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USMLE Step 1: Things I Cannot Remember > Endocrine > Flashcards

Flashcards in Endocrine Deck (41):
1

Appetite Regulation:

  • Ghrelin ⇒ 
  • Leptin ⇒ 
  • Endocannabinoids ⇒

  • Ghrelin ⇒ stimulates hunger
    • produced by the stomach
    • inc w/ sleep and Prader-Willi Syndrome
  • Leptin ⇒ satiety hormone
    • produced by adipose tissue
    • mutation of leptin gene ⇒ congenital obesity
    • dec w/ sleep deprivation
  • Endocannabinoids ⇒ stimulate cortical reward centers
    • inc desire for high fat foods (munchies)

2

What hormones use the cAMP signaling pathway?

FLAT ChAMP

  • FSH
  • LH
  • ACTH
  • TSH
  • C​RH
  • hCG
  • ADH
  • MSH
  • PTH, calcitonin, GHRH, glucagon

3

What hormones use the cGMP signaling pathway?

Vasodilators

  • ANP
  • BNP
  • NO (EDRF)

4

What hormones use the IP3 signaling pathway?

GOAT HAG

  • GnRH
  • Oxytocin
  • ADH (V1 - receptor)
  • TRH
  • Histamine (H1 - receptor)
  • Angiotensin II
  • Gastrin

5

What hormones use an intracellular receptor signaling pathway?

VETTT CAP

*Vitamin D, sex hormones, adrenal steroids, thyroid hormones

  • Vitamin D
  • Estrogen
  • Testosterone
  • T3/T4 
  • Cortisol
  • Aldosterone
  • Progesterone

6

What hormones use an intrinsic tyrosine kinase signaling pathway?

Growth factors (and MAP kinase pathway)

  • Insulin
  • IGF-1
  • FGF
  • PDGF
  • EGF

 

7

What hormones use a receptor-associated tyrosine kinase signaling pathway?

PIGGLET

*JAK/STAT pathway, acidophils, cytokines

  • Prolactin
  • Immunomodulators (cytokines)
  • GH
  • G-CSF
  • Erythropoietin
  • Thrombopoietin

 

8

What are the characteristics of MEN1?

(remember the diamond)

3 P's:

  1. Pituitary tumors 
    • prolactin and GH
  2. Parathyroid tumors 
  3. Pancreatic endocrine tumors
    • ZE syndrome, VIPomas, glucagonomas (rare)
  • mutation of MEN1 gene (menin, tumor suppressor)

9

What are the characteristics of MEN2A?

(remember the square)

2 P's:

  1. Parathyroid hyperplasia
  2. Pheochromocytoma
  3. Medullary thyroid carcinoma (secretes calcitonin)
  • marfinoid habitus
  • mutation in RET gene (codes for receptor tyrosine kinase)

10

What are the characteristics of MEN2B?

(remember the triangle)

1 P:

  1. Pheochromocytoma
  2. Oral/intestinal ganglioneuromatosis (mucosal neuromas)
  3. Medullary thyroid carcinoma (secretes calcitonin)
  • marfinoid habitus
  • mutation in RET gene (codes for receptor tyrosine kinase)

11

What are the rapid acting insulins?

  1. Aspart
  2. Glulisine
  3. Lispro

12

What are the short acting insulins?

Regular insulin

13

What are the intermediate acting insulins?

NPH

14

What are the long acting insulins?

  1. Detemir
  2. Glargine

15

Where is the most common thyroid ectopic tissue site?

tongue

16

Thyroglossal duct cyst vs. Branchial cleft cyst

  • Thyroglossal duct cyst ⇒ anterior midline neck mass that moves when swallowing
  • Branchial cleft cyst ⇒ cyst in the lateral neck (due to a persistent cervical sinus

17

The most common tumor of the adrenal medulla in adults:

Pheochromocytoma — episodic hypertension

18

The most common tumor of the adrenal medulla in children:

Neuroblastoma — rarely causes hypertension

19

Anterior pituitary is derived from the ____ _______

Anterior pituitary is derived from the oral ectoderm (Rathke pouch)

20

List the Anterior Pituitary Hormones: 

FLAT PiG

  • FSH
  • LH
  • ACTH
  • TSH
  • Prolactin
  • GH

21

Anterior Pituitary Hormones - Acidophils

GH and prolactin

22

Anterior Pituitary Hormones - Basophils

B-FLAT

Basophils -

  • FSH
  • LH
  • ACTH
  • TSH

23

  • Which pituitary hormones share the same α-subunit?
  • How are they different?

  • FSH, LH, TSH and β-HCG share the same α-subunit
  • Hormone specificity is determined by the β-subunit

24

What are the insulin-dependent tissues?

BRICK L

  • Brain
  • RBCs
  • Intestines
  • Cornea
  • Kidneys
  • Liver

25

Insulin-dependent glucose transporters: 

GLUT-4

  • adipose tissue, striated muscle
  • excercise can increase GLUT-4 expression

26

Insulin-independent glucose transporters:

  • GLUT-1:
    • RBCs, brain, cornea
  • GLUT-2 (bidirectional):
    • ß-islet cells, liver, kidneys, small intestine 
  • GLUT-3:
    • brain
  • GLUT-5 (fructose):
    • spermatocytes, GI tract

27

How is insulin regulated?

  • Glucose is the major regulator
    • ß2-agonists ⇒ ↑ insulin release
    • GH ⇒ ↑ insulin resistance ⇒ ↑ insulin release
  • Glucose enters cell ⇒ ↑ ATP generated from glucose metabolism ⇒ K+ channels close ⇒ ß cell membrane depolarizes ⇒ Voltage-gated Ca2+ channels open → Ca2+ influx ⇒ stimulation of insulin exocytosis

28

What are the physiologic effects of insulin? 

Anabolic effects:

  • ↑ glucose uptake into skeletal muscle and adipose tissue (insulin-dependent - GLUT4)
  • ↑ glycogen synthesis and storage
  • ↑ trig synthesis
  • ↑ Na+ retention (kidneys)
  • ↑ protein synthesis (muscles)
  • ↑ cellular uptake K+ and amino acids
  • ↓ glucagon release

29

What is the most common congenital adrenal hyperplasia?

21-hydroxylase deficiency

  • Infancy ⇒ salt wasting
  • Childhood ⇒ precocious puberty
  • XX ⇒ virilization

30

Effects of 17α-hydroxylase deficiency:

  • Mineralocorticoids:
  • Cortisol:
  • Sex Hormones:
  • BP:
  • [K+]:
  • Labs:
  • Presentation:

  • Mineralocorticoids: ↑
  • Cortisol: ↓
  • Sex Hormones: ↓
  • BP: ↑
  • [K+]: ↓
  • Labs: ↓ androstenedione
  • Presentation:
    • XY: pseudo-hermaphroditism (ambiguous genitalia, undescended testes)
    • XX: lack of secondary sexual development

31

Effects of 21-hydroxylase deficiency:

  • Mineralocorticoids:
  • Cortisol:
  • Sex Hormones:
  • BP:
  • [K+]:
  • Labs:
  • Presentation:

  • Mineralocorticoids: ↓
  • Cortisol: ↓
  • Sex Hormones: ↑
  • BP: ↓
  • [K+]: ↑
  • Labs: ↑ renin, ↑ 17-hydroxyprogesterone
  • Presentation: 
    • Infancy: salt wasting
    • Childhood: precocious puberty
    • XX: virilization

32

Effects of 11β-hydroxylase deficiency:

  • Mineralocorticoids:
  • Cortisol:
  • Sex Hormones:
  • BP:
  • [K+]:
  • Labs:
  • Presentation:

 

  • Mineralocorticoids: ↓
  • Cortisol: ↓
  • Sex Hormones: ↑
  • BP: ↑
  • [K+]: ↓
  • Labs: ↓ renin activity
  • Presentation: 
    • XX: virilization

33

What are the functions of cortisol?

Cortisol is a BIG FIB:

  • ↑ Blood pressure 
    • upregulates α1-receptor activity ⇒ ↑ sensitivity to NE and epi
    • With high levels, can bind to aldosterone receptor 
  • ↑ Insulin resistance (diabetogenic)
  • Gluconeogenesis, lipolysis, proteolysis
  • ↓ Fibroblast activity ⇒ causes striae
  • Inflammatory and Immune response
  • Bone formation (↓ osteoblast activity)

34

How does cortisol supress the Inflammatory/Immune response?

  • Inhibits production of leukotrienes and prostaglandins
  • Inhibits WBC adhesions ⇒ neutrophilia
  • Blocks histamine release from mast cells
  • ↓ eosinophils
  • Blocks IL-2 production
    • Exogenous cortisol ⇒ can lead to reactivation of TB and candidiasis

35

Which oral hypoglycemic agents can cause hypoglycemia?

  • Sulfonylureas
    • Chlorpropamide, Tolbutamide - 1st generation
    • Glimpepiride, Glipizide, Glyburide - 2nd generation
  • Amylin analogs
    • Pramlitinide

36

What oral hypoglycemic agents can cause hepatotoxicity?

Glitazones/thiaglitazones

  • Pioglitazone
  • Rosiglitazone

37

Which oral hypoglycemic agents cause UTIs and vaginal yeast infections?

SGLT-2 inhibitors

  • Canaglifozin 
    • can also cause glucosuria

38

What is the most serious adverse effect of biguanides (metformin)?

lactic acidosis

39

What oral hypoglycemic drugs ↑ insulin sensitivity?

  • Biguanides (Metformin)
    • exaxt mechanism unknown: ↑ peripheral glucose upake, ↑ glycolysis, ↓ gluconeogenesis
  • Glitazones/Thiaglitazones (Pioglitazone, Rosiglitazone)
    • ↑ insulin sensitivity in peripheral tissue
    • Binds to PPAR-γ nuclear transcription regulator

40

What are the side effects of Glitazones/Thiaglitazones?

  • Hepatotoxicity
  • Weight gain
  • HF
  • Edema
  • ↑ risk of fractures

41

Which oral hypoglycemic agents can cause pancreatitis?

GLP-1 receptors

  • Exenatide
  • Liraglutide