Deck 41: Chemical Signals in Animals

Question 1

The chemical structure of prostaglandins is derived from which of the following types of molecules?

A) oligosaccharides
B) fatty acids
C) steroids
D) amino acids

Answer 1

B

Question 2

Fludrocortisone is a steroid hormone used to treat disease. Which of the following most likely occurs when it encounters a target cell?

A) It binds to a receptor on the cell membrane and triggers a signal transduction pathway.
B) It diffuses through the cell membrane and binds to receptors in the cytoplasm or nucleus.
C) It interacts with a G-protein coupled receptor in the plasma membrane of the target cell.
D) It binds to protein receptors on the presynaptic membrane, increasing the firing rate of action potentials.

Answer 2

B

Question 3

Which of the following statements about growth factors is true?

A) They are modified fatty acids that stimulate bone and cartilage growth.
B) They are found on the surface of cancer cells and stimulate abnormal cell division.
C) They are local regulators that stimulate division and development of target cells.
D) They convey messages between nerve cells.

Answer 3

C

Question 4

Which of the following molecules is lipid soluble and acts on target cells at distant locations from where it is released?

A) insulin
B) epinephrine
C) thyroxine
D) cortisol

Question 5

Which of the following statements is true?

A) neurotransmitters diffuse into the bloodstream
B) neurohormones diffuse into the bloodstream
C) neurohormones diffuse a short distance and bind to receptors in a synapse
D) neurotransmitters act only on cells that make neurotransmitters

Question 6

Which of the following types of signal is released into the environment?

A) neural
B) paracrine
C) neuroendocrine
D) pheromones

Question 7

Which of the following organs includes endocrine and exocrine tissues?

A) the pituitary gland
B) parathyroid glands
C) salivary glands
D) the pancreas

Question 8

Testosterone is an example of a chemical signal that affects, variously, the very cells that synthesize it in the testis, the neighboring cells, and distant cells outside the gonads. Thus, testosterone is an example of ________.

A) a neurohormone signal, a neuroendocrine signal, and an exocrine product
B) a paracrine signal, a synaptic signal, and an exocrine product
C) an autocrine signal, a neuroendocrine signal, and a synaptic signal
D) an autocrine signal, a paracrine signal, and an endocrine signal

Question 9

Which of the following best explains why the steroid hormone aldosterone affects only a small number of target cells in the body?

A) only target cells are exposed to aldosterone
B) only target cells contain aldosterone receptors
C) aldosterone is unable to diffuse through nontarget cell membranes
D) nontarget cells destroy aldosterone before it can bind

Question 10

Which of the following types of cell-to-cell signaling describes tumor cells that secrete growth factors that induce surrounding cells to grow and divide?

A) autocrine
B) paracrine
C) endocrine
D) neuroendocrine

Question 11

Which of the following statements is true about both steroid and polypeptide?

A) They are derived from cholesterol.
B) They are water-soluble.
C) They travel through the bloodstream.
D) They diffuse into target cells and bind to receptors in the cytoplasm or nucleus.

Question 12

Which of the following correctly describes the target cells in autocrine signaling?

A) They are located within a synapse.
B) They are located in blood vessels.
C) They can be various cell types and are located next to the cells that secrete the autocrine signals.
D) They secrete autocrine signals.

Question 13

Which of the following are properties of steroid hormones?

A) Steroid hormones are water-soluble and travel freely in the bloodstream.
B) Steroid hormones usually exert their effects on target cells through membrane receptor proteins.
C) Steroid hormones only act locally, on cells close to where the steroid hormone was secreted.
D) Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.

Question 14

Which of the following statements about aspirin and ibuprofen is true?

A) They inhibit the synthesis of prostaglandins.
B) They inhibit the release of nitric oxide, a potent vasodilator.
C) They activate the paracrine signaling pathways that form blood clots.
D) They stimulate vasoconstriction in the kidneys.

Question 15

Molecules that act quickly over short distances are types of ________.

A) local regulators
B) neurohormones
C) neurotransmitters
D) pheromones

Question 16

Which of the following statements about polypeptides is true?

A) they are derived from cholesterol
B) most are lipid-soluble
C) some function as growth factors
D) most bind to transport proteins when circulating in blood

Question 17

A certain hormone activates the cAMP second messenger system in its target cells. Which of the following would yield the greatest response by a target cell?

A) apply the hormone to the extracellular fluid surrounding the cell
B) inject the hormone into the cytoplasm of the cell
C) apply cAMP to the extracellular fluid surrounding the cell
D) inject activated, cAMP-dependent protein kinase into the cytoplasm of the cell

Question 18

Which of the following are the two main systems for communication and control in most animals?

A) digestive system and circulatory system
B) circulatory system and nervous system
C) nervous system and endocrine system
D) endocrine system and circulatory system

Question 19

Tadpoles undergo metamorphosis in their development. The changes include reabsorption of the tail, growth of limbs, and the development of lungs. Amazingly, all of these changes are induced by thyroxine. Which of the following best explains the diverse effects of thyroxine?

A) Thyroxine binds to transport proteins that direct thyroxine to certain tissues.
B) Different tissues have thyroxine receptors that activate different signal transduction pathways.
C) Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus.
D) Thyroid hormone is divided into T3 and T4 as it travels through the bloodstream.

Question 20

Which of the following statements about endocrine glands is true?

A) They secrete a product onto a body surface or into a body cavity.
B) They secrete enzymes and bicarbonate.
C) The products are all enzymes.
D) They do not have ducts.

Question 21

The insect hormones ecdysteroid and PTTH ________.

A) reflect the coordinated responses of the endocrine and nervous systems
B) act in competitive inhibition of the same hormone receptor
C) are both released as a result of positive feedback
D) are an example of homeostasis maintained by antagonistic interactions

Question 22

Which one of the following statements is true?

A) Hormones often regulate homeostasis through antagonistic functions.
B) Hormones of the same chemical class usually have the same function.
C) Hormones are secreted by specialized cells usually located in exocrine glands.
D) Hormone pathways involved in homeostasis typically exhibit positive feedback.

Question 23

Which two hormones, in a lactating mammal, promote milk synthesis and milk release, respectively?

A) prolactin and calcitonin
B) prolactin and oxytocin
C) follicle-stimulating hormone and luteinizing hormone
D) luteinizing hormone and oxytocin

Question 24

Which of the following is a steroid hormone that coordinates molting in arthropods?

A) ecdysteroid
B) glucagon
C) thyroxine
D) growth hormone

Question 25

Diabetes insipidus is a disorder that results in the kidneys not being able to conserve water during urine production. Which hormone most likely plays a role in diabetes insipidus?

A) antidiuretic hormone (ADH)
B) thyroid stimulating hormone (TSH)
C) insulin
D) glucagon

Question 26

Which of the following organs is directly affected by antidiuretic hormone (ADH)?

A) anterior pituitary
B) posterior pituitary
C) thyroid
D) kidney

Question 27

Which of the following glands produces hormones that affect osmoregulation, reproduction, and metabolism?

A) parathyroid
B) anterior pituitary
C) mammary glands
D) thyroid

Question 28

Which of the following is the source of the hormones secreted by the posterior pituitary gland?

A) cerebellum
B) thalamus
C) hypothalamus
D) anterior pituitary gland

Question 29

Which of the following is a function of glucocorticoids?

A) promoting the immune response
B) promoting the release of fatty acids
C) increasing blood glucose levels
D) increasing insulin production

Question 30

Which of the following contain capillary beds connected by portal blood vessels?

A) hypothalamus and thalamus
B) anterior pituitary and posterior pituitary
C) hypothalamus and anterior pituitary
D) posterior pituitary and thyroid gland

Question 31

Oxytocin and antidiuretic hormone (ADH) are synthesized in the ________ and are released from the ________.

A) hypothalamus; posterior pituitary
B) hypothalamus ; hypothalamus
C) posterior pituitary; anterior pituitary
D) hypothalamus; anterior pituitary

Question 32

Which of the following is an example of a simple endocrine pathway?

A) control of metabolism by thyroid hormones
B) release of secretin by cells of the duodenum after exposure to low pH
C) release of antidiuretic hormone from the posterior pituitary gland to regulate water balance
D) regulation of growth by the production of growth hormone

Question 33

Which of the following pairs correctly describes an example of antagonistic hormones that regulate homeostasis?

A) thyroxine and parathyroid hormones regulate calcium balance
B) insulin and glucagon regulate blood glucose levels
C) progestins and estrogens control sexual differentiation
D) epinephrine and norepinephrine regulate the fight-or-flight responses

Question 34

Which of the following is a gas that functions as a local regulator and a neurotransmitter in humans?

A) nitric oxide
B) epinephrine
C) cortisol
D) carbon dioxide

Question 35

Which of the following functions would most likely be disrupted by an injury to the hypothalamus?

A) short-term memory
B) coordinated movements during locomotion
C) executive functions, such as decision making
D) regulation of water balance

Question 36

The mammary glands secrete milk in response to circulating oxytocin. A suckling baby feeding on this milk stimulates additional oxytocin release. These related events are an example of ________.

A) negative feedback
B) a hormone that acts in an antagonistic way with another hormone
C) positive feedback
D) signal transduction immediately changing gene expression in its target cells

Question 37

Which of the following is the most likely outcome of a reduction of blood flow in the portal system connecting the hypothalamus and the pituitary gland?

A) reduced levels of oxytocin in the blood
B) reduced levels of ADH in the blood
C) reduced levels of growth hormone in the blood
D) increased production of nitric oxide

Question 38

When a person drinks alcohol, the rate of urination increases. Which of the following best explains the increase in urination above normal rates?

A) Alcohol stimulates the release of thyroid hormones.
B) Alcohol inhibits the release of ADH.
C) Alcohol inhibits the actions of calcitonin.
D) Alcohol stimulates the release of oxytocin.

Question 39

A new type of pesticide sprayed onto fields of corn interferes with the ability of nematodes to find potential mates. This new pesticide most likely interferes with ________.

A) neurotransmitters
B) pheromones
C) autocrine signaling
D) neuroendocrine signaling

Question 40

Which of the following is the most likely cause of a goiter?

A) low levels of growth hormone
B) overproduction of thyroid hormone
C) high levels of calcium in the diet
D) low levels of iodine in the diet

Question 41

Which hormone is correctly paired with its action?

A) oxytocin-stimulates uterine contractions during childbirth
B) thyroxine-inhibits metabolic processes
C) ACTH-inhibits the release of glucocorticoids by the ­adrenal cortex
D) melatonin-raises blood calcium level

Question 42

Which one of the following is a type of catecholamine?

A) glucocorticoids
B) epinephrine
C) adrenocorticotropic hormone (ACTH)
D) mineralocorticoids

Question 43

What do steroid and peptide hormones typically have in common?

A) their solubility in cell membranes
B) their requirement for travel through the bloodstream
C) the location of their receptors
D) their reliance on signal transduction in the cell

Question 44

Which of the following best explains how epinephrine produces different effects in different target cells?

A) The target cells differ in their types of receptors.
B) The target cells have different sets of chromosomes.
C) Epinephrine binds to different chromosomes in the target cells' nuclei.
D) Epinephrine diffuses through target cell membranes at different rates.

Question 45

Certain diseases of the adrenal glands result in increased secretion of adrenal hormones. The symptoms include high blood pressure, increased heart rate, and elevated body temperature. Which of the following hormones is secreted by the adrenal glands and most likely contributes to these symptoms?

A) Cortisol
B) Epinephrine
C) Aldosterone
D) Insulin

Question 46

Which of the following best describes sex hormones in male and female vertebrates?

A) Androgens, estrogens, and progesterone are found in males and females, but in different proportions.
B) Males produce only androgens. Females produce only estrogens and progesterone.
C) Males produce androgens and progesterone. Females produce only estrogens.
D) Males and females produce androgens and estrogens. But males only have target receptors for androgens and females only have target receptors for estrogens and progesterone.

Question 47

Which of the following is affected by exposure to diethylstilbestrol (DES)?

A) the regulation of blood calcium levels
B) water resorption in the kidneys
C) sleep and wake cycles
D) reproduction and development

Question 48

In response to stress, the adrenal gland promotes the synthesis of glucose from noncarbohydrate substrates via the action of the steroid hormone ________.

A) estradiol
B) cortisol
C) thyroxine
D) adrenocorticotropic hormone (ACTH)

Question 49

Which of the following contributes to poor health when people experience chronic stress?

A) melatonin levels remain elevated
B) high levels of parathyroid hormones make blood sugar regulation difficult
C) high levels of glucocorticoids suppress the immune response
D) suppression of growth hormone allows pathogens to proliferate

Question 50

Growth factors are local regulators that ________.

A) are produced by the anterior pituitary
B) are modified fatty acids that stimulate bone and cartilage growth
C) are found on the surface of cancer cells and stimulate ­abnormal cell division
D) bind to cell-surface receptors and stimulate growth and ­development of target cells

Question 51

Which hormone contributes to calcium homeostasis in fishes and rodents by opposing the effects of parathyroid hormone (PTH)?

A) thyroxine
B) epinephrine
C) growth hormone
D) calcitonin

Question 52

Which of the following occurs under stressful conditions that include shock, low blood pressure, and low blood sugar levels?

A) PTH lowers blood calcium levels.
B) S cells release secretin.
C) ACTH stimulates the release of corticosteroids.
D) The thyroid gland releases calcitonin.

Question 53

Thyroxine can trigger growth, temperature tolerance, or osmoregulation depending on the organism in which it is produced. Which is the most likely mechanism for such diverse responses in different organisms?

A) The concentration of thyroxine varies in different organisms. Invertebrate organisms do not have as much thyroxine as vertebrate organisms.
B) Thyroxine and its receptor molecules have different binding affinities in different organisms.
C) Receptor molecules for thyroxine are located on different tissues in different organisms.
D) The function of thyroxine in a particular tissue is determined by the genes that are transcribed by the activated thyroxine receptor.

Question 54

The hypothalamus ________.

A) synthesizes all of the hormones produced by the pituitary gland
B) influences the function of only one lobe of the pituitary gland
C) produces only inhibitory hormones
D) regulates both reproduction and body temperature

Question 55

Which hormone regulates skin color in fishes, amphibians, and reptiles?

A) melanocyte-stimulating hormone
B) adrenocorticotropic hormone
C) thyroxine
D) parathyroid hormone

Question 56

Which of the following hormones is vital to maintaining a pregnancy in a mammal?

A) prolactin
B) melatonin
C) androgen
D) progesterone

Question 57

Which of the following correctly pairs a gland with its impact on the fight-or-flight reaction?

A) parathyroid glands, lead to increased metabolic rate
B) anterior pituitary gland, leads to cessation of gonadal function
C) adrenal medulla, leads to increased secretion of epinephrine
D) pancreas, leads to a reduction in the blood sugar concentration

Question 58

Which of the following events will be initiated by the fight-or-flight response following a stressful stimulus?

A) the hypothalamus releases prolactin
B) the anterior pituitary releases secretin
C) ADH secretion reduces urine output
D) liver cells convert glycogen into glucose

Question 59

Which statement is accurate?

A) Hormones that differ in effect reach their target cells by different routes through the body.
B) Pairs of hormones that have the same effect are said to have antagonistic functions.
C) Hormones are often regulated through feedback loops.
D) Hormones of the same chemical class usually have the same function.

Question 60

Which of the following is the most likely effect of a drug that increases adrenocorticotropic hormone (ACTH) synthesis?

A) increased release of glucocorticoids
B) increased release of prolactin
C) decreased release of cortisol
D) decreased release of calcitonin

Question 61

Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal?

A) greater production of T3 than of T4
B) hyposecretion of TSH
C) hypersecretion of MSH
D) a decrease in the thyroid secretion of calcitonin

Question 62

The relationship between the insect hormones ecdysteroid and PTTH is an example of ________.

A) an interaction of the endocrine and nervous systems
B) homeostasis achieved by positive feedback
C) homeostasis maintained by antagonistic hormones
D) competitive inhibition of a hormone receptor