The endocrine system relies on __________ that __________ all of the cells of the body.
hormones; reach (remember that only target cells have receptors for them) -Slide 1
A cell releases a cytokine, which binds to and acts on a neighboring cell. This represents an example of __________.
Which of the following examples is a true statement about the differences between hormones and neurotransmitters?
Neurotransmitters are secreted chemicals that diffuse a short distance, whereas hormones travel through the bloodstream to the target cell.
Which is an accurate statement regarding the difference between steroid and nonsteroid hormones?
Steroid hormones are lipids; nonsteroid hormones are made from one or more amino acids.
Because most chemical signals are unable to pass through the plasma membrane, the cellular action they initiate results from __________.
the activation of a signal transduction pathway
What is the role of a second messenger in hormone action?
It relays a hormone's message inside a target cell. (Most hormones are unable to cross plasma membranes. After binding to a surface receptor, a transduction event may result in the production of a second messenger within the cell.)
What result would you expect following the binding of epinephrine to an ?-type epinephrine receptor?
Blood flow to the intestines decreases.
Which of the following hormones is thought to act at the cellular level by inducing a change in gene expression?
Estrogen (Sex hormones such as estrogen are steroid hormones that can cross the plasma membrane and bind to receptors in the cytoplasm. The hormone-receptor complex has the proper conformation to bind to certain sites on DNA.)
Which of the following examples is a role of the local regulator nitric oxide (NO)?
When oxygen levels fall, nitric oxide activates an enzyme that relaxes smooth muscle. This dilates blood vessels and improves blood flow.
Ibuprofen is known for its pain-relieving and anti-inflammatory properties because it inhibits the synthesis of __________.
Which of the following conditions in a silkworm moth would result in metamorphosis from pupa to adult?
Low concentration of juvenile hormone and high concentration of ecdysteroid (Juvenile hormone promotes the retention of larval characteristics. When levels of juvenile hormone are low, ecdysteroid will stimulate formation of the pupal form and subsequent
In insects, ecdysteroid is released __________.
in response to prothoracicotropic hormone
Which of the following hormones have antagonistic effects?
Insulin and glucagon (These hormones decrease and increase blood sugar, respectively. It is important to note, however, that the mechanisms responsible for the effects are not opposite to one another.)
The major tropic action of growth hormone is to signal the __________ to release __________.
liver; insulin-like growth factors (IGFs)
How is the level of thyroxine in the blood regulated?
High levels of T3 and T4 inhibit the secretion of TRH and TSH
Hyperthyroidism, typically characterized by a high metabolic rate and high blood pressure, might be expected when __________.
thyroid-stimulating hormone (TSH) concentration is high
A goiter may form because __________.
low blood levels of T3 and T4 inhibit the negative feedback loop and an overload of TSH causes enlargement of the gland
Which of the following endocrine organs only stores hormones produced by the hypothalamus?
As a young girl, Maria suffered a head injury that damaged her pituitary. An injury to the pituitary is particularly serious because of all the functions controlled by this gland. As Maria got older, she and her doctors found that all of the following exc
blood sugar level
A doctor might give an expectant mother __________ to stimulate uterine contractions and induce labor. (Hint - same thing the professor says stimulates additional mammalian milk production)
The regulation of water volume in the blood involves which hormone?
Antidiuretic hormone (ADH) is secreted by the posterior pituitary and acts on the kidneys, increasing water retention and thus decreasing urine volume.
How does the hypothalamus control the secretion of growth hormone (GH) from the anterior pituitary?
The hypothalamus produces a releasing hormone that stimulates the pituitary to secrete GH.
Which of the following is a neurohormone secreted by the posterior pituitary?
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are tropic hormones that are also known as __________.
gonadotropins (FSH and LH are called gonadotropins because they stimulate the activities of male and female gonads: the testes and ovaries.)
Which of the following hormones specifically act(s) to trigger secretion of hormones by another endocrine gland?
Adrenocorticotropic hormone (ACTH)
Which is a correct statement about prolactin?
It controls fat metabolism and reproduction in birds
The mammary glands of a pregnant female will begin to produce milk in response to changes in the level of which of the following hormones?
Prolactin (Prolactin, produced by the anterior pituitary, stimulates milk production.)
Which is a correct statement about the thyroid gland?
Thyroid hormones trigger the change of an aquatic tadpole into a terrestrial bullfrog.
How does parathyroid hormone affect levels of Ca2+ in the blood?
When Ca2+ levels fall, PTH stimulates bone cells to decompose the matrix of bone and stimulates reabsorption of Ca2+ in the renal tubules.
Which of the following statements about the catecholamines secreted by the adrenal medulla is correct?
Epinephrine and norepinephrine are catecholamines.
Which of the following statements about the adrenal medulla is correct?
The gland is stimulated by nerve signals carried from the brain.
Which of the following endocrine glands releases steroid hormones?
Which of the following is a problem with the long-term use of glucocorticoids, such as cortisone, to treat inflammation?
Suppression of the immune system
Anabolic steroids, sometimes taken illegally by athletes and bodybuilders, are chemically related to natural __________ produced in the __________.
androgens; gonads (Anabolic steroids are synthetic androgens that are similar to hormones produced by the adrenal cortex and gonads. Taking these steroids interferes with natural negative feedback mechanisms.)
In the winter, the __________ of vertebrates is apt to produce __________ than in summer months.
pineal gland; more melatonin
Communication between animal cells through secreted signals can be classified by two criteria
The type of secreting cell, the route taken by the signal in reaching its target.
When hormones are secreted into extracellular fluids endocrine cells - how do they reach their targets?
Endocrine signaling helps the body to ________________, _______________, _____________, _____________
maintains homeostasis, mediates responses to stimuli, regulates growth and development, triggers changes underlying sexual maturity and reproduction.