patho chapter 40 endocrine
A nurse who works in the office of an endocrinologist is orienting a new staff member. Which teaching point should the nurse include in the orientation?
"A single hormone can act on not only one process or organ but often on several different locations or processes." A single hormone can exert various effects in different tissues, or conversely, a single function can be regulated by several different hormones. Hormones act both distantly from their source and more locally, as in the case of autocrine and paracrine actions. Hormones are normally present at all times. p. 1034.
Select the category of hormones that include norepinephrine and epinephrine.
Amines and amino acids Explanation: Hormones can be divided into three categories: (1) amines and amino acids; (2) peptides, polypeptides, proteins, and glycoproteins; and (3) steroids. The amines include norepinephrine and epinephrine. The second category, the peptides, includes polypeptides, proteins, and glycoproteins. The third category consists of the steroid hormones, which are derivatives of cholesterol. pg 1034
A client has developed a tumor of the posterior pituitary gland. The client is at risk for problems with secretions of:
Antidiuretic hormone (ADH) and oxytocin Explanation: The posterior pituitary secretes ADH and oxytocin/vasopressin, while the anterior pituitary secretes the hormones listed in the other choices. pg. 1034
The nurse is planning to collect a 24-hour urine sample for hormone assay. In which situation does the nurse collaborate with the health care provider to find an alternate type of testing?
Client has anuria. Explanation: The advantages of a urine test include the relative ease of obtaining urine samples and the fact that blood sampling is not required. The disadvantage is that reliably timed urine collections often are difficult to obtain and rely on adequate renal function. Anuria refers to the absence of urine output. pg 1043
Which hormone requires a carrier protein for transport through the blood?
Cortisol Explanation: Specific carrier proteins synthesized in the liver carry steroid hormones such as cortisol and thyroid hormone. The other listed options are peptide hormones and protein hormones that are water soluble and usually circulate unbound in the blood. pg 1036
After having a very stressful day in pathophysiology class, the student knows that which hormone (secreted by the adrenal cortex) will help decrease the effects of stress?
Cortisol, a glucocorticoid Explanation: Glucocorticoids, mainly cortisol, affect metabolism of all nutrients; regulate blood glucose levels; affect growth; have anti-inflammatory action; and decrease effects of stress. The other hormones do not affect stress levels. pg 1035
The nurse is reviewing the test results of a client who was given thyrotropin-releasing hormone (TRH) to evaluate the function of the pituitary gland. The nurse would recognize pituitary dysfunction as:
Decreased TSH levels Explanation: Stimulation tests are used when hypofunction of an endocrine organ is suspected. Failure to increase TSH levels after a TRH stimulation test suggests an inadequate capacity to produce TSH by the pituitary (i.e., the pituitary is dysfunctional in some way). pg 1034
Which type of imaging is preferred to evaluate the bone density of a client with hyperparathyroidism?
Dual energy x-ray absorptiometry (DXA) scan Explanation: Preferred types of scans for endocrine tissues include MRI of the pituitary gland and hypothalamus, CT scan of the adrenal glands, DXA scan of bone density, and ultrasound of possible nodules of the thyroid gland. Bone density may be decreased in a client with hyperparathyroidism. pg 1044
A nurse examines the laboratory values of a client in heart failure. Which value indicates a compensatory hormone mechanism?
Elevated atrial natriuretic hormone Explanation: In heart failure, the client experiences fluid backlog in the heart as venous blood continues to return, but cardiac output is reduced. This stretches the atria, which secrete atrial natriuretic hormone (or peptide) to stimulate vasodilation and increased renal excretion of sodium and water. This reduces the volume and the strain in the heart. pg 1034
A client has developed a tumor of the anterior pituitary gland. The nurse is aware that the client is at risk for alterations in which body function? Select all that apply.
Growth and metabolism Function of the thyroid gland Glucocorticoid hormone levels Function of the gonads Explanation: Hormones produced by the anterior pituitary control body growth and metabolism (GH), function of the thyroid gland (TSH), glucocorticoid hormone levels (ACTH), function of the gonads (FSH and LH), and breast growth and milk production (prolactin). The posterior pituitary gland stores and releases antidiuretic hormone (ADH) and oxytocin. pg 1035
Which physiologic process allows hormones to exert influence upon some cells and not others?
Hormone receptors Explanation: Hormone receptors are complex molecular structures (usually proteins) that are located either on the cell surface or inside target cells. The structure of these receptors is specific to a particular hormone, which allows target cells to respond to one hormone and not to others. For example, receptors in the thyroid are specific for thyroid-stimulating hormone, and receptors on the gonads respond to the gonadotropic hormones. Positive feedback control occurs when rising levels of a hormone cause another gland to release a hormone that is stimulating to the first. Protein binding describes the ability of proteins to form bonds with other substances. Pituitary-hypothalamic feedback describes negative feedback. pg 1037
The hypophysis is a unit formed by the pituitary and the hypothalamus. These two glands are connected by the blood flow in what system?
Hypophyseal portal system Explanation: The hypothalamus and pituitary (i.e., hypophysis) form a unit that exerts control over many functions of several endocrine glands as well as a wide range of other physiologic functions. These two structures are connected by blood flow in the hypophyseal portal system, which begins in the hypothalamus and drains into the anterior pituitary gland, and by the nerve axons that connect the supraoptic and paraventricular nuclei of the hypothalamus with the posterior pituitary gland. pg 1038
An infant whose mother had myxedema during the pregnancy has failed to meet standards for growth and is developmentally delayed. Which hormonal imbalance is this child exhibiting?
Hypothyroidism Explanation: Thyroid hormone is necessary for metabolism at all ages, as well as growth and development during childhood. Uncorrected thyroid insufficiency in childhood leads to cretinism, a condition with marked physical and intellectual disability. Myxedema is the term used for thyroid insufficiency in adults. pg 1034
The nurse is discussing positive feedback mechanisms. Which example best explains this mechanism?
Increased estradiol production causes increased follicle-stimulating hormone (FSH) production. Explanation: The positive feedback mechanism regulates hormones as follows: a rising level of a hormone causes another gland to release a hormone that is stimulating to the first. The other choices represent negative feedback mechanisms of control. p 1034
The nurse is discussing positive feedback mechanisms. Which example best explains this mechanism?
Increased estradiol production causes increased follicle-stimulating hormone (FSH) production. Explanation: The positive feedback mechanism regulates hormones as follows: a rising level of a hormone causes another gland to release a hormone that is stimulating to the first. The other choices represent negative feedback mechanisms of control. pg 1034
Which are examples of a negative feedback system? Select all that apply.
Insulin and glucagon Cortisol and adrenocorticotropic hormone Somatostatin and thyroid-stimulating hormone (TSH) Calcium and parathyroid hormone Explanation: In negative feedback, sensors detect a change in hormone levels and adjust hormone secretion to maintain optimal levels. In positive feedback control, rising levels of a hormone cause another gland to release a hormone that stimulates the first. Release of the female hormone estradiol during the follicular stage of the menstrual cycle causes increased release of gonadotropin (FSH), which further increases release of estradiol until the follicle dies and ceases production. pg 1042
A client develops hypocalcemia after thyroid surgery. Which hormonal imbalance caused this complication?
Lack of parathyroid hormone Explanation: The parathyroid glands are located on the posterior side of the thyroid gland. If the parathyroid glands are removed at the same time as the thyroid the client will experience a drop in serum calcium levels. pg 1039
Which body function is regulated by several hormones?
Lipolysis Explanation: Lipolysis, or the breakdown of lipids into fatty acids, is regulated by catecholamines, insulin, glucagon, cytokine, and tumor necrosis factor-alpha. Erythropoiesis is regulated by release of erythropoietin from the kidneys. Natriuresis, or sodium excretion by the kidney, is primarily controlled by the heart. Vitamin D manufacture is primarily controlled by the kidneys. pg 1034
Which body systems work with the endocrine system to regulate body functions? Select all that apply.
Peripheral nervous system Immune system Central nervous system Explanation: The central and peripheral nervous systems and the immune system work together with the endocrine system to regulate body functions. pg 1033
The nurse is caring for a client who has decreased secretion of arginine vasopressin from the posterior pituitary gland. When evaluating the client's fluid and electrolyte status, which alteration does the nurse anticipate will be present?
Polyuria Explanation: ADH (arginine vasopressin [AVP]), from the posterior pituitary gland, increases water reabsorption by the kidney. Deficiency of ADH leads to profound fluid loss from the kidney. pg 1035
When trying to explain hypothyroidism to a newly diagnosed client, the nurse stresses the fact that the thyroid hormone is transported in blood by specific:
Proteins Explanation: Some hormones, such as steroids and thyroid hormone, are bound to protein carriers for transportation to the target cell destination. The extent of carrier binding influences the rate at which hormones leave the blood and enter the cells. Cholesterol is a precursor for steroid hormone. Prohormones have an extra amino acid and are converted to hormones in the Golgi complex. pg 1037
The nurse is caring for a client who is receiving exogenous corticosteroids for rheumatoid arthritis. Recognizing that hormone levels are regulated by negative feedback, which laboratory test result does the nurse anticipate uncovering when reviewing the medical record?
Reduction in ACTH Explanation: The function of the negative feedback system is similar to that of the thermostat in a heating system. When the sensors detect a decrease in hormone levels, they initiate changes that cause an increase in hormone production. When hormone levels rise above the set point of the system, the sensors cause hormone production and release to decrease, driving the stimulating hormone down. pg 1041
A client has received an injection containing thyrotropin-releasing hormone (TRH) and is now being assessed for serum levels of thyroid-stimulating hormone (TSH). Which type of diagnostic testing is this client undergoing?
Stimulation testing Explanation: Introduction of TRH tests the pituitary gland's ability to produce TSH, and is an example of a stimulation test. Suppression testing examines a gland's response to a stimulus that would normally result in decreased hormone production. RIA and autoantibody testing are examples of direct and indirect measurement of serum levels of a hormone. pg 1043
During a near-miss accident while cycling, a client marvels at how fast he was able to react. He attributes this to his "fight or flight" response but then wonders why it lasts for only a short period. The client had a short burst of catecholamine activity because catecholamines are:
rapidly degraded by enzymes in circulation and at the tissue. Explanation: Most peptide hormones and catecholamines are water soluble and circulate freely in the blood, where they are degraded by enzymes and excreted by the kidneys and liver. Catecholamines are rapidly degraded by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). There is no breakdown by just being in circulation. Hormones are not used as fuel. Water-soluble hormones such as catecholamines are not bound to proteins. pg 1036
Cyclic adenosine monophosphate (cAMP) performs which role in the functioning of the endocrine system?
Acting as a second messenger to mediate hormone action on target cells Explanation: cAMP is one of the most common second messengers, whose role is to generate an intracellular signal in response to cell surface receptor activation by a hormone. cAMP does not mediate hormone synthesis, act as a receptor itself, or inactivate hormones. pg 1039
The nurse is assessing a client with thyrotoxicosis and the nurse is explaining how the thyroid gland is stimulated to release thyroid hormones. The nurse should describe what process?
Action of releasing hormones from hypothalamus Explanation: The synthesis and release of anterior pituitary hormones are largely regulated by the action of releasing or inhibiting hormones from the hypothalamus, which is the coordinating center of the brain for endocrine activity such as thyroid activity. There are no direct innervations for hormone release from the thyroid gland, and homeostatic receptors do not exist. Steady-state release of hormones does not occur. pg 1038
The nurse is assessing a client with thyrotoxicosis and the nurse is explaining how the thyroid gland is stimulated to release thyroid hormones. The nurse should describe what process?
Action of releasing hormones from hypothalamus Explanation: The synthesis and release of anterior pituitary hormones are largely regulated by the action of releasing or inhibiting hormones from the hypothalamus, which is the coordinating center of the brain for endocrine activity such as thyroid activity. There are no direct innervations for hormone release from the thyroid gland, and homeostatic receptors do not exist. Steady-state release of hormones does not occur. pg 1038
Which hormones illustrate non-vesicle-mediated synthesis? Select all that apply.
Aldosterone Cortisol Androgens Explanation: Hormones synthesized by non-vesicle-mediated pathways include the glucocorticoids, androgens, estrogens, and mineralocorticoids: all steroids derived from cholesterol. In the adrenal cortex, for example, progesterone and other steroid intermediates are enzymatically converted into aldosterone, cortisol, or androgens. The vesicle-mediated pathway is also used for secretion of a number of nonpolypeptide hormones and neurotransmitters such as the catecholamines (epinephrine and norepinephrine). pg 1036
The non-vesicle-mediated pathway has a role in synthesis and release of which hormones? Select all that apply.
Aldosterone Testosterone Explanation: Steroids such as aldosterone, estrogens, glucocorticoids, testosterone, and dehydroepiandrosterone use the non-vesicle-mediated pathway. The protein hormones and some of the nonpolypeptide hormones, such as dopamine, epinephrine, and norepinephrine, use the vesicle-mediated pathway. pg 1036
Select the category of hormones that include norepinephrine and epinephrine.
Amines and amino acids Explanation: Hormones can be divided into three categories: (1) amines and amino acids; (2) peptides, polypeptides, proteins, and glycoproteins; and (3) steroids. The amines include norepinephrine and epinephrine. The second category, the peptides, includes polypeptides, proteins, and glycoproteins. The third category consists of the steroid hormones, which are derivatives of cholesterol. pg 1034
Hormones can be synthesized by both vesicle-mediated pathways and non-vesicle-mediated pathways. What hormones are synthesized by non-vesicle-mediated pathways?
Androgens and estrogens Explanation: Hormones that are synthesized by non-vesicle-mediated pathways include the glucocorticoids, androgens, estrogens, and mineralocorticoids—all steroids derived from cholesterol. pg 1036
Which hormone is secreted based on a cyclic rather than a diurnal manner?
Follicle-stimulating hormone (FSH) Explanation: Hormone secretion varies widely over a 24-hour period. Some hormones, such as GH and adrenocorticotropic hormone (ACTH), have diurnal fluctuations that vary with the sleep-wake cycle. Others, such as the female sex hormones (e.g., follicle-stimulating hormone [FSH]) are secreted in a complicated cyclic manner. The levels of hormones such as insulin and antidiuretic hormone (ADH) are regulated by feedback mechanisms that monitor substances such as glucose (insulin) and water (ADH) in the body. The levels of many of the hormones are regulated by feedback mechanisms that involve the hypothalamic-pituitary-target cell system. pg 1038
A health care provider is assessing a client for a potential endocrine disorder. Assessment findings identify abnormalities with emotion, pain, and body temperature. Which mechanism of endocrine control will require further laboratory/diagnostic assessment?
Hypothalamus Explanation: The hypothalamus is the coordinating center of the brain for endocrine, behavioral, and autonomic nervous system function. It is at the level of the hypothalamus that emotion, pain, body temperature, and other neural input are communicated to the endocrine system. The anterior pituitary regulates several physiologic processes, including stress, growth, reproduction, and lactation. The cerebellum is involved in motor control, and the cerebral cortex is associated with sensory, motor, and association.
The nurse is discussing positive feedback mechanisms. Which example best explains this mechanism?
Increased estradiol production causes increased follicle-stimulating hormone (FSH) production. Explanation: The positive feedback mechanism regulates hormones as follows: a rising level of a hormone causes another gland to release a hormone that is stimulating to the first. The other choices represent negative feedback mechanisms of control. pg 1034
Following a stroke that disrupts blood flow to the pituitary gland, a client develops signs of hypopituitarism. Which manifestations are unexpected findings?
Increased volume of dilute urine Explanation: The hypothalamus produces a number of hormones that stimulate the anterior pituitary. It also produces antidiuretic hormone and oxytocin, the hormones that are stored and released in the posterior pituitary. If the pituitary is damaged or removed, expected manifestations that correspond to lack of thyroid-adrenocorticotropic hormone. These signs and symptoms include bradycardia, hypotension, cessation of menstruation, fluid volume deficit, and hyperkalemia. Because the posterior pituitary hormones are manufactured in the hypothalamus and would be unaffected by the tissue damage, the nurse would not expect symptoms of a lack of antidiuretic hormone, indicating the presence of diabetes insipidus. p. 1038.
An overweight, 14-year-old boy feels tired all the time. He sleeps 12 to 14 hours a day and has a voracious appetite but no energy to burn off the calories. He has been diagnosed with hypothyroidism brought about by the accumulation of a nonpitting mucosal edema. For which life-threatening condition should his care team be prepared?
Myxedema coma Explanation: Myxedema implies the presence of a nonpitting mucous type of edema caused by an accumulation of a hydrophilic mucopolysaccharide substance in the connective tissues throughout the body. The hypothyroid state may be mild, with only a few signs and symptoms, or it may progress to a life-threatening condition called myxedema coma. Pheochromocytoma is a tumor of the adrenal gland. Thyroid storm is related to hyperthyroidism. Paraneoplastic syndrome is a separate condition.
What is the most common mechanism of hormone control?
Negative feedback Explanation: With negative feedback, the most common mechanism of hormone control, some feature of hormone action directly or indirectly inhibits further hormone secretion so that the hormone level returns to an ideal level or set point. pg 1042
A client receives steroids for several months to treat an inflammatory condition. Which action by the primary health care provider indicates an understanding of the negative feedback mechanism when the client no longer needs the medication?
Prescribing a tapering dose of the medication over weeks explanation: Negative feedback occurs when secretion of one hormone causes a reduction in the secretion of the hormone that stimulates production of the first hormone. In this case, adrenocorticotropic hormone (ACTH) manufactured by the anterior pituitary would normally stimulate release of cortisol, but with the increase of cortisol produced by the secreting tumor, enough cortisol already floods the system that there should be a reduction in the ACTH level. Sudden withdrawal of the medication would leave the client without glucocorticoids and risk an Addisonian crisis. Gradual withdrawal of the medication allows the pituitary to measure the drop in cortisol levels and begin secreting ACTH. pg 1042
Several hormones, including growth hormone (GH) and thyrotropin-releasing hormone (TRH), are bound to and carried by which substance?
Proteins Explanation: Some hormones, such as steroids and thyroid hormone, are bound to protein carriers for transportation to the target cell destination. Cholesterol is a precursor for steroid hormone. Prohormones have an extra amino acid and convert to hormones in the Golgi complex. pg 1034
Select the most accurate statement regarding measurements of urinary hormone.
Provide a better measure of hormone levels during a designated period. Explanation: Measurements of urinary hormone or hormone metabolite excretion often are done on a 24-hour urine sample and provide a better measure of hormone levels during that period than hormones measured in an isolated blood sample. The advantages are relative ease of obtaining urine samples and blood sampling is not required. The disadvantages are that timed urine collections often are difficult to obtain and urine samples may be accidentally discarded or inaccurately preserved; drugs or disease states that alter hormone metabolism may interfere with the test results. pg 1043
The physician suspects a client may be experiencing hypofunction of an endocrine organ. Select the most appropriate test to determine organ function.
Stimulation tests Explanation: Stimulation tests are used when hypofunction of an endocrine organ is suspected. Suppression tests are used when hyperfunction of an endocrine organ is suspected. Genetic testing is used for DNA analysis, and imaging may be used as a follow-up after the diagnosis. pg 1043
A client undergoing an evaluation of hormone levels asks, "What regulates the hormone levels?" Which response by the nurse would be considered most accurate?
The hypothalamic-pituitary-target cell system The levels of many of the hormones are regulated by feedback mechanisms that involve the hypothalamic-pituitary-target cell system. Positive feedback control refers to rising levels of a hormone that causes another gland to release a hormone that is stimulating to the first. The hypophyseal portal system connects the supraoptic and paraventricular nuclei of the hypothalamus with the posterior pituitary gland. Exogenous forms of hormones (given as drug preparations) can influence the normal feedback control of hormone production and release. pg 1038