Produces a hormone that controls blood levels of calcium and potassium by their removal from bone tissue
Follicle cells of the thyroid gland produce thyroglobulin, while follicle cells of the parathyroid produce calcitonin
Peptide hormones enter the target cells and elicit a response by mediating neurotransmitter effects
Aldosterone is the most potent mineralocorticoid produced in the adrenals but the least abundant
Atrial natriuretic peptide is a hormone that controls blood pressure in part by increasing the urinary excretion of sodium
While glucagon is a small polypeptide, it is nevertheless very potent in its regulatory effects
The thyroid gland is a large gland that controls metabolic functions throughout the life of an individual
Many hormones synthesized in the gastrointestinal tract are chemically identical to brain neurotransmitters
The endocrine gland that is probably malfunctioning if a person has a high metabolic rate is the parathyroid
Growth hormone always exerts its influence by targeting other endocrine glands to produce hormones
Diabetes insipidus and diabetes mellitus are both caused by a genetic mutation involving the synthesis of insulin
Glucocorticoids are steroid hormones that usually enhance the immune responses when an individual is suffering from severe stress
All adenohypophyseal hormones except GH affect their target cells via a cyclic AMP second-messenger
Both "turn on" factors (hormonal, humoral, and neural stimuli) and "turn off" factors (feedback inhibition and others) may be modulated by the activity of the nervous system
Thyroid hormone exerts its influence by ________.
entering some cells and binding to intracellular receptors within the nuclei.
production by the adrenal gland is insignificant compared with sex hormone release from the gonads during late puberty
Sometimes prolonged excessive exposure to high hormone concentrations causes a phenomenon known as ________.
Which of the following is not a change that may be caused by hormonal stimulus?
direct control of the nervous system
The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on ___
the presence of the appropriate receptors on the cells of the target tissue or organ
Several hormones are synthesized in the hypothalamus and transported to the anterior pituitary gland. The mechanism of transportation from hypothalamus to anterior pituitary gland is through the ________.
hypophyseal portal system
The neurohypophysis or posterior lobe of the pituitary gland is not a true endocrine gland because ________.
it is only a hormone storage area that receives hormones from the hypothalamus for release
Insulin, a small (51-amino-acid) protein, is synthesized by the beta cells of the pancreas. This hormone is released ________.
when the body's glucose level rises
Steroid hormones exert their action by ________.
entering the nucleus of a cell and initiating or altering the expression of a gene
Normal development of the immune response is due in part to hormones produced by the ________.
The second-messenger mechanism of hormone action operates by ________.
binding to specific receptors and employing the services of G proteins and cAMP
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 necessary 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 diffuse easily into target cells
When it becomes necessary to enlist the fight-or-flight response, a hormone that is released during the alarm phase of the general adaptation syndrome is ________.
One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. Which of the following describes this mechanism?
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
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.
The most important regulator of electrolyte concentrations in extracellular fluids is ________.
Which of the following does not act as a second messenger in second-messenger systems of hormone action?
Select the correct statement about the structure or function of chemical messengers.
An amino acid derivative can be a hormone
Which of the following would be associated with the action of steroids on cells?
a hormone-receptor complex that interacts directly with the cell's DNA
Cellular responses to hormones that initiate second-messenger systems include ________.
possible activation of several different second-messenger systems
Which of the following is true about calcium homeostasis?
Parathyroid hormone is the single most important regulator of calcium levels in the blood
In circumstances where the body requires prolonged or increased levels of a hormone, the DNA of target cells will specify the synthesis of more receptors on the surface of the cells of the target organ. This is known as ________.
A man has been told that he is not synthesizing enough follicle-stimulating hormone (FSH), and for this reason he may be unable to father a child. Choose the correct statement to explain this problem.
FSH stimulates sperm production in the testes
Thyroxine is a peptide hormone, but its mechanism is different from other peptide hormones. Which of the following statements is true concerning this difference?
It does not require a second messenger to effect a response
Factors that inhibit TSH release do not include ________.
excessively high blood iodine concentrations
Glucocorticoids enable the body to deal appropriately with stress. They accomplish this by ________.
increasing blood glucose, fatty acid, and amino acid levels and enhancing blood pressure
Chemical substances secreted by cells into the extracellular fluids that regulate the metabolic function of other cells in the body are called ________.