Chapter 16: The Endocrine System (Part 2) – Flashcards
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The parathyroid glands maintain adequate levels of blood calcium. This is accomplished through
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targeting the bone and activating osteoclasts so that calcium will be released.
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Which organ is responsible for synthesizing ANP?
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The heart.
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Mineralocorticoid is to aldosterone as glucocorticoid is to
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cortisol.
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Leptin is secreted by
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adipocytes.
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The most important regulator of electrolyte concentrations in extracellular fluids is
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aldosterone.
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Which of the following is NOT a steroid-based hormone?
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Epinephrine.
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Which of the following would be associated with the action of steroids on cells?
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A hormone-receptor complex that interacts directly with the cell's DNA.
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Cellular responses to hormones from the hypothalamus
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first enter into the hypophyseal portal system.
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ACTH secretion is regulated by
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a hypothalamic secretion.
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Which of the following is true about calcium homeostasis?
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Parathyroid hormone is the single most important regulator of calcium levels in the blood.
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Aldosterone functions to
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increase sodium reabsorption.
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The only amine hormone to act like a steroid is
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thyroid hormone (TH).
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Which organ does NOT have hormone production?
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Liver
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In circumstances where the body requires prolonged or increased levels of a hormone, the DNA of target cells will specify the synthesis of more receptors on the surface of the cells of the target organ. This is known as
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up-regulation.
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Eicosanoids do NOT include
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hydrocortisones.
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A man has been told he is NOT synthesizing enough follicle-stimulating hormone, and for this reason he may be unable to father another child. Choose the correct statement to explain this problem.
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FSH stimulates sperm production in the testes.
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Which of the following organs is affected by thyroid hormone in adults?
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Liver.
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Thyroxine is a peptide hormone, but its mechanism is different from other peptide hormones because
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It does not require a second messenger to effect a response.
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How do glucocorticoids enable the body to deal appropriately with stress?
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By increasing blood glucose, fatty acid, and amino acid levels and enhancing blood pressure.
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What ion is sometimes used a second messenger of amino acid-based hormones?
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Calcium.
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What are steroids?
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Hormones synthesized from cholesterol.
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What is prolactin?
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A hormone that has only one known effect: to stimulate milk production by the breasts.
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What is the largest pure endocrine gland in the body?
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The thyroid.
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Which hormone stimulates production of RBCs and which organ or structure produces it?
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Erythropoietin; kidney.
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What extremely potent hyperglycemic hormone do alpha islet cells produce?
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Glucagon.
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What gland may influence our day/night cycles and even regulate the onset of sexual maturity?
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Pineal gland.
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What gland declines in size and function with age?
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The thymus.
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Endocrine gland stimuli include hormonal, _____ and _____.
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humeral and neural stimuli.
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As a result of stress the adenohypophysis releases ______, which stimulates the release of hormones from the adrenal cortex that retain sodium and water, increase blood sugar, and begin breaking down fats.
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ACTH.
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Corticotropin-releasing hormone (CRH) stimulates
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the pituitary to release adrenocorticotropic hormone (ACTH).
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Gonadotropin-releasing hormone (GnRH) stimulates
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the pituitary to release luteinizing hormone (LS) and follicle-stimulating hormone (FSH).
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Thyrotropin-releasing hormone (TRH) stimulates
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the pituitary to release thyroid-stimulating hormone (TSH).
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Growth hormone-releasing hormone (GHRH) stimulates
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the release of growth hormone 9GH) from the (GHRH) pituitary.
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What does somatostatin inhibit?
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The release of GH from the pituitary.
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What does dopamine inhibit?
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The release of prolactin from the pituitary.
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ACTH stimulates...
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the release of hormones from the adrenal cortex.
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Compare the structure and function of endocrine and exocrine glands.
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Endocrine glands are ductless glands that release hormones into the blood to be transported to other organs. Exocrine glands have ducts through which products are released.
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Why should the hypothalamus instead of the adenohypophysis be called the "master endocrine gland"?
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The hypothalamus controls anterior pituitary activity through regulatory factors.
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Why would one NOT expect to continue increasing in height with age?
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The amount of growth hormone secreted declines with age and the closure of the epiphyseal plates prohibits further growth in length of the long bones.
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A woman with excessive body hair, a deep voice, and an enlarged clitoris shows the outward symptoms of which hormonal dysfunction?
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Hypersecretion of gonadocorticoids.
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A person who drinks a lot of alcohol beverages must urinate frequently. Why?
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Alcohol inhibits ADH secretion.
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How is the heart involved as an endocrine gland?
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A few cardiac cells secrete atrial natriuretic peptide (ANP), which helps regulate salt output by the kidney. ANP inhibits aldosterone and signals the kidney to remove more salt.
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Briefly discuss target cell activation by hormone-receptor interaction.
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The first step is hormone-receptor binding to target cells, but interaction depends on blood levels of the hormone, relative number of receptors for that hormone on or in the target cells, and the strength of the union between the hormone and the receptor.
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Glucagon and insulin both target the cells of the liver and are both made in the pancreas, yet they have different effects on the cells they target. What accounts for this fact?
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Glucagon and insulin use different cell surface receptors.
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Basal metabolism declines with age. What factors contribute to that decline?
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Thyroid follicles fill with colloid and gland fibrosis occurs, resulting in hormone synthesis and release diminishing. Increase in body fat relative to muscle also contributes because muscle tissue is more active metabolically than fat.
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List the 4 mechanisms involved in the regulation of aldosterone secretion.
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1) the renin-angiotensin mechanism, 2) plasma concentration of sodium and potassium ions, 3) control exerted by ACTH, and 4) plasma concentration of atrial natriuretic peptide.
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What is the difference between autocrines and paracrines?
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Autocrines are self-regulating chemical messengers because their target is the cell from which they are manufactured. Paracrines are chemical messengers that act locally. They tend to affect only the cells immediately around them.
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Give an example of synergism in hormones.
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The liver will release glucose in the presence of glucagon or epinephrine. If both hormones are present, the amount of glucose is increased 150%.
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Growth hormones act indirectly to make the epiphyseal plate cartilage grow. What then acts directly to make it grow?
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The growth hormone stimulates the liver to release a growth factor called somatomedin, which in turn controls the epiphyseal plate cartilage.
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An autoimmune problem involving the thyroid gland
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Graves' disease
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Hyposecretion of growth hormone.
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Pituitary dwarfism.
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Hyposecretion of the pancreas.
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Diabetes mellitus.
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Hyposecretion of the adrenal cortex.
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Addison's disease.
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Hypersecretion of growth hormone.
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Acromegaly & gigantism.
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Hyposecretion of the thyroid in adults.
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Myxedema.
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Hypersecretion of the adrenal cortex.
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Cushing's disease.
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Hyposecretion of the thyroid in infants.
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Cretinism.
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Produces glucocorticoids.
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Adrenal glands/zona fasciculate.
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Produces epinephrine.
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Adrenal medulla.
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Produces aldosterone.
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Zona glomerulosa.
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Excess hormone levels result in Cushing's syndrome.
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Aldosterone/zona glomerulosa.
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Hormones mimic sympathetic nervous system neurotransmitters.
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Adrenal medulla.
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Produces androgens.
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Adrenal cortex/zona reticularis.
