Which of the following has both endocrine and exocrine functions?: (A) Pancreas, (B) Thyroid, (C) Spleen, (D) Kidney
Answer is A. Ans: a (Pancreas)Pancreas has both exocrine and endocrine functions.There are 4 distinct types of pancreatic cells in human.A cells (alpha) - GlucagonB cells (beta) - InsulinD cells (delta) - SomatostatinF cells - Pancreatic polypeptide D1 cells - VIPEndocrine pancreas secretes hormones -glucagon, insulin and somatosta-tin. Exocrine pancreas secretes digestive enzymes like trypsin, chymot-rypsin.Site and mechanism of hormone action:-Mechanism and siteHormoneAt nuclear receptorThyroid ormonesAt cytoplasmic receptorsSteroidal hormones eg:- Glucocorticoids, Mineralocortyicoids, Estrogen, Progestins.At cytoplasmic receptorsa) Direct transmembrane activation of tyrosine protein kinase -InsulinPhosphorylation cascade b) Through IP3/DAG generationVasopressin, oxytocinc) Through alteration of intracellular cAMP concentration - alteration of protein kinase A activityAdrenaline, glucagon, TSH,LH, FSH, PTHACTH, Calcitonin