Mastering A&P 2 CH 16 HW

Part complete Under normal conditions, increased levels of thyroid hormone in the blood will cause _______. -an increase in TSH levels -a decrease in TSH levels -an increase in thyrotropin releasing hormone (TRH) -no change in TSH levels

-a decrease in TSH levels Correct Increased thyroid hormone levels will inhibit the release of TSH from the pituitary.

What cells in the body respond to glucagon by breaking down glycogen and releasing glucose? -liver cells and cells in the pancreas -muscle cells -intestinal cells -liver cells -cells in the pancreas

-liver cells

All of the following conditions would stimulate the pancreas to release insulin EXCEPT one. Which one? -a rise in blood glucose levels -a rise in blood amino acid levels -acetylcholine release on the pancreatic cells -sympathetic activation

-sympathetic activation Correct Sympathetic activation is designed to increase blood glucose levels, so it inhibits the release of insulin.

A liver cell responds to insulin by -releasing insulin -breaking down glycogen and releasing glucose -taking in glucose and converting it to glycogen -releasing glucagon

-taking in glucose and converting it to glycogen

Growth factor hormones, such as insulin, bind to which type of receptor? -tyrosine kinase receptors -intracellular receptors -G proteins

-tyrosine kinase receptors Correct Yes, insulin binds to tyrosine kinase receptors and works without a second messenger.

Most water-soluble hormones exert their effects through the second messenger cyclic AMP (cAMP). This activity will test your understanding of the events that occur during cAMP signaling. Drag the events of cAMP signaling in the correct sequence from left to right.

1. Water-soluble hormone binds receptors 2. Receptor activates G protein 3. G protein activates adenylate cyclase 4. Adenylate cyclase generates cAMP 5. cAMP activates protein kinases Correct Activated protein kinases can then phosphorylate a variety of intracellular proteins to elicit the cell's response to the hormone.

Drag and drop the items below into the correct sequence from left to right.

1st Step: Hypothalamus secretes corticotropin-releasing hormone 2nd Step: Corticotropin-releasing hormone travels through the portal system to the anterior pituitary 3rd Step: Adrenocorticotropic hormone is secreted from the anterior pituitary 4th Step: ACTH travels in the blood to the adrenal cortex 5th Step: Glucocorticoids and mineralocorticoids are secreted 6th Step: Target cells produce metabolic and renal effects Correct In the long-term stress response, stressful stimuli cause the hypothalamus to release corticotropin-releasing hormone, or CRH. CRH then travels through the hypothalamic portal system to the anterior lobe of the pituitary gland. The anterior pituitary releases adrenocorticotropic hormone, or ACTH, which travels via the blood to the adrenal gland. The adrenal cortex is the specific target for ACTH, which produces more glucocorticoids, chiefly cortisol, and mineralocorticoids, namely aldosterone. As you have seen, glucocorticoids have pronounced metabolic effects on the liver, while the mineralocorticoids target the kidney to retain more water and sodium, resulting in increased blood pressure and blood volume.

Drag and drop the items below to the appropriate bin, depending if the item is associated with the short-term or long-term stress response.

Short-term stress response -activated by neural stimuli -hormone released; epinephrine -triggers the fight-or-flight response -targets the adrenal medulla Long-Term Stress Response -activated by hormonal stimuli -targets the adrenal cortex -hormone released; glucocorticoids -increased blood pressure; increased protein and fat catabolism Correct The long-term and short-term stress responses vary in their mechanisms: in the short-term response, stressful stimuli target the hypothalamus, which activates the sympathetic nervous system, ultimately impacting the adrenal medulla. The adrenal medulla releases the catecholamine hormones - epinephrine and norepinephrine - which result in many of the effects associated with the "fight or flight" mechanism. In the long-term response, stressors to the hypothalamus cause the release of corticotropin-releasing hormone, which targets the anterior pituitary gland. Adrenocorticotropic hormone travels in the blood and targets the adrenal cortex, resulting in the production of mineralocorticoids and glucocorticoids. The mineralocorticoids impact the kidney with increased sodium and water retention, while the glucocorticoids target the liver to increase production of glucose from fats and proteins, or mobilize them for energy.

When blood glucose levels are low -The pancreas releases insulin, which eventually causes blood glucose levels to increase. -The pancreas releases glucagon, which eventually causes blood glucose levels to increase. Liver cells convert more glucose to glycogen. -The pancreas releases glucagon, which eventually causes blood glucose levels to decrease. -The pancreas releases insulin, which eventually causes blood glucose levels to decrease.

The pancreas releases glucagon, which eventually causes blood glucose levels to increase.

Which of the cell types would secrete their product if the blood glucose level was rising, as during the digestion of a meal? -alpha cells -beta cells -pancreatic acinar cells

-beta cells Correct Beta cells secrete when the blood sugar rises. Their hormone allows body cells to take up glucose from the blood.

Which of the following adrenergic receptors increase cAMP levels? α2 receptors α1 receptors β receptors

β receptors Correct Yes, these receptors are coupled to adenylate cyclase by Gs receptors that increase cAMP.

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 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.

How do endocrine hormones reach their target cells? -Hormones are released at synapses adjacent to target cells. -Hormones are transported through the bloodstream to target cells. -Ducts transport hormones directly to target cells. -Hormones travel through the lymphatic system to target cells. -Hormones are produced by endocrine cells that are adjacent to target cells.

-Hormones are transported through the bloodstream to target cells Correct The bloodstream allows hormones to be distributed throughout the body.

Krista's treatment will likely involve destroying or surgically removing her thyroid gland. What effect will this have on her level of TSH? -TSH will increase -it will have no effect because TSH is not secreted by the thyroid -TSH will decrease

-TSH will increase Correct Destroying or removing the thyroid gland will cause thyroid hormone levels to plummet. This will cause an increase in the secretion of TSH from the pituitary.

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor? -Receptors can't enter the nucleus until the hormone is bound to it. -transcription factors -chaperone proteins (chaperonins)

-chaperone proteins (chaperonins) Correct Yes, each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site.

The body's tendency to maintain relatively constant internal conditions is called -homeostasis -positive feedback -diabetes -negative feedback -none of the above

-homeostasis

Acromegaly may be caused by all EXCEPT which of the following? -hypersecretion of GHRH (growth hormone-releasing hormone_ -pancreatic tumor -lack of negative feedback by insulin-like growth factors -hyposecretion of GH in adulthood

-hyposecretion of GH in adulthood Correct Acromegaly is a disorder resulting from excessive GH secretion after epiphyseal plates have closed. There are usually no adverse effects of GH hyposecretion in adults. However, GH hyposecretion in children slows the growth of long bones and, unless treated, results in pituitary dwarfism. Growth hormone secretion is stimulated by GHRH (growth hormone-releasing hormone).

Where is thyrotropin-releasing (TRH) made? -follicular cells of the thyroid gland -posterior pituitary -hypothalamus -anterior pituitary

-hypothalamus Correct The hypothalamus regulates the release of several hormones by producing releasing and inhibitory hormones, including thyrotropin-releasing hormone (TRH).

If a person's parathyroids are responding properly to a drop in blood calcium, which of the following should result? -bone mass and density will increase -Vitamin D levels in the blood will drop -more calcium will be present in feces -less calcium will be excreted in the urine by the kidneys

-less calcium will be excreted in the urine by the kidneys Correct The kidneys would be encouraged by PTH to retain more calcium, which would result is less calcium in the urine.

When blood glucose levels are high -the pancreas releases insulin -the pancreas releases glucagon -the pancreas releases glucose -the liver releases insulin -the liver releases glucagon

-the pancreas releases insulin Correct The pancreas responds to high blood glucose levels by releasing insulin.

Which hormone's receptor is always bound to DNA, even when the receptor is empty? -thyroid hormone -cortisol -insulin

-thyroid hormone Correct Yes, thyroid hormones are lipid soluble and their receptors are bound to the response elements of the DNA.

Which second messenger causes the release of calcium from the endoplasmic reticulum? -cAMP -DAG -IP3 -tyrosine kinase

-IP3 Correct Yes, inositol trisphosphate releases calcium from intracellular storage sites

What is the target of thyroid hormones? -hypothalamus -anterior pituitary -thyroid -cells of the body

-cells of the body Correct Thyroid hormones secreted by the thyroid gland target cells of the body to modulate metabolism.

Your patient has been diagnosed with Type I diabetes mellitus, and you are explaining how to administer insulin. Your patient states, "I don't want to do this. My brother-in-law has diabetes, and he just takes a pill and watches what he eats." What is your best response? -"Perhaps you can switch to pills and a special diet once your diabetes is under control." -"Great. Maybe your relative can give you some tips on how to manage your condition." -"I'll ask the doctor if you can try an oral pill and a low carbohydrate diet before using insulin." -"Your relative may have Type II diabetes. People with that condition can make insulin, but their cells don't respond to it properly. Your pancreas doesn't manufacture insulin"

-"Your relative may have Type II diabetes. People with that condition can make insulin, but their cells dont respond to it properly. Your pancreas doesn't manufacture insulin" Correct A simple explanation of the differences between Type I and Type II diabetes may help your patient to understand the importance of the prescribed insulin regimen.

Which of these would be an effect of an excess of thyroid hormones? -the thyroid would swell and produce a goiter -a would release less TRH -More thyroid hormone would be produced -B would release more TSH

-A would release less TRH Correct Excess thyroid hormone would have an inhibitory effect on A. This is a negative feedback mechanism.

Part complete Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones? -thyroid hormones -GH (growth hormone) -oxytocin -prolactin (PRL)

-GH (growth hormone) Correct Yes, GH stimulates IGFs from the liver. IGFs are required for the growth effect of GH on bone and skin.

Which of the following enzymes are important in the deactivation of cAMP and termination of signaling? -G Protein -Protein Kinase -Adenylate Cyclase -Phosphodiesterase

-Phosphodiesterase Correct The increase in cAMP levels is usually short-lived because the enzyme phosphodiesterase is constantly present in the cytoplasm of the target cells.

Which of the following would result from hypoparathyroidism? -a decrease in the release of calcium from bones -an increase in calcium absorption from food -an increase in calcium ion in circulating blood -an increase in calcium absorption in the kidney tubule

-a decrease in the release of calcium from bones Correct Hypoparathyroidism leads to reduced osteoclast activity in bones. The resulting lack of calcium in the blood increases excitability of neurons and muscles, producing tingling sensations.

Which is the correct order of events for hormones activating Gs proteins? -activation of a G protein, tyrosine kinase receptor, phosphorylation of intracellular proteins -activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP -activation of G protein, binding of GTP, activation of phospholipase C, activation of DAG and IP

-activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP Correct Yes, Gs proteins are stimulatory proteins that activate cAMP.

What is the mechanism of action of lipid-soluble hormones? -increasing protein kinases -activation of genes, which increases protein synthesis in the cell -phosphorylation of intracellular proteins

-activation of genes, which increases protein synthesis in the cell Correct Yes, 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 -activates a protein kinase -phosphorylates a protein

-acts as transcription factor and binds to DNA, activating a gene Correct Yes, then mRNA is synthesized.

Where is the thyroid gland located? -at the base of the brain near the hypothalamus -posterior to the sternum in the thoracic cavity -adjacent to the trachea in the neck -posterior to the parathyroid glands in the neck

-adjacent to the trachea in the neck Correct The thyroid is a butterfly or H-shaped gland in the anterior region of the neck just inferior to the larynx, with the lobes extending to each side of the trachea.

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) Correct Yes, ACTH stimulates the adrenal cortex to produce cortisol. Stress and ACTH are the main stimuli for cortisol.

The amplification of the signal from a water-soluble hormone is achieved through an increase in _______. -plasma membrane receptors -water-soluble hormone in the blood -cAMP in the cytoplasm -adenylate cyclase in the plasma membrane -phosphodiesterase in the cytoplasm

-cAMP in the cytoplasm Correct Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.

What is the function of the ventral hypothalamic neurons? -control secretion of oxytocin -control secretion of thyroid hormones -control secretion of thyroid stimulating hormone (TSH) -control secretion of antidiuretic hormone (ADH)

-control secretion of thyroid stimulating hormone (TSH) Correct Yes, 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? -epinephrine -insulin -cortisol

-cortisol Correct Yes, cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble.

Suppose Krista's hyperthyroidism was a result of a tumor that causes the anterior pituitary gland to become overactive. Which of the following would Krista's lab reports likely show? -low thyroid hormone, high TSH -high thyroid hormone, low TSH -high thyroid hormone, high TSH -low thyroid hormone, low TSH

-high thyroid hormone, high TSH Correct An increase in TSH from the anterior pituitary will increase levels of thyroid hormone. The high levels of thyroid hormone will not be able to inhibit the anterior pituitary by negative feedback due to the presence of the tumor.

What type of stimulation controls parathyroid release? -paracrine -hormonal -neural -humoral

-humoral Correct The parathyroid is stimulated by the actual level of calcium in the blood rather than by neural or hormonal stimulus.

Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized? -kidney -hypothalamus -posterior pituitary -anterior pituitary

-hypothalamus Correct Yes, ADH is synthesized mainly in the supraoptic nucleus of the hypothalamus. It is stored in the posterior pituitary in axon terminals.

As the adrenal gland releases glucocorticoids, which of the following effects may be observed? Select all the answers that apply.

-increased blood glucose levels -increased blood levels of amino acids -decrease in immune system function -lipid breakdown in the liver will increase Correct With long-term stress, the glucocorticoid hormones, chiefly cortisol, are instrumental in the body. The primary targets include the liver, resulting in increased gluconeogenesis and increased catabolism of lipids and proteins. In larger amounts, the depression of the immune system can result.

Adrenocortical androgens are normally converted in females into estrogens. However, in adrenogenital syndrome, females develop a beard and a masculine pattern of body hair distribution; this occurs due to ______. -negative feedback that inhibits estrogen production -conversion of estrogens into testosterone -insufficient level of enzymes that convert androgens into estrogens -increased testosterone secretion

-insufficient level of enzymes that convert androgens into estrogens Correct During the end steps of sex hormone, synthesis androstendione is converted into either testosterone or estrogen. If the body lacks the enzyme to convert androstendione to estrogen, the remaining pathway to testosterone will predominate.

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 Correct 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 is the significance of the slight swelling (called a goiter) in Krista's neck? -her thyroid gland is producing but not secreting excessive amounts of thyroid hormone -the auto-antibodies of Graves' disease have caused inflammation of her thyroid gland -it is a sign that her thyroid gland is overactive -it is unrelated to her condition

-it is a sign that her thyroid gland is overactive Correct Goiters almost always occur in hyperthyroidism and result from increased cell numbers and cell size in the thyroid gland as thyroid hormone production increases.

Body cells that respond to insulin include -muscle cells only -liver cells only -liver cells, as well as most other cells of the body -liver cells and muscle cells only -intesitnal cells only

-liver cells, as well as most other cells of the body

What is the most important regulatory factor controlling the circulating levels of thyroid hormone? -a circadian rhythm of release -thyrotropin-releasing hormone (TRH) -negative feedback -thyroid-stimulating hormone (TSH)

-negative feedback Correct Yes, 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 hormone is regulated by a neuroendocrine ("letdown") reflex?] -oxytocin -cortisol -antidiuretic hormone (ADH)

-oxytocin Correct 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)

Cyclic AMP is degraded by __________. AMPadenylate cyclase G proteins phosphodiesterase protein kinase

-phosphodiesterase Correct Phosphodiesterase degrades cyclic AMP into AMP

Which intracellular substance degrades cAMP, thus inactivating the response to a hormone? -protein kinase C -adenylate cyclase -phosphodiesterase -phospholipase C

-phosphodiesterase Correct Yes, phosphodiesterase is an intracellular enzyme that degrades cAMP.

What is the role of activated protein kinases? -Phosphorylate ADP to ATP. -Degrade cAMP to AMP. -Phosphorylate proteins. -Activate adenylate cyclase. -Convert ATP to cAMP by phosphorylation.

-phosphorylate proteins Correct Phosphorylation can activate different proteins causing the response of the cell to water-soluble hormone.

Water-soluble hormones affect target cells by binding to __________. -adenylate cyclase -plasma membrane receptors -cytoplasmic receptors -protein kinases -cAMP

-plasma membrane receptors Correct Water-soluble hormones bind to specific receptors in the plasma membrane, whereas steroid hormones bind to cytoplasmic receptors.

Which of the following triggers the release of glucagon? -releases of somatostatin -hyperglycemia -release of insulin -prolonged fasting

-prolonged fasting Correct 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 Correct 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.

Your patient has been admitted to the intensive care unit with a severe head injury. As you monitor his urine output, you find that it has fallen sharply. Lab tests indicate that his serum osmolality is lower than normal (i.e., his plasma is too dilute). What should you suspect? -parathyroid hormone (PTH) -syndrome of inappropriate antidiuretic hormone (SIADH) -thyroid-stimulating hormone (TSH) -prolactin

-syndrome of inappropriate antidiuretic hormone (SIADH) Correct Antidiuretic hormone (ADH) is released from the posterior pituitary in response to rising serum osmolality. This causes the kidneys to preserve water, helping to restore normal solute/water balance. Your patient is retaining water despite a dilute plasma, suggesting that he is making "inappropriate" ADH. This problem may occur after head trauma or in some cancers.

Which of the following is NOT secreted by the thyroid? -triiodothyronine -calcitonin -thyroxine -thyroid-stimulating hormone

-thyroid-stimulating hormone Correct Thyroid-stimulating hormone (TSH) is secreted by the anterior pituitary gland.

What type of hormones bind to receptors located on the cell membrane? -lipid-soluble hormones, such as thyroid hormones and cortisol -water-soluble hormones, such as insulin and epinephrine

-water-soluble hormones, such as insulin and epinephrine Correct Yes, peptides and catecholamines are water-soluble hormones that cannot diffuse through the plasma membrane.

Drag the hormone on the left to its correct function on the right

Corticotropin-releasing hormone: Stimulates the anterior pituitary to release ACTH Epinephrine: Increased dilation of bronchioles and heart rate Adrenocorticotropic hormone: Targets the adrenal gland to release glucocorticoids and mineralocorticoids Cortisol: Increased metabolic effects from the liver Aldosterone: Increased sodium and water absorption Correct Each of these hormones plays a distinctive role in the body. Epinephrine, along with norepinephrine, target the cardiovascular and respiratory systems, producing increases in heart rate and blood pressure, along with increased dilation of the respiratory bronchioles. Blood glucose and metabolic rate increases are also important functions of epinephrine. Corticotropin-releasing hormone and adrenocorticotropic hormone are tropins; that is, their target organs are other endocrine glands. Corticotropin-releasing hormone targets the anterior pituitary, causing the release of adrenocorticotropic hormone; this, in turn, affects the adrenal cortex to release glucocorticoids and mineralocorticoids. Lastly, cortisol and aldosterone are the chief secretions of the glucocorticoids and mineralocorticoids, respectively; cortisol targets the liver for various metabolic effects, while aldosterone impacts the kidneys, causing them to retain more sodium and water.