Q1. Which of the following is TRUE of the absoluterefractory period?

Select one:
a) it establishes the maximum frequency with which a nerve cell canconduct action potentials
b) it does not end until the Na+/K+ pump has restored the ions totheir original summate
c) two of the above are correct
d) a, b, and c are correct

Q2. In order for a neuron to move from the absolute tothe relative refractory period, a majority of that neuron's sodiumchannels must have their:

Select one:

a) inactivation gates open
b) activation gates closed
c) inactivation gates closed
d) activation gates open and inactivation gates closed

Q3. Which of the following statements concerningpropagation of action potentials is TRUE?

Select one:
a) saltatory conduction occurs only in myelinated fibers
b) during the propagation of action potentials, the actionpotential gets progressively smaller as it moves down themembrane
c) during contiguous conduction, localized current flow causeshyperpolarization of an adjacent portion of the membrane
d) the action potentials can undergo spatial and temporalsummation
e) more than one of the above is correct

Q4. Which of the following is NOT true of gradedpotentials?

Select one:
a) They are produced after the binding of neurotransmitter toreceptor
b) they will decrease in magnitude as the current flows away fromthe initial site
c) they are produced at chemically-gated ion channels
d) they are limited in duration by the refractory period of themembrane

Q5. Assume that a post-synaptic neuron has twopre-syanptic inputs: X and Y. When pre-synapitc neuron X isstimulated, the post-synaptic membrane becomesslightly

Select one:
a) excitatory
b) inhibitory
c) not enough info

Q6. assume that a post-synaptic neuron has twopre-syanptic inputs: X and Y. Given that pre-synaptic neuron Xcauses hyperpolarization of the post-synaptic membrane, what kindof permeability changes may have occurred in the post-synapticneuron?

Select one:
a) increase permeability both Ca2+ and K+
b) increased permeability to K+ but not Na+
c) increased permeability to anionic proteins
d) increased permeability to Ca2+
e) increased permeability to both K+ and Na+

Q7. Which type of autonomic receptor is found in thesynapse of the parasympathetic postganglionic fiber with theeffector organ?

Select one:

a) alpha
b) nicotinic
c) beta-2
d) beta-1
e) muscarinic

Q8. With pre-marathon training, a runner's body adjustsby increasing the amount of acetylcholinesterase. What would be thephysiological effect on skeletal muscle fibers?

Select one:

a) it would inhibit the release of Ach from the presynapticcell
b) it would inhibit the attachment of Ach to muscarinicreceptors
c) it would lead to a faster speed of contraction

Q9. Acetylcholine stimulates an action potential in themuscle cell membrane by:

Select one:
a) Opening channels in the neuromuscular junction which allowsodium to move out of the muscle cell
b) Opening channels in the neuromuscular junction which allowpotassium to move into the muscle cell
c) Opening channels in the neuromuscular junction which allowsodium to move in and potassium to move out, though sodium movesfaster than potassium because both chemical and electricalgradients drive sodium into the cell
e) Opening channels in the neuromuscular junction which allowsodium to move in and potassium to move out, though potassium movesfaster than sodium because potassium is closer toequilibrium

Q10. As ATP binds to the myosin head,

Select one:
a) the myosin head detaches from actin
b) the myosin molecule lengthens
c) the myosin head attaches more tightly to actin
d) the myosin molecule shortens
e) the myosin head's actin binding site is physically blocked

Q11. Which type of autonomic receptor is found on theadrenal medullary cells?

Select one:
a) alpha
b) nicotinic
c) beta-2
d) beta-1
e) muscarinic

Q12. Compared to epinephrine, norepinephrine has agreater affinity for what type of receptor?

Select one:
a) alpha
b) nicotinic
c) beta-2
d) beta-1
e) muscarinic

Q13. Phosphocreatine

Select one:
a) provides the muscle cell with a quick energy source
b) removes Ach from the neuromuscular junction
c) blocks the myosin binding site in a relaxed muscle
d) responsible for the release of Ach
e) pumps Ca2+ back into the sarcoplasmic reticulum

Q14. In twitch summation,

Select one:
a) the muscle fiber is stimulated again before the filaments havecompletely returned to their resting position
b) stronger muscle contractions occur but stronger actionpotentials do not uoccur
c) a second action potential occurs in the muscle fiber, before thefirst action potential is finished
d) both a and b are correct
e) all of the above are correct

Q15. The force generated by a single musclefiber:

Select one:
a) is always the same
b) can be increased by increasing the frequency of actionpotentials
c) can be increased by motor unit recruitment
d) more than one of the above is correct

Q16. an isometric(static) musclecontraction:

Select one:
a) muscle tissue shortens
b) muscle tension exceeds the force of the load
c) the load is moved
d) both b and c are correct
e) none of the above is correct

Q17. Which of the following statements concerning thecharacteristics of different muscle fiber types isFALSE?

Select one:
a) the higher the ATPase activity, faster the speed ofcontraction
b) muscle fibers containing large amounts of myoglobin have a darkred color in comparison to the paler fibers, which have littlemyoglobin
c) oxidative types of muscle fibers contain a lot ofmyoglobin
d) scientific studies have found that, with selective training of amuscle tissue, slow twitch fibers can transform into fast twitchfibers and vise versa
e) in response to weight training, fast twitch fibers increaseprotein synthesis