What are endocrine glands? Ductless glands that secrete hormones into intracellular spacesWhat is a target organ cell? A cell that has receptors for a specific hormone
What are the two major classes of hormones? Nonsteroid and steroid hormonesWhat is a second messenger mechanism? Chemical that provides communication within a hormone’s target cellWhat are steroid hormones? Hormones that can pass through the target cell’s membrane to the nucleus where they bind with a receptor to form a hormone-receptor complexGive an example of a steroid hormone. Estrogen
Give an example of positive feedback. During labor, muscle contractions become stronger by means of a positive feedback mechanism that regulates the secretion of oxytocin.Give an example of negative feedback. Insulin
What is the name of a physician who specializes in endocrine disorders? EndocrinologistWhat are some diseases caused by hypersecretion of a hormone? Hypoglycemia, Graves disease, gigantism, water retention, Cushing syndromeWhat are some diseases caused by hyposecretion of a hormone? Goiter, cretinism, dwarfism, diabetes insipidus, Addison disease, myxedema
Do prostaglandins meet the definition of a typical hormone? NoHow do prostaglandins differ from most hormones? Prostaglandins only influence the activities of neighboring cells.What research is being conducted with prostaglandins? The role of prostaglandins in the treatment of high blood pressure, asthma, and ulcers
Why is the anterior pituitary gland sometimes called the master gland? It controls the thyroid gland, the adrenal cortex, the ovarian follicles, and the corpus luteum.What do the major hormones do? ACTH stimulates the adrenal cortex, causing it to increase in size and secrete larger amounts of its hormones.See Table 11-1.
How do growth hormones promote normal growth? They speed up the movement of amino acids out of the blood and into the cells, which accelerates the cells’ anabolism of amino acids to form tissue proteins.
What does the hyposecretion of ADH cause? Diabetes insipidusHow are dehydration and electrolyte imbalances treated? With injections or nasal sprays containing ADH
In addition to oxytocin and ADH, what substances does the hypothalamus produce? Releasing and inhibiting hormones that travel to the anterior pituitary glandThe hypothalamus regulates many body functions related to homeostasis. Give some examples. Body temperature, appetite, and thirst
How do T3 and T4 influence body cells? They speed up their release of energy from foods.How does calcitonin help maintain homeostasis of blood calcium? It decreases blood calcium concentrations.Where is the thyroid located? In the neck just below the larynxPlace thumb and forefinger on each side of the trachea and swallow. The part you feel that goes up and down is the thyroid.
How does PTH increase calcium? It stimulates bone-resorbing cells to increase their breakdown of bone’s hard matrix, which frees the calcium stored there.
Where is the adrenal gland? It curves over the top of each kidney.What are hormones secreted by the adrenal cortex called? CorticoidsWhat are the adrenal cortex and the adrenal medulla? The adrenal cortex is the outer part of an adrenal gland; the medullais its inner part.What is the chief mineralocorticoid? AldosteroneWhat does aldosterone do? Increases the amount of sodium and decreases potassium in the blood.
Secretion of glucocorticoid quickly increases when the body is under stress.
During periods of prolonged stress, glucocorticoids may have harmful side effects because they are anti-inflammatory and cause blood vessels to constrict.
How do endocrine glands differ from pancreatic islets? Endocrine glands are much larger than pancreatic islets.
What happens if the pancreatic islets don’t secrete enough insulin? Blood glucose increases: hyperglycemia.
How are most screening tests for diabetes mellitus done? With a drop of bloodTesting for sugar in the urine is another common screening procedure.
The cells of the testes produce what? SpermThe interstitial cells in the testes secrete what male sex hormone directly into the blood? Testosterone
Where is the thymus located? In the mediastinum
These hormones maintain the corpus luteum during pregnancy.What fact led to the development of the early pregnancy test? During the earliest weeks of pregnancy the kidneys excrete chorionic gonadotropins into the urine.
Why is this gland named “pineal”? Because it resembles a pine nut.
Nearly every organ and system has an endocrine function.