Patho Ch 31 and 32
As part of maintaining homeostasis, hormones secreted by endocrine cells are inactivated continuously to:
Prevent accumulation. Feedback: Continuous inactivation of secreted hormones is necessary to prevent accumulation that could disrupt the feedback mechanism. Increased secretion stimulates production of more receptor sites. Metabolic waste absorption is not a function of the endocrine system.
Which of the following physiologic processes is a direct effect of the release of growth hormone by the anterior pituitary?
Production of insulin-like growth factors (IGFs) by the liver. Feedback: GH cannot directly produce bone growth; instead, it acts indirectly by causing the liver to produce IGFs. It affects neither metabolic rate nor the function of the hypothalamic-pituitary-thyroid feedback system.
A client with many nonspecific complaints has been ordered a positron emission tomography (PET) scanning for evaluation of:
Tumors located on the endocrine glands. Feedback: Positron emission tomography (PET) scanning is being used more widely for evaluation of endocrine tumors. PET scans do not calculate the pancreas response to insulin. A DEXA is used for diagnosis and monitoring of osteoporosis (bone density). Isotopic imaging includes radioactive scanning of the thyroid (using radioiodine) and parathyroids.
Which of the following clients are at risk for developing hypothyroidism? Select all that apply.
A client who is prescribed amiodarone for frequent dysrhythmias, A client who has precancerous thyroid lesions who underwent ablation with radiation, A female experiencing an autoimmune disorder called thyroiditis, and A bipolar client prescribed lithium carbonate. Feedback: The most common cause of hypothyroidism is Hashimoto thyroiditis, an autoimmune disorder in which the thyroid gland may be totally destroyed by an immunologic process. It is the major cause of goiter and hypothyroidism in children and adults. Hypothyroidism may result from thyroidectomy (i.e., surgical removal) or ablation of the gland with radiation. Certain goitrogenic agents, such as lithium, and the antithyroid drugs propylthiouracil and methimazole in continuous dosage can block hormone synthesis and produce hypothyroidism with goiter. Large amounts of iodine (i.e., ingestion of kelp tablets or iodide-containing cough syrups, or administration of iodide-containing radiographic contrast media or the cardiac drug amiodarone, which contains 75 mg of iodine per 200-mg tablet) also can block thyroid hormone production and cause goiter, particularly in persons with autoimmune thyroid disease. Myxedema is associated with severe hypothyroidism and is characterized by a non pitting mucus-type edema caused by the accumulation of hydrophobic extracellular matrix substances in the connective tissues of a number of body tissues. Although the myxedema is most obvious in the face and other superficial parts, it also affects many of the body organs and is responsible for many of the manifestations of the hypothyroid state.
When educating a client with possible glucocorticoid dysfunction, the nurse will explain that the CRH controls the release of ACTH. The best time to perform the blood test to measure peak ACTH levels would be:
A) 06:00 to 08:00 AM. Feedback: Levels of cortisol increase as ACTH levels rise and decrease as ACTH levels fall. There is considerable diurnal variation in ACTH levels, which reach their peak in the early morning (around 6 to 8 AM) and decline as the day progresses.
Which of the following residents of a long-term facility is exhibiting clinical manifestations of hypothyroidism?
A) An 80-year-old woman who has uncharacteristically lost her appetite and often complains of feeling cold. Feedback: Loss of appetite and cold intolerance are characteristic symptoms of hypothyroidism. Arrhythmias, agitation, and infections are not typically associated with hypofunction of the thyroid gland.
A diabetic client is controlled on Avandia (rosiglitazone), a thiazolidinedione medication that acts at the level of nuclear peroxisome proliferator-activated receptors (PPARs) to promote:
A) Glucose uptake. Feedback: The thiazolidinedione medications, which are used in the treatment of type 2 diabetes mellitus, act at the level of nuclear PPAR-y receptors to promote glucose uptake and utilization by adipose tissue cells. These drugs do not increase release of insulin from the pancreas, increase BMR, or promote weight loss.
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:
A) Proteins. Feedback: 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 hormones. Prohormones have an extra amino acid and are converted to hormones in the Golgi complex.
Which of the following physiologic processes best exemplifies a positive feedback mechanism?
A) The increase in prolactin secretion that occurs with more frequent breast-feeding. Feedback: A positive feedback mechanism occurs when one hormonal or physiologic factor stimulates further hormonal release, creating a cascade that will increase until corrected. Correction of alterations in homeostasis is normally achieved using negative feedback mechanisms, such as those accomplished by insulin, parathyroid hormone, and ADH.
A lung cancer client with small cell carcinoma may secrete an excess of which hormone causing an ectopic form of Cushing syndrome due to a non pituitary tumor?
ACTH. Feedback: The third form (of Cushing syndrome) is ectopic Cushing syndrome, caused by a non pituitary ACTH-secreting tumor. Certain extra pituitary malignant tumors such as small cell carcinoma of the lung may secrete ACTH or, rarely, CRH and produce Cushing syndrome. The adrenal sex hormone dehydroepiandrosterone (DHEA) contributes to the pubertal growth of body hair, particularly pubic and axillary hair in women. Thyroid-stimulating hormone (TSH) levels are used to differentiate between primary and secondary thyroid disorders. Although secretion of growth hormone (GH) has diurnal variations over a 24-hour period, with nocturnal sleep bursts occurring 1 to 4 hours after onset of sleep, it is unrelated to ACTH and/or CRH secretion.
Paracrine action involves which of the following characteristics?
Act locally on cells other than those that produce the hormone. Feedback: When hormones act locally on cells other than those that produced the hormone, the action is called paracrine. Paracrine action is not synonymous with autoregulation, and action on the same cells that produced the hormone is autocrine action.
Cyclic adenosine monophosphate (CAMP) performs which of the following roles in the functioning of the endocrine system?
Acting as a second messenger to mediate hormone action on target cells. Feedback: 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.
The signs and symptoms of abrupt cessation of pharmacologic glucocorticoids closely resemble those of:
Addison disease. Feedback: Although the etiology differs, the adrenal cortical insufficiency resulting from the abrupt cessation of glucocorticoids is nearly identical to Addison disease in terms of physiologic effects.
Hormones are usually divided into categories according to their structure. The release of epinephrine would be classified as:
Amines and amino acids. Feedback: Hormones are divided into three categories according to their structures: amines and amino acids; polypeptides, proteins, and glycoproteins; and steroids. The amine and amino acid hormones include norepinephrine and epinephrine, which are derived from a single amino acid (i.e., tyrosine). The peptide, polypeptide, protein, and glycoprotein hormones can be as small as thyrotropin-releasing hormone (TRH), which contains three amino acids, and as large, and as large and complex as growth hormone (GH) and follicle-stimulating hormone (FSH). Steroid hormones, such as the glucocorticoids, are derivatives of cholesterol.
Which of the following individuals displays the precursors to acromegaly?
An adult with an excess of growth hormone due to an adenoma. Feedback: When growth hormone (GH) excess occurs in adulthood or after the epiphyses of the long bones have fused, it causes a condition called acromegaly, which represents an exaggerated growth of the ends of the extremities.
When discussing luteinizing hormone and follicle-stimulating hormone with students, the instructor will emphasize that these hormones are under the control of:
Anterior pituitary gland. Feedback: The pituitary gland has been called the master gland because its hormones control the functions of many target glands and cells. The anterior pituitary gland or adenohypophysis contains five cell types: (1) thyrotropes, which produce thyrotropin, also called TSH; (2) corticotropes, which produce corticotropin, also called ACTH; (3) gonadotrophs, which produce the gonadotropins, LH, and FSH; (4) somatotrophs, which produce GH; and (5) lactotrophs, which produce prolactin.
A 33-year-old client has been admitted to the hospital for the treatment of Graves disease. Which of the following assessments should the client's care team prioritize?
Assessment of the client's vision and oculomotor function/ Feedback: Ophthalmopathy occurs in a large proportion (up to one third) of clients with Graves disease and may result in permanent vision damage. This supersedes the importance of cardiac, neurologic, and peripheral vascular assessments, although these assessments are relevant to the broader effects of hyperthyroidism that the client may likely experience.
The release of insulin from the pancreatic beta cells can inhibit its further release from the same cells. This is an example of which type of hormone action?
Autocrine. Feedback: Hormones can exert autocrine action on the cells from which they were produced. Retinoids are compounds with hormone-like actions. Juxtracrine action involves a chemical messenger embedded in a plasma membrane that interacts with a specific receptor on a juxtaposed cell. Arachidonic acid is a precursor for eicosanoid compounds (similar to retinoids).
One of the first signs that indicates an infant may have congenital hypothyroidism is:
C)Prolonged period of physiologic jaundice. Feedback: With congenital lack of the thyroid gland, the infant usually appears normal and functions normally at birth because of hormones supplied in utero by the mother. Prolongation of physiologic jaundice, caused by delayed maturation of the hepatic system for conjugating bilirubin, may be the first sign. There may be respiratory difficulties and a hoarse cry, feeding difficulties, and an enlarged abdomen. This condition will not interfere with meconium passage, elevated ICP resulting in full, tight fontanels, or having a palpable mass in the neck.
A woman who is exhibiting clinical manifestations of a pituitary adenoma will likely complain of: Select all that apply.
Cessation of menses, Unusual milk secretion unrelated to pregnancy, and Infertility. Feedback: The signs and symptoms of pituitary adenomas include endocrine abnormalities related specifically to functional hormone-secreting adenomas and to the local mass effects from the expanding tumor. Lactotrophic adenomas are the most frequent type of hyperfunctioning pituitary adenoma. Hyperprolactinemia inhibits the pulsatile secretion of LH, which is essential for normal ovulation in women. Thus, manifestations of hyperprolactinemia are easily recognized to include amenorrhea (lack of menses), galactorrhea (spontaneous milk secretion unrelated to pregnancy), and infertility.
Which of the following hormones are synthesized by non-vesicle-mediated pathways? Select all that apply.
Estrogen and Aldosterone. Feedback: Glucocorticoids, androgens, estrogens, and mineralocorticoids (aldosterone is an example of a mineralocorticoid) are all hormones synthesized by non-vesicle-mediated pathways. Epinephrine and insulin are synthesized by vesicle-mediated pathways.
Which of the following pathophysiologic phenomena may result in a diagnosis of Cushing disease?
Excess ACTH production by a pituitary tumor. Feedback: Three important forms of Cushing syndrome result from excess glucocorticoid production by the body. One is a pituitary form, which results from excessive production of ACTH by a tumor of the pituitary gland. Hypopituitarism and destruction of the adrenal cortex are associated with Addison disease. Disruption of the HPA system is not implicated in the etiology of Cushing disease.
A nursing student who has a history of brain tumors that resulted in partial removal of her pituitary gland years ago is asking her OB/GYN doctor about her ability to breast-feed her infant. This is based on which physiological function of the pituitary gland that facilitates breast milk production?
Lactotrophs Ans: D Feedback: The anterior pituitary gland or adenohypophysis contains five cell types: (1) thyrotropes, which produce thyrotropin, also called TSH; (2) corticotropes, which produce corticotropin, also called ACTH; (3) gonadotrophs, which produce the gonadotropins, LH, and FSH; (4) somatotrophs, which produce GH; and (5) lactotrophs, which produce prolactin that is involved with breast growth and milk production.
Which of the following clinical manifestations would support the medical diagnosis of Cushing syndrome? Select all that apply.
Excessive facial hair growth, Blood glucose level in 200 mg/dL range, and "Buffalo hump" on back. Feedback: The major manifestations of Cushing syndrome represent an exaggeration of the many actions of cortisol. There is muscle weakness, and the extremities are thin. Derangements in glucose metabolism are found in approximately 75% of clients, with clinically overt diabetes mellitus occurring in approximately 20% of clients. The glucocorticoids possess mineralocorticoid properties; this causes fluid retention and hypertension resulting from sodium retention, water retention, and hypervolemia. An increase in androgen levels causes hirsutism. Altered fat metabolism causes a peculiar deposition of fat characterized by a protruding abdomen; subclavicular fat pads or "buffalo hump" on the back; and a round, plethoric "moon face."
When sensors detect a change in a hormone level, the hormonal response is regulated by which of the following mechanisms that will return the level to within normal range,
Feedback. Feedback (negative and sometimes positive) mechanisms respond to levels that are too high or too low. The level of many of the hormones in the body is regulated by negative feedback mechanisms. The function of this type of system is similar to that of the thermostat in a heating system. For example, when the sensors detect a decrease in blood levels, they initiate changes that cause an increase in hormone production. Metabolic responses and increased/decreased production occur as a consequence of hormone level fluctuations, not as a regulating mechanism. Action potential is not a regulating mechanism for this function.
Loss of pituitary function can result in deficiencies/loss of which of the following hormones' secretions? Select all that apply.
Growth hormone, Luteinizing hormone, Follicle stimulating hormone, and Prolactin Feedback: Anterior pituitary hormone loss is usually gradual, especially with progressive loss of pituitary reserve due to tumors or previous pituitary radiation therapy (which may take 10 to 20 years to produce hypopituitarism). The loss of pituitary function tends to follow a classic course beginning with the loss of GH, LH, and FSH secretion followed by deficiencies in TSH, then ACTH, and finally prolactin.
The immunosuppressive and anti-inflammatory effects of cortisol cause:
Inhibition of prostaglandin synthesis. Feedback: Large quantities of cortisol are required for an effective anti-inflammatory action. The increased cortisol blocks inflammation at an early stage by decreasing capillary permeability and stabilizing the lysosomal membranes so that inflammatory mediators are not released. Cortisol suppresses the immune response by reducing humoral and cell-mediated immunity. Cortisol also inhibits prostaglandin synthesis, which may account in large part for its anti-inflammatory actions. Cortisol stimulates glucose production by the liver; as glucose production by the liver rises and peripheral glucose use falls, a moderate resistance to insulin and hyperglycemia develop.
A hormone has been synthesized in the rough endoplasmic reticulum of an endocrine cell after which it has moved into the Golgi complex, been packaged in a vesicle, and been released into circulation. From the following list, which hormone is synthesized and released in this manner?
Insulin. Feedback: Insulin is a peptide hormone; as such, its synthesis and release are vesicle mediated. Glucocorticoids (such as cortisol), androgens (such as testosterone), and estrogens are synthesized by non-vesicle-mediated pathways.
A client with excessive production of growth hormone level will likely exhibit which clinical manifestations? Select all that apply.
Large hands and feet due to increased production of GH, Excess thirst and urination due to decreased glucose uptake, and Difficulty chewing food. Feedback: Growth hormone causes increased release of free fatty acids from adipose tissue, leading to increased concentration of free fatty acids in body fluids. In addition, GH exerts multiple effects on carbohydrate metabolism, including decreased glucose uptake by tissues such as skeletal muscle and adipose tissue, increased glucose production by the liver, and increased insulin secretion. Each of these changes results in GH-induced insulin resistance. Impaired glucose tolerance occurs in as many as 50% to 70% of persons with acromegaly; overt diabetes mellitus subsequently can result. The predominant effect of prolonged growth hormone (GH) excess is to increase glucose levels despite an insulin increase. Persons with classic GH deficiency have normal intelligence, short stature, and obesity with immature facial features. Exceptionally tall children (i.e., genetic tall stature and constitutional tall stature) can be treated with sex hormones—estrogens in girls and testosterone in boys—to effect early epiphyseal closure and stop bone growth.
While teaching a science class, the instructor mentions that both autocrine and paracrine hormonal actions occur without entering the bloodstream. The instructor then asks the students, "What cells do paracrine actions affect?" The student with the correct answer is:
Local. Feedback: Paracrine actions are hormonal interactions with local cells other than those that produce the hormone; autocrine actions are with self-cells (cells from which they were produced). Both autocrine and paracrine hormonal actions affect target cells. Neither paracrine or autocrine actions affect cell storage.
The iatrogenic form of Cushing syndrome is caused by:
Long-term cortisone therapy. Feedback: Three important forms of Cushing syndrome result from excess glucocorticoid production by the body. One is a pituitary form, which results from excessive production of ACTH by a tumor of the pituitary gland, called Cushing disease. The second form is the adrenal form, caused by a benign or malignant adrenal tumor. The third form is ectopic Cushing syndrome, caused by a non pituitary ACTH-secreting tumor, often carcinoma of the lung. Iatrogenic Cushing syndrome results from long-term therapy with one of the potent pharmacological preparations of glucocorticoids.
The most common cause of thyrotoxicosis is Graves disease. When assessing this client, the nurse should put priority on which of the following signs/symptoms?
Ophthalmopathy. Feedback: Graves disease is characterized by a triad of hyperthyroidism, goiter, ophthalmopathy (exophthalmos), or less commonly, dermopathy (pretibial edema due to accumulation of fluid and glycosaminoglycans). Even in persons without exophthalmos (i.e., bulging of the eyeballs seen in ophthalmopathy), there is an abnormal retraction of the eyelids and infrequent blinking such that they appear to be staring. Although the myxedema of hypothyroidism is most obvious in the face and other superficial parts, it also affects many of the body organs. Common to all types of thyrotoxicosis, rather than unique to Graves disease, cholesterol blood levels are decreased; muscle proteins are broken down and used as fuel, which accounts for the muscle fatigue that occurs with all types of hyperthyroidism.
Which of the following statements best describes the relationship between the hypothalamus and the posterior pituitary in the normal functioning of the endocrine system?
Posterior pituitary hormones are produced in the hypothalamus but released from the pituitary gland. Feedback: The posterior pituitary hormones, ADH and oxytocin, are synthesized in the cell bodies of neurons in the hypothalamus that have axons that travel to the posterior pituitary, where they are released when needed. The two glands do not contribute components that are subsequently combined.
When comparing the endocrine and nervous system functions, the nurse knows that the endocrine system: Select all that apply.
Releases hormones into the blood that is transported throughout the body, Glands are widely scattered throughout the body, and Takes longer to respond to innervations but has prolonged actions when they arrive Feedback: The endocrine system uses chemical messengers called hormones as a means of controlling the flow of information between the different tissues and organs of the body. It does not act alone, however, but interacts with the nervous system to coordinate and integrate the activity of body cells. Hormones regulate and integrate body functions. Hormones act on specific target cells, but they cause a variety of effects on tissues. Hormones do not transport other substances; hormones are transported and present in body fluids at all times. The endocrine system uses hormones released into the blood and transported throughout the body to influence the activity of body tissues. Tissue and organ responses to endocrine hormones tend to take much longer than the response to neurotransmitters, but once initiated, they tend to be much more prolonged than those induced by the nervous system. The glands of the endocrine system are widely scattered throughout the body.
A client has just undergone a diagnostic cardiac angiogram. As part of their ordered labs, the physician has ordered a thyroid panel. The physiological principle behind ordering this lab tests includes which of the following correlations? Hyperthyroidism can cause: Select all that apply.
Rise in oxygen consumption and Increase in cardiac output. Feedback: Cardiovascular and respiratory functions are strongly affected by thyroid function. With an increase in metabolism, there is a rise in oxygen consumption and production of metabolic end products, with an accompanying increase in vasodilation. Blood volume, cardiac output, and ventilation all are increased as a means of maintaining blood flow and oxygen delivery to body tissues. Heart rate and cardiac contractility are enhanced as a means of maintaining the needed cardiac output, whereas there is little change in blood pressure because the increase in vasodilation tends to offset the increase in cardiac output.
Primary adrenal insufficiency is manifested by:
Serum sodium level of 120 mmol/L (low) and blood glucose level of 48 mg/dL (low). Feedback: Primary adrenal insufficiency is adrenal cortical hormone deficiency with elevated adrenocorticotropic hormone (ACTH) levels caused by a lack of feedback inhibition. Manifestations are related primarily to mineralocorticoid deficiency, causing increased urinary losses of sodium, chloride, and water, along with decreased excretion of potassium. The result is hyponatremia, loss of extracellular fluid, decreased cardiac output, and hyperkalemia. Because of a lack of glucocorticoid, the person with Addison disease has poor tolerance to stress. This deficiency causes hypoglycemia, lethargy, weakness, fever, and gastrointestinal symptoms such as anorexia, nausea, vomiting, and weight loss. Hypopigmentation results from elevated ACTH levels.
A client has received an injection containing thyrotropin-releasing hormone (TRH) and is now being assessed for levels of thyroid-stimulating hormone (TSH). This client has undergone which of the following diagnostic tests?
Stimulation testing. Feedback: 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.
When hypofunction of an endocrine organ is suspected, which hormone test can be administered to measure and assess target gland response?
Stimulation. Feedback: Stimulating hormone can be given to identify (determine hypofunction) if the target gland is able to increase hormone response to increased stimulation. Agglutination with enzymes is a way of measuring hormone antigen levels. The 24-hour urine sample measures hormone metabolite excretion. Radioactive hormone-antibody binding levels are a method of measuring plasma levels.
A client who has been taking 80 mg of prednisone, a glucocorticoid, each day has been warned by his primary care provider to carefully follow a plan for the gradual reduction of the dose rather than stopping the drug suddenly. What is the rationale for this directive?
Stopping the drug suddenly may cause acute adrenal insufficiency. Feedback: Chronic suppression of the HPA system by the use of steroids causes atrophy of the adrenal gland, and the abrupt withdrawal of drugs can cause acute adrenal insufficiency. Activity of the HPA system is consequently insufficient. The efficacy of the drug is not the primary concern, and necrosis of the gland itself does not occur.
A client has developed the facial appearance that is characteristic of myxedema, along with an enlarged tongue, bradycardia, and voice changes. Which of the following treatment modalities is most likely to benefit this client?
Synthetic preparations of T3 or T4. Feedback: Myxedema and the client's other signs are associated with hypothyroidism, which necessitates thyroid hormone replacement. B-Adrenergic blocking drugs and antithyroid drugs are indicated in the treatment of hyperthyroidism, whereas treatments relevant to adrenal cortical function are not relevant to hypothyroidism.
Which of the following clinical manifestations following thyroidectomy would alert the nurse that the client is going into a life-threatening thyroid storm? Select all that apply.
Temperature of 104.2°F, Telemetry showing heart rate of 184, and Extremely agitated. Feedback: Thyroid storm, or crisis, is an extreme and life-threatening form of thyrotoxicosis, rarely seen today. When it does occur, it is seen most often in undiagnosed cases or in person with hyperthyroidism that has not been adequately treated. It often is precipitated by stress such as an infection, diabetic ketoacidosis, physical or emotional trauma, or manipulation of a hyperactive thyroid gland during thyroidectomy. It is manifested by a very high fever, extreme cardiovascular effects (tachycardia, HF, angina), and severe CNS effects (agitation, restlessness, and delirium).
Thyroid and steroid hormones, which exert their effect on target cells by way of nuclear receptors, have which of the following characteristics?
The ability to cross the cell membrane of target cells. Feedback: Hormones that utilize nuclear receptors enter the target cell (i.e., cross the cell membrane) and bind to receptors in the cell nucleus that are gene regulatory proteins. These hormones do not selectively utilize second messengers, and they do not interact with surface receptors. They are not both lipid and water soluble.
When describing to a newly diagnosed diabetic client how insulin is regulated, the nurse will draw upon her knowledge of which hormonal regulation mechanism?
The hypothalamic-pituitary-target cell system. Feedback: The hypophysis (pituitary plus hypothalamus) and hypothalamus stimulatory hormones regulate the release and synthesis of anterior pituitary hormones. 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.
When explaining factors that influence the number of receptors present on target cells, the instructor will likely mention: Select all that apply.
The role antibodies may have on receptor proteins. A decreased hormone level may produce increased receptor numbers. A sustained excess hormone level brings about a decrease in receptor numbers. Feedback: Target cell response varies with the number and affinity of the relevant receptors. The number of hormone receptors on a cell may be altered for any of several reasons. Antibodies may destroy or block the receptor proteins. Increased or decreased hormone levels often induce changes in the activity of the genes that regulate receptor synthesis. For example, decreased hormone levels often produce an increase in receptor numbers by means of a process called up-regulation; this increases the sensitivity of the body to existing hormone levels. Likewise, sustained levels of excess hormone often bring about a decrease in receptor numbers by down-regulation, producing a decrease in hormone sensitivity.
Which of the following statements about immunoradiometric assay (IRMA) testing for is measuring plasma hormone levels the most accurate?
These tests are very specific since they utilize two antibodies instead of one. Feedback: Immunoradiometric assay (IRMA) testing is very specific since they utilize two antibodies instead of one. These two antibodies are directed against two different parts of the molecule, and therefore IRMA assays are more specific. Hormones circulating in the plasma were first detected by bioassay test, which used an intact animal or a portion of tissue from an animal to calculate specificity and sensitivity. ELISA testing procedure utilizes antibody-coated plates to produce colored reactions. The IRMA is a blood test, not a urine test.
While discussing the elimination of hormones from the body to prevent overaccumulation, which of the following hormones are eliminated in bile? Select all that apply.
Unbound adrenal hormones, Gonadal steroid hormones, and Thyroid hormones. Feedback: Steroid hormones are bound to protein carriers for transport and are inactive in the bound state. Unbound adrenal and gonadal steroid hormones are conjugated in the liver, which renders them inactive, and then excreted in the bile or urine. Thyroid hormones also are transported by carrier molecules. The free hormone is rendered inactive by the removal of amino acids in the tissues, and the hormone is conjugated in the liver and eliminated in the bile. The catecholamine production is measured by some of their metabolites. In general, peptide hormones also have a short life span in the circulation. Their major mechanism of degradation is through binding to cell surface receptors, with subsequent uptake and degradation by peptide-splitting enzymes in the cell membrane or inside the cell.
In major athletic competition, athletes are required to submit to liquid chromatography testing looking for:
Use of performance-enhancing agents to increase the chances of winning. Feedback: For some steroid or peptide hormones, mass spectrometry is becoming increasingly useful and can be combined with other analytical techniques, such as liquid chromatography. These approaches provide definitive identification of the relevant hormone or compound according to its chemical or physical characteristics (e.g., unequivocal detection of performance-enhancing agents in sports).
A student nurse is taking a test on the endocrine system. From the following list of clinical manifestations, she needs to select the ones she would see in hypothyroidism. Which answers should she select? Select all that apply.
Weight gain despite loss of appetite, Coarse brittle hair, and Puffy face with swollen eyelids. Feedback: The hypometabolic state associated with hypothyroidism is characterized by a gradual onset of weakness and fatigue, a tendency to gain weight despite a loss of appetite, and cold intolerance. As the condition progresses, the skin becomes dry and rough and the hair becomes coarse and brittle. Reduced conversion of carotene to vitamin A and increased blood levels of carotene may give the skin a yellowish color. The face becomes puffy with edematous eyelids, and there is thinning of the outer third of the eyebrows. Nervousness with fine muscle tremors and heat intolerance are signs of hyperthyroidism.
Which of the following individuals is experiencing the effects of a primary endocrine disorder? A client:
Who has low calcium levels because of the loss of his parathyroid gland. Feedback: The loss of a gland, and the subsequent absence of the hormone that it normally produces, results in a primary endocrine disorder. The lack of a stimulating hormone such as ACTH or TSH results in a secondary disorder, whereas hypothalamic dysfunction causes tertiary endocrine disorders.
Which of the following clinical manifestations lead the health care worker to suspect the client is at the end-stage expression of hypothyroidism? A client: Select all that apply.
Who takes analgesics for chronic pain that goes into a coma and Brought to the emergency department with hypothermia who presents with low serum sodium levels. Feedback: Myxedematous coma is a life-threatening, end-stage expression of hypothyroidism. It is characterized by coma, hypothermia, cardiovascular collapse, hypoventilation, and severe metabolic disorders including hyponatremia, hypoglycemia, and lactic acidosis. With the hypermetabolic state of hyperthyroidism, there are frequent complaints of nervousness, irritability, and fatigability. Weight loss is common despite a large appetite. Other manifestations include tachycardia, palpitations, shortness of breath, excessive sweating, muscle cramps, and heat intolerance.