Endocrine Physiology Flashcards
1
Q
Transport of Steroid Hormones
A
Bound to proteins
2
Q
Active form of Steroid Hormones
A
Free & Unbound Form
3
Q
Main site of inactivation of Hormones
A
Liver
4
Q
Mechanism for removal of hormones
A
Kidneys, Liver
5
Q
Onset of hormonal effects
A
Seconds to months
6
Q
Number of hormones receptors
A
Variable
7
Q
Minimum amount of hormone to produce effect
A
1 picogram per ml
8
Q
Epi + NE effects on the heart
A
Additive effects (synergy)
9
Q
FSH & Testosterone on spermatogenesis
A
Complementary effects (synergy)
10
Q
Cortisol on NE and Epi in blood vessels; T3 on Epi in Lipolysis
A
Permissive effects
11
Q
Estrogen blocking Prolactin effect on breast during pregnancy
A
Antagonistic effects
12
Q
2 ways to regulate hormone effects
A
Hormone secretionHormone receptors
13
Q
Self-limiting; More common; Hormone has biologic actions that directly or indirectly, inhibit further secretion of the hormone
A
Negative feedback
14
Q
Self-augmenting; Rare, exploding; Hormone has biologic actions that directly or indirectly, stimulate further secretion of the hormone
A
Positive feedback
15
Q
Hormone feeds back all the way to HPA
A
Long-loop feedback
16
Q
Hormone from Pituitary feeds back to the Hypothalamus
A
Short-loop feedback
17
Q
Hypothalamic hormone feeds back on its own secretion
A
Ultra-short-loop feedback
18
Q
Example of negative feedback that does not utilize HPA
A
Insulin
19
Q
Examples of Positive Feedback
A
Estrogen-induced LH & FSH surge, Oxytocin during labor and lactation
20
Q
Decrease in receptor number or receptor affinity
A
Down-regulation of receptors
21
Q
Increase in receptor number or receptor affinity
A
Up-regulation of receptors
22
Q
Lies in sella turcica; Connected to the median eminence of Hypothalamus via Pituitary/Hypophysial stalk
A
Pituitary Gland
23
Q
Transmit hypothalamic hormones to the pituitary without passing through the systemic circulation
A
Hypothalamic-Hypophysial Portal Blood Vessels
24
Q
Adenohypophysis; Derived from oral ectoderm (Rathke’s Pouch); With Basophilic and Acidophilic Cells
A
Anterior Pituitary
25
Neurohypophysis; Derived from neural ectoderm (neural outgrowth of hypothalamus); With Pituicytes
Posterior Pituitary
26
From Basophilic Cells
FSHLHACTHTSHMSH
27
From Acidophilic Cells
GHProlactin
28
From Pituicytes
VasopressinOxytocin
29
If the pituitary stalk is damaged, all anterior pituitary hormones would decrease, EXCEPT
Prolactin
30
In terms of number, what are the top 2 cells in the anterior pituitary?
Somatotropes (40%) Corticotropes (20%)
31
What are the 3 families of hormones in the anterior pituitary?
TSH, LH, FSHMSH, ACTHGH, Prolactin
32
Both catabolic and anabolic; Released in pulsatile fashion (every 2 hours); Nocturnal peak: 1 hour after Stage 3 or 4 sleep
Growth Hormone
33
Growth Hormone
Somatotropin
34
Stops Growth Hormone
Somatostatin
35
IGF
Somatomedin
36
Direct Actions of GH
Increases blood glucose levels (Diabetogenic Effect)Increased protein deposition in muscles and other tissuesRequires adequate insulin and carbohydrate concentrateIncreased lipolysisIncreased Insulin-like Growth Factor (IGF) productionPossible anti-aging effects
37
Indirect Actions of GH
Increases Bone Length and Bone thicknessIncreases protein synthesis in muscles and most organs
38
Secretion of GH INCREASED
Starvation HypoglycemiaLow fatty acid levelsExerciseExcitementTraumaTestosteroneEstrogenGHRHDeep sleep
39
Secretion of GH DECREASED
HyperglycemiaHigh fatty acids levelsAging ObesitySomatostatin/SRIF (Somatostatin-release Inhibiting Hormone)Exogenous GHSomatomedins
40
Secretion of GH requires
Normal plasma levels of thyroid hormones
41
Decreased GH, MCC of Dwarfism, Defect in FGF receptor 3
Achondroplasia (AD)
42
Increased GH, With skeletal deformities (large hands, feet, membranous bones)
Acromegaly
43
Increased GH, Without skeletal deformities, symmetrical
Gigantism
44
Stimulates milk production (lactogenesis); Inhibits ovulation or spermatogenesis; Stimulates breast development during puberty and pregnancy
Prolactin
45
Prolactin Stimulation
PregnancyBreast feedingSleepStressTRHDopamine antagonists
46
Prolactin Inhibition
DopamineBromocriptineSomatostatinProlactin (negative feedback)
47
Aka ADH or AVP; Secreted by supraoptic nuclei of the hypothalamus; Responds to ECF changes detected by osmoreceptors in the Organum Vasculosum
Vasopressin
48
Most potent stimulus for Vasopressin
Increases plasma osmolality
49
Effects of Vasopressin
Increases water permeability via insertion of AQP2 in the late distal tubule and collecting duct (V2 receptors); Acts within 5-10 minsPeripheral vasoconstriction (V1 receptors)
50
Urine volume in Central Diabetes Insipidus
High
51
Urine volume in Peripheral Diabetes Insipidus
High
52
Urine volume in SIADH
Low
53
Urine Osmolarity in Central Diabetes Insipidus
Low
54
Urine Osmolarity in Peripheral Diabetes Insipidus
Low
55
Urine Osmolarity in SIADH
High
56
ADH levels in Central Diabetes Insipidus
Low
57
ADH levels in Peripheral Diabetes Insipidus
High
58
ADH levels in SIADH
High
59
Treatment in Central Diabetes Insipidus
DDAVP (ADH analog)
60
Treatment in Peripheral Diabetes Insipidus
Thiazide diuretics
61
Treatment in SIADH
Demeclocycline (ADH antagonist)
62
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)
63
From paraventricular nuclei of the hypothalamus; Milk ejection (contraction of myoepithelial cells); uterine contraction
Oxytocin
64
Stimuli for Oxytocin
Suckling of the breastSight, sound, smell of infantOrgasmDilation of cervix
65
Synthesized by the follicular epithelial cells of the thyroid
Thyroid Hormones
66
Actions Thyroid Hormones
Increases mitochondria and Na-K-ATPase pump activityIncreases cholesterol secretion to bile and number of liver LDL receptorsFor bone formation and bone maturation
67
Regulation of Thyroid Hormone Secretion
Mediated by TRH and TSH levels
68
RDA of Iodine per day
150ug
69
High levels of iodine inhibiting organification and iodine thyroid hormone synthesis
Wolff-Chaikoff Effect
70
Bone Age
Hypothyroidism
71
Liver and Kidney Failure: TBG levels?
Decreased TBG
72
Estrogen or pregnancy: TBG levels?
Increased TBG
73
Enzyme that converts T4 to T3
5' Iodinase
74
T4 can also be converted to
rT3 (inactive)
75
Fever, changes in sensorium, tachycardia in pts w/ hyperthyroidism
Thyroid Storm
76
Increase thyroid size due to trophic effects of high levels of TSH and TSH-like substances
Goiter
77
Thyroid diseases with goiter
Graves diseaseTSH-secreting tumorHashimoto's diseaseIodine Deficiency
78
Thyroid diseases with no goiter
Ingestion of T4, TSH deficiency
79
Aldosterone (Mineralocorticoid)
Zona Glomerulosa
80
Cortisol, Corticosterone (Glucocorticoids)
Zona Fasciculata
81
De-hydro-epi-androsterone (DHEA) and Androstenedione (weak androgens)
Zona Reticularis
82
Inhibits 11beta-hydroxylase
Metyrapone
83
Inhibits Desmolase
Ketoconazole
84
Adrenal Androgens in Males and Females respectively
Insignificant, Significant (respectively)
85
Need ACTH for 1st step but otherwise controlled by RAAS
Zona Glomerulosa
86
Characteristics of cortisol secretion
Pulsatile, diurnal
87
4 Diabetogenic hormones
GHCortisolGlucagonEpinephrine
88
Triggers for Aldosterone Secretion
Dec ECF volumeHyperkalemia
89
Islets of Langerhans: Secrete Insulin and Amylin
Beta Cell 60%
90
Islets of Langerhans: Secrete Glucagon
Alpha Cell 25%
91
Islets of Langerhans: Secrete Somatostatin
Delta Cell 10%
92
Islets of Langerhans: Secrete Pancreatic Polypeptide
F Cell/ PP Cell 5%
93
A protein that contains an A chain and B chain joined by disulfide bonds
Insulin
94
Main determinant of Insulin Secretion
Blood Glucose levels
95
Half-life of Insulin
6 minutes
96
Degradation of Insulin by
Insulinase (in the liver)
97
Increases glucose uptake into cells; Increases glycogen formation; Decreases glycogenolysis;Decreases gluconeogenesis
Decreased Blood Glucose
98
Increases amino acid uptake ➡️ Increases protein synthesis
Decreased blood amino acids
99
Increases fat deposition
Decreased blood fatty acids
100
Decreases lipolysis
Decreased blood ketoacids
101
Increases K uptake into cells
Decreased blood potassium
102
Effect of insulin on the brain
None
103
Insulin: 2nd messenger
Tyrosine kinase
104
Glucagon: 2nd messenger
cAMP
105
Marker for endogenous insulin
C peptide
106
When proinsulin becomes insulin, what part is cleaved off?
C Peptide (connecting peptide)
107
GLUT transport is found in Beta Cells
GLUT-2
108
Oral vs IV Glucose: greater insulin secretion
Oral glucose
109
Secrete collagen and ground substance where calcium precipitates; Bone resorption
Osteoblast
110
Secrete lysosomal enzymes, citric acid and Lactic acid
Osteoclasts
111
Hyperreflexia, spontaneous twitching, muscle cramps and tingling and numbness
Hypocalcemia
112
Constipation, polyuria, polydipsia, and neurologic signs of hyporeflexia, lethargy, coma, death
Hypercalcemia
113
Signs of hypocalcemia
Chvoestek & Trousseau
114
Increased serum anions; effect on calcium levels
Hypocalcemia
115
Acidosis: effect on calcium levels
Hypercalcemia
116
Alkalosis: effect on calcium levels
Hypocalcemia
117
What is the location of PTH receptors?
Osteoblast
118
Would thyroidectomy cause hypercalcemia due to absent calcitonin?
No, since calcitonin does not participate in minute-to-minute calcium regulation
119
What is secreted by osteoblast to inhibit osteoclastic activity in hyperparathyroidism?
Alkaline phosphatase
120
Secreted by chief cells of parathyroid gland
PTH
121
Stimulation of PTH
HypocalcemiaHypomagnesemia
122
Secreted by parafollicular cells of thyroid gland
Calcitonin
123
Stimulation of Calcitonin
High plasma Ca
124
What is the treatment for humoral hypercalcemia of malignancy?
Furosemide (inhibits renal Ca reabsorption) Etidronate (inhibits bone resorption)
125
Presents with short stature, short neck, obesity, subcutaneous calcification, and shortened fourth metatarsals and metacarpals?
Albright Hereditary Osteodystrophy (Pseudohypoparathyroidism Type Ia)
126
Vitamin D resistance is seen in which condition?
Chronic renal failure
