USMLE- Endocrine and physiology II

mezacavu's version from 2018-04-04 12:29

Section 1

Question Answer
What structure secretes PTH (parathyroid hormone)?Chief cells of parathyroid
What are the 4 principals functions of PTH?1)increases bone resorption of calcium and phosphate 2)increases kidney reabsorption of calcium in distal convoluted tubule 3) decreases reabsorption of phosphate in proximal convoluted tubule 4)increases of 1,25-(OH)2 D3 (calcitriol) production by stimulating kidney 1alpha-hydroxylase
What the letters means in the mnemonic ''PTH''?Phosphate Trashing Hormone (increase production of M-CSF and RANK-L in osteoblasts, stimulating osteoclasts
What increase PTH secretion?diminution of serum Ca2+, diminution of serum Mg2+
What decrease PTH secretion?important diminution of serum Mg2+
What are the common causes of diminution of Mg2+?diarrhea, aminoglycosides, diuretics and alcohol abuse
Is true to say that PTH leads to increase Ca2+ reabsorption and decrease PO4 3- reabsorption in the kidney?yes

Section 2

Question Answer
What is the other name for vitamin D?cholecalciferol
Where come from D3 and D2?D3 from sun exposure in skin. D2 ingested from plants, Both converted to 25-OH in liver and to 1,25-(OH)2 (active form) in kidney
What are the function of vitamin D?increases absorption of dietary Ca2+ and PO4 3-, increases bone resorption of Ca2+ and PO4 3-
What substance cause an increase in 1,25-(OH)2 production?increase PTH, decrease [Ca2+], decrease PO4 3-
Does 1,25-(OH)2 inhibit its own production (negative feedback)?yes
What is the disease in kids and the disease in adult that are caused by vitamin D deficiency?Rickets in kids and ostemalacia in adults
What is the impact of 1,25- (OH)2 in absorption of Ca2+ and PO4 3- in the gut?increase absorption of both

Section 3

Question Answer
What structure secretes calcitonin?Parafollicular cells (C cells) of thyroid
What is the function of calcitonin?decreases bone resorption of calcium
What causes an increase in calcitonin secretion?increase serum Ca2+
What is the mnemonic for function of calcitonin?CalciTONin TONes down calcium levels

Section 4

Question Answer
What are the 6 signaling pathways of endocrine hormones?1) cAMP 2) cGMP 3)IP3 4)Steroid receptor 5)intrinsic tyrosine kinase 6) receptor-associated tyrosine kinase
What is the mnemonic for endocrine hormones using cAMP signaling pathway?FLAT CHAMP: Fsh, Lh, Acth, Tsh,Crh, hCG, Adh (V2 receptor), Msh, Pth, calcitonin, GHRH and glucagon
What endocrine hormones use cGMP signaling pathway?ANP, NO (EDRF) think vasodilators
What is the mnemonic for endocrine hormones using IP3 signaling pathway?GGOAT: GnRH, GHRH, Oxytocin, ADH (V1 receptor), TRH, histamine (H1), angiotensin II, gastrin
What endocrine hormones using intrinsic tyrosine kinase signaling pathway?Insulin, IGF-1, FGF, PDGF, EGF (map kinase pathway, think growth factors)
What is the mnemonic for endocrine hormones using receptor-associated tyrosine kinase signaling pathway?PIG: Prolactin, Imminomodulators (cytokines, IL-2,IL-6,IL-8,IFN) GH (jack/stat pathway, think acidophiles and citokines)