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Flashcards in Endocrine Deck (73)
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1

insulin receptor

tyrosine kinase receptor that induces glucose uptake into insulin-dependent tissues via GLUT-4 receptors and affects gene transcription.

2

Regulation of insulin release

Glucose enters beta cell and is metabolized, increasing ATP. ATP closes K+ channels leading to depolarization. VG Ca++ channels open leading to Ca++ influx and exocytosis of insulin.

3

Effects of somatostatin

Decreases growth hormone and TSH release from the pitutiary. Analogues can thus be used to treat acromegaly.

4

Effects of TRH

increases TSH and prolactin

5

Two functions of growth hormone

Stimulates growth through IGF-1
Increases insulin resistance (diabetogenic)

6

Regulation of growth hormone

Released in pulses in response to GHRG. Secretion higher during exercise and sleep. Secretion inhibited by glucose and somatostatin.

7

Ghrelin

Stimulates hunger and GH release. Produced by stomach

8

Leptin

Satiety hormone produced by adipose tissue

9

Regulation of ADH

Osmoreceptors in hypothalamus
Hypovolemia

10

17-alpha-hydroxylase deficiency

High mineralocorticoids; low cortisol and sex steroids. High BP, low K+, low androstenedione, non-virilizing. Males have ambiguous genitalia at birth, females lack secondary sex development.

11

21-hydroxylase deficiency

Most common cause of CAH. high sex hormones; low mineralocorticoids and cortisol. Low BP and high K+. High 17-OH-progesterone and high renin activity.

12

11beta-hydroxylase deficiency

Low aldosterone and cortisol but high 11-beta-deoxycorticosterone results in increased BP. High sex hormones. Virilization and salt wasting.

13

Cortisol functions

BIG FIB:
-increases BP
-increases insulin resistance
-increases gluconeogenesis
-decreases fibroblast activity which is what causes striae in cushings
-decreases inflammatory/immune response: inhibits leukotriene and PG production, inhibits WBC adhesion resulting in neutrophilia, blocks histamine release, reduces eosinophils, blocks IL-2 production
-decreases bone formation

14

functions of vitamin D

-increaes absorption of Ca++ and phosphorus in gut
-increases bone resorption, increasing Ca++ and phosphorus

15

regulation of vitamin D

Active levels increased by high PTH and low Ca++ and phosphorus

16

Functions of PTH

-increases bone resorption of Ca++ and phosphorus by increasing production of RANK-L which binds RANK receptor on osteoclasts to stimulate them
-increases kidney reabsorption of Ca++ in distal tubule
-decreases reabsorption of phosphorus in distal tubule
-increases active vitamin D production in kidney

17

Regulation of PTH

increased by low Ca++, high phos, low Mg++. Decreased by very low Mg++.

18

Hormones that signal through cAMP

FLAT ChAMP: FSH, LH, ACTH, TSH, CRH, hCG, ADH, MSH, PTH, calcitonin, GHRH

Pituitary hormones: FSH, LH, TSH, ADH (V2 receptor), ACTH, MSH (all but prolactin and oxytocin)
Hypothalamic hormones: CRH, GHRH
Others: hCG, PTH, calcitonin, glucagon

19

Hormones that signal through cGMP

ANP, BNP, NO

20

Hormones that signal through IP3

GOAT HAG: GnRH, oxytocin, ADH (V1 receptor), TRH, histamine (H1 receptor), angiotensin II, gastrin

21

Hormones that signal through intracellular receptor

Steroid hormones, thyroid hormone, vitamin D

22

Hormones that signal through intrinsic tyrosine kinase

Insulin, IGF-1, other growth factors

23

Hormones that signal through receptor-associated tyrosine kinase (JAK/STAT)

PIGG(L)ET: prolactin, immunomodulators, GH, G-CSF, EPO, thrombopoietin

24

Functions of T3

4Bs:
-brain maturation
-bone growth
-beta-adrenergic effects
-increased basal metabolic rate

25

Symptoms of adrenal insufficiency

Weakness, fatigue, orthostatic hypotension, muscle aches, weight loss, GI disturbance, sugar/salt cravings

26

Primary vs secondary vs tertiary adrenal insufficiency

Primary: Def of aldo and cortisol. Hypotension, hyperkalemia, and metabolic acidosis. ACTH high resulting in hyperpigmentation. Can be acute due to massive hemorrhage or chronic due to Addison disease

Secondary: Decreased ACTH production. No hyperpigmentation or hyperkalemia

Tertiary: Abrupt withdrawal of chronic exogenous steroid use

27

Neuroblastoma of adrenal medulla

Most common tumor of adrenal medulla in kids. Usually seen in those less than 4. Neural crest derivative with overexpression of N-myc. Pathology includes Homer-Wright rosettes.

Presents with abdominal distension and firm, irregular mass (vs smooth Wilms tumor). May see dancing eyes-dancing feet.

Labs: elevated HVA, VMA in urine due to breakdown or dopamine and NE. Bombesin and neuron-specific enolase pos.

28

Genetic syndromes associated with pheo

NF1, VHL, MEN2A, MEN2B

29

treatment of pheo

1) irreversible alpha antag (before beta blocker to prevent hypertensive crisis)
2) beta blocker
3) surgery

30

Reflexes in hypoand hyperthyroidism

decreased in hypo, increased in hyper