Question 1

Which of the following relaxes smooth muscle?

Accepted Answer

A)  Stimulat ion of MLCK 
B)  Opening of voltage-gated Ca2+ ch an ne ls 
C)  Inhibit ion of MLCP 
D)  NO (nitric oxide) 
E)  Release of Ca2+ from the SR 
A)  Stimulat ion of MLCK 
B)  Opening of voltage-gated Ca2+ ch an ne ls 
C)  Inhibit ion of MLCP 
D)  NO (nitric oxide) 
E)  Release of Ca2+ from the SR D

Question 2

Bulges in axons from which neurotransmitter can be diffusely secreted are called

Accepted Answer

A)  N er ve ter m ina ls 
B)  Varicosities 
C)  Nuclei 
D)  G an glia 
E)  Plexus 
A)  N er ve ter m ina ls 
B)  Varicosities 
C)  Nuclei 
D)  G an glia 
E)  Plexus B

Question 3

"Ca2+ sen sitization" in s m ooth m usc le refe rs to

Accepted Answer

A)  The ability of Ca2+ to act ivate MLCK 
B)  Production of force at lower than normal levels of cytoplasmic [Ca2+] 
C)  Ca2+ activat ion of MLCP 
D)  Reduction in cytoplasmic [Ca2+] by phosphorylation of phospholamban 
E)  None of the above 
A)  The ability of Ca2+ to act ivate MLCK 
B)  Production of force at lower than normal levels of cytoplasmic [Ca2+] 
C)  Ca2+ activat ion of MLCP 
D)  Reduction in cytoplasmic [Ca2+] by phosphorylation of phospholamban 
E)  None of the above B

Question 4

Be ta 2 receptors on smooth muscle cells work through a G s m ec ha nis m tha t ac tiva tes ad en ylyl cyclas e. T his pr odu ces 3',5'cyc lic AM P. T he c AM P ac tivates PK A tha t

Accepted Answer

A)  Releases Ca2+ from the S R th roug h IP 
B)  Releases Ca2+ from the SR through RyR receptors and Increases force by activat ing MLCK 
C)  Depolarizes the membrane, leading to Ca2+ entry by the voltage-gated Ca chan ne l, and Increases force by activat ing MLCK 
D)  Phosphorylates protein phosphatase and relaxes the smooth muscle by dephosphorylating the m yos in lig ht c ha in 
E)  Phosphorylates phospholamban, reducing [Ca2+] and relaxing the smooth muscle by reduc ing M LCK activity 
A)  Releases Ca2+ from the S R th roug h IP 
B)  Releases Ca2+ from the SR through RyR receptors and Increases force by activat ing MLCK 
C)  Depolarizes the membrane, leading to Ca2+ entry by the voltage-gated Ca chan ne l, and Increases force by activat ing MLCK 
D)  Phosphorylates protein phosphatase and relaxes the smooth muscle by dephosphorylating the m yos in lig ht c ha in 
E)  Phosphorylates phospholamban, reducing [Ca2+] and relaxing the smooth muscle by reduc ing M LCK activity

Question 5

Ac tiva tion of m yos in lig ht c ha in p ho sp ha tas e (M LC P) in s m oo th m us cle sh ou ld

Accepted Answer

A)  Increase smooth muscle force 
B)  Re lax s m oo th m us cle 
C)  Increase the [Ca2+] in smooth m uscle cells 
D)  D ep ola rize the sm oo th m us cle ce lls 
E)  Increase Ca2+ release from the SR 
A)  Increase smooth muscle force 
B)  Re lax s m oo th m us cle 
C)  Increase the [Ca2+] in smooth m uscle cells 
D)  D ep ola rize the sm oo th m us cle ce lls 
E)  Increase Ca2+ release from the SR

Question 6

An example of electromechanical coupling in smooth m uscle is activation of contraction by

Accepted Answer

A)  Release of Ca2+ via G 
B)  Increased cytosolic [Ca2+] through voltage-gated Ca2+ cha nn els 
C)  Activation of protein phosphatase via G -protein coupled receptors 
D)  Ca2+ release through RyR 
E)  Ca2+ uptake into the SR m ediated by phospholamban phosphorylation 
A)  Release of Ca2+ via G 
B)  Increased cytosolic [Ca2+] through voltage-gated Ca2+ cha nn els 
C)  Activation of protein phosphatase via G -protein coupled receptors 
D)  Ca2+ release through RyR 
E)  Ca2+ uptake into the SR m ediated by phospholamban phosphorylation

Question 7

The fun ction o f M LC K in s m ooth m usc le cells is to

Accepted Answer

A)  Ph os ph or ylate ac tin 
B)  Ph os ph oryla te th e reg ulat ory lig ht c ha in o f m yos in 
C)  D ep ho sp ho ryla te tr op om yos in 
D)  Ph os ph or ylate tro po m yos in 
E)  Regulate the Ca2+ sensitivity of TnC 
A)  Ph os ph or ylate ac tin 
B)  Ph os ph oryla te th e reg ulat ory lig ht c ha in o f m yos in 
C)  D ep ho sp ho ryla te tr op om yos in 
D)  Ph os ph or ylate tro po m yos in 
E)  Regulate the Ca2+ sensitivity of TnC

Question 8

Ca2+ exit from sm ooth muscle cells is accomplished through

Accepted Answer

A)  SERCa2a 
B)  R yR 
C)  NCX, sodium-calcium exchange 
D)  IP3R 
E)  Voltage-gated Ca2+ ch an ne ls 
A)  SERCa2a 
B)  R yR 
C)  NCX, sodium-calcium exchange 
D)  IP3R 
E)  Voltage-gated Ca2+ ch an ne ls

Question 9

Ac tiva tion of m yos in lig ht c ha in k ina se (M LC K) in s m oo th m us cle sh ou ld

Accepted Answer

A)  Increase smooth m uscle force 
B)  R ela x s m oo th m us cle 
C)  Increase the [Ca2+] in smooth m uscle cells 
D)  D ep ola rize the sm oo th m us cle ce lls 
E)  Increase Ca2+ release from the SR 
A)  Increase smooth m uscle force 
B)  R ela x s m oo th m us cle 
C)  Increase the [Ca2+] in smooth m uscle cells 
D)  D ep ola rize the sm oo th m us cle ce lls 
E)  Increase Ca2+ release from the SR

Question 10

Myosin light chain kinase is activated by

Accepted Answer

A)  Ca2+ bo un d to calm od ulin 
B)  PKA 
C)  cAMP 
D)  IP3 
E)  Diacylglycerol 
A)  Ca2+ bo un d to calm od ulin 
B)  PKA 
C)  cAMP 
D)  IP3 
E)  Diacylglycerol

Question 11

Pharmacom echanical coupling develops smooth muscle force by

Accepted Answer

A)  Release of Ca2+ via G 
B)  Voltage-gated Ca2+ ch an ne ls a ctiv ate d b y ac tion po ten tials 
C)  Voltage-gated Ca2+ channels activated by mem brane potential change without action po ten tials 
D)  Ca2+ release through RyR 
E)  Ca2+ uptake into the SR m ediated by phospholamban phosphorylation 
A)  Release of Ca2+ via G 
B)  Voltage-gated Ca2+ ch an ne ls a ctiv ate d b y ac tion po ten tials 
C)  Voltage-gated Ca2+ channels activated by mem brane potential change without action po ten tials 
D)  Ca2+ release through RyR 
E)  Ca2+ uptake into the SR m ediated by phospholamban phosphorylation

Question 12

The sarcolemma of smooth muscles cells can let in Ca2+ through

Accepted Answer

A)  Voltage-gated Ca2+ cha nn els 
B)  PMCA 
C)  SERCa2a 
D)  R yR 
E)  IP3R 
A)  Voltage-gated Ca2+ cha nn els 
B)  PMCA 
C)  SERCa2a 
D)  R yR 
E)  IP3R

Question 13

Addition of some chemicals can cause contraction of smooth muscle without changing the mem brane potential. The mechanism by which this happens is called

Accepted Answer

A)  Electromechanical coupling 
B)  Excitation-contraction coupling 
C)  Pharamcomechanical coupling 
D)  Unitary smooth m uscle contraction 
E)  Multi unit smooth m uscle contraction 
A)  Electromechanical coupling 
B)  Excitation-contraction coupling 
C)  Pharamcomechanical coupling 
D)  Unitary smooth m uscle contraction 
E)  Multi unit smooth m uscle contraction

Question 14

Sm oo th m us cle ce lls

Accepted Answer

A)  Lack striations 
B)  Are sm aller than sk eletal musc le fibers 
C)  Have o ne nucleus instead of m any as in skeletal mu scle fibers 
D)  R es po nd to a va rie ty of sig na ls 
E)  All of the above 
A)  Lack striations 
B)  Are sm aller than sk eletal musc le fibers 
C)  Have o ne nucleus instead of m any as in skeletal mu scle fibers 
D)  R es po nd to a va rie ty of sig na ls 
E)  All of the above

Question 15

The proteins that release Ca2+ from the SR into the cytosol of sm ooth m uscle are

Accepted Answer

A)  RyR 
B)  SERCa2a 
C)  IP3R 
D)  NCX 
E)  Both A and C are correct 
A)  RyR 
B)  SERCa2a 
C)  IP3R 
D)  NCX 
E)  Both A and C are correct

Question 16

Increased cytosolic [Ca2+] in smooth muscle cells can be accomplished by release of Ca2+ from internal stores. These internal stores are in the

Accepted Answer

A)  Caveolae 
B)  M itoc ho nd ria 
C)  Golgi apparatus 
D)  Nucleus 
E)  SR, sarcoplasmic reticulum 
A)  Caveolae 
B)  M itoc ho nd ria 
C)  Golgi apparatus 
D)  Nucleus 
E)  SR, sarcoplasmic reticulum

Exam 24: Smooth Muscle

Which of the following relaxes smooth muscle?

Bulges in axons from which neurotransmitter can be diffusely secreted are called

"Ca2+ sen sitization" in s m ooth m usc le refe rs to

Be ta 2 receptors on smooth muscle cells work through a G s m ec ha nis m tha t ac tiva tes ad en ylyl cyclas e. T his pr odu ces 3',5'cyc lic AM P. T he c AM P ac tivates PK A tha t

Ac tiva tion of m yos in lig ht c ha in p ho sp ha tas e (M LC P) in s m oo th m us cle sh ou ld

An example of electromechanical coupling in smooth m uscle is activation of contraction by

The fun ction o f M LC K in s m ooth m usc le cells is to

Ca2+ exit from sm ooth muscle cells is accomplished through

Ac tiva tion of m yos in lig ht c ha in k ina se (M LC K) in s m oo th m us cle sh ou ld

Myosin light chain kinase is activated by

Pharmacom echanical coupling develops smooth muscle force by

The sarcolemma of smooth muscles cells can let in Ca2+ through

Addition of some chemicals can cause contraction of smooth muscle without changing the mem brane potential. The mechanism by which this happens is called

Sm oo th m us cle ce lls

The proteins that release Ca2+ from the SR into the cytosol of sm ooth m uscle are

Increased cytosolic [Ca2+] in smooth muscle cells can be accomplished by release of Ca2+ from internal stores. These internal stores are in the

Physical Foundations Ii: Electrical Force Potential Capacitance and Current

Chemical Foundations I: Chemical Energy and Intermolecular Forces

Chemical Foundations Ii: Concentration and Kinetics

Diffusion

Electrochemical Potential and Free Energy

Cell Structure

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Atp Production Iii: Fatty Acid Oxidation and Amino Acid Oxidation

Origin of the Membrane Potential

The Action Potential

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Skeletal Muscle Mechanics

Contractile Mechanisms in Skeletal Muscle

Neuromuscular Junction and Ec Coupling

Muscle Energetics Fatigue and Training

Organization of the Nervous System

Cells Synapses and Neurotransmitters

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Spinal Reflexes

Balance and Control of Movement

the Chemical Senses

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Overview of the Cv System and Blood

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The Heart As a Pump

Cellular Basis of Cardiac Contractility

the Cardiac Function Curve

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Digestion and Absorption of the Macronutrients

Energy Balance and Regulation of Food Intake

General Principles of Endocrinology

Hypothalamus and Pituitary Gland

The Thyroid Gland

The Endocrine Pancreas

"Ca₂+ sen sitization" in s m ooth m usc le refe rs to

Ca₂+ exit from sm ooth muscle cells is accomplished through

The sarcolemma of smooth muscles cells can let in Ca₂+ through

The proteins that release Ca₂+ from the SR into the cytosol of sm ooth m uscle are

Increased cytosolic [Ca₂+] in smooth muscle cells can be accomplished by release of Ca₂+ from internal stores. These internal stores are in the