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Uworld Journal COPY > Endocrine and Biochemistry > Flashcards

Endocrine and Biochemistry Flashcards

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1
Q

Mechanism of potassium iodide =

A

Competitively inhibits the uptake of radioactive iodine into follicular cells. Increased iodine also decreases release of T4/T3 due to the Wolff Chaikoff Effect.

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2
Q

Function of smooth ER = (3)

A
  • produces steroids and phospholipids (contains the appropriate enzymes)
  • acts as the sarcoplasmic reticulum for striated muscles
  • detoxification of drugs
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3
Q

What medication can be given to men who are suffering from gynecomastia?

A

SERM - inhibits ER in breast tissue

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4
Q

Hypoketotic hypoglycemia in a young kid after a long period of fasting is most likely a deficiency in _

A

FA beta-oxidation

Most likely it is inhibition of acyl CoA dehydrogenase enzyme.
Will not be able to oxidize FA for energy and cannot produce ketone bodies

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5
Q

Superior thyroid artery and vein travel with _ nerve

A

external branch of the superior laryngeal nerve

-innervates the cricothyroid muscle

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6
Q

Inferior thyroid artery and vein travel with _ nerve

A

recurrent laryngeal nerve

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7
Q

Gene from Albright Hereditary Osteodystrophy is inherited from mother/father

A

mother - due to imprinting of father’s genes
AD

defective Gs alpha subunit in the PTH receptor = pseudohypoparathyroidism - end organ resistance to PTH

presentation:

  • serum= low Ca, high P, high PTH
  • shortened 4th/5th digits
  • short stature
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8
Q

Conn syndrome =

A

Primary adrenal adenoma

increased aldo
decreased renin

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9
Q

Addison’s disease =

A

Primary adrenal insufficiency

decreased aldo
decreased cortisol

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10
Q

Metyrapone stimulation test

A

Blocks the last step of cortisol synthesis (11DOC -> cortisol)

Helps dx adrenal insufficiency

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11
Q

11-beta hydroxylase deficiency findings

female genitalia =

A
  • decreased aldo
  • increased 11-DOC (not salt wasting)
  • increased BP
  • decreased renin
  • increased androstenedione

female genitalia are ambiguous (due to increased androstenedione)

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12
Q

21 hydroxylase deficiency findings

female genitalia =
male genitalia =

A
  • decreased aldo (salt wasting)
  • decreased BP
  • increased renin
  • increased 17-hydroxyprogesterone
  • increased androstenedione

female genitalia are ambiguous (due to increased androstenedione)
male genitalia is normal and they are identified later due to salt wasting

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13
Q

17-alpha hydroxylase deficiency findings

female vs male genitalia

A
  • increased aldo (not salt wasting)
  • increased BP
  • decreased androstenedione

females - born with normal genitalia but will not have secondary sex characteristics
males - born undervirilized or with female external genital (due to decreased androstenedione)

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14
Q

Insulin independent glucose uptake locations (6)

A
  • Brain
  • RBC
  • Intestine
  • Cornea
  • Kidney
  • Liver
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15
Q

MEN 1

A
  • Pituitary adenoma (prolactin or GH)
  • Pancreas endocrine tumor (Zollinger-Ellison (gastrinoma), Insulinoma, VIPoma, Glucagonoma)
  • Parathyroid adenomas

mutation in MEN1 gene - menin tumor suppressor protein

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16
Q

MEN2A

A
  • Parathyroid hyperplasia
  • Thyroid medullary carcinoma (C cell tumor - secrete calcitonin)
  • Pheochromocytoma

mutation in RET gene - receptor tyrosine kinase
affects cells of neural crest origin!

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17
Q

MEN2B

A
  • Thyroid medullary carcinoma (C cell tumor - secretes calcitonin)
  • Pheochromocytoma
  • Muosal neuroma (oral/intestinal ganglioneuromatosis)

mutation in RET gene - receptor tyrosine kinase
associated with marfanoid habitus

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18
Q

Hashimoto thyroiditis associated HLA subtype =

A

HLA-DR5, DR3

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19
Q

Diabetes Mellitus Type 1 associated HLA subtype =

A

HLA-DR4

HLA-DR3

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20
Q

Vitamin _ deficiency -> hemolytic anemia, acanthocytosis, posterior column or spinocerebellar tract demyelination

A

Vitamin E deficiency

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21
Q

Niacin is derived from _ and requires what two cofactors?

A

Derived from tryptophan

Cofactors = B2 (riboflavin), B6 (pyridoxine)

Niacin is B3
Requires B2, B6
(6/2=3)

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22
Q

Elfin facies + intellectual disability with well developed verbal skills + hypercalcemia =

A

Williams Syndrome - microdeletion of long arm Chr 7 (includes elastin gene)

Hypercalcemia is due to increased vitamin D sensitivity

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23
Q

Myotnia + Cataracts + Testicular atrophy + CTG repeat =

A

myotonic dystropy type 1

mutation in the DMPK gene -> abnormal myotonin protein kinase

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24
Q

Cancers associated with Li Fraumeni Syndrome (4)

A
  • Sarcoma
  • Breast
  • Leukemia
  • Adrenal gland
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25
Cross linking of elastin is done by _ enzyme
lysyl oxidase with copper cofactor required this is the same enzyme that crosslinks collagen fibrils
26
Mutation in ATP7A + brittle, kinky hair + growth retardation =
Menke disease -decreased copper absorption which leads to a decreased collagen and elastin synthesis
27
Coarse facial features + clouded corneas + limited joint movements + increased plasma lysosomal enzymes + child
I cell disease - inhibits N-acetylglycosaminyl-1-phosphotransferase enzyme Results in the failure of the golgi to add a mannose-6-phosphate to glycoproteins that are supposed to be degraded in the lysosome
28
Ribosomes: prokaryotic vs eukaryotic - 80s - 70s
- 80s = 40s+60s -> eukaryotes - 70s = 30s+50s -> prokaryotes eukaryotes - even numbers prokaryotes - odd numbers
29
tRNA thymine + pseudouracil + cytosine sequence is used for
tRNA-ribosome binding
30
tRNA dihydrouracil residue is used for
tRNA recognition of the correct aminoacyl tRNA synthetase
31
anti-spliceosome snRNP antibody =
anti-Smith antibody = SLE!
32
Lac operon requires what to function?
available lactose glucose can be low or high but as long as lactose is available, there will be transcription of the lac operon
33
Histones are rich in what 2 amino acids?
- Lysine | - Arginine
34
Vomiting + Rice water stools + Garlic breath
Arsenic poisoning
35
Infant with increased serum alanine + lactic acidosis + neurological deficits =
Pyruvate Dehydrogenase Complex deficiency - X-linked - Treatment = ketogenic diet (high fat, low carb, high lysine and leucine) Lysine and Leucine are ketogenic AA -generates the ketone body precursor to acetyl CoA and therefore does not go through the pyruvate pathway
36
Locations of HMP shunt/Pentose Phosphate Pathway (4)
- lactating mammary gland - liver - adrenal cortex - RBC
37
Essential AA (9)
``` Met Val His Ile Phe Thr Trp Leu Lys ```
38
Acidic AA (2)
Asp | Glu
39
Basic AA (3)
Arg Lys His (neutral at body pH)
40
underlying pathology for Graves' proptosis =
Inflammation Steroids help decrease the ophthalmic symptoms
41
Main pathogenesis of T1DM =
autoimmune insulinitis - cell mediated destruction of the beta-pancreatic cells
42
NADPH is used in what reactions? (4)
- Reduction of glutathione (prevents oxidative damage) - Synthesis of cholesterol - Synthesis of FA - Synthesis of steroids
43
Physical and mental retardation + megaloblastic anemia + increased orotic acid in urine What is the treatment?
Orotic aciduria Treatment = uridine supplementation
44
Painful rash on face, groin and perineum involving crusting, coalescing erythematous borders with central bronze induration. Light microscopy shows superficial necrolysis.
Glucagonoma
45
Sympathetic stimulation of pancreatic beta cells =
Decreases insulin release due to the alpha-2>beta-2 ``` alpha-2 = decreases insulin release due to Gi beta-2 = increases insulin release due to Gs ```
46
Why are non-selective beta blockers dangerous in DM patients?
Exacerbates the hypoglycemia and masks the adrenergic symptoms that hypoglycemia can cause
47
Thyroid biopsy - empty appearing nuclei with central clearing + nuclear grooves
Papillary thyroid carcinoma - empty nuclei = Owl's eyes - also presents with psamomma bodies
48
Thyroid nodule that is invading the capsule and surrounding vasculature
Follicular thyroid carcinoma note: this cannot be diagnosed via fine needle biopsy
49
Thyroid biopsy - lymphocytic infiltrate with well developed germinal centers and eosinophilic metaplasia of the cells surrounding the follicles
Hashimoto thyroiditis eosinophilic metaplasia = Hurthle cells The follicles are making the antibodies (autoimmune pathogenesis) - anti-microsomal Ab - anti-thyroglobulin Ab
50
Thyroid biopsy - granulomatous inflammation + follows a flu-like illness + painful + increased ESR
Subacute (de Quervain) thyroiditis
51
Young patient with a hard painless thyroid
Ridel fibrosing thyroiditis
52
Beriberi is a _ deficiency
Thiamine (B1) Causes peripheral neuropathy (“dry”) or peripheral neuropathy + dilated cardiomyopathy (“wet”)
53
What 5 AA can be synthesized into propionyl CoA?
- Valine - Leucine - Isoleucine - Methionine - Threonine
54
What AA is used to make NO?
Arginine
55
What 2 AA are used to make urea?
Arginine | Aspartate
56
What AA is used to make GABA?
Glutamate
57
What 3 things can Tryptophan be made into?
- Serotonin - Melatonin - Niacin
58
Fetal adrenal cortex releases what steroid?
DHEA
59
GH release is stimulated by hyper/hypoglycemia?
Hypoglycemia Glucose inhibits GH release
60
5 yo + exophthalmos + lytic bone lesions at the base of the skull + polyuria + polydipsia
Langerhans histiocytosis with Diabetes Insipidus
61
Mutations in follicular thyroid carcinoma? (2)
- RAS oncogene | - PAX8-PPAR gamma fusion gene
62
Tapping on facial nerve leading to contraction occurs in increased/decreased serum Ca?
Chvostek sign - Indicates decreased serum Ca - Usually due to hypoparathyroidism - low PTH, low Ca
63
Locations of ADH receptors
V1 - vascular smooth muscle V2 - cortical collecting duct and vascular endothelium
64
GH is _ in striated muscle and _ in adipose tissue
- anabolic in striated muscle | - catabolic in adipose tissue
65
Maturity onset diabetes of the young/gestational diabetes is caused by a mutation in _ enzyme
Glucokinase
66
Underlying cause of DKA?
Lack of insulin
67
Renal osteodystrophy occurs with _ hyperparathyroidism
Secondary or Tertiary - Due to an underlying renal problem -> decreased vitamin D -> decreased Ca from gut -> decreased serum Ca -> increased PTH - Renal problem -> increased serum P because it cannot be removed properly
68
Subperiosteal resorption with cystic degeneration + decreased serum phosphate + increased serum calcium + increased urinary calcium =
Primary hyperparathyroidism and Osteitis fibrosa cystica
69
Infant, 46XY, small phallus, hypospadias, small testes palpated in the inguinal area, serum T normal, BP normal.
Defective 5-alpha reductase -> decreased DHT therefore external genitalia is not formed correctly (pseudohermaphroditism)
70
Does maternal insulin cross the placenta?
NO Maternal glucose DOES cross the placenta and the fetus' pancreatic beta cells begin to secrete their own insulin (pancreatic beta cell hyperplasia)
71
Prolonged ACTH stimulation of the adrenal cortex causes _a_ of the _b_ and _c_ layers
a=Hyperplasia b=Fasciculata c=Reticularis
72
Cortisol - anabolic or catabolic?
Mostly catabolic except for in the live (+GNG and glycogenesis) Opposite of insulin.
73
Insulin vs Glucagon - phosphorylator vs dephosphorylator
``` Insulin = dephosphorylator Glucagon = phosphorylator ```
74
light microscopy of the thyroid: Nests or sheets of polygonal or spindle shaped cells with extracellular amyloid deposits that stain with congo red
Medullary thyroid carcinoma | -part of MEN2A or MEN2B
75
Alcohol suppresses what reactions resulting hypoglycemia?
Inhibits GNG - inhibition of alpha-KG DH and PDH enzymes due to lack of thiamine (B1) - inhibition of all reactions that require NAD due to the fact ethanol -> acetyl CoA used it all up - inhibition of transketolase enzymes due to lack of thiamine (B1) Alcohol does not inhibit any enzymes in the glycogenolysis pathway. This is the main route of glucose production until hepatic glycogen stores are depleted.
76
Patient with increased T4, decreased radioactive iodine uptake, hyperthyroid symptoms
Ingestion of exogenous thyroxine (people do this for weight loss purposes) The TSH level will also be decreased (which is related to the decreased radioactive iodine uptake)
77
``` TCA enzyme(s) that require niacin (3) ```
Niacin (B3) = NAD - Isocitrate DH - Alpha-ketoglutarate DH - Malate DH
78
TCA enzyme that requires riboflavin
Riboflavin (B2) = FAD | -Succinate DH requires FAD to make FADH2 (this enzyme is also complex II in the ETC)
79
Lower leg skin thickening and induration + elevated T4 + decreased TSH =
Graves hyperthyroidsim
80
Grave's disease associated HLA subtype =
HLA-DR3
81
Celiac disease associated HLA subtype =
HLA-DQ2 and DQ8
82
Excessive ingestion of raw egg whites causes _ deficiency
Biotin (B7) -Dermatitis, alopecia, enteritis Enzymes that require biotin: carboxylation reactions - Pyruvate carboxylase - Acetyl CoA carboxylase - Propionyl CoA carboxylase
83
Young child, Progressive spastic diplegia (bilateral leg stiffness), Growth delay, Abnormal chorioathetoid movements, Elevate arginine levels, Normal ammonia levels
Arginase deficiency - cannot make urea from urea cycle - treatment: low protein diet
84
3 antioxidant enzymes:
- superoxide dismutase - glutathione peroxidase - catalase converts ROS -> O2 + H2O
85
What pathway are these enzymes a part of? - Aldose reductase - Sorbitol dehydrogenase
Polyol pathway -occurs in seminal vesicles, retina, lens, renal papilla, Schwann cells glucose -(aldose reductase)-> sorbitol -(sorbitol dehydrogenase)-> fructose Sorbitol cannot readily cross membranes so in the certain tissues, it gets stuck -cataracts in the lens
86
Pancreatic ductal secretions and absorptions during high flow
Secretion: HCO3-, Na+, H2O Absorption: Cl-
87
Elevated baseline/fasting insulin levels with normal glucose levels =
Insulin resistance An insulinoma would have elevated insulin levels with hypoglycemia

Uworld Journal COPY (12 decks)

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