Practice Questions Endocrine System

The hypothalamus controls the anterior pituitary by means of A) releasing hormones. B) second messengers. C) third messengers. D) antibodies. E) cytokines.

A.

Testosterone is an example of A) an androgen. B) an estrogen. C) a progestin. D) a catecholamine. E) melatonin.

A.

Oxytocin and ADH are produced by the __________ and stored in the __________. A) hypothalamus; posterior pituitary B) adenohypophysis; kidneys C) anterior pituitary; thyroid D) adrenal cortex; adrenal medulla E) posterior pituitary; anterior pituitary

A.

The secretion of hormone A causes a change in the amount of protein X in an organism. If this mechanism works by positive feedback, which of the following statements represents that fact? A) An increase in A produces an increase in X. B) An increase in X produces a decrease in A. C) A decrease in A produces an increase in X. D) A and B are correct. E) B and C are correct.

A.

Which of the following does not represent a chemical signal? A)movement of a signal from one end of a nerve to the other end of the nerve B) movement of a signal from one nerve to the next C) an immune cell releasing a cytokine D) a chemical released that affects the cell that releases it E)chemicals released into the bloodstream from nerve cells

A.

Which of the following endocrine structures is (are) not controlled by a tropic hormone from the anterior pituitary? A) pancreatic islet cells B) thyroid gland C) adrenal cortex D) ovaries E) testes

A.

Which of the following is (are) true? A)Hormones regulate cellular functions, and generally negative feedback regulates hormone levels. B)The circulating level of a hormone is held constant through a series of positive feedback loops. C) Both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors. D)The ducts of endocrine organs release their contents into the bloodstream. E) Only A and C are true.

A.

Which of the following is an endocrine gland? A) parathyroid gland B) salivary gland C) sweat gland D) sebaceous gland E) gallbladder

A.

Which of the following statements about endocrine glands is incorrect? A) The parathyroids regulate metabolic rate. B) The thyroid participates in blood calcium regulation. C) The pituitary participates in the regulation of the gonads. D) The adrenal medulla produces ʺfight-or-flightʺ responses. E)The pancreas helps to regulate blood sugar concentration.

A.

One reason a person might be severely overweight is due to A) an undersecretion of thyroxine. B) a defect in hormone release from the posterior pituitary. C) a lower than normal level of insulin-like growth factors. D) hyposecretion of oxytocin. E) a higher than normal level of melatonin.

A. *Thyroxine is T3, a thyroid hormone

Estradiol is an example of A) an androgen. B) an estrogen. C) a progestin. D) a catecholamine. E) melatonin.

B.

Only certain cells in the body are target cells for the steroid hormone aldosterone. Which of the following is the best explanation for why these are the only cells that respond to this hormone? A) Only target cells are exposed to aldosterone. B) Only target cells contain receptors for aldosterone. C) Aldosterone is unable to enter nontarget cells. D)Nontarget cells destroy aldosterone before it can produce its effect. E)Nontarget cells convert aldosterone to a hormone to which they do respond.

B.

Prostaglandins are local regulators whose basic structure is derived from A) oligosaccharides. B) fatty acids. C) steroids. D) amino acids. E) nitric oxide

B.

When an individual is subject to short-term starvation, most available food is used to provide energy (metabolism) rather than building blocks (growth and repair). Which hormone would be particularly active in times of food shortage? A) epinephrine B) glucagon C) oxytocin D) antidiuretic hormone E) insulin

B.

Which combination of hormones helps a mother to produce milk and nurse her baby? A) prolactin and calcitonin B) oxytocin and prolactin C) follicle-stimulating hormone and luteinizing hormone D) luteinizing hormone and oxytocin E) oxytocin, prolactin, and luteinizing hormone

B.

Which of the following glands is controlled directly by the hypothalamus or central nervous system but not the anterior pituitary? A) ovary B) adrenal medulla C) adrenal cortex D) testis E) thyroid

B.

Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal? A) a disproportionate production of T3 to T4 B) hyposecretion of TSH C) hypersecretion of TSH D) hypersecretion of MSH E) a decrease in the thyroid secretion of calcitonin

B.

Which of the following statements about hormones is incorrect? A) Glands that produce them are ductless glands. B)They are produced only by organs called endocrine organ C) Some are water soluble and some are not. D) They often maintain steady-state conditions. E) They may turn genes off or on.

B. *Also produced by endocrine cells in non-endocrine organs

Which of the following is secreted by the pancreas? A) ecdysone B) glucagon C) thyroxine D) oxytocin E) growth hormone

B. *Glucagon and insulin

What happens when beta cells of the pancreas release insulin into the blood? A)Blood glucose levels rise to a set point and stimulate glucagon release. B) Body cells take up more glucose. C) The liver breaks down glycogen to glucose. D)Alpha cells are stimulated to release glucose into the blood. E) Both B and D are correct.

B. *Insulin decreases glucose in blood by having body cells take up more

An example of antagonistic hormones controlling homeostasis is A) thyroxine and parathyroid hormone in calcium balance. B) insulin and glucagon in glucose metabolism. C) progestins and estrogens in sexual differentiation. D) epinephrine and norepinephrine in fight-or-flight responses. E) oxytocin and prolactin in milk production.

B. *Insulin lowers blood glucose levels, and glucagon raises blood glucose levels

Iodine is added to commercially-prepared table salt to help prevent deficiencies of this essential mineral. Which gland(s) require(s) iodine to function properly? A) parathyroids B) adrenal C) thyroid D) pancreas E) ovaries and testes

C.

Short blood vessels connect two capillary beds lying in which of the following? A) hypothalamus and thalamus B) anterior pituitary and posterior pituitary C) hypothalamus and anterior pituitary D) posterior pituitary and thyroid gland E) anterior pituitary and adrenal gland

C.

The endocrine system and the nervous system are structurally related. Which of the following cells best illustrates this relationship? A) a neuron in the spinal cord B) a steroid-producing cell in the adrenal cortex C) a neurosecretory cell in the hypothalamus D) a brain cell in the cerebral cortex E) a cell in the pancreas that produces digestive enzymes

C.

The results most likely occurred because progesterone exerts an effect on the A) general health of the rat. B) size of the fetus. C) maintenance of the uterus. D) gestation period of rats. E) number of eggs fertilized

C.

Which of the following are not part of homeostasis promotion or maintenance? A)A stimulus causes an endocrine cell to secrete a particular hormone, which decreases the stimulus. B)A hormone acts in an antagonistic way with another hormone. C) A hormone is involved in a positive feedback loop. D)Signal transduction brings about a response in the target cell. E)Secretin promotes an increase in the pH of the duodenum.

C.

Which of the following examples is incorrectly paired with its class? A) cytokines-local regulator B) estrogen-steroid hormone C) prostaglandin-peptide hormone D) ecdysone-steroid hormone E) neurotransmitter-local regulator

C.

Which of the following is not an accurate statement? A)Hormones are chemical messengers that travel to target cells through the circulatory system. B)Hormones often regulate homeostasis through antagonistic functions. C)Hormones of the same chemical class usually have the same function. D)Hormones are secreted by specialized cells usually located in endocrine glands. E) Hormones are often regulated through feedback loops.

C.

Which of the following stimulates and maintains metabolic processes? A) ecdysone B) glucagon C) thyroxine D) oxytocin E) growth hormone

C.

Which of the following endocrine disorders is notcorrectly matched with the malfunctioning gland? A) diabetes and pancreas B) giantism and pituitary C) goiter and adrenal medulla D) tetany and parathyroid E) dwarfism and pituitary

C. *Goiter caused by malfunctioning thyroid

Which of the following hormones is incorrectly paired with its action? A)oxytocin: stimulates uterine contractions during childbirth B) thyroxine: stimulates metabolic processes C) insulin: stimulates glycogen breakdown in the liver D)ACTH: stimulates the release of glucocorticoids by the adrenal cortex E)melatonin: affects biological rhythms, seasonal reproduction

C. *Insulin is a protein secreted by pancreas that lowers blood glucose levels--regulated by glucose levels in blood

The main target organs for tropic hormones are A) muscles. B) blood vessels. C) endocrine glands. D) kidneys. E) nerves.

C. *tropic hormones regulate the function of other endocrine cells or glands *nontropic hormones directly stimulate

A cell that contains proteins enabling a hormone to selectively bind to its plasma membrane is called a(n) A) secretory cell. B) plasma cell. C) endocrine cell. D) target cell. E) regulatory cell.

D.

Which hormone exerts antagonistic action to PTH (parathyroid hormone)? A) thyroxine B) epinephrine C) growth hormone D) calcitonin E) glucagon

D.

Which of the following statements about hormones is incorrect? A) They are produced by endocrine glands. B)They are modified amino acids, peptides, or steroid molecules. C) They are carried by the circulatory system. D)They are used to communicate between different organisms. E) They elicit specific biological responses from target cells.

D.

Which of the following statements about hormones is incorrect? A) They are secreted into the extracellular fluid. B) They circulate in blood or hemolymph. C) They communicate messages throughout the body. D) They travel through a dedicated pathway. E) Not all cells respond to a particular hormone.

D.

Which of the following stimulates the contraction of uterine muscle? A) ecdysone B) glucagon C) thyroxine D) oxytocin E) growth hormone

D.

Tropic hormones from the anterior pituitary directly affect the release of which of the following? A) parathyroid hormone B) calcitonin C) epinephrine D) thyroxine E) glucagon

D. *Anterior pituitary affects release of tropic hormone TSH (thyroid stimulating hormone), which affects release of T3/T4

Which of the following statements about the hypothalamus is incorrect? A) It functions as an endocrine gland. B) It is part of the central nervous system. C) It is subject to feedback inhibition by certain hormones. D)It secretes tropic hormones that act directly on the gonads. E)Its neurosecretory cells terminate in the posterior pituitary.

D. *Don't directly act on gonads--FSH and LH are hypothalamic hormones secreted by neurosecretory cells and enter a capillary network to drain into portal vein that connects with secondary capillary network in anterior pituitary

Which of the following have nontropic effects only? A) FSH B) LH C) TSH D) MSH E) ACTH

D. *Tropic effects only: FSH, LH, TSH, ACTH *Nontropic effects only: Prolactin, MSH *Nontropic and Tropic effects: GH

Which of the following glands shows both endocrine and exocrine activity? A) pituitary B) parathyroid C) salivary D) pancreas E) adrenal

D. *includes kidneys, stomach, liver, and pancreas

Blood samples taken from an individual who had been fasting for 24 hours would have which of the following? A) high levels of insulin B) high levels of glucagon C) low levels of insulin D) low levels of glucagon E) both B and C

E.

Which of the following is secreted by the anterior pituitary? A) ecdysone B) glucagon C) thyroxine D) oxytocin E) growth hormone

E.

If a person drinks a large amount of water in a short period of time, he or she may die from water toxicity. ADH can help prevent water retention through interaction with target cells in the A) anterior pituitary. B) posterior pituitary. C) adrenal gland. D) bladder. E) kidney.

E. *ADH is hormone produced by neurosecretory cells of hypothalamus and is transported to posterior pituitary, where they are stored. *Nerve signals trigger release or neurohormone ADH

Which of the following statements about hormones that promote homeostasis is incorrect? A)A stimulus causes an endocrine cell to secrete a particular hormone. B) The hormone travels in the bloodstream to target cells. C) Specific receptors bind with the hormone. D)Signal transduction brings about a response in the target cell. E)This response feeds back to promote the release of more hormone.

E. *Usually negative feedback