BIOL 2222 CH 16 Endocrine System PDF

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Patel, Ekta1

Chapter 16 The Endocrine System Level 1 Remember/Understand Q1. The major stimulus for release of parathyroid hormone is (a) hormonal, (b) humoral, (c) neural. Q2. The anterior pituitary secretes all but (a) antidiuretic hormone, (b) growth hormone, (c) gonadotropins, (d) TSH. Q3. A hormone not involved in glucose metabolism is (a) glucagon, (b) cortisone, (c) aldosterone, (d) insulin. Q4. Parathyroid hormone (a) increases bone formation and lowers blood calcium levels, (b) increases calcium excretion from the body, © decreases calcium absorption from the gut, (d) demineralizes bone and raises blood calcium levels. Q5. Choose from the following key to identify the hormones described. Key: (a) aldosterone (e) oxytocin (b) antidiuretic hormone (f) prolactin (c) growth hormone (g) T4 and T3 (d) luteinizing hormone (h) TSH C (1) important anabolic hormone; many of its effects mediated by IGFs A & B (2) cause the kidneys to conserve water and/or salt (two choices) F (3) stimulates milk production D (4) tropic hormone that stimulates the gonads to secrete sex hormones E (5) increases uterine contractions during birth G (6) major metabolic hormone(s) of the body A (7) causes reabsorption of sodium ions by the kidneys. H (8) tropic hormone that stimulates the thyroid gland to secrete thyroid hormone B & E (9) secreted by the posterior pituitary (two choices) A (10) the only steroid hormone in the list. Q6. A hypodermic injection of epinephrine would (a) increase heart rate, increase blood pressure, dilate the bronchioles of the lungs, and increase digestive activity, (b) decrease heart rate, decrease blood pressure, constrict the bronchioles, and increase digestive activity, (c) decrease heart rate, increase blood pressure, constrict the bronchioles, and decrease digestive activity, (d) increase heart rate, increase blood pressure, dilate the bronchioles, and decrease digestive activity. Q7. Testosterone is the male as which hormone is to the female? (a) luteinizing hormone, (b) progesterone, (c) estrogen, (d) prolactin

Patel, Ekta2 Q8. If anterior pituitary secretion is deficient in a growing child, the child will (a) develop acromegaly, (b) become a dwarf but have fairly normal body proportions, (c) mature sexually at an earlier than normal age, (d) affect only non-hormone-producing organs. Q9. If there is adequate carbohydrate intake, secretion of insulin results in (s) lower blood glucose levels, (b) increased cell utilization of glucose, (c) storage of glycogen, (d) all of these. Q10. Hormones (a) are produced by exocrine glands, (b) are carried to all parts of the boy in blood, (c) remain at constant concentration in the blood, (d) affect only non-hormone-producing organs. Q11. Some hormones act by (a) increasing the synthesis of enzyme, (b) converting an inactive enzyme into an active enzyme, (c) affecting only specific target organs, (d) all of these. Q12. Absence of thyroid hormone would result in (a) increased heart rate and increased force of heart contraction, (b) depression of the CNS and lethargy, (c) exophthalmos, (d) high metabolic rate Q13. Define Hormone. Answer: Hormones are the chemical substances that are secreted by the cells of endocrine gland. These are secreted directly into extracellular fluids that regulate the metabolic function of the other cells in the body. Hormones are divided into two types based on their metabolic function. They are -- Amino acid-based hormones and steroid hormones. Amino acid-based hormones are the derivatives of amino acid, they include amines, peptides and proteins. Q14. Name a hormone secreted by a muscle cell and two hormones secreted by neurons. Answer: The growth hormones (GH) like insulin-like growth factors (IGFs) are secreted by a muscle cell. These IGFs stimulate the growth by absorbing nutrients from blood and aiding in building of proteins and DNA, which allow growth by cell division. They also help in formation of collagen fibers and deposition of bone matrix, which helps in building skeletal muscles. The two hormones that are produced by neurons are antidiuretic hormone (ADH) and oxytocin hormones of posterior pituitary gland. The ADH promotes re-absorption of water in kidney tubule cells whereas oxytocin promotes contraction of uterine or cervix during cell birth and also initiates lactation.

Level 2 Apply/Analyze Q15. (a) Describe the body location of each of the following endocrine organs: anterior pituitary, pineal gland, pancreas, ovaries, testes, and adrenal glands. (b) List the hormones produced by each organ Answer: (a) The body location of each of the endocrine organs are:  Anterior pituitary gland is located the glandular portion of a pituitary gland.  Pineal gland is located in the diencephalon  The pancreas is located in the abdomen close to the stomach, which acts as an exocrine and endocrine gland.  The ovaries of the female are located in the abdominopelvic cavity. They are paired and small.  The male testes are located in an extra abdominal skin pouch called the scrotum.

Patel, Ekta3 (b) The hormones produced by each organ are:  Anterior pituitary produces six hormones. They are Growth hormones (GH), Thyroid stimulating hormones (TSH), Adrenocorticotropic hormone (ACTH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), and Prolactin (PRL).  The pineal gland produces melatonin hormone that influences daily rhythms.  The endocrine portion of pancreatic islets releases insulin and glucagon.  The ovaries produce estrogen and progesterone hormones that are helpful in maintaining the female reproductive system.  Testes produce testosterone hormone that is helpful in maintaining the male reproductive system. Q16. The anterior pituitary is often referred to as the master endocrine organ, but it, too, has a "master". What controls the release of anterior pituitary hormones? Answer: The anterior pituitary is known as master endocrine gland. This is because it controls all the activities if other endocrine glands. The actions of anterior pituitary gland re regulated by hypothalamus. An anterior pituitary gland secrets six hormones- Growth hormones (GH), Thyroid stimulating hormones (TSH), Adrenocorticotropic hormone (ACTH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), and Prolactin (PRL). Hypothalamus controls the secretions of anterior pituitary gland. It sends signals to anterior pituitary gland to release the hormones at an appropriate time. Thus, they secrete specific hormone in response to specific stimuli. The release of anterior pituitary gland inhibited by receiving specific inhibiting hormones. Q17. The posterior pituitary is not really an endocrine gland. Why not? What is it? Answer: The posterior pituitary is one quality that is composed of axons of hypothalamic neurons. It stores antidiuretic hormone (ADH) and oxytocin hormone that regulate the water balance in our body in response to the stimuli. The stimuli of ADH and oxytocin are transferred from supraoptic and paraventricular nuclei through hypothalamic neurons. They also help in storing hormone, thus posterior pituitary gland is not an endocrine gland. Q18. Endemic goiter is not really the result of a malfunctioning thyroid gland. What does cause it? Answer: The conditions with colloidal, or endemic, goiter to due to malfunctioning of thyroid gland. The condition is said to be myxedema. Myxedema is mucous swelling that is caused due to hyposecretion of the thyroid gland. The condition of myxedema occurs mainly due to lack of iodine in the ingested food. The lack of iodine in chosen food causes the enlargement of thyroid gland that protrudes into a colloidal goiter in adults. Thus, lack of iodine in ingested food causes myxedema. Q19. Roger Proulx has severe arthritis and has been taking prednisone (a glucocorticoid) for two months. He isn't feeling well, complains of repeated “colds,” and is extremely “puffy" (edematous). Explain the reason for these symptoms. Answer: Prednisone is a glucocorticoid, which is used as an anti-inflammatory drug majorly for arthritis. In this case, the person RP is suffering from severe arthritis, and hence anti-inflammatory drug, prednisone to get treated it. As the arthritis is severe, he might have been using some larger doses of

Patel, Ekta4 prednisone that too, for two months. So, due to this prolonged usage, glucocorticoids would have exerted some symptoms, which may result in Cushing’s syndrome. The symptoms with Cushing’s syndrome include loss of muscle and bone proteins, increase in the blood glucose levels, and retention of water and salt. Due to the loss of protein from the bones and muscles, the patient is suffering from repeated colds. Due to the retention of water and salts, edematic condition (puffiness) is seen with moon like face. He also has the poor wound healing.

Level 3 Evaluate/Synthesize Q20. What type of hormone receptor-plasma membrane bound or intracellular- would be expected to provide the most long-lived response to hormone binding and why? Answer: Water soluble hormones are one of hormones that act on receptors of plasma membrane. These targeted receptors attach with hormones and form a coupling action through the regulatory molecules, which are known as G proteins. These G proteins mediate the response ofc the target cell through intracellular secondary messengers. The genes could directly activate by the lipid-soluble hormones like steroid and thyroid hormones. Receptors of water-soluble hormones must be in the plasma membrane since these hormones cannot enter the cell. The receptors for steroid and thyroid hormones can enter cell because they are lipsoluble, which provides long-lived response. Thus, long-lived responses could be provided by hormones to affect target cells. Q21. Name two endocrine glands (or regions) that are important in the stress response and explain why they are important. Answer: The adrenal gland is important in the stress response. Stressful stimuli cause the hypothalamus to activate the adrenal medulla through sympathetic nerve impulses and the adrenal cortex via hormonal signals. In response to stimuli, adrenal secretes two hormones I.e. Epinephrine and norepinephrine, which regulate short term stress response. In response to stimuli, adrenal cortex produces two hormones I.e. mineralocorticoids and glucocorticoids, which are important in the longterm stress response. Thus, these hormones are important. Q22. How are the hyperglycemia and lipidemia of insulin deficiency linked? Answer: The hyperglycemia is a condition that occurs at low blood glucose levels in the body. The hormones of hyperglycemia are released due to low blood glucose level and produce glucose by breaking down of glycogen into glucose. The produced glucose is released directly into the blood, by causing a rise in blood glucose level. Lipidemia is a condition in which sugars cannot be used as cellular fuel. Hence more fats are mobilized, resulting in production of high fatty acid levels in the blood. In contrast to hyperglycemia, lipidemia also increases sugar levels in the blood. Thus, hyperglycemia and lipidemia of insulin deficiency are linked. Q23. List some problems that elderly people might have as a result of decreasing hormone production. Answer: The elderly people face various problems due to a decrease in the hormone production. Some of the problems are:   

Decrease in insulin production leads to a diabetic condition like diabetic mellitus. Decrease in the production of antidiuretic hormone results in the condition diabetic insipidus. Decrease in Prolactin results in poor milk production in nursing women.

Patel, Ekta5   

Decrease in mineralocorticoids and glucocorticoids of adrenocortical hormones lead to Addison’s disease. Decrease in growth hormone enables muscle atrophy in old age. Decrease in estrogen in women leads to osteoporosis.

Q24. Mary Morgan has just been brought into the emergency room of City General Hospital. She is perspiring profusely and is breathing rapidly and irregularly. Her breath smells like acetone (sweet and fruity), and her blood glucose tests out at 650 mg/100mL of blood. She is in acidosis. Which hormone drug should be administered, and why? Answer: The normal blood glucose levels in a healthy person before meals (fasting) should be between 70 to 100 mg per deciliter. After meals, the blood glucose levels should be less than 180 mg per deciliter. But in the given case, the blood glucose levels of person MM are very high. They are 650mg per 100ml means 650mg per deciliter. It is absolutely more than the normal levels. Perhaps, she is a diabetic patient and was untreated. As she is a diabetic patient, in her body, the fats are being converted into fatty acids. These fatty acids get metabolized to ketone bodies (which include acetone, acetoacetic acid etc.). These ketone bodies get accumulated in the body and that is why her blood pH turned down. Thus, she became metabolic acidosis. Due to the ketone bodies, her breath smells sweet and fruity due to the exhalation of acetone. To treat this condition, insulin is to be administered immediately. Insulin is an endocrine hormone, which regulate the blood sugar levels. This hormone made up of two chains called “A” and “B.” The A chain has 21 amino acids and the B chain has 30 amino acid. Totally one Insulin has 51 amino acids. The A and B chains are bonded by the inter disulphide bonds and the A chain has an intra-disulphide bridge between 6 (cysteine) and 13 (cysteine) amino acids. It promotes the formation of energy storage molecules and other processes typical of the absorptive phase such as the synthesis of glycogen, proteins, and lipids. Beta cells in pancreas Insulin secretion

Most tissues

Adipose tissue

Liver and muscle

Liver

Glucose uptake (Except brain, liver, exercising Fatty acid muscle) and triglyceride synthesis Glycogen synthesis Fatty acid and triglyceride synthe Amino acid up take ↓ Lipolysis ↓ Glycogenolysis ↓ Gluconeogenesis protein breakdown ↓ Protein synthesis Initial stimulus Physiological response

Patel, Ekta6 Diabetes occurs in the people due to the deficiency or absence of insulin or improper utilization of insulin. Anyways, when insulin is administered, it improves that membrane transport of glucose into the cells of the muscle and fat. Breakdown of glycogen to glucose in inhibited by the insulin. After the glucose enters its target cell, insulin also helps in inhibiting the gluconeogenesis. It also inhibits the conversion of amino acids and fats into glucose. By these functions, insulin can decrease the blood glucose levels. Insulin also helps further by hastening the activities of the enzymes, which:   

Perform the catalysis of oxidation of glucose to ATP (adenosine triphosphate) production Convert glucose molecules to glycogen Convert glucose to fat

Thereby, Insulin is the hormone that helps to decrease the plasma glucose levels in our body. Q25. Kyle, a 5-year-old, has been growing by leaps and bounds; his height is 100% above normal for his age. He has been complaining of headaches and vision problems. A CT scan reveals a large pituitary tumor. (a) Which hormone is being secreted in excess? (b) What condition will Kyle will exhibit if corrective measures are not taken? (c) What is the probable cause of his headaches and visual problems? Answer: The five-year boy, “K” is growing very faster than his age and his height is 100% normal for his age. Due to his condition he is facing some problems like vision problem and headache. Do, he went to CT (computerized tomography) scan and it is showing a large pituitary tumor. (a) So, based on the given data, the growth hormone is being secreted in excess. The hypothalamus stimulates the release of the growth hormone (GH), or somatotropin, from the anterior pituitary gland. GH targets nearly every cell in the body and promotes growth and development. It promotes protein synthesis and cellular growth. It is particularly important during the stage of childhood development. (b) Gigantism occur due to excessive secretion of growth hormone in children, thus, if the corrective and proper measures are not taken, then “K” will show physical abnormalities, like gigantism. (c) The Optic nerve is formed by axons of ganglionic cells, which leaves the eye through optic disk. Optic nerves of each eye transmit the sensation to the brain. The medial fibers (of optic nerves) of both sides cross at chiasma, which is present near the center of the base of cerebral cortex. This, the likely cause of “K” vision problems and headache is that his optic chiasma is compressed by the inferiorly protruding pituitary gland. Q26. Aaron, a 42-year-old single father, goes to his physician complaining of nausea and chronic fatigue. He reports having felt fatigue and listless for about half a year, but he had attributed this to stress. He has lost considerable weight and, strangely, his skin looks tanned, even though he spends long hours at work and rarely ventures outside. His doctor finds very low blood pressure and a rapid, weak pulse. Blood tests show Aaron does not have anemia, but his plasma glucose, cortisol, and Na + are low, and his plasma K+ is high. His doctor orders an ACTH stimulation test, in which Aaron’s secretion of cortisol is measured after he is given a synthetic form of ACTH. (a) What would account for Aaron’s low plasma Na+ and high plasma K+?

Patel, Ekta7 (b) What is the reason for doing an ACTH stimulation test? (c) Which gland is primarily affected if ACTH does not cause a normal elevation of cortisol secretion? What is this abnormality called? (d) Which gland is primarily affected id ACTH does cause an elevation of cortisol secretion? Answer: (a) Mr. “S” low has low plasma Na+ (sodium) and high plasma K+ (potassium) due to low levels of the mineralocorticoid called aldosterone. The disease condition may be Addison’s disease or adrenal insufficiency. Hence, Mr. “S” loses weight and has hypertension. (b) Here, Mr. “S” was given an ACTH (Adrenocorticotropic hormone) stimulation test, thus the doctor can observe the response of the adrenal glands towards the hormone. This test is primarily used for accessing the functioning of the adrenal glands and secondary for accessing the functioning of the pituitary glands. (c) If the cortisol levels are not elevated sufficiently with the ACTH stimulation, then it leads to adrenal insufficiency. The adrenal glands are abnormal in function and unable to secrete cortisol in spite of excess stimulation with ACTH. The abnormality is called Addison’s disease or adrenal insufficiency. (d) If ACTH does cause an elevation of cortisol secretion, then it states that pituitary gland is primarily affected....