Alexa Spurling Dr. Morris Anatomy and Physiology 15 Apr 2019 Checkpoint Questions 18-22 18. How do the adrenal cortex and adrenal medulla compare with regard to location and histology? - The adrenal cortex is divided into three zones, and each of the zones secrete a different hormone. They include: zona glomerulosa, mineralocorticoids, and zona fasciculata. It is peripherally located on the adrenal gland, unlike the adrenal medulla which is located on the inner region of the adrenal gland and synthesizes epinephrine and norepinephrine with their hormone producing cells, ch - romaffin cells. 19. How is secretion of adrenal cortex hormones regulated? - Secretion of the adrenal cortex hormones is regulated by glucocorticoids which regulate metabolism and resistance to stress. This process occurs through the negative feedback system, which happens in response to ACTH from the anterior pituitary gland. There are six main effects that glucocorticoids have on the body: Protein breakdown, glucose formation, lipolysis, resistance to stress, anti-inflammatory effects and depression of immune responses. 20. How is the adrenal medulla related to the autonomic nervous system? - The inner region of the adrenal medulla is a modified sympathetic ganglion from the same embryonic tissue as other sympathetic ganglia. However, its cells lack axons but they form clusters around larger blood vessels. It also contains chromaffin cells, which produce the hormones for the medulla. 21. How are blood levels of glucagon and insulin controlled? - Blood levels of glucagon and insulin are controlled by the level of blood glucose in the blood. Alpha or A cells secrete glucagon and Beta or B cells produce insulin. Glucagon increases blood level when it falls below normal and insulin lowers blood glucose level when it is too high. Together, insulin and glucagon help maintain a state called homeostasis in which conditions inside the body remain steady. When blood sugar is too high, the pancreas secretes more insulin. When blood sugar levels drop, the pancreas releases glucagon to raise them. Islet cells in the pancreas are responsible for releasing both insulin and glucagon. The pancreas contains many clusters of these cells. There are several different types of islet cell, including beta cells, which release insulin, and alpha cells, which release glucagon. 22. What are the effects on secretion of insulin and glucagon of exercise verses eating a carb and protein rich meal? - The effects of of exercise vs. eating a carbohydrate and protein rich meal on the secretion of insulin and glucagon can vary. Exercise and eating a protein rich meal decreases blood glucose level which stimulates glucagon. When blood levels increase, insulin is secreted to regulate it in the blood.
