Thyroid Development
Thyrglossal duct cyst
- Branchial cleft cysts are located laterally
Fetal Adrenal Gland
Zona Glomerulosa
-Most cortical, secretes aldosterone in response to renin-angiotensin 2
Zona Fasicularis
-Secretes coritsol in response to ACTH/CRH
Zona Reticularis
-Secretes Sex steroids, also increased by ACTH and CRH
Adrenal Medulla
-Contains NC derived chromafin cells (S-100 +) that secrete Epi (some nor epi, 10%) in response to Ach releaased from preganglionic sympathetics that branch from IML at T10-L1 and travel along splanchinics
Pheochormocytoma
- Located with MBIG scan which will detect location of ectopic caetacholamine synthesis
Neuroblastoma
Kids
Arterial Supply of Adrenal
Venous Drainage
- R: Adrenal drains to renal the to IVC
Posterior Pituitary
Anterior Pituitary
Endocrine Pancreas
Islets of langerhans
Insulin Physiologic Release
-Elevated glucose enters beta cells through Glut-2 which is high capacity but low affinity. Increase glucose leads to increase ATP. Elevated ATP closes K channel leading to depolarization, opening of V-gated Ca channels which signal release of insulin.
Insulin Secreted hormonally
Insulin sepressed hormonally
- Also suppressed by somatostatin
Glut -1
Insulin independent
Glut - 2
Glut - 4
Insulin Dependent
Insulin effects on electrolytes
Proinsulin
Secreted as disulfide bridged dimer with C peptide
-Can be used to see if insulinoma or facticous
Glucagon
-Released from alpha cells in response to hypoglycemia
Theraputic uses of glucagon
-Can be used to treat beta blocker overdose. Both are Gs receptors