35 year old man comes to the physician because of severe midline back pain during the past 4 weeks. he has gained 8kg(18lb) during the past 6 months. visual field testing shows decreased peripheral vision in both eyes. an x-ray of the chest shows compression fractures at t10 and l1. there is a healing left rib fracture posteriorly at t8. imaging studies show a pituitary macroadernoma. the most likely cause of his condition is a tumor producing which of the following hormones?
a. acthb. growth hormonec. luteinizing hormoned. prolactine. thyroid-stimulating hormone.

 the correct answer is A. ACTH

Explanation:

ACTH  stands for Adrenocorticotropic hormone  Adrenocorticotropic hormone (ACTH, also adrenocorticotropin, corticotropin) is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with its precursor corticotropin-releasing hormone from the hypothalamus). Its principal effects are increased production and release of cortisol by the cortex of the adrenal gland. ACTH is also related to the circadian rhythm in many organisms.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.