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46 Cards in this Set
- Front
- Back
Are most of the effects mediated by GH direct or indirect?
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Indirect (via IGF)
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IGF are small protein hormones also known as...?
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Somatomedins
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What is the most important regulator of postnatal growth?
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IGF-1
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How do IGF-1 and GH levels in the blood differ throughout the day?
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IGF-1 levels are constant throughout the day
GH levels are variable with peaks and valleys |
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Besides hormones, what physical factors regulate GH?
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1. Stress
2. Exercise 3. Nutrition 4. Sleep |
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What are the primary controllers of GH release?
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1. GHRH (stimulatory)
2. Somatostatin (inhibitory) |
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Somatostatin regulates GH in response to which stimulatory factors?
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1. GHRH
2. Low blood glucose |
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How do high levels of IGF-1 affect GH?
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Inhibits GH directly by suppressing its secretion and indirectly by stimulating somatostatin secretion
(negative feedback loop) |
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What is the effect of high levels of IGF-1 on somatostatin secretion?
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Stimulation
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Which hormones inhibit GH secretion?
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1. Somatostatin
2. High levels of IGF-1 3. High levels of GH (autocrine) |
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Are basal concentrations of GH in blood high or low?
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Very low
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When is the most intense period of GH release in children and young adults?
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Shortly after the onset of deep sleep
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If a child had a normal birth weight, and now has normal bone age and normal age of puberty, but has a target height below the 3rd percentile, what variant of normal growth is this?
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Familial short stature
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What is the effect of a thyroid deficiency on mature height?
What is the effect of excess thyroid on mature height? |
Deficiency --> Reduced height
Excess --> No effect (normal height) |
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How do thyroid deficiencies and excess thyroid affect growth rate and bone maturation?
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Deficiency --> very slow growth rate, very slow bone maturation
Excess --> mild acceleration of both |
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Short stature is defined as height below what percentile?
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3rd percentile (or -2SDs)
(most often not pathological) |
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Is growing at a slow rate (crossing percentiles) usually non-pathological or should it be a concern that needs evaluation?
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Slow growth rate (growth failure) warrants evaluation
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Failure to thrive is usually caused by..?
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Malnutrition
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GH insensitivity results in what syndrome?
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Laron syndrome
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Which gene is affected in Laron syndrome?
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GHR
(GH deficiency) |
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Which condition results in immune deficiency, high GH production, and low IGF-1, IGFBP-3?
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STAT5b deficiency
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What is the result of an IGF-1 gene mutation on Prenatal and postnatal growth?
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Both are decreased
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What is the effect of a GH insensitivity on prenatal and postnatal growth?
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Prenatal --> not affected
Postnatal --> decreased |
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What is the effect of IGF-1 gene mutation on GH, IGF-1, and IGFBP-3?
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GH--> increased
IGF-1 --> decreased IGFBP-3 --> not affected |
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Which condition results from an IGF2 gene mutation?
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Russel-silver syndromE
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Which condition results in deafness, microcephaly, and CHO intolerance?
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IGF-1 mutation
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What is the effect of Russel Silver syndrome on prenatal and postnatal growth?
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(IFG2 abnormality)
*Both are decreased |
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Which gene is affected in IGF resistance?
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IGF1R
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What is the effect of IGF resistance on prenatal and postnatal growth?
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Both are decreased
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Will birth weight be normal or abnormal with a GH deficiency?
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Normal
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Will birth weight be normal or abnormal with an IGF1 gene mutation?
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Abnormal--> low birth weight
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Will birth weight be normal or abnormal with an IGF1R mutation?
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Abnormal--> low birth weight
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Describe the clinical features seen with a GH deficiency?
(birth weight, growth rate, height, bone age, weight) |
1. Normal birth weight
2. Failure to grow in first 6 months 3. Short stature 4. Delayed bone age 5. Normal weight for height |
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Describe the laboratory diagnosis for GH deficiency?
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1. Low IGF-1 and IGFBP-3
2. Increased GH level after simulation (i.e. clonidine, arginine, usually <7ng/ mL) |
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List 3 general causes for a congenital GH deficiency.
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1. GH axis gene mutations (GH1, GHRH)
2. Abnormal CNS/ hypothalamic development 3. Idiopathic |
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List 4 general causes for an acquired GH deficiency.
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1. Craniopharyngioma
2. CNS Dysgerminoma 3. Glioma 4. Langerhans cell histiocytosis |
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Which condition is a congenital malformation syndrome characterized by optic nerve hypoplasia and absence of the septum pellucidum?
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Septo-optic dysplasia
(Morsier syndrome) |
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Septo-optic dysplasia is also known as which syndrome?
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Morsier syndrome
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List 5 intracranial malformations seen in septo-optic dysplasia.
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1. Hypoplasia of Optic N
2. Absence of septum pellucidum 3. Schizencephaly (gray matter malformation) 4. Lobar holoprosencephaly (forebrain fails to develop into 2 hemispheres) 5. Hypopituitarism |
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Craniopharyngiomas can result with what type of visual deficit?
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Bilateral hemianopsia
(tumor may compress on optic chiasm) |
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What is the most common location of an intracranial germinoma?
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On or near the midline-- often in the pineal or suprasellar areas. Common in hypothalamic regions.
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Langerhans cell histiocytosis affects which organs?
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Can affect almost any organ
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What type of individuals are more susceptible to developing Langerhans cell histiocytosis?
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Children
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Multifocal unisystem LCH (Langerhans cell histiocytosis) is characterized by what signs and symptoms?
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1. Fever
2. Bone lesions 3. Diffuse eruptions (scalp and in the ear canals) 4. ~50% of cases involve the pituitary stalk --> Diabetes insipidus |
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What is the Hand-Shuller-Christian triad?
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1. Diabetes insipidus
2. Exopthalmos 3. Lytic bone lesions |
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What is the treatment for GH deficiency?
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1. Replacement with recombinant human GH
2. Replace any associated deficiencies (i.e. thyroxine, cortisol) |