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26 Cards in this Set

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1. Binding of hormones to plasma membrane receptors leads to the activation of intracellular protein kinases. Which of the following statements about protein kinases is CORRECT?

a. Protein kinases transfer the terminal phosphate of AMP to serines, threonines, or tyrosine in proteins.

b. Calcium binding to calmodulin activates calmodulin kinase.

c. Protein kinase A is activated by diacylglycerol (DAG)

d. Protein kinase C is activated by cyclic AMP (cAMP)

e. Activation of tyrosine kinase activity requires a second messenger, like cAMP.
b. Calcium binding to calmodulin activates calmodulin kinase.
2. Prostaglandins, thromboxanes and leukotrienes are regulatory molecules.
Which of the following statements about these molecules is NOT CORRECT?

a. Prostaglandins, thromboxanes and leukotrienes are eicosanoids derived from arachidonic acid.

b. Eicosanoid synthesis is stimulated when arachidonic acid is excised from membrane phospholipids by phospholipase A2

c. Prostaglandins, thromboxanes and leukotrienes are second messengers that directly regulate protein kinase activity.

d. Prostaglandins, thromboxanes and leukotrienes are secreted from cells, bind G-protein coupled receptors and regulate cellular levels of second messengers, i.e., cAMP and intracellular free Ca+2

e. Prostaglandins, thromboxanes and leukotrienes are regulatory ligands that are involved in local inflammatory processes.
c. Prostaglandins, thromboxanes and leukotrienes are second messengers that directly regulate protein kinase activity.
3. Neurosecretory cells play an important role in neuroendocrinology. Which of the following statements is CORRECT?

a. Neurosecretory cells are glandular (epithelial, endocrine) cells that have the capacity to secrete hormones.

b. Neurosecretory cells secrete hydrophobic hormones, like steroids.

c. Neurosecretory cells secrete hormones from axonal termini that end at the level of the median eminence and posterior pituitary.

d. Hormones secreted from neurosecretory cells at the level of the median eminence enter the blood and will flow directly into the general (systemic) circulation.

e. Neurosecretory cells secrete hormones in a constant, non-pulsatile, fashion.
c. Neurosecretory cells secrete hormones from axonal termini that end at the level of the median eminence and posterior pituitary.
4. Components of the endocrine system include:

a. hormones and receptors

b. target cells

c. hormone producing cells and a circulatory system for hormone delivery

d. a post-receptor mechanism to alter cell function

e. all of the above are correct
e. all of the above are correct
5. Which of the following statements about hormone receptors is NOT CORRECT?

a. Desensitization of receptors is due to a hormone-induced change in hormone binding (affinity) to the receptor or to a decline in receptor abundance.

b. The effective dose (ED50, units = moles/liter) and the equilibrium dissociation constant (Kd, units=moles/liter) represent the concentration of hormone required to achieve the maximum biological response and 100% of receptors occupied by hormone.

c. Plasma membrane receptors bind hydrophilic hormones.

d. Hormone structure is an important determinant in the binding of hormones to receptors and in the hormonal control of cell function.

e. Nuclear receptors bind hydrophobic hormones.
b. The effective dose (ED50, units = moles/liter) and the equilibrium dissociation constant (Kd, units=moles/liter) represent the concentration of hormone required to achieve the maximum biological response and 100% of receptors occupied by hormone.
6. G-proteins play an important role in hormone regulation of cell function.
Which of the following statements about G-proteins is NOT CORRECT?


a. G-proteins are membrane bound proteins that consists of 3 subunits, alpha, beta and gamma

b. The alpha subunit binds guanosine triphosphate (GTP) and has GTPase activity.

c. Hormone binding to receptors induces GDP to dissociate from the alpha subunit; the alpha subunit then binds GTP.

d. The alpha-GDP subunit complex activates enzymes, like adenylyl cyclase, that synthesize second messengers.

e. The alpha-GTP subunit complex activates enzymes, like adenylyl cyclase, that synthesize second messengers.
d. The alpha-GDP subunit complex activates enzymes, like adenylyl cyclase, that synthesize second messengers
7. Which of the following statements about the posterior pituitary is CORRECT?

a. The posterior pituitary is neural tissue, an extension of the hypothalamus

b. Hormones secreted from the posterior pituitary flow into the general (systemic) circulation.

c. Vasopressin (anti-diuretic hormone, ADH) and oxytocin are two posterior pituitary hormones

d. Vasopressin secreting cells do not secrete oxytocin.

e. All of the above statements are correct.
e. All of the above statements are correct.
8. Which of the following statements about vasopressin and oxytocin is NOT CORRECT?

a. The active forms of vasopressin and oxytocin are 9 amino acid peptides that contain a disulfide bond.

b. Vasopressin is a key hormone involved in the control of whole body water balance.

c. An increase in blood volume stimulates vasopressin secretion.

d. Vasopressin binds receptors in the kidney that inhibits loss of water in the urine.

e. Oxytocin is a key hormone in female physiology. Oxytocin binds receptors in smooth muscle in the uterus and myoepithelial cells in the mammary gland. In each case, oxytocin binding to membrane receptors stimulates cell contraction.
c. An increase in blood volume stimulates vasopressin secretion.
9. The most abundant chemical in the body (as a % of body weight) is:

a. Water

b. Calcium

c. Fat

d. Protein

e. Carbohydrate
a. Water
10. Which of the following statements about the anterior pituitary is NOT CORRECT?

a. Neurosecretory cells with axonal termini ending at the level of the median eminence secrete protein, peptide or catecholamine hormones that enter the local pituitary circulation. These hypothalamic hormones control the secretion of anterior pituitary hormones.

b. Hypothalamic hormones controlling anterior pituitary hormone secretion include TRH, CRH, GHRH, GnRH, somatostatin and dopamine.

c. The somatotroph represents the least abundant anterior pituitary cell type; these cells secrete only ACTH.

d. Anterior pituitary hormone secretion is regulated by feedback inhibition.

e. Pulsatile secretion of anterior pituitary hormones is regulated by pulsatile secretion of hypothalamic releasing hormones and release inhibiting hormones.
c. The somatotroph represents the least abundant anterior pituitary cell type; these cells secrete only ACTH.
11. Which of the following statements about growth hormone (GH) is NOT CORRECT?

a. Somatostatin stimulates and GHRH inhibits GH secretion.

b. Blood levels of GH increase at night and during puberty.

c. GH binds receptors in target cells. This receptor interacts with a separate protein that has tyrosine kinase activity, i.e., Janus or JAK kinase.

d. GH stimulates IGF-1 secretion from liver. Therefore, the liver is an endocrine gland, regulated by GH.

e. IGF-1 is a feedback inhibitor of GH secretion.
a. Somatostatin stimulates and GHRH inhibits GH secretion.
12. Which of the following steps IS NOT involved in the synthesis and secretion of thyroid hormones, T4 and T3?

a. Dietary iodine is required for T4 and T3 synthesis.

b. Iodide (I-) is covalently attached to tyrosines in thyroglobulin by a peroxidase at the apical surface of thyroid follicular cells.

c. Iodinated tyrosines within the thyroglobulin protein are coupled together to form iodothyronines.

d. Iodinated thyroglobulin is secreted into the blood. The thyroid hormones (T4 and T3) are released from thyroglobulin by blood proteases.

e. Iodinated thyroglobulin is stored in the colloid. Secretion of thyroid hormones (T4 and T3) requires thyroglobulin to be taken up by the thyroid follicular cell (endocytosis) and degraded by lysosomal proteases. T4 and T3 are secreted into the blood.
d. Iodinated thyroglobulin is secreted into the blood. The thyroid hormones (T4 and T3) are released from thyroglobulin by blood proteases.
13. Which of the following BEST describes the regulation of calcium (Ca+2) absorption by the intestine.

a. Dietary Ca+2 in the intestinal lumen is transported into intestinal mucosa cells through a Ca+2 channel.

b. Intracellular Ca+2 binds calbindin and is transported into the interstitial space and blood by a Ca+2-ATPase (a pump).

c. 1,25 (OH)2-Vitamin D3 will bind receptors in nuclei of intestinal mucosal cells and stimulate the transcription of genes encoding calbindin and Ca+2-ATPase.

d. Increased blood levels of calcium (and phosphate) provide key substrates for bone mineralization, i.e., deposition of calcium and phosphate in bone.

e. All of the above statements are correct.
e. All of the above statements are correct.
14. Hormones of the adrenal gland are essential for life. Which of the following statements about adrenal hormones is NOT CORRECT?

a. Hormones secreted from the adrenal gland include: glucocorticoids, mineralocorticoids, androgens and catacholamines.

b. Glucocorticoids, mineralocorticoids and androgens are synthesized in the adrenal cortex; cholesterol is the precursor for steroid synthesis.

c. Catacholamines are synthesized in the adrenal cortex; serine is the precursor for catecholamine synthesis.

d. Adrenal hormones coordinate the body’s response to stress.

e. Glucocorticoids dampen the immune system.
c. Catacholamines are synthesized in the adrenal cortex; serine is the precursor for catecholamine synthesis.
15. The endocrine system plays a role in which of the following physiological processes:

a. growth and development

b. reproduction

c. energy metabolism, utilization and storage

d. maintenance of the internal environment

e. all of the above are correct
e. all of the above are correct
16. Thyroid hormone plays a major role in whole body metabolism. Which of the following statements about thyroid hormone is NOT CORRECT?
a. Hashimoto’s disease is an autoimmune disease. Patients with Hashimoto’s disease are hyperthyroid with elevated blood T3 levels.

b. T3 is the active form of the hormone. T3 binds nuclear receptors and regulates gene expression leading to changes in protein abundance and cell function.

c. T3 and T4 are hydrophobic hormones that are transported in the circulation in association with binding proteins like thyroxine binding globulin.

d. T3 regulates the basal metabolic rate, (BMR). T3 effects on BMR include control of fat and carbohydrate oxidation which impacts oxygen consumption and respiration, as well as cardiac output.

e. T3 is a feedback regulator of thyroid function by inhibiting the secretion of TRH from the hypothalamus and TSH from the anterior pituitary.
a. Hashimoto’s disease is an autoimmune disease. Patients with Hashimoto’s disease are hyperthyroid with elevated blood T3 levels.
17. Glucocorticoids play a major role in whole body carbohydrate, fat and protein metabolism. Key metabolic pathways that are regulated by glucocorticoids include:

a. Glycogen synthesis and gluconeogenesis in the liver

b. Lipolysis (Lipid breakdown) in adipose tissues

c. Protein breakdown in muscle and other tissues

d. Interference with glucose uptake by muscle and adipose tissue

e. All of the above pathways listed above are regulated by glucocorticoids.
e. All of the above pathways listed above are regulated by glucocorticoids.
18. Catacholamines are synthesized and secreted from cells in the adrenal gland. Which of the following statements is NOT CORRECT?

a. Epinephrine is synthesized in and secreted from Chromaffin cells in the adrenal medulla.

b. Phenylethanolamine-N-methyl transferase is the rate limiting enzyme in the pathway for synthesis of epinephrine.

c. Epinephrine is stored in secretory granules; acetylcholine secreted from cholinergic preganglionic fibers stimulates exocytosis of adrenal medulla secretory granules and epinephrine secretion.

d. Epinephrine has a very short half life (minutes) in the blood; it binds G-protein coupled receptors called adrenergic receptors.

e. Adrenergic receptors regulate cellular levels of cAMP and intracellular free Ca+2.
b. Phenylethanolamine-N-methyl transferase is the rate limiting enzyme in the pathway for synthesis of epinephrine.
19. A patient is fasted from 8 PM in the evening to 8 AM (post-absorptive phase) the next morning. The patient consumes no caloric food or beverage during this time. Which statement about whole body metabolism is NOT CORRECT?

a. So long as blood glucose is sufficient, the brain uses glucose at a rate of 6 grams/hour regardless of the time of day.

b. At 8 AM, blood levels of insulin will be elevated, while blood levels of glucagon, epinephrine and cortisol will be suppressed.

c. At 8 AM, glucagon and epinephrine stimulate glucose production by increasing glycogen breakdown and gluconeogenesis in the liver.

d. At 8 AM, cortisol stimulates skeletal muscle protein breakdown; the amino acids are used as substrates for gluconeogenesis.

e. At 8 AM, epinephrine and cortisol stimulate lipolysis (triglyceride breakdown) in adipose tissue to release fatty acids. Fatty acids are used as a fuel source for muscle and other tissues.
b. At 8 AM, blood levels of insulin will be elevated, while blood levels of glucagon, epinephrine and cortisol will be suppressed.
20. Thyroid stimulating hormone (TSH) plays an important role in controlling blood levels of thyroid hormone. Which of the following statements about TSH is NOT CORRECT?

a TSH stimulates the conversion of T4 to T3 by deiodinases in non-thyroidal tissues, like the liver.

b. TSH stimulates all facets of T4 and T3 synthesis and secretion from thyroid follicular cells.

c. TSH stimulates follicular cell growth; both hyperplasia and hypertrophy.

d. TSH secreted from anterior pituitary thyrotrophs is stimulated by TRH and inhibited by T3 and somatostatin.

e. TSH levels decrease in Graves disease.
a TSH stimulates the conversion of T4 to T3 by deiodinases in non-thyroidal tissues, like the liver.
21. Body mass is related to energy balance. We are in balance (constant body weight) when energy input (calories consumed as protein, carbohydrate and fat) equals energy output (all biochemical reactions in the body).
Which of the following statements about metabolism and appetite control is NOT CORRECT?

a. The 3 macronutrients are carbohydrate, protein and fat. Fat contains the most energy (9.4 kcal/g).

b. The body produces heat (thermogenesis) because biochemical transformations are inefficient and produce heat.

c. Appetite is controlled by the ventromedial nucleus of the hypothalamus.

d. Leptin is a hormone secreted from the liver that stimulates appetite.

e. Obesity is associated with positive energy balance. At least 30% of the US population is obese, i.e., BMI > 30.
d. Leptin is a hormone secreted from the liver that stimulates appetite.
22. Glucose regulates insulin secretion form pancreatic beta-cells. Which of the following statements about the glucose-sensing mechanism regulating insulin secretion from pancreatic beta-cells is NOT CORRECT?

a. Glucose is transported into pancreatic beta-cells through a glucose transporter, GLUT4.

b. Glucose is phosphorylated by glucokinase.

c. Metabolism of glucose increases cellular ATP levels.

d. Elevated ATP closes ATP-sensitive K+-channels and promotes membrane depolarization.

e. Membrane depolarization opens Ca+2-channels allowing the flow of Ca+2 into cells, an event that promotes exocytosis and insulin secretion.
a. Glucose is transported into pancreatic beta-cells through a glucose transporter, GLUT4.
23. Which of the following BEST describes the physiological function of parathyroid hormone (PTH)?

a. PTH will stimulate osteoclast to synthesize type I collagen and form bone.

b. PTH will bind nuclear receptors.

c. PTH will inhibit renal 1-alpha-hydroxylase activity.

d. PTH will increase the formation of 1,25-dihydroxy-vitamin D3 [1,25(OH)2-Vitamin D3] in the kidney.

e. PTH will act directly on intestinal cells to inhibit calcium uptake from the diet.
d. PTH will increase the formation of 1,25-dihydroxy-vitamin D3 [1,25(OH)2-Vitamin D3] in the kidney.
24. Which of the following statements is CORRECT?

a. Blood levels of hormones are in the millimolar (mM) range

b. Blood levels of hormones are determined by the rate of hormone production (secretion) and the rate of hormone disposal (removal from the blood, degradation).

c. All hormones are hydrophobic and must be transported in the blood bound to proteins.

d. Physiological processes, like growth are controlled by only one hormone, like growth hormone.

e. Each hormone has only one physiological role, e.g., insulin controls only blood glucose levels.
b. Blood levels of hormones are determined by the rate of hormone production (secretion) and the rate of hormone disposal (removal from the blood, degradation).
25. Which of the following statements about plasma binding proteins (like thyroxine binding protein and transcortin) is NOT CORRECT?

a. Plasma binding proteins are also hormone receptors.

b. Plasma binding proteins bind hydrophobic hormones with high affinity

c. Hormone binding to plasma binding proteins is saturable.

d. Hormone structure is an important determinant in hormone binding to plasma binding proteins.

e. Plasma binding proteins bind and transport hydrophobic hormones in the blood.
a. Plasma binding proteins are also hormone receptors.
26. Growth is a complex physiological process that is affected by diet, genetic background, age and hormones. Which of the following statements is NOT CORRECT?

a. After puberty, blood levels of growth hormone decline with age, leading to decreased IGF-1 production, nitrogen retention and muscle growth.

b. Sufficient dietary calcium, phosphate and vitamin D are required for normal bone growth.

c. Increased skeletal growth is associated with increased bone mass and length, widening of the epiphyseal plates where osteoblast activity predominates over osteoclast activity, as well as elevated blood levels of growth hormone and IGF-1.

d. Steroids are important for growth. Cholesterol is a precursor for all steroids. The diet is the only source of cholesterol for steroid synthesis.

e. Insufficient dietary iodine will lead to goiter formation, hypothyroidism and impaired growth and development.
d. Steroids are important for growth. Cholesterol is a precursor for all steroids. The diet is the only source of cholesterol for steroid synthesis.