Endocrine Physiology Flashcards
0
Q
Active form of Steroid Hormones
A
Free & Unbound Form
1
Q
Transport of Steroid Hormones
A
Bound to proteins
2
Q
Main site of inactivation of Hormones
A
Liver
3
Q
Mechanism for removal of hormones
A
Kidneys, Liver
4
Q
Onset of hormonal effects
A
Seconds to months
5
Q
Number of hormones receptors
A
Variable
6
Q
Minimum amount of hormone to produce effect
A
1 picogram per ml
7
Q
Epi + NE effects on the heart
A
Additive effects (synergy)
8
Q
FSH & Testosterone on spermatogenesis
A
Complementary effects (synergy)
9
Q
Cortisol on NE and Epi in blood vessels; T3 on Epi in Lipolysis
A
Permissive effects
10
Q
Estrogen blocking Prolactin effect on breast during pregnancy
A
Antagonistic effects
11
Q
2 ways to regulate hormone effects
A
Hormone secretion
Hormone receptors
12
Q
Self-limiting; More common; Hormone has biologic actions that directly or indirectly, inhibit further secretion of the hormone
A
Negative feedback
13
Q
Self-augmenting; Rare, exploding; Hormone has biologic actions that directly or indirectly, stimulate further secretion of the hormone
A
Positive feedback
14
Q
Hormone feeds back all the way to HPA
A
Long-loop feedback
15
Q
Hormone from Pituitary feeds back to the Hypothalamus
A
Short-loop feedback
16
Q
Hypothalamic hormone feeds back on its own secretion
A
Ultra-short-loop feedback
17
Q
Example of negative feedback that does not utilize HPA
A
Insulin
18
Q
Examples of Positive Feedback
A
Estrogen-induced LH & FSH surge, Oxytocin during labor and lactation
19
Q
Decrease in receptor number or receptor affinity
A
Down-regulation of receptors
20
Q
Increase in receptor number or receptor affinity
A
Up-regulation of receptors
21
Q
Lies in sella turcica; Connected to the median eminence of Hypothalamus via Pituitary/Hypophysial stalk
A
Pituitary Gland
22
Q
Transmit hypothalamic hormones to the pituitary without passing through the systemic circulation
A
Hypothalamic-Hypophysial Portal Blood Vessels
23
Q
Adenohypophysis; Derived from oral ectoderm (Rathke’s Pouch); With Basophilic and Acidophilic Cells
A
Anterior Pituitary
24
Neurohypophysis; Derived from neural ectoderm (neural outgrowth of hypothalamus); With Pituicytes
Posterior Pituitary
25
From Basophilic Cells
```
FSH
LH
ACTH
TSH
MSH
```
26
From Acidophilic Cells
GH
| Prolactin
27
From Pituicytes
Vasopressin
| Oxytocin
28
If the pituitary stalk is damaged, all anterior pituitary hormones would decrease, EXCEPT
Prolactin
29
In terms of number, what are the top 2 cells in the anterior pituitary?
Somatotropes (40%)
| Corticotropes (20%)
30
What are the 3 families of hormones in the anterior pituitary?
TSH, LH, FSH
MSH, ACTH
GH, Prolactin
31
Both catabolic and anabolic; Released in pulsatile fashion (every 2 hours); Nocturnal peak: 1 hour after Stage 3 or 4 sleep
Growth Hormone
32
Growth Hormone
Somatotropin
33
Stops Growth Hormone
Somatostatin
34
IGF
Somatomedin
35
Direct Actions of GH
Increases blood glucose levels (Diabetogenic Effect)
Increased protein deposition in muscles and other tissues
Requires adequate insulin and carbohydrate concentrate
Increased lipolysis
Increased Insulin-like Growth Factor (IGF) production
Possible anti-aging effects
36
Indirect Actions of GH
Increases Bone Length and Bone thickness
| Increases protein synthesis in muscles and most organs
37
Secretion of GH INCREASED
```
Starvation
Hypoglycemia
Low fatty acid levels
Exercise
Excitement
Trauma
Testosterone
Estrogen
GHRH
Deep sleep
```
38
Secretion of GH DECREASED
```
Hyperglycemia
High fatty acids levels
Aging
Obesity
Somatostatin/SRIF (Somatostatin-release Inhibiting Hormone)
Exogenous GH
Somatomedins
```
39
Secretion of GH requires
Normal plasma levels of thyroid hormones
40
Decreased GH, MCC of Dwarfism, Defect in FGF receptor 3
Achondroplasia (AD)
41
Increased GH, With skeletal deformities (large hands, feet, membranous bones)
Acromegaly
42
Increased GH, Without skeletal deformities, symmetrical
Gigantism
43
Stimulates milk production (lactogenesis); Inhibits ovulation or spermatogenesis; Stimulates breast development during puberty and pregnancy
Prolactin
44
Prolactin Stimulation
```
Pregnancy
Breast feeding
Sleep
Stress
TRH
Dopamine antagonists
```
45
Prolactin Inhibition
Dopamine
Bromocriptine
Somatostatin
Prolactin (negative feedback)
46
Aka ADH or AVP; Secreted by supraoptic nuclei of the hypothalamus; Responds to ECF changes detected by osmoreceptors in the Organum Vasculosum
Vasopressin
47
Most potent stimulus for Vasopressin
Increases plasma osmolality
48
Effects of Vasopressin
```
Increases water permeability via insertion of AQP2 in the late distal tubule and collecting duct (V2 receptors); Acts within 5-10 mins
Peripheral vasoconstriction (V1 receptors)
```
49
Urine volume in Central Diabetes Insipidus
High
50
Urine volume in Peripheral Diabetes Insipidus
High
51
Urine volume in SIADH
Low
52
Urine Osmolarity in Central Diabetes Insipidus
Low
53
Urine Osmolarity in Peripheral Diabetes Insipidus
Low
54
Urine Osmolarity in SIADH
High
55
ADH levels in Central Diabetes Insipidus
Low
56
ADH levels in Peripheral Diabetes Insipidus
High
57
ADH levels in SIADH
High
58
Treatment in Central Diabetes Insipidus
DDAVP (ADH analog)
59
Treatment in Peripheral Diabetes Insipidus
Thiazide diuretics
60
Treatment in SIADH
Demeclocycline (ADH antagonist)
61
In SIADH, the brain reduces intracellular osmolytes to prevent cell swelling. What happens if you rapidly correct the hyponatremia?
Osmotic Demyelination Syndrome ( Central Pontine Myelinolysis)
62
From paraventricular nuclei of the hypothalamus; Milk ejection (contraction of myoepithelial cells); uterine contraction
Oxytocin
63
Stimuli for Oxytocin
Suckling of the breast
Sight, sound, smell of infant
Orgasm
Dilation of cervix
64
Synthesized by the follicular epithelial cells of the thyroid
Thyroid Hormones
65
Actions Thyroid Hormones
Increases mitochondria and Na-K-ATPase pump activity
Increases cholesterol secretion to bile and number of liver LDL receptors
For bone formation and bone maturation
66
Regulation of Thyroid Hormone Secretion
Mediated by TRH and TSH levels
67
RDA of Iodine per day
150ug
68
High levels of iodine inhibiting organification and iodine thyroid hormone synthesis
Wolff-Chaikoff Effect
69
Bone Age < Chronological Age
Hypothyroidism
70
Liver and Kidney Failure: TBG levels?
Decreased TBG
71
Estrogen or pregnancy: TBG levels?
Increased TBG
72
Enzyme that converts T4 to T3
5' Iodinase
73
T4 can also be converted to
rT3 (inactive)
74
Fever, changes in sensorium, tachycardia in pts w/ hyperthyroidism
Thyroid Storm
75
Increase thyroid size due to trophic effects of high levels of TSH and TSH-like substances
Goiter
76
Thyroid diseases with goiter
Graves disease
TSH-secreting tumor
Hashimoto's disease
Iodine Deficiency
77
Thyroid diseases with no goiter
Ingestion of T4, TSH deficiency
78
Aldosterone (Mineralocorticoid)
Zona Glomerulosa
79
Cortisol, Corticosterone (Glucocorticoids)
Zona Fasciculata
80
De-hydro-epi-androsterone (DHEA) and Androstenedione (weak androgens)
Zona Reticularis
81
Inhibits 11beta-hydroxylase
Metyrapone
82
Inhibits Desmolase
Ketoconazole
83
Adrenal Androgens in Males and Females respectively
Insignificant, Significant (respectively)
84
Need ACTH for 1st step but otherwise controlled by RAAS
Zona Glomerulosa
85
Characteristics of cortisol secretion
Pulsatile, diurnal
86
4 Diabetogenic hormones
GH
Cortisol
Glucagon
Epinephrine
87
Triggers for Aldosterone Secretion
Dec ECF volume
| Hyperkalemia
88
Islets of Langerhans: Secrete Insulin and Amylin
Beta Cell 60%
89
Islets of Langerhans: Secrete Glucagon
Alpha Cell 25%
90
Islets of Langerhans: Secrete Somatostatin
Delta Cell 10%
91
Islets of Langerhans: Secrete Pancreatic Polypeptide
F Cell/ PP Cell 5%
92
A protein that contains an A chain and B chain joined by disulfide bonds
Insulin
93
Main determinant of Insulin Secretion
Blood Glucose levels
94
Half-life of Insulin
6 minutes
95
Degradation of Insulin by
Insulinase (in the liver)
96
Increases glucose uptake into cells; Increases glycogen formation; Decreases glycogenolysis;
Decreases gluconeogenesis
Decreased Blood Glucose
97
Increases amino acid uptake ➡️ Increases protein synthesis
Decreased blood amino acids
98
Increases fat deposition
Decreased blood fatty acids
99
Decreases lipolysis
Decreased blood ketoacids
100
Increases K uptake into cells
Decreased blood potassium
101
Effect of insulin on the brain
None
102
Insulin: 2nd messenger
Tyrosine kinase
103
Glucagon: 2nd messenger
cAMP
104
Marker for endogenous insulin
C peptide
105
When proinsulin becomes insulin, what part is cleaved off?
C Peptide (connecting peptide)
106
GLUT transport is found in Beta Cells
GLUT-2
107
Oral vs IV Glucose: greater insulin secretion
Oral glucose
108
Secrete collagen and ground substance where calcium precipitates; Bone resorption
Osteoblast
109
Secrete lysosomal enzymes, citric acid and Lactic acid
Osteoclasts
110
Hyperreflexia, spontaneous twitching, muscle cramps and tingling and numbness
Hypocalcemia
111
Constipation, polyuria, polydipsia, and neurologic signs of hyporeflexia, lethargy, coma, death
Hypercalcemia
112
Signs of hypocalcemia
Chvoestek & Trousseau
113
Increased serum anions; effect on calcium levels
Hypocalcemia
114
Acidosis: effect on calcium levels
Hypercalcemia
115
Alkalosis: effect on calcium levels
Hypocalcemia
116
What is the location of PTH receptors?
Osteoblast
117
Would thyroidectomy cause hypercalcemia due to absent calcitonin?
No, since calcitonin does not participate in minute-to-minute calcium regulation
118
What is secreted by osteoblast to inhibit osteoclastic activity in hyperparathyroidism?
Alkaline phosphatase
119
Secreted by chief cells of parathyroid gland
PTH
120
Stimulation of PTH
Hypocalcemia
| Hypomagnesemia
121
Secreted by parafollicular cells of thyroid gland
Calcitonin
122
Stimulation of Calcitonin
High plasma Ca
123
What is the treatment for humoral hypercalcemia of malignancy?
Furosemide (inhibits renal Ca reabsorption)
| Etidronate (inhibits bone resorption)
124
Presents with short stature, short neck, obesity, subcutaneous calcification, and shortened fourth metatarsals and metacarpals?
Albright Hereditary Osteodystrophy (Pseudohypoparathyroidism Type Ia)
125
Vitamin D resistance is seen in which condition?
Chronic renal failure
