CH 6: Communication, Integration, and Homeostasis

The most significant difference between a paracrine and an autocrine is the

method of transport.

cell that responds to it.

cell that releases it.

route of transport.

There are no differences–they are the same.

cell that responds to it.

Which is NOT a basic method of cell-to-cell communication?

contact-dependent signals

mechanical signals

diffused chemical signals

cytoplasmic transfer of signals

nerve and blood-transported signals

mechanical sifgnals

Neurotransmitters and neurohormones both

are released by neurons.

affect only cells with a specific receptor.

travel in the blood to their target cell.

are released by neurons and affect only cells with a specific receptor.

are produced by all cells.

are released by neurons and affect only cells with a specific receptor.

Choose the true statement.

Steroid hormones are generally made in advance and stored until needed.

Paracrine signals are used for long-distance communication.

Neurotransmitters are a type of neurohormone.

Autocrine signals are produced by and act upon the same cell.

Autocrine signals are produced by and act upon the same cell.

A hormone affects ________.

all cells in the body, but different types of cells produce different responses to the hormone

only specific target cells, because nontarget cells lack the receptors for the hormone

only specific target cells, because hormones are delivered only to those cells

all cells in the body, because hormones are secreted into blood, which is then transported everywhere

only specific target cells, because nontarget cells lack the receptors for the hormone

Lipophilic hormones

usually bind to receptors inside the cytoplasm or nucleus.

usually bind to receptors on the surface of the cell.

function by activating cAMP.

cannot diffuse through the cell membrane.

function by way of a second messenger system.

usually bind to receptors inside the cytoplasm or nucleus.

Cyclic AMP activates

a G protein.

hormone receptors.

adenylyl cyclase.

protein hormones.

protein kinase A.

protein kinase A

Diacylglycerol is produced from

phospholipase C.

cyclic AMP.

a G protein.

protein kinase A.

phosphatidylinositol bisphosphate.

phosphatidylinositol bisphosphate.

The binding of lipophilic messengers, such as steroid hormones, to their receptors triggers

cyclic nucleotide formation.

adenylyl cyclase activation.

G protein inhibition.

protein kinase activation.

gene transcription.

gene transcription

The most rapid intracellular responses to signals result from activation of receptors that are also __________.

second messengers

ion channels

amplifiers

enzymes

ion channels

Which type of receptor alters the cytoskeleton when a ligand binds to it?

Integrin receptor

Receptor-channel

G protein-coupled receptor (GPCR)

Receptor-enzyme

Integrin receptor

Which characteristic must a signaling molecule have in order to bind to a cytosolic or nuclear receptor?

It must be a gene activator.

It must contain significant polarity to allow it to associate with its receptor.

It must be actively transported across the membrane.

It must be lipophilic.

It must be lipophilic.

A drug binds to a receptor in the nucleus. This binding turns on a gene to make a protein. This drug is ____.

lipophobic and hydrophobic.

Lipophobic and hydrophilic.

lipophilic and hydrophobic.

lipophilic and hydrophilic.

lipophilic and hydrophobic.

Which of the following is a similarity between ion receptor channels and G protein-coupled receptors?

Both activate second messengers.

Both are signal transducers.

Both allow ions to diffuse through the receptor.

Both bind extracellular ligands.

both bind extracellular ligands

When calcium becomes available inside a cell, it comes from

intracellular storage.

extracellular fluid.

extracellular fluid and intracellular storage.

It is always available as a major cytosol cation.

extracellular fluid and intracellular storage.

When adenylyl cyclase is activated,

cAMP is broken down.

calcium ions are released from intracellular stores.

steroids are produced.

protein kinases are metabolized.

cAMP is formed.

cAMP is formed.

One intracellular calcium-binding protein is

calmodulin.

nitric oxide.

IP3.

calcitonin.

calcitriol.

calmodulin.

Which gas is also a paracrine signaling molecule?

Nitrous oxide

Carbon dioxide

Sulfur dioxide

Nitric oxide

nitric oxide

Naproxen is a COX inhibitor that can decrease pain. Why does this drug have this effect?

It decreases production of the leukotrienes.

It decreases production of prostaglandins.

It increases the production of thromboxanes.

It inhibits lipoxygenase activity.

it decreases production of prostaglandins.

The neurotransmitter epinephrine __________.

affects all blood vessels in the same way, because the response of a target is specific for the neurotransmitter

causes some blood vessels to dilate and others to constrict, because different blood vessels have different receptors for epinephrine

affects all blood vessels in the same way, because all blood vessels have only one type of epinephrine receptor

has effects that are the opposite of those of the neurohormone norepinephrine

causes some blood vessels to dilate and others to constrict, because different blood vessels have different receptors for epinephrine

Which of the following is the best example of an antagonist?

Atenolol is a beta blocker drug that binds to β1-adrenergic receptors, decreasing blood pressure.

Epinephrine and norepinephrine each bind to α- and β-adrenergic receptors but with different affinities.

Serotonin binds the 5-HT receptor and activates phospholipase C but not phospholipase A2.

Glucagon binds the glucagon receptor (a G protein-coupled receptor) and causes the release of glucose from hepatocytes.

Atenolol is a beta blocker drug that binds to β₁-adrenergic receptors, decreasing blood pressure.

An integrating center

is an electrical and/or chemical signal that travels to the effector.

is the disturbance or change that sets the pathway in motion.

is the minimum stimulus that must be achieved to set the reflect response in motion.

evaluates incoming signals and compares it with the setpoint.

evaluates incoming signals and compares it with the setpoint.

Match the term with its description:

A. threshold
B. effector
C. integrating center
D. setpoint
E. sensory receptor


continuously monitors its environment for a specific variable

threshold

effector

integrating center

setpoint

sensory receptor

sensory receptor

Which is NOT an example of homeostasis?

Increased blood sugar stimulates the release of a hormone from the pancreas that stimulates the liver to store blood sugar.

Increased blood pressure in the aorta stimulates mechanisms to lower blood pressure.

Increased blood calcium levels stimulates the release of a hormone that lowers blood calcium levels.

Decreased body temperature stimulates a neural response that increases body temperature.

Increased estrogen during the menstrual cycle increases the number of progesterone receptors in the uterus.

Increased estrogen during the menstrual cycle increases the number of progesterone receptors in the uterus.

Compared with endocrine reflexes, neural reflexes __________.

respond rapidly but are longer-lasting

respond rapidly but are short

respond slowly but are longer-lasting

respond slowly but are short

Respond rapidly but are short.

Cannon's second postulate states that some systems of the body are under tonic control. What does this statement mean?

The body has the ability to adjust the levels of regulated variables.

Some chemical signals can have the opposite effects of other chemical signals on the same organ.

Some organs function without any input or signals from external sources

The tonic, an area of the brain, is responsible for controlling certain body systems.

The body has the ability to adjust the levels of regulated variables.

Which of the following is a similarity between neural and endocrine reflexes?

Stimulus intensity can be increased with increased signal.

Signals travel to many different organs.

Responses are short.

Responses are fast.

Stimulus intensity can be increased with increased signal.

Which of the following is NOT a means by which cell signal pathways are terminated?

The extracellular signal molecule may be transported into cells.

The extracellular signal molecule may be degraded.

The signal is terminated by the binding of an inactivator molecule to the signal molecule.

The signal may be pumped out of the cell or into storage.

The signal is terminated by the binding of an inactivator molecule to the signal molecule.

Which molecule of the GPCR-adenylyl cyclase signal transduction system phosphorylates proteins to create the cellular response?

Inositol triphosphate

Phosphatase

Protein kinase A

Protein kinase C

Protein kinase A