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BIO360 - Animal Physiology Exam 1 (Chapters 1 - 8)

Which of the following is an important characteristic of lipids?

They can be linked into long chains.

They dissolve in water.

They can be converted to hormones.

They are nonpolar.

They are nonpolar. pg33

What is a substance that can moderate the change in pH of a solution?

An enzyme

A polar compound

A buffer

Peptide

A buffer pg 49

Which compound is hydrophobic?

Potassium ions (K+)

Sugar

Butter

Table salt

Butter

Lemon juice has a pH of about 2.0, compared to a pH of about 1.0 for stomach acid. Therefore, the concentration of H+ in stomach juice is ________ than that of lemon juice.

10 times higher

2 times lower

2 times higher

10 times lower

10 times higher pg48

Define interstitial fluid, indicating if it is inside or outside cells (intracellular or extracellular).

Interstitial fluid is the intracellular fluid found in all cell types.

Interstitial fluid is the extracellular fluid inside the circulatory system.

Interstitial fluid is the intracellular fluid of the blood cells.

Interstitial fluid is extracellular fluid outside the circulatory system and the cells.

Interstitial fluid is extracellular fluid outside the circulatory system and the cells.

Functions of the cell membrane include physical isolation of the cell from its surroundings, regulation of exchange, structural support, and which other function?

Communication between the cell and its environment

Radiation of heat to prevent protein denaturation and cell stress.

Extracting energy from the environment for cell survival

Binding and delivery of oxygen

Communication between the cell and its environment 65

Cell membranes are mainly constructed from ________.

lipids and carbohydrates

lipids and proteins

nucleic acid and proteins

carbohydrates and proteins

lipids and proteins 66

Mitochondria are unique organelles in several ways. They contain a specific genome that allows them to produce their own proteins. They can undergo replication to create more mitochondria within a cell. What other characteristic make mitochondria unique from other organelles?

They have a double wall creating two separate compartments.

Mitochondria store calcium.

Their outer membrane is made up of lipid.

They contain enzymes and proteins.

They have a double wall creating two separate compartments. 71?

Which tissues would likely have cells with the greatest number of gap junctions?

Epidermis

Mucosal layer of the GI tract

Bone

Cardiac muscle

Cardiac muscle 79

***GAP JUNCTIONS ARE USED FOR CELL-CELL COMMUNICATION. These junctions are ideal for cardiac muscle. Cardiac muscle requires a lot of communication because each cell must contract simultaneously each time the heart beats***

Which two fluid compartments make up the extracellular fluid?

Plasma and interstitial fluid

Cytosol and plasma

Intracellular fluid and plasma

Interstitial fluid and intracellular fluid

Plasma and interstitial fluid 65

In a system that includes a ball and a ramp, when would potential energy be greatest?

When the ball comes to rest at the bottom of the ramp

When the ball was at rest at the top of the ramp

When the ball is at its maximal velocity

When the ball first begins to roll down the ramp

When the ball was at rest at the top of the ramp 101

What type of reaction releases energy?

An exergonic reaction

A reversible reaction

An endergonic reaction

A thermodynamic reaction

An exergonic reaction 103

A kinase moves which functional group or molecule?

Amino groups

Phosphate

Hydroxyl

H2O

Phosphate 108

Enzymes ________.

are altered in structure as a result of chemical reactions

allow for chemical reactions to occur, which would otherwise not be possible

increase the rate of chemical reactions

determine the direction of the chemical reaction (i.e., whether molecules are produced or broken down).

increase the rate of chemical reactions 105

What is the definition of "metabolism?"

It is the reaction in an organism that uses energy.

It is the total of all the chemical reactions in an organism.

It is the reaction in an organism that releases energy.

It is the reaction in an organism that takes large molecules and breaks them into smaller units.

It is the total of all the chemical reactions in an organism. 109

What is the simplest way for a human cell to acquire the activation energy necessary for metabolic reactions?

Couple an exergonic reaction with an endergonic reaction.

Allow more water to flow across the cell membrane and use the kinetic energy to drive reactions.

Use the energy in sunlight to drive chemical reactions.

Increase the internal cellular temperature.

Couple an exergonic reaction with an endergonic reaction. 104

During aerobic metabolism of glucose, most ATP is produced during which group of chemical reactions?

Conversion of pyruvate to acetyl CoA

Citric acid cycle

Electron transport (yielding 26-28 molecules of ATP per molecule of glucose)

Glycolysis

Electron transport (yielding 26-28 molecules of ATP per molecule of glucose) 111-115?

Which of the following best describes the function of enzymes?

Enzymes slow down chemical reactions so they don't proceed too fast, thus causing problems.

Enzymes will turn into specific molecules as needed by the body, such as ATP.

Most reactions are due to the addition of a phosphate ion (phosphorylation) to a molecule to create a reaction. The phosphate ions come from enzymes.

Enzymes lower the activation energy level of a chemical reaction, thus making it so the reaction will proceed.

Enzymes lower the activation energy level of a chemical reaction, thus making it so the reaction will proceed. 107

How does the intracellular fluid compartment differ from the extracellular fluid compartment?

Sodium ions are more concentrated inside cells than in the plasma.

Proteins are more concentrated in the interstitial fluid than in cells.

Bicarbonate ions (HCO3 -) are more concentrated inside cells than in either the interstitial fluid or plasma.

Potassium ions are more concentrated inside cells than in the extracellular space.

Potassium ions are more concentrated inside cells than in the extracellular space. 172
(Answers Box #2)

If a swimmer cuts his foot on a seashell while wading in the ocean and bleeds into the seawater, his red blood cells (erythrocytes) will shrink. What does this tell us about seawater?

The seawater is hypotonic to the erythrocytes.

The erythrocyte cell membrane is not permeable to seawater.

The seawater is isotonic to the erythrocytes.

The seawater is hypertonic to the erythrocytes.

The seawater is hypertonic to the erythrocytes. 134

How can a solution be hyperosmotic but hypotonic?

If the concentration of nonpenetrating solutes is less in the solution than in a cell

If the concentration of penetrating solutes is higher in the solution than in a cell

If the total concentration of solutes in the solution is less than in a cell

If the amount of solutes is the same in the cell and solution

If the concentration of nonpenetrating solutes is less in the solution than in a cell 135

What is the mechanism of action of the cystic fibrosis transmembrane conductance regulator (CFTR)?

It allows for the active pumping of chloride from the extracellular fluid to the intracellular fluid.

It allows for the diffusion of sodium across the epithelium of the cell.

It allows for the diffusion of chloride across the epithelium of a cell.

It moves ATP from the inside of the cell to the outside of the cell.

It allows for the diffusion of chloride across the epithelium of a cell.

How is the function of the CFTR altered in someone with cystic fibrosis?

The CFTR channel is absent.

The CFTR functions in reverse.

The CFTR channel does not respond to ATP.

There is excessive functionality of the CFTR channel.

The CFTR channel is absent. Paragraph 3

Why is the thick mucus in Daniel's lungs a sign that he might have cystic fibrosis?

Without the CFTR, mucus cannot be thinned.

The CFTR is needed to produce a thick mucus.

When not working properly, the CFTR pulls liquids out of the mucus causing it to thicken.

none of the above

Without the CFTR, mucus cannot be thinned.

Why would tasting salty sweat on the foreheads of babies lead a midwife to assume that the baby might be afflicted with cystic fibrosis?

The CFTR allows for chloride to leave the sweat and re-enter the cells, creating a hypotonic sweat.

The CFTR channel actively pumps chloride into the lumen when someone is afflicted with cystic fibrosis.

The water in the lumen of the sweat duct is suctioned out by a defective CFTR channel.

When the CFTR is not functioning properly, it pumps an excessive amount of sodium into the lumen of the sweat duct.

The CFTR allows for chloride to leave the sweat and re-enter the cells, creating a hypotonic sweat.

What is the most important distinction between the membrane transporters known as channel proteins and those known as carrier proteins?

Channel proteins transport water-soluble molecules. Carrier proteins transport water-insoluble molecules.

Channel proteins do not require energy, whereas carrier proteins do require energy.

Channel proteins create water-filled passages for small molecules that do not bind to the protein. Carrier proteins transport larger molecules by binding to them.

Channel proteins transport only very small molecules. Carrier proteins transport macromolecules.

Channel proteins create water-filled passages for small molecules that do not bind to the protein. Carrier proteins transport larger molecules by binding to them. 146

What properties must a molecule have to pass through a cell membrane by simple diffusion?

They must be polar and ionic.

They must be small and/or lipophilic.

The temperature must be high enough to increase the speed of the molecule so it has ample force to pass through the membrane.

They must be able to change shape to pass between the lipid molecules of the membrane.
Essentials Figure: An Application of Osmolarity and Tonicity

They must be small and/or lipophilic. 165

Which of the following statements correctly describes the relationship between intracellular fluid (ICF) and extracellular fluid (ECF)?

All of the contents within the ICF are readily exchanged with the contents of the ECF.

Total solute concentration differs in the ECF when compared to the ICF.

The ICF and the ECF are in a chemical equilibrium.

The types of solutes and their distribution between the ICF and ECF are not the same.

The types of solutes and their distribution between the ICF and ECF are not the same. 130

A solution containing:
Which of the following conditions below has the highest osmolarity?

5 mOsm of potassium (K+) and 3 mOsm of sodium (Na+)

3 mOsm of sodium (Na+) and 4 mOsm of chloride (Cl-)

2 mOsm of chloride (Cl-)

7 mOsm of sodium (Na+)

5 mOsm of potassium (K+) and 3 mOsm of sodium (Na+)

Solute/Volume = Concentration

You have prepared a beaker containing two membranes that are permeable only to water. This beaker has three separate compartments each containing the following osmolarities:How would you describe the osmolarity of compartment A relative to compartment B?

A. 10 Osmol/L
B. 13 Osmol/L
C. 7 Osmol/L

Compartment A is hyposomotic to compartment B.

Compartment A is isosmotic to compartment B.

Compartment A is hyperosmotic to compartment B.

Compartment A is hyposomotic to compartment B.

Using the same scenario as Part E, how would you describe the osmolarity of compartment B relative to compartment C?
A. 10 Osmol/L
B. 13 Osmol/L
C. 7 Osmol/L.

Compartment B is hyposomotic to compartment C.

Compartment B is isosmotic to compartment C.

Compartment B is hyperosmotic to compartment C.

Compartment B is hyperosmotic to compartment C.

You have a total body concentration of 900 mosmol dissolved in 3 liters of solution. If you added 0.5 liters of a solution with 150 mosmol of NaCl to the body, what would the new total body concentration be?

450 mOsM

300 mOsM

350 mOsM

700 mOsM

300 mOsM

The Breakdown:

900mosmol / 3L = 300mOsM

150 mosmol / 0.5L = 300mOsM

Channel proteins that can be opened or closed are called ____ channels.

receptor-mediated

carrier

Gated

signal

Gated 147

Membrane receptors are involved in various types of cell signaling. Some membrane receptors function as _____ channels.

chemically gated

mechanically gated

voltage-gated

open

chemically gated

Cell membranes are primarily made of _____ molecules.

cholesterol

Phospholipid

carbohydrate

protein

Phospholipid

What type of membrane transporter would be activated by an action potential?

A voltage-gated channel

A chemically-gated channel

A carrier protein

An open channel

A voltage-gated channel

What will happen to the cells of a patient who is provided with an intravenous solution that is isosmotic to intracellular fluids?

The question cannot be answered with certainty without knowing the identity of the solutes present in the IV solution.

The cells will shrink, because isosmotic solutions are hypertonic.

The cells will retain their normal shape, because isosmotic solutions result in no net change in water concentration.

The cells will swell, because isosmotic solutions are hypotonic.

The question cannot be answered with certainty without knowing the identity of the solutes present in the IV solution.

The membrane potential of most cells ________.

determined primarily by sodium

results in a net negative electrical charge in the body

is negative, except when there is a change in membrane permeability to ions.

is negative at all times

is negative, except when there is a change in membrane permeability to ions.

What will occur if solution A (500ml solution containing 400mosmol/L nonpenetrating solute) is separated by a biological membrane from solution B (4L solution containing 600mosmol/L nonpenetrating solute)?

The volume of B will increase.

The volume of A will increase.

There will be no net volume change.

Solute will flow from solution B to solution A.

The volume of B will increase.

Which type of membrane transport generally requires that the transported molecule dissolve in the lipid membrane?

Phagocytosis

Active transport

Facilitated diffusion

Simple diffusion

Simple diffusion

The permeability of a membrane to a particular molecule is related to two variables. Which two variables is it related to and what is the relationship?

It is directly proportional to both lipid solubility and molecular speed.

It is indirectly proportional to both molecular size and shape.

It is indirectly proportional to the square of the diffusion distance and directly proportional to temperature.

It is directly proportional to lipid solubility and inversely proportional to the size of the molecule.

It is directly proportional to lipid solubility and inversely proportional to the size of the molecule.

Which membrane proteins bind ligands and trigger another membrane event?

Receptors

Structural proteins

Transporters

Enzymes

Receptors 156

Where is most of the water in the body located?

Interstitial fluid

Intracellular fluid

Lumen of the digestive and urinary tracts

Plasma

Intracellular fluid 132

Which of the following statements makes an accurate distinction between type 1 and type 2 diabetes?

Both are characterized by an inability to make insulin.

Type 1 diabetes is characterized by high levels of insulin while type 2 diabetes is characterized by low insulin levels.

Type 1 diabetes occurs when cells of the pancreas stop making insulin while type 2 diabetes occurs when the cells are no longer sensitive to insulin.

Both are characterized by normal levels of insulin, but the cells of the body are no longer responsive to the hormone.

Type 1 diabetes occurs when cells of the pancreas stop making insulin while type 2 diabetes occurs when the cells are no longer sensitive to insulin.

If you give a patient who recently developed diabetes a shot of insulin and blood glucose levels do not change, what type of diabetes does he or she most likely have?

type 2

type 1

It is possible that they could have either.

There is not enough information to tell.

type 2

Is Marvin's high blood glucose level the direct cause for concern expressed by the nurse?

Yes. The body should never have a high level of glucose in the blood.

No. Blood glucose levels are always high in the body and should therefore not be a cause for concern.

No. Blood glucose normally spikes after a meal; it is the fact that it is high under a fasted state that suggests a problem with homeostatic controls.

Yes. High glucose levels are thought to be toxic to all cells of the body.

No. Blood glucose normally spikes after a meal; it is the fact that it is high under a fasted state that suggests a problem with homeostatic controls.

If glucose levels are low, how would you predict activation of the beta cell and insulin release to change?

increase; decrease

decrease; increase

decrease; decrease

increase; increase

decrease; decrease

A given hormone affects ________.

only specific target cells, because nontarget cells lack the appropriate receptors

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

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

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

only specific target cells, because nontarget cells lack the appropriate receptors

Extracellular signal molecules are also called

neurotransmitters.

ligands.

receptors.

hormones.

ligands.

Conversion of an extracellular signal into an intracellular one is called

signal transduction.

transmogrification.

translation.

transcription.

signal transduction.

Amplifier enzymes produce

kinases.

second messengers.

phosphorylated proteins.

ATP.

second messengers.

Administration of ibuprofen can decrease pain. Why would this COX-2 inhibitor have this effect?

It blocks production of prostaglandins.

It enhances the production of thromboxanes.

It would inhibit lipoxygenase activity.

It blocks production of the leukotrienes.

It blocks production of prostaglandins.

What are Prostaglandins?

Eicosanoid family. Molecules that regulate physiological systems.

The neurotransmitter norepinephrine ________.

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

has effects that are opposite those of the neurohormone epinephrine

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

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

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

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

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

The extracellular signal molecule may be transported away from the receptor.

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

The extracellular signal molecule may be degraded.

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

Alpha-adrenergic receptors have a higher affinity for norepinephrine than for epinephrine. Beta-adrenergic receptors have a higher affinity for epinephrine than for norepinephrine. Which concept about receptor function do these statements reflect?

Specificity

Amplification

Up-regulation

Antagonists

Specificity

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

Atenolol is a drug that binds to β1-adrenergic receptors reducing blood pressure.

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

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

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

Atenolol is a drug that binds to β1-adrenergic receptors reducing blood pressure

What are the 6 basic components of a reflex pathway?

S.I.I.E.O.R

Sensor
Input Signal
Integrator
Effector
Output Signal
Response

Name the 7 stages of a Reflex Pathway

S.S.A.I.E.E.R

1. Stimulus
2. Sensor
3. Afferent Signal
4. Integrator
5. Efferent Signal
6. Effector
7. Response

Describe the function of an afferent neuron.

to release neurohormones into the circulatory system

to deliver information about the physiological variable to the integrator

to release neurotransmitters onto an organ

to deliver information to the target tissue

to deliver information about the physiological variable to the integrator

A simple endocrine pathway will include which of the following?

endocrine organ

efferent neuron

afferent neuron

sensor

neurotransmitter

circulatory system

classic hormone

neurohormone

brain

target tissue

endocrine organ
classic hormone
target tissue
sensor

Which of the following best describes the role of endocrine organs in both simple and complex reflex pathways?

to function as a sensor and integrator

to deliver information about the stimulus to the brain

to release neurohormones into the circulatory system

to be the target organs

to function as a sensor and integrator

Specialized neurons in the brain respond to changes in blood osmolarity (solute concentration). When blood osmolairty strays outside of homeostatic range, these neurons release a neurotransmitter that acts upon neurons in the posterior pituitary. When stimulated, the neurons in the posterior pituitary will release a different chemical that will travel via the circulatory system to the kidneys. How would you classify this type of simple reflex?

simple endocrine

simple neural

neurohormone

complex neuroendocrine

neurohormone

In order to prevent damage due to overstretching, skeletal muscles contain specialized sensors. As a muscle stretches, information from these sensors is sent via afferent neurons to the spinal cord where the information is integrated. After integration is complete, an output signal is sent via efferent neurons to the muscle, preventing it from being stretched further. This is an example of what type of reflex pathway?

simple endocrine

simple neural

complex neuroendocrine

neurohormone

simple neural

Arrange in order:

1. Gastrin stimulates parietal cell
2. Parietal cell releases HCL
3. Effernt neurons stimulate the G cell
4. Meal containing protein enters the stomach
5. G-cell releases gastrin into circulation
6. Afferent Neurons send info to nervous system in gut lining

4, 6, 3, 5, 1, 2

Identify the role of the G cell in the gut lining.

integrator

generates response

sensor

target organ

integrator

In the sequence of events mapped out in Part I, what is response?

release of gastrin from the G cell

delivery of sensory information to the nervous system of the gut

entry of food containing protein into the stomach

release of hydrochloric acid by the parietal cell

release of hydrochloric acid by the parietal cell

What is the best example of a first messenger?

Na+, which binds to the Na+/K+ATP pump and is actively transported out of a cell in exchange for K+.

Dystrophin, which associates with costameres to transmit the force of muscle contraction to the extracellular matrix.

Myosin, which binds to actin and causes muscle contraction.

Insulin, which causes the target cell to take up glucose from the blood.

Insulin, which causes the target cell to take up glucose from the blood.

What determines which cells act as targets for endocrine signals?

Those with receptors specific for the signaling molecule.

Those in the same area as the cells that release the hormone.

Those cells that are derived from the same embryonic tissue as the endocrine organ.

Those with a high density of CAMs.

Those with receptors specific for the signaling molecule.

Which form of cell-to-cell communication uses the direct transfer of electrical and chemical signals?

Contact dependent signaling

Autocrine signaling

Gap junction signaling

Endocrine signaling

Gap junction signaling

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

second messengers

ion channels

amplifiers

enzymes

ion channels

Which gas is also a paracrine signaling molecule?

Nitrous oxide

Sulphur dioxide

Carbon dioxide

Nitric oxide

Nitric oxide

Compared to endocrine reflexes, neural reflexes ________.

respond rapidly and are longer-lasting

respond slowly and are very brief

respond slowly, but are longer-lasting

respond rapidly, but are very brief

respond rapidly, but are very brief

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

Inositol triphosphate

Protein kinase C

Protein kinase A

Phosphatase

Protein kinase A

The hypothalamus senses the temperature of the blood via thermoreceptors. When blood temperature begins to drop, the hypothalamus releases a hormone, TRH, that stimulates the release of TSH from the anterior pituitary gland. TSH causes the thyroid gland to release thyroid hormone (TH). TH causes an increase in body temperature, which causes the hypothalamus to stop releasing TRH. In this reflex response loop, which tissue acts as the integrating center?

The hypothalamus

Thermoreceptors

The thyroid gland

The anterior pituitary

The hypothalamus

Active transport of molecules across membranes requires ATP because ________.

the molecules are moved against the concentration gradient (uphill)

more than one molecule is transported at a time

the transport protein moves or has moving gates

the transported molecules are not soluble in the lipid membrane

the molecules are moved against the concentration gradient (uphill)

The time required for molecules in a solution to move from A to B is proportional to the square of the distance from A to B. What property of diffusion does this principle explain?

Diffusion is rapid over short distances but slow over longer distances.

Diffusion is inversely related to molecular weight and size.

The rate of diffusion depends upon the concentration gradient of the molecule.

Diffusion rate is directly proportional to distance.

Diffusion is rapid over short distances but slow over longer distances.

Ion channels can be opened or closed via three signal transduction mechanisms. Two of them are extracellular signals and second messengers. What is the third mechanism for opening or closing ion channels?

Altered membrane permeability to Ca2+

Electrical signals

Phosphorylation

G protein action

G protein action

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

It must be a gene activator.

It must be actively transported across the membrane.

It must be lipophilic and able to diffuse across the plasma membrane.


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

It must be lipophilic and able to diffuse across the plasma membrane.

Why is the resting membrane potential (Vm) approximately - 70 mV for most cells?

Most membranes are 40 times more permeable to K+ than to Na+.

Most membranes are 10 times more permeable to Na+ than to K+.

The large concentration of proteins in the interstitial space draws Na+ out of the cell making it negatively charged.

Most cells contain a large concentration of Cl- making them negatively charged.

Most membranes are 40 times more permeable to K+ than to Na+.

The membrane potential of most cells ________.

determined primarily by sodium

is negative at all times

results in a net negative electrical charge in the body

is negative, except when there is a change in membrane permeability to ions

is negative, except when there is a change in membrane permeability to ions

Negative feedback in reflex loops ________.

is "negative" because it opposes homeostasis

is responsible for triggering the response to the stimulus

is rare compared to positive feedback

is common because it promotes homeostasis

is common because it promotes homeostasis

The ion that controls the widest variety of intracellular activities is ________.

chloride

potassium

sodium

calcium

calcium

Signal molecules that degrade most rapidly, resulting in very brief effects, are ________.

hormones

paracrines

ions

gases such as nitric oxide

gases such as nitric oxide

What are the second messengers in the GPCR-phospholipase C signal transduction system?

Ca2+and calmodulin

cAMP and cGMP

Inositol triphosphate and diacylglycerol

ATP and NADH

Inositol triphosphate and diacylglycerol

Which of the following hormones has intracellular receptors?

insulin

epinephrine

Cortisol

Cortisol

What is the mechanism of action of lipid-soluble hormones?

increasing protein kinases

phosphorylation of intracellular proteins

activation of genes, which increases protein synthesis in the cell

activation of genes, which increases protein synthesis in the cell 215

After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?

activates a protein kinase

directly alters protein synthesis at the ribosome

acts as a transcription factor and binds to DNA, activating a gene

phosphorylates a protein

acts as a transcription factor and binds to DNA, activating a gene

Which hormone's receptor is always bound to DNA, even when the receptor is empty?

thyroid hormone

insulin

cortisol

thyroid hormone

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?

Receptors can't enter the nucleus until the hormone is bound to it.

transcription factors

chaperone proteins

chaperone proteins (chaperonins)

What distinguishes a hormone from other signaling molecules such as cytokines, or paracrine or autocrine signaling molecules?

Hormones are secreted into the bloodstream.

Hormones act when they are in high concentrations.

Hormones are nucleotides while other signals are peptides or lipids.

Hormones bind to receptors on the cell surface.

Hormones are secreted into the bloodstream.

Hormones act when they are in high concentrations.
***No, they act at low [ ]

Hormones are nucleotides while other signals are peptides or lipids.
***NO - most hormones are peptides and proteins

Hormones bind to receptors on the cell surface.
***NO - cortisol is a hormone that has intracellular receptors

A new hormone is discovered. Analysis of its synthesis suggests that it is synthesized on demand and has a long half-life in the bloodstream once it is released. It seems to activate gene transcription in its target cells though no cell surface receptors can be identified. What type of hormone is this most likely to be?

A catecholamine

A thyroid hormone

A peptide

A steroid

A catecholamine
***Catecholamines are neurohormones. They bind to membrane recepts like peptide hormones do. Also have short half-life

A thyroid hormone
***Also behave like steroid hormones but have short half life

A peptide
***Peptide hormones need membrane receptors for entry. Short half-life

A steroid 214

When might negative feedback fail to regulate hormone production, and how would this affect hormone secretion?

A pathology in the endocrine gland could prevent negative feedback from working, resulting in hyposecretion.

Negative feedback may cause down-regulation of receptors in the target cells, resulting in hyposecretion.

A pathology in the endocrine gland could prevent negative feedback from working, resulting in hypersecretion.

Negative feedback may disable the receptors in the target cells, decreasing their response to hormones and causing even more hormone to be secreted.

A pathology in the endocrine gland could prevent negative feedback from working, resulting in hypersecretion.

Norepinephrine and epinephrine cause an increase in heart rate (HR) and stroke volume (SV), which is the amount of blood pumped out during each heart beat, but the effect is enhanced when thyroid hormone (TH) is also present. Oddly, TH has little effect on HR and SV alone. What is the effect of TH on HR and SV called?

Hypersecretion

Cooperation

Synergism

Permissiveness

Permissiveness

Most amine hormones are derived from which source?

Freely circulating amine groups

Tyrosine

Cholesterol

An iodinated peptide

Tyrosine 216

What is the role of the hypothalamus with regard to hormone release and endocrine function?

to release trophic hormones that stimulate the anterior pituitary

to release classic hormones for delivery to the systemic tissues

to release trophic hormones that act on the nervous tissue of the brain

to release classic hormones that inhibit hormone release from the anterior pituitary

to release trophic hormones that stimulate the anterior pituitary 223

Which loss of function would occur if you were to sever the connection between the hypothalamus and the anterior pituitary?

There would be no loss of function.

The portal system would carry tropic hormones from the hypothalamus to the anterior pituitary at an accelerated rate.

The anterior pituitary would not release hormones in response to trophic hormone stimulation.

There would no longer be a release of trophic hormones from the hypothalamus.

All three losses of function listed above would occur if you severed the connection between the hypothalamus and the anterior pituitary.

The anterior pituitary would not release hormones in response to trophic hormone stimulation.

How would you classify the type of chemical released by the posterior pituitary (e.g., classic hormone, neurotransmitter etc.)?

Choose the best answer.

classic hormone

trophic hormone

neurotransmitter

Neurohormone

Neurohormone 221

Which of the following are released by the posterior pituitary?
Select all that apply.

Vasopressin

Oxytocin

prolactin

luteinizing hormone

Vasopressin 219

Oxytocin 219

Where are the neurohormones released by the posterior pituitary produced?

by neuroglia located at the end of the posterior pituitary

in the axon terminal of the neurons that project from the hypothalamus through to the infundibulum

by the endocrine cells located within the posterior pituitary

in the neuronal cell bodies found in the hypothalamus

in the neuronal cell bodies found in the hypothalamus 219

Mrs. Johnson does goes in to visit her doctor because of some health issues that she has been having. One of the many tests that were run on Mrs. Johnson revealed that she had no circulating concentrations of vasopressin. The doctor does a further analysis of her hypothalamus and posterior pituitary to see what might be causing this problem. Predict which of the following might explain Mrs. Johnson's condition.

The cells in the posterior pituitary that release vasopressin are inactive.

The neuronal cell bodies in the hypothalamus are damaged.

The rate of blood flow through the posterior pituitary has increased.

All of the listed answer are possible explanations for the observation.

The neuronal cell bodies in the hypothalamus are damaged.

Which of the following statements regarding the anterior and posterior pituitary is correct?

Anterior pituitary is composed of endocrine tissue while the posterior pituitary is composed of neural tissue.

Both are composed of endocrine tissue.

Anterior pituitary is composed of neural tissue while the posterior pituitary is composed of endocrine tissue.

Both are composed of neural tissue.

Anterior pituitary is composed of endocrine tissue while the posterior pituitary is composed of neural tissue.

What tropic hormone stimulates cortisol from the adrenal gland?

thyroid stimulating hormone (TSH)

growth hormone (GH)

luteinizing hormone (LH) and follicle stimulating hormone (FSH)

adrenocorticotropic hormone (ACTH)

adrenocorticotropic hormone (ACTH)

What is the function of the ventral hypothalamic neurons?

control secretion of thyroid stimulating hormone (TSH)

control secretion of oxytocin

control secretion of antidiuretic hormone (ADH)

control secretion of thyroid hormones

control secretion of thyroid stimulating hormone (TSH)

Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones?

thyroid hormones

GH (growth hormone)

prolactin (PRL)

oxytocin

GH (growth hormone)

**GH stimulates liver to release IGF-1**

Which of the following hormones is regulated by a neuroendocrine ("letdown") reflex?

cortisol

antidiuretic hormone (ADH)

Oxytocin

Oxytocin

Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized?

posterior pituitary

Hypothalamus

kidney

anterior pituitary

Hypothalamus

What is the most important regulatory factor controlling the circulating levels of thyroid hormone?

negative feedback

thyroid-stimulating hormone (TSH)

thyrotropin-releasing hormone (TRH)

a circadian rhythm of release

negative feedback

If the release of thyroid hormone (TH) was regulated by a long-loop negative feedback system, where would the target cells be located to which TH would bind to inhibit the pathway?

The posterior pituitary

The hypothalamus

The anterior pituitary

The thyroid gland

The hypothalamus

What type of hormones bind to receptors located on the cell membrane?

lipid-soluble hormones, such as thyroid hormones and cortisol

water-soluble hormones, such as insulin and epinephrine

water-soluble hormones, such as insulin and epinephrine

Which intracellular substance degrades cAMP, thus inactivating the response to a hormone?

Phosphodiesterase

protein kinase C

phospholipase C

adenylate cyclase

Phosphodiesterase

Growth factor hormones, such as insulin, bind to which type of receptor?

G proteins

tyrosine kinase receptors

intracellular receptors

tyrosine kinase receptors

Which is the correct order of events for hormones activating Gs proteins?

activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP

activation of G protein, binding of GTP, activation of phospholipase C, activation of DAG and IP3

activation of a G protein, tyrosine kinase receptor, phosphorylation of intracellular proteins

activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP

Which second messenger causes the release of calcium from the endoplasmic reticulum?

tyrosine kinase

IP3

cAMP

DAG

IP3

Which of the following adrenergic receptors increase cAMP levels?

β receptors

α1 receptors

α2 receptors

β receptors

The membrane potential of most cells ________.

is negative at all times

determined primarily by sodium

results in a net negative electrical charge in the body

is negative, except when there is a change in membrane permeability to ions

is negative, except when there is a change in membrane permeability to ions

Why is the resting membrane potential (Vm) approximately - 70 mV for most cells?

Most membranes are 10 times more permeable to Na+ than to K+.

The large concentration of proteins in the interstitial space draws Na+ out of the cell making it negatively charged.

Most cells contain a large concentration of Cl- making them negatively charged.

Most membranes are 40 times more permeable to K+ than to Na+.

Most membranes are 40 times more permeable to K+ than to Na+.

The sympathetic and parasympathetic nervous systems are divisions of which system?

Somatic motor nervous system

Sensory nervous system

Central nervous system

Autonomic nervous system

Autonomic nervous system

The part of the neuron that receives most of the incoming signals is the ________.

dendrite

cell body

soma

axon

dendrite

Which glial cell produces myelin in the central nervous system?

Oligodendrocytes

Ependymal cells

Astrocytes

Schwann cells

Oligodendrocytes

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?

Resting membrane potential (RMP)

Action potential

Positive membrane potential

Threshold potential

Resting membrane potential (RMP)

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?

Voltage-gated channels

Sodium-potassium ATPases

Ligand-gated channels

Leak channels

Leak channels

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?

The outside surface of the plasma membrane is much more negatively charged than the inside surface.

The inside surface of the plasma membrane is much more positively charged than the inside surface.

The inside surface of the plasma membrane is much more negatively charged than the outside surface.

There is no electrical potential difference between the inside and the outside surfaces of the plasma membrane.

The inside surface of the plasma membrane is much more negatively charged than the outside surface.

The plasma membrane is much more permeable to K+ than to Na+. Why?

There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

Ligand-gated cation channels favor a greater influx of Na+ than K+.

The Na+-K+ pumps transport more K+ into cells than Na+ out of cells.

There are many more voltage-gated K+ channels than voltage-gated Na+ channels.

There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors.

The presence of a resting membrane potential and leak channels

The presence of concentration gradients and leak channels

The presence of concentration gradients and Na+-K+ pumps

The presence of concentration gradients and voltage-gated channels

The presence of concentration gradients and leak channels

What prevents the Na+ and K+ gradients from dissipating?

H+-K+ ATPase

Na+ cotransporter

Na+-K+ ATPase

Na+ and K+ leaks

Na+-K+ ATPase

The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____.

Na+; K+

K+; Na+

K+; Cl-

Na+; Cl-

K+; Na+

During depolarization, which gradient(s) move(s) Na+ into the cell?

only the chemical gradient

only the electrical gradient

both the electrical and chemical gradients

Na+ does not move into the cell. Na+ moves out of the cell.

both the electrical and chemical gradients

What is the value for the resting membrane potential for most neurons?

-90 mV

+30 mV

-70 mV

-70 mV

The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped?

K+ is pumped out of the cell and Na+ is pumped into the cell.

Both Na+ and K+ are pumped into the cell.

Both Na+ and K+ are pumped out of the cell.

Na+ is pumped out of the cell and K+ is pumped into the cell.

Na+ is pumped out of the cell and K+ is pumped into the cell.

The concentrations of which two ions are highest outside the cell.

Na+ and A- (negatively charged proteins)

K+ and Cl-

K+ and A- (negatively charged proteins)

Na+ and Cl-

Na+ and Cl-

Which of the following neurons or groups of neurons are NOT considered to be a part of the efferent pathway?

somatic motor
sensory
parasympathetic
sympathetic

sensory

The part of the neuron that receives most of the incoming signals is the ________.

dendrite
cell body
soma
axon

dendrite

What did Dr. McKhann observe in the children in Beijing and why did this observation lead him to question the original diagnosis of Guillain-Barré syndrome?
Hint 1.
Think about both efferent and afferent pathways.

Children were not able to move but they did have sensory function.

Children did not have sensory or motor function.

Children were able to move around but they did not have sensory function.

Children were not able to move but they did have sensory function.

Why would the conduction velocity of a neuron be used to diagnose demyelinating diseases?
Hint 1.
Myelin surrounds the axon of large somatic motor neurons.

In a demyelinating disease, myelin production increases, which leads to an increase in conduction velocity.

In a demyelination disease, myelin is degraded, which will increase conduction velocity.

In a demyelinating disease, myelin production increases, which leads to a reduction in conduction velocity.

In a demyelination disease, myelin is degraded, which will decrease conduction velocity.

In a demyelination disease, myelin is degraded, which will decrease conduction velocity.

If the children from Beijing did in fact have a demyelinating disease, what would have been the result of Dr. McKhann's conduction velocity test?
Hint 1.
Demyelination will cause a loss of myelin.

increased conduction velocity
decreased conduction velocity
no change in conduction velocity

decreased conduction velocity

Why is the diminished strength of the action potential observed by Dr. McKhann a problem with axons and not myelination?
Hint 1.
Axons propagate action potentials to their targets.

There is no known link between the axon and the action potential.

Because the axonal membrane contains the ion channels necessary to conduct the action potential.

Because the axon contains synaptic vesicles that quickly travel down to their target tissue.

Because the axon diameter determines conduction velocity.

Because the axonal membrane contains the ion channels necessary to conduct the action potential.

What would happen to the membrane potential if a cell suddenly becomes more permeable to Na+?

Hyperpolarize
It would reverse polarity.
Repolarize
Depolarize

Depolarize

What happens if a graded stimulus is of sufficient strength to reach threshold at the trigger zone?

An action potential occurs.

The membrane is hyperpolarized.

The cell becomes more permeable to Cl-.

The graded stimulus moves through the cell more quickly.

An action potential occurs.

Which two properties determine the conduction velocity in a mammalian neuron?

The leak resistance of the membrane and myelination

Axon diameter and the leak resistance of the membrane

The voltage-gated K+ ion channel concentration and axon diameter.

Myelination and voltage-gated Na+ channel concentration

Axon diameter and the leak resistance of the membrane

Which type of receptor would bind acetylcholine and be found in skeletal muscle?

ß-adrenergic
NMDA receptors
Nicotinic cholinergic
Muscarinic cholinergic

Nicotinic cholinergic

Which of the following would NOT cause the membrane potential to change from -70 mV to +30 mV?

Sodium ions entering the cell.
Calcium ions entering the cell.
Chloride ions leaving the cell.
Potassium ions leaving the cell.

Potassium ions leaving the cell.

Where do most action potentials originate?

Hint 1. Parts of a neuron
Most input to a neuron is to the cell body and dendrites. If a neuron is excited to threshold, an action potential will be generated in the first part of the axon. Identify this part.

Axon terminal
Nodes of Ranvier
Initial segment
Cell body

Initial segment

What opens first in response to a threshold stimulus?

Hint 1. Voltage-gated channels
Action potentials occur in areas of the plasma membrane that are densely populated with voltage-gated, or voltage-sensitive, ion channels. Which type of voltage-gated channel is the most rapid to open in response to a threshold stimulus?

Voltage-gated K+ channels
Ligand-gated cation channels
Ligand-gated Cl- channels
Voltage-gated Na+ channels

Voltage-gated Na+ channels

What characterizes depolarization, the first phase of the action potential?
Hint 1. Resting membrane potential
A resting membrane potential (RMP) is exhibited by all cells, and it is caused by an unequal distribution of ions across the plasma membrane. To measure the RMP, a reference electrode is placed near the outside surface of the plasma membrane and a recording electrode is placed near the inside surface. The recorded value is always negative. Thus, the inside surface of the plasma membrane is polarized to a negative value at rest.

The membrane potential changes to a less negative (but not a positive) value.

The membrane potential changes from a negative value to a positive value.

The membrane potential reaches a threshold value and returns to the resting state.

The membrane potential changes to a much more negative value.

The membrane potential changes from a negative value to a positive value.

What characterizes repolarization, the second phase of the action potential?

Once the membrane depolarizes to a threshold value of approximately -55 mV, it repolarizes to its resting value of -70 mV.

As the membrane repolarizes to a negative value, it goes beyond the resting state to a value of -80 mV.

Before the membrane has a chance to reach a positive voltage, it repolarizes to its negative resting value of approximately -70 mV.

Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

Hint 1. Resting membrane potential
A resting membrane potential (RMP) is exhibited by all cells, and it is caused by an unequal distribution of ions across the plasma membrane. To measure the RMP, a reference electrode is placed near the outside surface of the plasma membrane and a recording electrode is placed near the inside surface. The recorded value is always negative. Thus, the inside surface of the plasma membrane is polarized to a negative value at rest.

What event triggers the generation of an action potential?

The membrane potential must depolarize from the resting voltage of -70 mV to its peak value of +30 mV.

The membrane potential must hyperpolarize from the resting voltage of -70 mV to the more negative value of -80 mV.

The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.

The membrane potential must return to its resting value of -70 mV from the hyperpolarized value of -80 mV.

The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.

Hint 1. Voltage-gated channels
Action potentials occur in areas of the plasma membrane that are densely populated with voltage-gated, or voltage-sensitive, ion channels. This type of channel opens in response to voltage change.

What is the first change to occur in response to a threshold stimulus?


Voltage-gated Ca2+ channels change shape, and their activation gates open.

Voltage-gated K+ channels change shape, and their activation gates open.

Voltage-gated Na+ channels change shape, and their inactivation gates close.

Voltage-gated Na+ channels change shape, and their activation gates open.

Correct
Yes! The activation gates of voltage-gated Na+ channels open very rapidly in response to threshold stimuli. The activation gates of voltage-gated K+ channels are comparatively slow to open.

Voltage-gated Na+ channels change shape, and their activation gates open.

Correct
Yes! The activation gates of voltage-gated Na+ channels open very rapidly in response to threshold stimuli. The activation gates of voltage-gated K+ channels are comparatively slow to open.

Hint 1. Voltage-gated channels
Action potentials occur in areas of the plasma membrane that are densely populated with voltage-gated, or voltage-sensitive, ion channels. Threshold stimuli cause conformational changes that open these channels.

The sympathetic and parasympathetic nervous systems are divisions of which system?

Central nervous system
Somatic motor nervous system
Sensory nervous system
Autonomic nervous system

Autonomic nervous system

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