Please answer all questions and correctly, thank you. This is the continuation o

Question

Please answer all questions and correctly, thank you.

This is the continuation of Felix Hernandez's complicated case. Felix was first introduced to us when he was evaluated by the gait and balance (GAB) clinic after several falls put him at risk for serious injury. A referral to an endocrinologist, an endocrine system specialist, was one of many useful recommendations made by the multidisciplinary GAB clinic team. This case reviews the clinical findings made by Dr. Aaron Young after his appointment with Mr. Hernandez.

The Hernandez couple finds themselves, once again, in a specialist examination room. Dr. Young introduces himself and explained his role in Felix's healthcare. Dr. Young had received a full report from Felix's primary care physician, which included all the clinical lab results, GAB clinic assessment notes, and GAB clinic final recommendations. Felix was curious about exactly what an endocrinologist does, and how that was going to keep him from falling down again. Felix had spent over an hour with a neurologist who explained how the nervous system helped keep him from falling.

1. Dr. Young explains how chemical signals from both the endocrine and nervous systems respond to changes in Felix's body or his surrounding environment. Which of the following statements is false with regard to the types of chemical signals used by the endocrine system?

Dr. Young explains how chemical signals from both the endocrine and nervous systems respond to changes in Felix's body or his surrounding environment. Which of the following statements is false with regard to the types of chemical signals used by the endocrine system?

A) Endocrine signals are secreted into the blood and travel to exert their effects on distant target tissues.

B) Autocrine signals are secreted into the surrounding interstitial fluid where they affect the same cell or cell type.

C) Paracrine signals are secreted into the blood and travel to distant target tissues where they exert their effects.

D) Paracrine signals are secreted into the surrounding interstitial fluid where they exert their effects on surrounding different cell types.

2. Dr. Young described how several endocrine organs were anatomically linked to the central nervous system. The brain contains the hypothalamus and the pituitary gland, which work together to regulate many bodily functions, including hunger and thirst. Both of these were issues that Felix had discussed with the dietician and gerontologist at GAB clinic previously. These endocrine structures also play a vital role in the regulation of other endocrine organs found throughout the body.

Dr. Young explains that the hypothalamus and pituitary gland can regulate the activities of other endocrine organs. Predict the response of the hypothalamus and pituitary gland if the blood level of thyroid hormones decreases.

A) The secretion of thyrotropin-releasing hormone (TRH) increases, which stimulates the secretion of thyroid-stimulating hormone (TSH) that in turn stimulates the thyroid gland to secrete more thyroid hormones.

B) The secretion of thyrotropin-releasing hormone (TRH) increases, which inhibits the secretion of thyroid-stimulating hormone (TSH) that inhibits the release of thyroid hormones from the thyroid gland.

C) The secretion of thyrotropin-releasing hormone (TRH) increases, which stimulates the secretion of thyroid-stimulating hormone (TSH) that inhibits the release of thyroid hormones from the thyroid gland.

D) The secretion of thyrotropin-releasing hormone (TRH) is inhibited, which then inhibits the secretion of thyroid-stimulating hormone (TSH) that stimulates the release of thyroid hormones from the thyroid gland.

3. An abnormal thyroid panel was one of the clinical lab tests that concerned the GAB team. They noted that Mr. Hernandez's level of thyroid stimulating hormone (TSH) was abnormally elevated, while his thyroxine (T4) level was abnormally low. These lab results indicated that Mr. Hernandez likely suffered from hypothyroidism and would need to start thyroid hormone replacement therapy. This could be one of the reasons that Felix felt tired and weak recently. Usually the diagnosis of hypothyroidism and thyroid replacement therapy can be managed by the primary care physician. However, the GAB team was also concerned that there might be more to Felix's case, as other abnormalities were noted in his chemistry panel. Felix's serum sodium ion level was low and his serum potassium ion level was elevated. Felix was also slightly hypoglycemic, as his serum glucose level was abnormally low. For this reason, Felix's primary care physician had elected to wait for Dr. Young's assessment prior to starting any new drug therapy.

Thyroid function testing indicates that Felix has hypothyroidism. Which of the following statements best describes why his level of thyroid-stimulating hormone (TSH) is elevated?

A) Only the anterior pituitary detects low T4 levels and secretes TSH; the thyroid is unable to respond and the T4 level never returns to a normal range.

B) An inadequate T4 level inhibits the release of TRH, and the lack of TRH enables the anterior pituitary to increase TSH secretion. The thyroid gland is unable to respond to TSH and the T4 level never returns to a normal range.

C) The hypothalamus fails to respond to the low T4 level, and the lack of TRH enables the anterior pituitary to increase TSH secretion. The thyroid gland is unable to respond to TSH and the T4 level never returns to a normal range.

D) An inadequate level of T4 stimulates TRH to increase the amount of TSH, but the thyroid gland is unable to respond to TSH and the T4 level never returns to a normal range.

4. The adrenal medulla provides an example of the close relationship between the endocrine and nervous systems that Dr. Young discussed with Felix. If Felix's blood pressure drops, what hormone(s) will be released by the chromaffin cells in the adrenal medulla?

A) Catecholamines

B) Aldosterone

C) Cortisol

D) Glucocorticoids and mineralocorticoids

5. Felix's blood glucose level is consistently low, which is a risk factor for falling. Medications that reduce the blood glucose level, such as insulin products, commonly cause hypoglycemia. Felix has never been diagnosed with diabetes mellitus, nor has he taken any medications that cause hypoglycemia. There are tumors called insulinomas that may be located outside the pancreas that secrete high amounts of insulin. Dr. Young explains that he thinks this possibility is unlikely, but he will investigate it nonetheless.

During a recent stay in the hospital, Felix felt very sweaty, confused, and weak. His nurse used a bedside glucometer device to check Felix's blood glucose level, which was extremely low. The nurse administered an intravenous dose of both dextrose and glucagon per hospital protocol for hypoglycemia. The glucagon will do all of the following except:

A) trigger cellular uptake of amino acids and glucose into liver and muscle cells, leading to an increase in the blood glucose level.

B) trigger the release of fats from adipose tissue, which could be used for gluconeogenesis.

C)stimulate the breakdown of glycogen into glucose via glycogenolysis, which would increase the blood glucose level.

D)trigger protein catabolism in muscle tissue, which would release amino acids that could be used in gluconeogenesis.

6. Dr. Young ordered a serum vitamin D panel and a testosterone level test in addition to a bone density scan for Felix. He was concerned that Felix's loss of muscle mass and bone density could lead to a bone fracture from even a minor misstep while walking. Dr. Young also repeated the serum chemistry panel to make sure that the previous lab results were accurate. Recall that Felix had some electrolyte abnormalities (low sodium ion and elevated potassium ion levels). Felix's blood urea nitrogen (BUN) and serum creatinine levels were also elevated, which indicated some degree of kidney insufficiency.

After several liters of intravenous fluids have been infused for episodes of hypotension, Felix has become hypertensive. How does atrial natriuretic peptide (ANP) secreted by certain cardiac muscle cells work to reduce Felix's blood pressure?

A) ANP causes vasoconstriction and sodium ion retention.

B) ANP causes vasodilation and sodium ion retention.

C) ANP causes vasodilation and natriuresis.

D) ANP causes vasoconstriction and natriuresis.

7. Felix's hypothyroidism means his levels of thyroid hormone are inadequate. What did the thyroid hormones fail to do that led to an episode of hypoglycemia?

A) Stimulate the release of glucagon and growth hormone in order to increase blood glucose concentration.

B) Stimulate gluconeogenesis in order to increase blood glucose concentration.

C) Stimulate gluconeogenesis in order to decrease blood glucose concentration.

D) Stimulate the release of insulin in order to decrease blood glucose concentration.

Explanation / Answer

ANSWER: 1. (C) Paracrine signals are secreted into the blood and travel to distant target tissues where they exert their effects.

2. (A) The secretion of thyrotropin-releasing hormone (TRH) increases, which stimulates the secretion of thyroid-stimulating hormone (TSH) that in turn stimulates the thyroid gland to secrete more thyroid hormones.

3. (D) An inadequate level of T4 stimulates TRH to increase the amount of TSH, but the thyroid gland is unable to respond to TSH and the T4 level never returns to a normal range.

4. (A) Catecholamines.

5. (A) trigger cellular uptake of amino acids and glucose into liver and muscle cells, leading to an increase in the blood glucose level.

6. (C) ANP causes vasodilation and natriuresis.

7. (B) Stimulate gluconeogenesis in order to increase blood glucose concentration.

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