What is the analog of somatostatin used for?
Treat acromegaly
60
What is the somatostatin analog?
Ocreotide
61
Prolactin release is stimulated by what hypothalamic hormone?
TRH
62
What is the function of TRH?
Increase release of TSH and prolactin
63
What pathologic conditions increase TRH?
Primary and secondary hypothyroidism
64
What is the effect of increased TRH secretion as seen in primary and secondary hypothyroidism?
Increased prolactin secretion causing galactorrhea
65
Where is prolactin secreted from?
Mainly anterior pituitary
66
Prolactin is structurally homologous to what other hormone?
Growth Hormone (GH)
67
Libido is associated with excessive amounts of what anterior pituitary hormone?
Prolactin
68
What is the function of prolactin?
Milk production, inhibit ovulation and spermatogenesis
69
What hypothalamic hormone is inhibited by prolactin?
GnRH
70
What dopamine agonist can be used to treat prolactinoma and inhibit prolactin secretion?
Bromocriptine
71
What is the effect of antipsychotics and estrogens on prolactin secretion?
Stimulate production via dopamine antagonistic effects
72
How does prolactin inhibit its own secretion?
Increases dopamine release
73
How does dopamine inhibit prolactin secretion?
Tonic release of dopamine via tuberoinfundibular pathway of hypothalamus
74
What are the effects on TRH by increasing plasma T3/T4?
Decreased TRH
75
What are the effects of pregnancy on prolactin release?
Increases estrogen which stimulates prolactin release
76
What are the effects of spermatogenesis and ovulation on prolactin release?
Increase FSH and LH which inhibit prolactin release
77
What is the effect of progesterone on prolactin release?
Inhibits prolactin release
78
What is the effect of nipple stimulation on prolactin release?
Increases prolactin release
79
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
80
What is the effect of GH on insulin?
Increases insulin resistance
81
What hormone is released by liver vi GH stimulation?
IGF-1
82
What type of release is seen in GH?
Pulsatile release
83
What is the effect of excess GH release?
Adults - Acromegaly
| Children - Gigantism
84
What is the main cause of excess GH release?
Pituitary adenoma
85
What is the treatment for acromegaly or gigantism?
Ocreotide or surgery
86
What inhibits release of GH?
Glucose, somatostatin via negative feedback by somatomedin
87
When is secretion of GH seen?
Exercise, deep sleep, puberty and hypoglycemia
88
Sleep deprivation or starvation lead to a decrease of which appetite regulatory hormone?
Leptin
89
Sleep deprivation and Prader-Willi syndrome lead to an increase of which appetite regulatory hormone?
Ghrelin
90
Where is leptin made?
Adipose tissue
91
Where is ghrelin made?
Stomach
92
What area of the brain is affected by endocannabinoids?
Hypothalamus and nucleus accumbens
93
What hormone regulates serum osmolarity and blood pressure?
ADH
94
What ADH receptors regulate serum osmolarity?
V2 receptors
95
What ADH receptors regulate blood pressure?
V1 receptors
96
How is osmolarity via ADH regulated?
Insertion of aquaporin channels in in principal cells of renal collecting duct
97
What ADH levels are seen in central diabetes insipidus?
Decreased ADH levels
98
What ADH levels are seen in nephrogenic diabetes insipidus?
Normal or increased ADH levels
99
What type of mutation can cause nephrogenic DI?
V2 receptor mutation
100
What ADH analog is used to treat central DI and nocturnal enuresis?
Desmopressin acetate
101
What are the primary regulators of ADH?
Osmoreceptors in hypothalamus
102
What condition can cause release of ADH?
Hypovolemia
103
Which antifungal will inhibit cholesterol desmolase?
Ketoconazole
104
Ketoconazole will inhibit which cholesterol enzyme?
Cholesterol desmolase
105
What is the rate-limiting step of cholesterol synthesis?
StAR
106
What enzyme is responsible for the conversion of testosterone to DHT?
5-alpha-reductase
107
Which drug inhibits 5-alpha-reductase?
Finasteride
108
The hormonal breast cancer drug, exemestane, will inhibit which enzyme?
Aromatase
109
Which hormonal breast cancer drugs are known to inhibit aromatase?
Exemestane and anastrozole
110
What is the only steroid that is not protein bound and is water soluble since it is sulfated?
DHEA
111
What enzyme, responsible for aldosterone, is acted on by angiotensin II?
Aldosterone synthase
112
What enzyme in cholesterol synthesis is acted on by ACTH?
Cholesterol synthase
113
What are common findings in all congenital adrenal enzyme deficiencies?
Increased ACTH, enlarged adrenal glands, decreased cortisol and skin hyperpigmentation
114
Which enzyme deficiency leads to ambiguous genitalia and undescended testes in men and lack of 2ndary sexual development in girls?
17-a-hydroxylase
115
What potassium levels are seen in patient with decreased androstenedione and lack of 2ndary sexual development?
Hypokalemia
116
17-a-hydroxylase deficiency will result in what sex hormone levels?
Decreased
117
What hormones are produced in excess in 17-a-hydroxylase deficiency?
Mineralocorticoids
118
What is the most common congenital adrenal enzyme deficiency?
21-B-hydroxylase deficiency
119
What potassium levels are seen in 21-B-hydroxylase deficiency?
Hyperkalemia
120
21-B-hydroxylase deficiency results in what mineralocorticoid levels?
Decreased
121
Precocious puberty and salt wasting seen in infancy with decreased BP is seen in which congenital adrenal enzyme deficiency?
21-B-hydroxylase deficiency
122
What renin levels are seen in 21-B-hydroxylase deficiency?
Increased renin levels
123
Hypokalemia, increased sex hormones, high blood pressure and virilization is seen in what congenital adrenal enzyme deficiency?
11-B-hydroxylase
124
17-a-hydroxyprogesterone is increased in which congenital adrenal enzyme deficiency?
21-B-hydroxylase
125
What is the effect of Cortisol on hyperglycemia?
Increases gluconeogenesis and insulin resistance
126
What effects does cortisol have on wound healing?
Decreased inflammatory and immune response
127
What effects does cortisol have on TB and candidiasis?
Reactivation via blockage of IL-2 production
128
What effect does chronic stress have on cortisol?
Causes prolonged secretion
129
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
130
What is the active form of calcium?
Ionized or free calcium
131
How is calcium found in the body?
Ionized (45%), bound to albumin (40%), and bound to anions (15%)
132
Cramps, pain, paresthesias, and carpopedal spasms are seen with what electrolyte imbalance?
Hypocalcemia
133
What causes increased binding of calcium to albumin
Increases in pH
134
What is the primary regulator of PTH
Ionized/free calcium
135
What effect do pH changes have on PTH secretion?
Can effect PTH levels based on pH
136
What effect do changes in albumin levels have on PTH secretion?
None
137
How does acidosis affect calcium levels?
Increases free calcium which decreases PTH levels
138
How does alkalosis affect calcium levels?
Decreases free calcium which increases PTH levels
139
D2 is obtained from what sources?
Ingestion of plants
140
D3 is obtained from what sources?
Sun exposure and ingestion of plants
141
Where in the body does vitamin D2 or D3 get converted to 25-OH?
Liver
142
Where in the body does vitamin 25-OH get converted to 1,25-(OH)2?
Kidneys
143
What is the active form of vitamin D?
1,25-(OH)2
144
What is the function of vitamin D?
Increase absorption of calcium and phosphate in gut and enhance bone mineralization
145
What increases production of 1,25-(OH)2?
Increased PTH and decreased calcium and phosphate
146
What does vitamin D deficiency cause in children?
Rickets
147
What does vitamin D deficiency cause in adults?
Osteomalacia
148
What is the inactive form of vitamin D?
24,25-(OH)2 D3
149
What is the function of PTH?
Increase calcium reabsorption and decrease phosphate reabsorption in the kidneys
150
What increases reabsorption of both calcium and phosphate from the gut?
1,25-(OH)2 D3
151
Where is parathyroid hormone secreted from?
Chief cells of he parathyroid
152
Where in the renal tubule is calcium reabsorbed?
Distal convoluted tubule
153
Where in the renal tubule is phosphate reabsorption blocked?
Proximal convoluted tubule
154
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
155
What is calcitrol?
1,25-(OH)2 D3, the active form of vitamin D
156
How does PTH effect serum calcium and phosphate levels?
Increases calcium and decreases phosphate
157
How does PTH effect urine calcium and phosphate levels?
Decreases calcium and increases phosphate
158
How does PTH effect urine cAMP levels?
Increases cAMP
159
What PTH like hormone ins commonly increased in malignancies like squamous cell carcinoma of the lung or renal cell carcinoma?
PTHrP
160
What is the effect of PTH on osteoblasts and osteocytes?
Stimulates RANK-L
161
What is the effect of RANK-L on osteoclast activity?
Binds to RANK receptor on osteoclast and increases calcium via bone resorption
162
What serum calcium, phosphate, and magnesium levels are seen with increased PTH
Decreased calcium, phosphate, and magnesium levels
163
What is the effect of markedly decreased magnesium levels on PTH?
Decreases PTH
164
What commonly causes decreases in magnesium levels?
Diarrhea, aminoglycosides, diuretics and alcohol abuse
165
Where is calcitonin secreted from?
Parafollicular cells (C cells) of the thyroid
166
What enzyme in the kidney is responsible for converting vitamin D into its active form?
1-alpha-hydroxylase
167
What serum calcium, phosphate, and magnesium levels cause PTH to be secreted?
Decreased levels
168
What effect does an increase in 1,25-(OH)2 D3 have on PTH?
Negative feedback, inhibits PTH
169
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
170
What hormone opposes actions of PTH?
Calcitonin
171
What effect does calcitonin have on calcium?
Decreases bone resorption of calcium
172
What effect does increased serum calcium have on calcitonin?
Increases calcitonin secretion
173
Where is T3 formed mostly?
At target organs
174
What anterior pituitary hormone functions synergistically with T3/T4?
GH
175
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
176
How do increased T3/T4 levels effect TRH?
Anterior pituitary - decreased sensitivity to TRH
| Hypothalamus - decreased TRH release
177
How does TRH effect T3/T4?
TRH stimulates TSH release from pituitary which stimulates follicular cells in thyroid to release T3/T4
178
Effect where excess iodine temporarily inhibits thyroid peroxidase causing decreased iodine organification and production of T3/T4
Wolff-Chaikoff effect
179
What protein is responsible for binding most T3/T4 in blood?
Thyroxine-binging globulin (TBG)
180
Which form of T3/T4 is active form?
Unbound form
181
When are decreased TBG levels seen?
Liver disease and steroid use
182
When are increased TBG levels seen?
Pregnancy and OCP use
183
What sex hormone increases TBG?
Estrogen
184
What enzyme is responsible for the peripheral conversion of T4 to T3?
5'-deiodinase
185
What thyroid hormone is the major thyroid product?
T4
186
Which thyroid hormone has a greater affinity for the nuclear receptor in target tissues?
T3
187
Which enzyme is responsible for oxidation, organification of iodide and coupling of MIT and DIT?
Thyroid peroxidase
188
T4 is composed of what two molecules?
2 DIT molecules
189
T3 is composed of what two molecules
1 DIT + 1 MIT
190
Which drug inhibits both thyroid peroxidase and 5'-deiodinase?
Propylthiouracil (PTU)
191
Which drug inhibits only thyroid peroxidase?
Methimazole
192
What effect do glucocorticoids have on thyroid hormone production?
Inhibit peripheral conversion of T4 to T3
193
Which endocrine hormones are associated with cAMP?
FLAT ChAMP:
FSH, LH, ACTH, TSH, CRH, hCG, ADH, MSH, PTH
calcitonin, GHRH, glucagon, histamine
194
Which cAMP associated endocrine hormones have V2 receptor binding?
FSH, LH, ACTH, TSH, CRH, hCG, ADH
195
Which cAMP associated endocrine hormones have H2 receptor binding?
MSH, PTH, calcitonin, GHRH, glucagon, histamine
196
Which endocrine hormones are associated with cGMP?
```
BAD GraMPa (think vasodilators):
BNP, ANP, EDRF
```
197
Which endocrine hormones are associated with intracellular receptors?
PET CAT on TV:
Progesterone, Estrogen, Testosterone
Cortisol, Aldosterone, T3/T4, Vitamin D
198
Which endocrine hormones are associated with receptor tyrosine kinase?
MAP kinase pathway (think Growth Factors):
| insulin, IGF-1, FGF-1, PDGF, EGF
199
Which endocrine hormones are associated with non-receptor tyrosine kinase?
JAK/STAT pathway (PIGGLET) acidophils and cytokines:
| Prolactin, Immunomodulators, GH, G-CSF, Erythropoietin, Thrombopoietin
200
What binding hormone causes gynecomastia in men?
Increased sex-hormone binding globulin
201
What binding hormone causes hirsutism in women?
Decreased sex-hormone binding globulin
202
What hormone binds testosterone?
Sex-hormone binding globulin
203
What condition in women increases sex-hormone binding globulin?
OCPs and pregnancy
