Chapter 16 Mastering (my questions)
Hypersecretion of what hormone can produce the effects of gigantism? growth hormone (GH) thyroid hormones (TH) aldosterone thyroid-stimulating hormone (TSH)
growth hormone (GH) Growth hormone has effects on metabolism as well as growth. Hypersecretion can lead to gigantism.
What is the role of activated protein kinases? Convert ATP to cAMP by phosphorylation. Activate adenylate cyclase. Degrade cAMP to AMP. Phosphorylate proteins. Phosphorylate ADP to ATP.
Phosphorylate proteins. Phosphorylation can activate different proteins causing the response of the cell to water-soluble hormone.
Which hormone stimulates mammary glands to produce milk in nursing mothers? prolactin follicle-stimulating hormone adrenocorticotropic hormone oxytocin
Prolactin Prolactin stimulates the mammary glands of the nursing mother to produce milk. After birth, the infant's suckling stimulates release of prolactin-releasing factors in the mother, encouraging continued milk production.
What area of the brain is designated by letter A? pineal gland thalamus limbic system hypothalamus
hypothalamus The hypothalamus contains nuclei that produce hormones that travel down neurons and are then secreted into the blood in the pituitary gland.
Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized? kidney hypothalamus posterior pituitary anterior pituitary
hypothalamus ADH is synthesized mainly in the supraoptic nucleus of the hypothalamus. It is stored in the posterior pituitary in axon terminals.
Where is thyrotropin-releasing hormone (TRH) made? anterior pituitary follicular cells of the thyroid gland hypothalamus posterior pituitary
hypothalamus The hypothalamus regulates the release of several hormones by producing releasing and inhibitory hormones, including thyrotropin-releasing hormone (TRH).
Cyclic AMP is degraded by __________. G proteins phosphodiesterase AMP protein kinase adenylate cyclase
phosphodiesterase Phosphodiesterase degrades cyclic AMP into AMP.
Water-soluble hormones affect target cells by binding to: protein kinases cAMP adenylate cyclase plasma membrane receptors cytoplasmic receptors
plasma membrane receptors Water-soluble hormones bind to specific receptors in the plasma membrane, whereas steroid hormones bind to cytoplasmic receptors inside the cell.
Which of the following triggers the release of glucagon? hyperglycemia prolonged fasting release of somatostatin release of insulin
prolonged fasting Glucagon acts to stimulate release of glucose into the blood to counteract falling levels.
Pheochromocytoma produces symptoms of uncontrolled sympathetic nervous system activity. Which of the following is common to both adrenal chromaffin cells and adrenergic fibers of the sympathetic nervous system? the presence of axons capable of secreting substances that are capable of increasing heart rate secretion of epinephrine secretion of norepinephrine All of the listed responses are correct.
secretion of norepinephrine Adrenal chromaffin cells are capable of releasing the hormones epinephrine and norepinephrine into the systemic circulation. Post-ganglionic neurons of the symphathetic nervous system also release norepinephrine.
What unusual amino acid-based hormone uses the direct gene activation method illustrated in this image? mineralocorticoids thyroxine glucocorticoids growth hormone
thyroxine Thyroxine is an unusual amino acid-based hormone that, unlike other peptide hormones, uses the direct gene activation method. Since thyroxine is water-soluble, it is transported into the cell by a membrane carrier protein, unlike the hormone seen here.
The various hormones secreted by the anterior pituitary that regulate the secretion of hormones from other endocrine organs are called __________. steroids tropins statins amines
tropins Four of the six anterior pituitary hormones—thyroid-stimulating hormone (thyrotropin), adrenocorticotropic hormone (corticotropin), follicle-stimulating hormone and luteinizing hormone (gonadotropins)—are tropins (tropic hormones) that regulate the secretory action of other endocrine glands.
Which of the following pairs correctly matches the adrenal gland structure with the class of hormones it produces? zona reticularis: aldosterone zona fasciculata: catecholemines medulla: glucocorticoids zona glomerulosa: mineralocorticoids
zona glomerulosa: mineralocorticoids The zona glomerulosa produces mineralocorticoids
Which of these conditions would promote aldosterone release from the adrenal glands? A drop in blood pressure is sensed in the kidney. Blood potassium levels fall. The body becomes parasympathetically activated. An increase in blood pressure is sensed in the heart.
A drop in blood pressure is sensed in the kidney. A drop in blood pressure would cause the kidney to release renin, a hormone that will eventually promote the release of aldosterone from the zona glomerulosa of the adrenal cortex.
Which of these would be an effect of an excess of thyroid hormones? More thyroid hormone would be produced. A would release less TRH. B would release more TSH. The thyroid would swell and produce a goiter.
A would release less TRH. Excess thyroid hormone would have an inhibitory effect on A. This is a negative feedback mechanism.
What hormone, indicated by letter B, is released by the anterior pituitary to target the adrenal cortex when the body is under stress? corticotropin-releasing hormone (CRH) angiotensin II adrenocorticotropic hormone (ACTH) atrial natriuretic peptide (ANP)
Adrenocorticotropic hormone (ACTH) from the pituitary modulates the release of aldosterone. The term tropic refers to a hormone that acts on another endocrine gland.
Hypocalcemia could be caused by the ______. apoptosis of parathyroid cells failure of osteoclasts to respond to PTH (parathyroid hormone/parathormone) malfunction of the parathormone receptors in kidney tubule cells All of the listed responses are correct.
All of the listed responses are correct. Parathyroid hormone (parathormone) is secreted in response to hypocalcemia. It functions to stimulate osteoclast activity, enhances the reabsorption of calcium by the kidneys, and increases absorption of calcium ions by the intestinal mucosal cells.
At which point has the hormone bound to its intracellular receptor but not yet entered the nucleus?
B The receptor-hormone complex has formed and is about to enter the nucleus.
Which of these glands is responsible for regulating minerals in the body but is also part of the sympathetic division of the autonomic nervous system?
C The adrenal glands have a medulla that contains postganglionic neurons of the sympathetic division of the autonomic nervous system. Its cortex helps regulates mineral levels in the body, along with other functions.
Where are the hormones oxytocin and antidiuretic hormone (ADH) stored?
C The axon terminals of neurons of the hypothalamic-hypophyseal tracts store and secrete ADH and oxytocin in the capillaries of the inferior hypophyseal artery.
How do endocrine hormones reach their target cells? Hormones travel through the lymphatic system to target cells. Ducts transport hormones directly to target cells. Hormones are produced by endocrine cells that are adjacent to target cells. Hormones are transported through the blood stream to target cells. Hormones are released at synapses adjacent to target cells.
Hormones are transported through the blood stream to target cells. The blood stream allows hormones to be distributed throughout the body.
Damage of which of the following brain structures could cause central diabetes insipidus? Hypothalamus Cerebrum Thymus Pons
Hypothalamus
What is the mechanism of action of lipid-soluble hormones? phosphorylation of intracellular proteins increasing protein kinases activation of genes, which increases protein synthesis in the cell
activation of genes, which increases protein synthesis in the cell lipid-soluble hormones diffuse into the nucleus or they diffuse into the cytoplasm and then move into the nucleus, where they affect transcription and translation.
After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do? directly alters protein synthesis at the ribosome acts as a transcription factor and binds to DNA, activating a gene phosphorylates a protein activates a protein kinase
acts as a transcription factor and binds to DNA, activating a gene (which then initiates synthesis of mRNA)
What tropic hormone stimulates cortisol from the adrenal gland? adrenocorticotropic hormone (ACTH) luteinizing hormone (LH) and follicle stimulating hormone (FSH) growth hormone (GH) thyroid stimulating hormone (TSH)
adrenocorticotropic hormone (ACTH) ACTH stimulates the adrenal cortex to produce cortisol. Stress and ACTH are the main stimuli for cortisol.
What gland secretes growth hormone? posterior pituitary adrenal cortex thyroid gland anterior pituitary
anterior pituitary
Which hormone aids in water resorption? parathyroid hormone antidiuretic hormone adrenocorticotropic hormone thyroid hormone
antidiuretic hormone Antidiuretic hormone (ADH) stimulates the kidney tubules to reabsorb water.
What hormone released into the blood by the posterior pituitary would reduce the amount of urine that is formed? cortisol oxytocin thyroid-stimulating hormone (TSH) antidiuretic hormone (ADH)
antidiuretic hormone (ADH) Antidiuretic hormone (ADH) targets the kidneys and modulates how much water is lost in the urine.
The amplification of the signal from a water-soluble hormone is achieved through an increase in: adenylate cyclase in the plasma membrane phosphodiesterase in the cytoplasm cAMP in the cytoplasm water-soluble hormone in the blood plasma membrane receptors
cAMP in the cytoplasm Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.
What is the target of thyroid hormones? cells of the body anterior pituitary hypothalamus thyroid
cells of the body Thyroid hormones secreted by the thyroid gland target cells of the body to modulate metabolism.
What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor? chaperone proteins (chaperonins) Receptors can't enter the nucleus until the hormone is bound to it. transcription factors
chaperone proteins (chaperonins) each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site.
What is the function of the ventral hypothalamic neurons? control secretion of oxytocin control secretion of thyroid stimulating hormone (TSH) control secretion of antidiuretic hormone (ADH) control secretion of thyroid hormones
control secretion of thyroid stimulating hormone (TSH) neurohormones from the ventral hypothalamic neurons, known as releasing (RH) and inhibiting (IH) hormones, control the release of anterior pituitary hormones such as adrenocorticotropic hormone (ACTH) and TSH.
Which of the following hormones has intracellular receptors? insulin epinephrine cortisol
cortisol cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble. Lipid soluble hormones work on intracellular receptors.
What type of cell is shown at letter C? parathyroid cells parafollicular cells follicular cells beta cells
follicular cells Follicular cells of the thyroid line the follicles and manufacture the materials within them.
Which letter represents the hormone that promotes a decrease in blood pressure and increases the excretion of sodium and water in urine?
D The letter D indicates atrial natriuretic peptide, which is released from the heart when high blood pressure is sensed. It causes more sodium ("natrium") to be placed in the urine ("uretic").
Up-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels. True or false
False Prolonged exposure to high hormone concentrations would result in down-regulation (not up-regulation), which involves a decrease in the number of receptors for that hormone. Down-regulation desensitizes the target cells, so they respond less vigorously to hormonal stimulation, preventing them from overreacting to persistently high hormone levels.
Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones? thyroid hormones oxytocin prolactin (PRL) GH (growth hormone)
GH (growth hormone) GH stimulates IGFs (insulin like growth factors) from the liver. IGFs are required for the growth effect of GH on bone and skin.
If a person's parathyroids are responding properly to a drop in blood calcium, which of the following should result? Vitamin D levels in the blood will drop. Bone mass and density will increase. Less calcium will be excreted in the urine by the kidneys. More calcium will be present in feces.
Less calcium will be excreted in the urine by the kidneys. The kidneys would be encouraged by PTH to retain more calcium, which would result is less calcium in the urine.
Where is the pancreas located?
The pancreas occupies a retroperitoneal position partially behind the stomach.
What type of stimulation controls parathyroid release? hormonal neural paracrine humoral
humoral The parathyroid is stimulated by the actual level of calcium in the blood rather than by neural or hormonal stimulus.
A blow to the head may cause diabetes insipidus by ______. triggering the hypersecretion of hypothalamic-inhibiting hormones triggering the hyposecretion of hypothalamic-inhibiting hormones interfering with the normal transmission of nerve impulses to the posterior pituitary interfering with the normal transmission of nerve impulses from the posterior pituitary
interfering with the normal transmission of nerve impulses to the posterior pituitary Specialized neurons called neurosecretory cells produce anti-diuretic hormone in the paraventricular nuclei of the hypothalamus. This hormone is then transported down the axons of these neurons and stored in their axon terminals, which are located in the posterior pituitary. The hormone is released from the axon endings when associated neurons fire action potentials, and it passes down the axon to the axonal terminals.
What material is stored in the lumen of the thyroid follicle? thyroid hormones T3 and T4, ready to be immediately released iodinated thyroglobulin, from which thyroid hormone can be produced pure iodine, so the thyroid has a constant supply enzymes that produce thyroglobulin
iodinated thyroglobulin, from which thyroid hormone can be produced Follicular cells prepare thyroglobulin, which is released and bound with iodine in the follicle. This material is stored in the follicle until thyroid hormone is needed by the body.
What property of a hormone would allow it to pass unassisted through a plasma membrane? bound to a protein complex charged protein-based lipid-soluble
lipid-soluble Hormones that are lipid-soluble can dissolve through the plasma membrane.
What is the most important regulatory factor controlling the circulating levels of thyroid hormone? thyroid-stimulating hormone (TSH) a circadian rhythm of release negative feedback thyrotropin-releasing hormone (TRH)
negative feedback negative feedback controls the levels of circulating thyroid hormone. If levels are high, negative feedback will decrease thyroid-stimulating hormone (TSH) (and thyrotropin-releasing hormone (TRH) to some degree), thus decreasing the thyroid hormones.
Which of the following hormones is regulated by a neuroendocrine ("letdown") reflex? oxytocin cortisol antidiuretic hormone (ADH)
oxytocin Yes, suckling of the infant (or stretching of the uterus) increases release of oxytocin, which causes the milk let-down effect (or increased uterine contractions).
Which gland secretes the most important hormone controlling calcium balance in the blood? thyroid parathyroid adrenal thymus
parathyroid Parathyroid hormone (PTH) is the single most important hormone controlling calcium balance in the blood. Falling blood Ca2+ levels trigger PTH release, and rising blood Ca2+ levels inhibit its release. PTH promotes bone resorption to release Ca2+ into the blood, inhibits excretion of Ca2+ in the urine, and stimulates the synthesis of Calcitriol, which in turn increases absorption of Ca2+ from our diet.
All of the following conditions would stimulate the pancreas to release insulin EXCEPT one. Which one? acetylcholine release on the pancreatic cells a rise in blood amino acid levels sympathetic activation a rise in blood glucose levels
sympathetic activation Sympathetic activation is designed to increase blood glucose levels, so it inhibits the release of insulin.
Which of the following occurs in situations where different hormones produce the same effects at the same target cell and their combined effects are amplified? permissiveness synergism summation antagonism
synergism Synergism occurs when more than one hormone produces the same effects at the target cell and their combined effects are amplified. For example, let's say both hormone "A" and hormone "B" cause the liver to release glucose into the blood. When they act together, the amount of glucose released might be 150% of what is released if each hormone acts independently.
Which of the following best describes gluconeogenesis? conversion of glucose to fat breakdown of glycogen into glucose synthesis of glucose from noncarbohydrate sources creation of glycogen from glucose
synthesis of glucose from noncarbohydrate sources The term genesis means "to create," and neo means "new," so this term literally means "to create new sugar."
Which hormone's receptor is always bound to DNA, even when the receptor is empty? cortisol thyroid hormone insulin
thyroid hormone thyroid hormones are lipid soluble and their receptors are bound to the response elements of the DNA.
