Mastering Biology Chapter 49

When comparing endocrine system feedback inhibition to an analogous thermostat, which would best represent the furnace? A. cell-to-cell signals B. the effector C. the central nervous system D. sensory input

The effector. This acts to restore the balance via alternate inputs.

Which of the following statements about endocrine glands and the hormones they produce is true?

Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.

What hormonal signal is important in the metamorphosis of amphibians? A. increase in thyroid hormones B. a decrease in juvenile hormone C. an increase in ecdysone D. an increase in thyroid hormone and a decrease in juvenile hormone.

An increase in thyroid hormone. This signals metamorphosis in amphibians.

_____ are the main male hormones. A. progesterones B. mineralocorticoids C. androgens D. luteinizing hormones E. estrogens

Androgens. Androgens, such as testosterone, are the main male hormones.

What hormone promotes water retention by the kidneys? A. follicle-stimulating hormone (FSH) B. prolactin C. antidiuretic hormone (ADH) D. melatonin E. glucagon

Antidiuretic hormone (ADH). A diuretic promotes water loss; thus it makes sense that ADH (secreted by the anterior pituitary) promotes water conservation.

Which of the following is an accurate pathway of hormonal release? A. CNS, anterior pituitary, hypothalamus B. CNS, hypothalamus, anterior pituitary C. Anterior pituitary, CNS, hypothalamus D. Hypothalamus, CNS, anterior pituitary

CNS, hypothalamus, anterior pituitary

You are a physician supervising a patient's recovery from the surgical removal of the posterior pituitary. Which of the following symptoms would you expect to have to treat?

Dehydration.

ob/ob mice lack which of the following? A. triglycerides B. a leptin receptor C. cortisol D. leptin

Leptin. ob/ob mice lack this hormone, which is a satiation or "stop eating" hormone, and are obese.

Metamorphosis in frogs is stimulated by which of the following hormones? A. growth hormone B. juvenile hormone C. thyroid hormone D. testosterone

Thyroid hormone. The thyroid hormone triiodothyronine, or T3, is responsible for the changes that occur in frog metamorphosis.

Cortisol secretion is directly stimulated by which of the following hormones? A. corticotropin-releasing hormone (CRH) B. oxytocin C. adrenocorticotropic hormone (ACTH) D. luteinizing hormone

adrenocorticotropic hormone (ACTH). ACTH released by the pituitary gland stimulates release of cortisol in the adrenal gland.

True or false? For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.

false. Only low concentrations of hormones are needed in the bloodstream to activate a signal transduction pathway, which works by producing second messengers inside the cell that amplify the hormonal signal.

What is the role of cAMP in the signal transduction pathway activated by epinephrine? A. it catalyzes the breakdown of glycogen to glucose B. it binds to and activates protein kinase A, which then phosphorylates other enzymes C. It activates adenylyl cyclase D. it binds to the receptor protein on a target cell.

it binds to and activates protein kinase A, which then phosphorylates other enzymes

Which of the following is a structure that allows hormone-receptor complexes to bind to specific DNA sequences? A. hormone-response element (HRE) B. promoter C. zinc finger D. enhancer

zinc finger

Which hormone opposes the action of parathyroid hormone? A. calcitonin B. insulin C. thyroxine D. thymosin E. glucagon

Calcitonin. Parathyroid hormone increases blood calcium levels; calcitonin lowers blood calcium levels.

What would occur if receptors were damaged so that there was no negative feedback after CRH was initially released? A. FSH would be continually released B. ADH would not be released C. ACTH would not be released D. Cortisol would be continually released

Cortisol would be continually released. Cortisol typically signals the stopping of CRH release.

Why might different cells be able to respond to T3 in very different ways? A. they cannot. Specific hormones trigger only specific responses. B. T3 is actually three separate hormones. C. different receptors D. the conformation of T3 is temperature dependent.

Different receptors. The hormone could spark very different processes depending on which receptor is triggered.

Hormones exert what type of cell-to-cell signaling? A. neural B. paracrine C. autocrine D. endocrine

Endocrine. Hormones are endocrine signals; they are carried between cells by blood or other body fluids.

Which of these hormones are responsible for the "fight or flight" response to danger? A. insulin and glucagon B. thyroxine and calcitonin C. androgens and estrogens D. antidiuretic hormone (ADH) and oxytocin E. epinephrine and norepinephrine

Epinephrine and norepinephrine. These hormones, secreted by the adrenal medulla, are responsible for the "fight or flight" response.

The main hormone released in response to short-term stress is _______, and to long-term stress is _______. A. leptin; cortisol B. epinephrine; cortisol C. cortisol; epinephrine D. epinephrine; leptin

Epinephrine; cortisol. Epinephrine triggers an immediate response; cortisol manages a long-term response.

True or false? Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.

False.

Adrenocorticotropic hormone (ACTH) triggers the release of _____ in response to stress. A. melatonin B. insulin C. glucocorticoids D. thymosin E. parathyroid hormone

Glucocorticoids. In response to stress, ACTH stimulates the adrenal cortex to secrete glucocorticoids.

How can a cell respond to more than one hormone? A. it cannot B. by allowing several hormones to bind to the same receptor C. it has different receptors for each hormone D. by responding only to the hormone in the greatest ammount

It has different receptors for each hormone

Why are hormones better suited for regulating sexual development rather than electrical signals alone? A. hormones are very poor in their signaling B. hormones require less energy to produce C. hormones are long-lived and can spread quickly throughout the body. D. hormones convey information more quickly.

Hormones are long-lived and can spread quickly throughout the body. Sexual development requires inputs from tissues and organs throughout the body.

Which of these glands secretes releasing hormones? A. hypothalamus B. adrenal cortex C. thymus D. ovaries E. testes

Hypothalamus. The hypothalamus secretes both releasing and inhibiting hormones

The spring release of hormones in seasonally reproducing animals is stimulated by________. A. increasing photoperiod B. decreased rainfall C. decreasing photoperiod D. warming environmental temperatures

Increasing photoperiod. The lengthening day is sensed by animals' photoreceptors, which send signals to the hypothalamus, where signals are initiated that direct production of sex hormones.

Which hormone stimulates hormone production by the ovaries and testes? A. progesterone B. testosterone C. glucocorticoids D. luteinizing hormone (LH) E. estrogens

Luteinizing hormone (LH). LH stimulates hormone production by both the ovaries and testes.

Which of the following statements about the pituitary gland is false?

Neurosecretory cells produce hormones that are stored in the anterior pituitary.

Where are the adrenal glands located in humans? A. in the brain B. in the neck C. in the pelvic cavity D. on top of the kidneys

On top of the kidneys. One function of the adrenal glands is to increase reabsorption of Na+ by the kidneys.

What accounts for the fact that the hormone estrogen only affects the uterus, hypothalamus, and mammary glands? A. Only the uterus, hypothalamus, and mammary glands have estrogen receptors. B. Estrogen receptors are intracellular. C. Only the uterus, hypothalamus, and mammary glands have estrogen hormone-response elements. D. Estrogen only reaches the uterus, hypothalamus, and mammary glands.

Only the uterus, hypothalamus, and mammary glands have estrogen receptors.

Which hormone stimulates milk production? A. parathyroid hormone B. mineralocorticoids C. prolactin D. thyroid-stimulating hormone (TSH) E. thymosin

Prolactin. Prolactin, secreted by the anterior pituitary, stimulates milk production by the mammary glands.

Which molecules determine the tissue specificity of hormones? A. receptors B. hormone-response elements C. second messengers D. agonists

Receptors

Which type of hormone is lipid soluble? A. steroids B. DNA C. polypeptides D. amino acid derivatives

Steroids

High levels of which of the following two hormones will result in development of a male human? A. testosterone and Müllerian-inhibiting hormone B. estrogen and Müllerian-inhibiting hormone C. testosterone and growth hormone D. testosterone and estrogen

Testosterone and Müllerian-inhibiting hormone. Testosterone induces development of the male reproductive tract; Müllerian-inhibiting hormone inhibits development of the female reproductive tract.

How is the production of hormones such as thyroxine and estrogen regulated?

The hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones.

Negative feedback is defined as ________. A. the release of one hormone is stimulated by another hormone B. the release of one hormone is inhibited by another hormone C. the product of a process inhibits its production D. the product of a process stimulates its production

The product of a process inhibits its production. The inhibition element illustrates why the process is considered "negative" feedback.

Which of the following statements about lipid-soluble hormones is true? A. they bind to DNA as soon as they enter the cell B. they bind to receptors on the plasma membrane C. they act by affecting the transcription of genes D. they act by producing second messengers

They act by affecting the transcription of genes

How does a polypeptide hormone compare in its mode of action from a steroid that binds to a cell-surface receptor? A. Polypeptide hormones do not operate via signal transduction. B. Polypeptide hormones are lipid soluble and therefore penetrate the cell easily. C. They are both similar in mode of action. D. Polypeptide hormones do not utilize a second messenger.

They are both similar in mode of action.

What is the function of endocrine glands?

They release hormones into the bloodstream for distribution around the body.

Why is the observation that one hormone may bind to more than one type of receptor important?

This is one reason that the same hormone can trigger different effects in different tissues.

In experiments where researchers suspect that a hormone may be responsible for a certain physiological effect, they may cut the neurons leading to the organ where the effect being studied occurs. What is the purpose of cutting these neurons? B. to impair the normal functions of the organ so that the hormonal effect can be more easily studied C. to make sure that the effect is not occurring through actions in the nervous system D. to make sure that the organ being affected cannot function unless the researchers stimulate it with an external electrical probe

To make sure that the effect is not occurring through actions in the nervous system.

True or false? The homeostatic system for blood calcium concentration is maintained by the hormones calcitonin and parathyroid hormone.

True

True or false? The pancreas is responsible for producing hormones that maintain the homeostatic levels of glucose in the blood.

True