Final answer:
The incorrect statement about endocrine histology is B, which incorrectly describes the pancreatic islets as the exocrine portion of the pancreas when they are actually the endocrine portion, secreting hormones such as insulin and glucagon.
Step-by-step explanation:
The statement that is NOT true regarding endocrine histology is: B. The pancreas has an exocrine portion consisting of pancreatic islets and an endocrine portion consisting of acinar. In fact, the pancreas's exocrine portion consists of acinar cells that secrete digestive enzymes, while the endocrine portion is made of the pancreatic islets, or islets of Langerhans, where hormones like insulin and glucagon are produced.
The thyroid gland is accurately described as consisting of rings of simple cuboidal follicle cells surrounding colloid. The adrenal cortex indeed has 3 zones that secrete different types of hormones, and the adrenal medulla is modified nervous tissue and part of the sympathetic nervous system.