[Notes] - Chapter 17: Functional Organization of the Endocrine System

Chapter 17: Functional Organization of the Endocrine System

Multiple Choice

1.   The endocrine system
A)   releases neurotransmitters into ducts.
B)   secretes chemicals that reach their targets through the bloodstream.
C)   communicates via frequency-modulated signals.
D)   contains organs called exocrine glands.
E)   is isolated from the nervous system.
Answer: in attachment
Level: 1

2.   Hormones are intercellular chemical signals that
A)   are secreted into the external environment where they act.
B)   affect only non-hormone producing organs or tissues.
C)   help coordinate growth, development and reproduction.
D)   alter the sensitivity of neurons to neurotransmitters.
E)   operate primarily by positive feedback.
Answer: in attachment
Level: 1

3.   Most endocrine glands communicate with their target tissues using _____ signals.
A)   frequency-modulated
B)   amplitude-modulated
C)   pitch-modulated
D)   resonance-modulated
E)   harmonic
Answer: in attachment
Level: 1

4.   An intercellular chemical signal that is produced by neurons but functions like a hormone would be called a
A)   neuropathogen.
B)   neurotransmitter.
C)   neurocrine.
D)   neurohormone.
E)   neurosynthesizer
Answer: in attachment

5.   Given the following list of organic molecules, which includes hormones? 1. nucleic acid derivatives 2. polypeptides 3. steroids 4. proteins
A)   1, 3, 4
B)   1, 2, 3
C)   2, 3, 4
D)   1, 2, 3, 4
E)   1, 2, 4
Answer: in attachment
Level: 1

6.   Hormonal secretion can be regulated by
A)   the action of a substance other than a hormone.
B)   the nervous system.
C)   other hormones.
D)   all of the above.
E)   none of the above.
Answer: in attachment
Level: 1

7.   Secretion of TSH (thyroid-stimulating hormone) is regulated by
A)   the action of a substance other than a hormone.
B)   the nervous system.
C)   the action of other hormones.
D)   the parasympathetic nervous system.
E)   the sympathetic nervous system.
Answer: in attachment
Level: 2

8.   An example of a situation where the nervous system regulates the rate of hormonal secretion is when
A)   LH stimulates ovulation.
B)   increasing blood glucose levels stimulate insulin secretion.
C)   TSH stimulates the release of thyroxine.
D)   TRH stimulates the release of TSH.
E)   sympathetic neurons stimulate the release of epinephrine. Answer:
Answer: in attachment
Level: 2

9.   Which of the following statements regarding hormone transport and distribution is false?
A)   Only free hormones can diffuse through capillary walls and bind to target tissues.
B)   Hormones can be transported free in the plasma or bound to plasma proteins.
C)   Plasma protein concentration has no influence on free hormone concentration.
D)   Hormones bind only to certain types of plasma proteins.
E)   All of the statements are true.
Answer: in attachment
Level: 1

10.   The half-life of a hormone allows one to determine
A)   the rate of hormone secretion.
B)   the identify of a hormone.
C)   the rate at which hormones are eliminated from the body.
D)   the rate of action of a hormone.
E)   the rate of travel through the blood to a target.
Answer: in attachment
Level: 1

11.   Hormones with short half-lives
A)   are usually lipid-soluble.
B)   are maintained at relatively constant levels.
C)   have concentrations that increase slowly.
D)   regulate activities of delayed onset and long duration.
E)   regulate activities of rapid onset and short duration.
Answer: in attachment
Level: 1

12.   Once a hormone is conjugated in the liver
A)   its half-life is increased.
B)   it can be rapidly eliminated.
C)   it can be stored for later use.
D)   it is actively transported into cells.
E)   it is more slowly eliminated.
Answer: in attachment
Level: 1

13.   How do hormones and target cells recognize one another?
A)   by signs
B)   by the location of the target cells
C)   by the presence of specific receptor molecules on the target cells
D)   by the function of the target cells
E)   by the location of the hormones
Answer: in attachment
Level: 1

14.   In some forms of diabetes, an insensitivity to insulin seems to be present.  This insensitivity could be the result of
A)   up-regulation.
B)   over-regulation.
C)   down-regulation.
D)   a lack of regulation.
E)   modulation.
Answer: in attachment
Level: 2

15.   Up-regulation
A)   results in a decrease in the number of receptor sites in the target cell.
B)   produces an increase in the sensitivity of the target cell to the hormone.
C)   is found in target cells that maintain a constant level of receptors.
D)   produces insensitivity to the hormone in the target tissue.
E)   moves the receptors up on the membrane.
Answer: in attachment
Level: 1

16.   Hormone receptor molecules may be ____ in order to change the target cell's sensitivity to a given hormone.
A)   increased in number
B)   decreased in number
C)   chemically altered
D)   moved
E)   A, B, C
Answer: in attachment
Level: 1

17.   Receptors for most water-soluble hormones are located
A)   in the cytoplasm of their target cells.
B)   on the plasma membrane of their target cells.
C)   in the lysosomes of their target cells.
D)   on the nuclear membrane of their target cells.
E)   on the endoplasmic reticulum of their target cells.
Answer: in attachment
Level: 1

18.   Which of the following is a regulatory protein associated with membrane-bound receptor molecules?
A)   ATP
B)   calcium
C)   GnRH
D)   G protein
E)   FSH
Answer: in attachment
Level: 1

19.   A hormone binds to its receptor.  Arrange the events that follow in correct sequence.
1. alpha subunit-GTP complex alters cell activity
2. GTP binds to the alpha subunit replacing GDP
3. activity of alpha subunit terminated by phosphodiesterase.
4. alpha subunit separates from other two subunits
5. G-protein subunits separate from the receptor
A)   5, 4, 2, 1, 3
B)   4, 2, 1, 3, 5
C)   5, 2, 1, 4, 3
D)   5, 4, 2, 1, 3
E)   3, 4, 1, 2, 5
Answer: in attachment
Level: 3

20.   The role of cAMP when it acts as an intracellular mediator in cells is to
A)   bind to and activate protein kinase.
B)   activate genes in the nucleus to produce mRNA.
C)   directly activate structural enzymes in the cytoplasm of the target cell.
D)   catalyze a cascade reaction that ultimately activates genes on the DNA.
E)   control levels of calcium in the cell.
Answer: in attachment
Level: 2

21.   When a hormone binds to a membrane–bound receptor,
A)   membrane channels are destroyed.
B)   cyclic GMP might be produced to act as an intracellular mediator.
C)   the nucleus is phosphorylated to prevent G-protein activation.
D)   messenger RNA is formed.
E)   cellular DNA is altered.
Answer: in attachment
Level: 1

22.   Phosphodiesterase functions
A)   as a membrane-bound receptor molecule.
B)   to inactivate cyclic AMP.
C)   to attach phosphate groups to enzymes.
D)   to combine GTP with cyclic AMP.
E)   activates cGMP.
Answer: in attachment
Level: 1

23.   Arrange the following events in proper sequence:
1. The activating hormone interacts with a membrane-bound receptor.
2. Cyclic AMP causes the cell to carry out a function characteristic for that specific hormone.
3. Adenylyl cyclase catalyzes the transformation of ATP to cyclic AMP.
4. Adenylyl cyclase is activated.
A)   1, 2, 3, 4
B)   1, 4, 3, 2
C)   3, 4, 2, 1
D)   1, 3, 2, 4
E)   1, 3, 4, 2
Answer: in attachment
Level: 2

24.   Which of the following events occurs last?
A)   IP3 (inositol triphosphate) is produced.
B)   Epinephrine combines with membrane-bound receptor on smooth muscle cell.
C)   Calmodulin binds to the enzyme that phosphorylates myosin and cross-bridges form.
D)   IP3 stimulates Ca++ release from the endoplasmic reticulum.
E)   Ca++ binds with calmodulin.
Answer: in attachment
Level: 2

25.   When a few intracellular mediator molecules activate several enzymes and each of these activated enzymes activate still other enzymes, the hormone has initiated
A)   a cascade effect.
B)   a double loop effect.
C)   a protein kinase effect.
D)   a cyclic effect.
E)   a negative feedback cycle.
Answer: in attachment
Level: 1

26.   Which of the following occurs when a hormone binds to an intracellular receptor?
A)   activation of cyclic AMP
B)   activation of mRNA synthesis
C)   increased lipid synthesis by ribosomes
D)   opens membrane channels.
E)   alters membrane permeability.
Answer: in attachment
Level: 1

27.   Steroid hormones
A)   bind to membrane receptors.
B)   diffuse easily through the plasma membrane.
C)   act by activating cAMP.
D)   are inactivated by phosphodiesterase.
E)   are water soluble.
Answer: in attachment
Level: 1

28.   Consider the following events in the intracellular receptor model:
1. Hormone receptor complex binds to DNA.
2. Messenger RNA directs synthesis of specific proteins.
3. Hormone binds to receptors either in cytoplasm or nucleus.
4. Messenger RNA synthesis is activated.
5. Synthesized proteins produce the response of the cell.
Which of these events occurs in the nucleus?
A)   1, 3, 5
B)   1, 3, 4
C)   1, 2, 3
D)   3, 4, 5
E)   All events occur in the nucleus.
Answer: in attachment
Level: 2

Refer to the following figure for questions 29-33.
 

29.   What is “A” on the diagram?
A)   pancreas
B)   adrenals
C)   pituitary
D)   thyroid
E)   thymus
Answer: in attachment
Level: 1

30.   What is “B” on the diagram?
A)   pancreas
B)   adrenals
C)   pituitary
D)   thyroid
E)   thymus
Answer: in attachment
Level: 1

31.   What is “C” on the diagram?
A)   pancreas
B)   adrenals
C)   pituitary
D)   thyroid
E)   thymus
Answer: in attachment
Level: 1

32.   What is “D” on the diagram?
A)   pancreas
B)   adrenals
C)   pituitary
D)   thyroid
E)   thymus
Answer: in attachment
Level: 1

33.   What is “E” on the diagram?
A)   pancreas
B)   adrenals
C)   pituitary
D)   thyroid
E)   thymus
Answer: in attachment
Level: 1

For questions 34 to 38 match the chemical signal with the appropriate description.
A)   chemicals produced by neurons that function as hormones
B)   chemical secreted into the environment that can modify the physiology and behavior of another individual
C)   chemical secreted by presynaptic terminal
D)   influences same cell type from which it is secreted
E)   chemical secreted into blood by specialized cells; travels some distance to target tissues

34.   neurohormone
Answer: in attachment
Level: 1

35.   autocrine
Answer: in attachment
Level: 1

36.   hormone
Answer: in attachment
Level: 1

Refer to: Ref 17-2
37. pheromone
Answer: in attachment
Level: 1

38.   neurotransmitter
Answer: in attachment
Level: 1

For questions 39 to 46 match the description with the type of receptor model.
A)   intracellular receptor model
B)   membrane-bound receptor model

39.   used by most lipid-soluble hormones
Answer: in attachment
Level: 2

40.   intracellular mediator
Answer: in attachment
Level: 2

41.   G-protein
Answer: in attachment
Level: 2

42.   receptor molecule interacts with DNA
Answer: in attachment
Level: 2

43.   cyclic AMP or cyclic GMP involved
Answer: in attachment
Level: 2

44.   generally observe a latent period
Answer: in attachment
Level: 2

45.   messenger RNA synthesis regulated
Answer: in attachment
Level: 2

46.   membrane channels may be opened or closed
Answer: in attachment
Level: 2

For questions 47 to 51 match the hormones with appropriate structural categories.
A)   protein
B)   glycoprotein
C)   polypeptide
D)   amino acid derivative
E)   steroid

47.   cortisol
Answer: in attachment
Level: 1

48.   insulin
Answer: in attachment
Level: 1

49.   thyroid hormone
Answer: in attachment
Level: 1

50.   ADH
Answer: in attachment
Level: 1

51.   Follicle-stimulating hormone
Answer: in attachment
Level: 1

Fill in the Blank

52. Hormones act on specific _______ tissues called tissues.
Answer: target
Level: 1

53.   _______ chemical signals are released by cells and affect other cell types locally without being transported in blood.
Answer: paracrine
Level: 1

54.   Increasing levels of thyroid hormones decrease TSH levels.  This is an example of _______ feedback.
Answer: negative
Level: 1

55.   The length of time needed to eliminate half of a dose of a hormone is called its _______ ________.
Answer: half life
Level: 1

56.   An example of an intracellular mediator is _______.
Answer: in attachmentyclic AMP
Level: 1

Essay Questions

57.   Cells communicate with one another using a language of chemicals.  List one role each of the following plays in cellular communication.
a. hormones
b. cell membranes
c. receptor molecules
Answer: in attachment)   Hormones attach to cells and influence their activity in some specific fashion.
B)   Cell membranes contain the receptor molecules for those hormones that use membrane-bound receptors to achieve their effects.
C)   Receptor molecules are chemicals that hormones bind to.  Specific receptors are used to identify target cells to a given hormone.  The hormone-receptor complex initiates the response of the target cells.
Level: 2

58.   Hormone Z, responsible for maintaining normal blood levels of chemical A, binds to membrane-bound receptors on its target cells.  These target cells use G-protein and cyclic AMP to carry out the response of hormone Z.  Predict the consequences if a drug is taken that inhibits the action of cyclic AMP.
Answer: If the action of cyclic AMP is inhibited, then the action of hormone Z is inhibited.
Level: 3