1			The endocrine system communicates with target cells by way of
			A)	electrical signals.
			B)	chemical messengers secreted into the bloodstream.
			C)	chemical messengers secreted through ducts into other organ.
			D)	chemical messengers that do not leave the cell where they are produced.
2			What is it about a cell that identifies it as a target cell for a hormone?
			A)	the presence of a receptor specific for that hormone
			B)	its location near the gland that secretes the hormone
			C)	the ability of the target cell to perform a specific function
			D)	its ability to inactivate the hormone
3			What do all hormones have in common?
			A)	They are made from amino acids.
			B)	They are bound to transport molecules in the blood.
			C)	They bind to and interact with a receptor in the target cell.
			D)	They use the second messenger mechanism to control the target cell.
4			Members of which group of hormones are made from cholesterol?
			A)	amines
			B)	peptides
			C)	proteins
			D)	steroids

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5			Which statement is correct?
			A)	Each endocrine gland secretes only one hormone.
			B)	Each target cell may be capable of responding to several hormones.
			C)	Each hormone affects only one type of target cell.
			D)	The release of all hormones is controlled by other hormones.
6			In general, the response of target cells to endocrine stimulation is ____ than their response to nervous stimulation.
			A)	faster and more brief
			B)	slower and more prolonged
			C)	more accurate
			D)	more restricted to a small area of the body
7			Chemical signals that are secreted into the environment to modify the behavior and physiology of other individuals are termed
			A)	neurohormones
			B)	autocrine chemical signals
			C)	paracrine chemical signals
			D)	pheromones

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8			One cell releases a chemical messenger that diffuses through the tissue fluid to a nearby target cell. The chemical messenger is called a(n)
			A)	autocrine
			B)	paracrine
			C)	endocrine
			D)	neurocrine

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9			When blood glucose levels decrease, hormone "A" is secreted. Based on this information, hormone A is controlled by
			A)	changes in the level of a chemical in the blood.
			B)	direct stimulation by the nervous system.
			C)	stimulation by a hormone released from another endocrine gland.
			D)	a hypothalamic releasing factor.
10			ACTH secretion is controlled by several factors. Which of these statements describes negative feedback control of ACTH secretion?
			A)	ACTH stimulates cortisol secretion.
			B)	CRH stimulates ACTH secretion.
			C)	Cortisol inhibits ACTH secretion.
			D)	ACTH inhibits cortisol secretion.
11			Hormone "A" stimulates the release of hormone "B." As levels of hormone "B" increase, the secretion of hormone "A" is inhibited. This is an example of
			A)	negative feedback.
			B)	positive feedback.
			C)	neural control.
			D)	amplification.

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12			The secretion of which hormone does not exhibit a diurnal or circadian pattern?
			A)	ACTH
			B)	melatonin
			C)	ADH
			D)	growth hormone
13			The secretion of TSH is inhibited by
			A)	negative feedback from T3 and T4.
			B)	negative feedback from TRH.
			C)	hyposecretion of T3 and T4.
			D)	hypersecretion of TRH.
14			The nervous system regulates the secretion of each of these hormones EXCEPT
			A)	oxytocin.
			B)	parathyroid hormone.
			C)	ADH.
			D)	epinephrine.

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15			Assume that there are a fixed number of hormone receptors in each target cell. At a point where each receptor in a cell is already bound to a hormone molecule, adding more hormone molecules will
			A)	increase the target cell's response.
			B)	have no further effect on the target cell's response.
			C)	decrease the target cell's response.
			D)	cause the receptors to release the hormones that were previously bound to them.
16			Assume a normal and constant hormone secretion rate coupled with a decreased plasma protein level. The lower the plasma protein concentration, the
			A)	higher the percentage of bound hormone molecules.
			B)	higher the percentage of free (unbound) hormone molecules.
			C)	fewer hormone molecules are available to bind to target cells.
			D)	fewer hormone molecules are inactivated or eliminated.
17			The half life of a hormone can be increased by which of the following means?
			A)	by actively transporting the hormone back into the cell and recycling it to be used again as a hormone
			B)	by enzymatically breaking down the hormone
			C)	by binding the hormone with specific plasma proteins
			D)	by excreting the hormone into the urine
18			Which of the following is not true for a hormone with short half life?
			A)	They are generally water soluble.
			B)	Their concentration increases and decreases rapidly within the blood.
			C)	They bind to plasma proteins, which prevents their breakdown.
			D)	They regulate activities which begin quickly and last for a short duration.
19			Which of the following hormones will have a longer half life?
			A)	growth hormone
			B)	estrogen
			C)	oxytocin
			D)	ADH
20			As the concentration of free hormone molecules increases in the blood;
			A)	more hormone molecules diffuse out of the blood and reach target cells.
			B)	fewer hormone molecules diffuse and reach target cells.
			C)	no movement is seen as the concentration of hormone has no affect on diffusion.
			D)	target cells become unresponsive to the hormone.
21			In the case of a disease in which hormone levels are normal but the target cells are not responding, the cause may be
			A)	up-regulation in the target cells.
			B)	up-regulation in the hormone-secreting cells.
			C)	down-regulation in the target cells.
			D)	increased sensitivity in the target cells.
22			Down-regulation
			A)	occurs when target cells decrease the number of hormone receptors in response to high hormone levels or prolonged exposure.
			B)	increases the number of hormone receptors per target cell.
			C)	makes target cells more sensitive to a hormone.
			D)	occurs when the target cell is exposed to low hormone levels over a long period of time.

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23			Which component of a cell acts like a "switch" to turn cellular activities on or off when a hormone binds to it?
			A)	DNA
			B)	receptor molecule
			C)	endoplasmic reticulum
			D)	ribosomes
24			Which of the following is not true for a "ligand"?
			A)	Ligands are molecules that bind to proteins to change their functions.
			B)	An example of a ligand is a hormone
			C)	Ligands bind to molecules at specific binding sites.
			D)	A specific ligand can bind to different types of binding sites.
25			Up-regulation is a(n)
			A)	increase in the number of target cells for a particular hormone.
			B)	increase in the levels of the hormone carrying out the action.
			C)	increase in the number of receptors on a target cell.
			D)	decrease in the sensitivity of target cell to a hormone.

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26			What is happening when one hormone molecule causes the activation of thousands of enzyme molecules in a target cell?
			A)	amplification
			B)	up-regulation
			C)	saturation
			D)	antagonistic effects
27			Which of the following describes the standard measurement to determine the rate at which hormones are eliminated from the body?
			A)	whole-life
			B)	half-life
			C)	metabolic rate
			D)	transport rate
28			Which of the following would reduce the amount of hormone concentration in the blood circulation?
			A)	conjugation with sulfate groups
			B)	the amount of active transport
			C)	the amount of the hormone that irreversibly binds to plasma proteins
			D)	All of the above.
29			Which of the following will lengthen the half-life of hormones?
			A)	reversible binding with plasma proteins
			B)	proteolytic enzymes in the circulation
			C)	metabolism
			D)	excretion
30			Where would be the most common site for conjugation of hormones in the body?
			A)	kidneys
			B)	blood
			C)	liver
			D)	spleen
31			If someone were given a drug that inhibits the action of adenylate cyclase, the result would be that cells using cAMP as a second messenger would
			A)	not be able to respond to the hormone at all.
			B)	exhibit a prolonged response to the hormone.
			C)	respond no differently than cells in someone who had not been given the drug.
			D)	use the drug as a second messenger.
32			In the cyclic AMP second-messenger mechanism of hormone action, which of these events happens immediately after the hormone binds to its receptor?
			A)	Adenylate cyclase is activated.
			B)	Cyclic AMP is converted to AMP.
			C)	Protein kinases are activated.
			D)	A G protein is activated.
33			Some hormones act on their target cells by causing the formation of a second messenger such as cyclic AMP inside the cell. Which of these intracellular enzymes terminates the action of the cyclic AMP?
			A)	adenylyl cyclase
			B)	monamine oxidase
			C)	acetylcholinesterase
			D)	phosphodiesterase
34			In the second messenger mechanism,
			A)	one hormone needs to act on the target cell before a second hormone can act on it.
			B)	one hormone interferes with the action of a second hormone.
			C)	two hormones act together on a target cell, with the second hormone having the greater effect.
			D)	the hormone binds to a membrane receptor, which activates an enzyme that catalyzes the formation of a second messenger inside the cell.
35			When cAMP is used as a second messenger, its action is to
			A)	activate a G protein.
			B)	activate a protein kinase.
			C)	initiate an enzyme cascade.
			D)	bind with the hormone.
36			Calmodulin is found in target cells in which the second messenger is
			A)	cAMP.
			B)	cGMP.
			C)	calcium.
			D)	diacylglycerol.
37			An example of a ligand that cannot pass through the plasma membrane is
			A)	epinephrine
			B)	testosterone
			C)	aldosterone
			D)	T3 hormone
38			Intracellular hormone receptors are normally found in ___________ and ____________ of the cell.
			A)	ribosome, cytoplasm
			B)	cytoplasm, plasma membrane
			C)	cytoplasm, nucleus
			D)	nucleus, plasma membrane
39			When a ligand enters the cell and binds to intracellular receptors, which of the following events takes place?
			A)	increased synthesis of cAMP.
			B)	conversion of GDP to GTP.
			C)	opening of calcium channels.
			D)	increased synthesis of mRNA and proteins.
40			Which of the following hormones works by activation of genes.
			A)	GH
			B)	insulin
			C)	corticosterone
			D)	glucagon
41			Which of these is NOT a steroid hormone?
			A)	progesterone
			B)	testosterone
			C)	cortisol
			D)	thyroid hormone
42			A hormone that penetrates the plasma membrane of its target cells and binds to a receptor in the nucleus is classified as a(n) _____ hormone.
			A)	nonsteroid
			B)	protein
			C)	peptide
			D)	steroid
43			Which class of hormone exhibits amplification at the target cell?
			A)	steroid hormones
			B)	nonsteroid hormones
			C)	hormones derived from cholesterol
			D)	hormones that bind to a receptor in the target cell nucleus