Many functions in the body are controlled by hormones – chemical signals that are secreted by one organ or tissue, but have effects in multiple areas. Calcium can enter the body from what we eat and drink.  It circulates through blood and is used by many organs, so it’s level is carefully regulated.  The amount of calcium in the blood is maintained at a relatively constant level by two hormones; for our purposes, we’ll just call them hormone A and hormone B.  Hormone A is secreted by the parathyroid gland and it functions to increase blood calcium levels.  Hormone B is secreted by parafollicular cells (C cells) in the thyroid gland and it functions to decrease blood calcium levels.  Calvin, a teenage boy, begins eating ChocoRite™ Calcium Bites, a very tasty calcium supplement.  He likes them so much that he ends up eating a whole package one afternoon.  1.Where does hormone B come from? A)From the calcium regulatory cells B)From the parathyroid gland C)From calcium supplements, like the ChocoRite™ Bites D)From the parafollicular cells of the thyroid gland 2.After eating all of these calcium supplements, what do you think will happen to Calvin’s hormone levels? A)Both hormone B and hormone A levels will increase B)Both hormone B and hormone A levels will decrease C)Hormone B level will increase and hormone A level will decrease D)Hormone B level will decrease and hormone A level will increase

Many functions in the body are controlled by hormones – chemical signals that are secreted by one organ or tissue, but have effects in multiple areas.

Calcium can enter the body from what we eat and drink.  It circulates through blood and is used by many organs, so it’s level is carefully regulated.  The amount of calcium in the blood is maintained at a relatively constant level by two hormones; for our purposes, we’ll just call them hormone A and hormone B.  Hormone A is secreted by the parathyroid gland and it functions to increase blood calcium levels.  Hormone B is secreted by parafollicular cells (C cells) in the thyroid gland and it functions to decrease blood calcium levels. 

Calvin, a teenage boy, begins eating ChocoRite™ Calcium Bites, a very tasty calcium supplement.  He likes them so much that he ends up eating a whole package one afternoon.