Hormones often cause a cell to elicit multiple responses; this is because___________________.
during protein kinase activation, enzymes phosphorylate many other enzymes
cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. in order for cells to respond, it is necesarry for first and second messengers to communicate. This is possible because _________________.
G protein acts as the link between first and second messengers
Thyroid hormone (a small iodinated amine) enters target cells in a manner similar to ________________.
steroid hormones, because both defuse easily into target cells
One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. What is this mechanism?
The major targets of growth hormone are_____________.
bones and skeletal muscles
The parathyroid glands maintain adequate levels of blood calcium. This is accomplished through ___________________.
targeting the bone and activating osteoclasts so that calcium will be released