This positively charged ion is in highest concentrations outside of cells:

a. sodium


The resting membrane is permeable to:


b. potassium


The part of the neuron that receives nervous signals is called the:


b. dendrite


The resting membrane potential is:

a. —70 mV (more negative inside)


The diagram below depicts the neuron in:













The diagram below is a picture of:


b. a sarcomere


The action potential is when:


b. the membrane potential rapidly becomes more positive +30-50 mV then returns to a negative value


In the action potential, which of the following is the correct order of events:

a. threshold potential, opening of voltage gated sodium channels, opening of voltage gated potassium channels


The diagram below shows tropomyosin and calmodulin. Which of the following is true:

a. myosin cannot bind to actin in this state



Tetrodotoxin blocks:


c. voltage gated sodium channels

Propagation of action potentials can be increased in speed by:


b. having schwann cells and nodes in between them


the speed of action potentials is as fast as:


b. 225 mph


when the action potential gets to the end of the axon, this causes:

a. vesicles containing neurotransmitter to release into the synaptic cleft


The signal that tells vesicles containing neurotransmitter to migrate to the axon terminal surface and release their contents is:

a. increased calcium



In the case of motor neurons that innervate muscle cells, the binding of neurotransmitter to the muscle cell causes:

a. the T tubules to release calcium


The sarcomere is comprised of two major proteins


c. myosin and actin

The binding sites on actin are blocked in muscle in the resting (non-contracting) state by:


b. tropomyosin


The binding of calcium to calmodulin causes:

a. tropomyosin to pull away from actin


ATP causes:


c. myosin to detach from actin

In sarcomere shortening, the muscle contracts (shortens) by:


c. myosin pulling on actin

Fast twitch muscle fibers shorten quickly and rely on anaerobic metabolism. These fibers are called:

b. type II


Smooth muscle:


c. is an involuntary muscle found in organs like the small intestine

The thick filament is made of:


b. myosin









The picture below is of:


c. striated (skeletal) muscle



Low serotonin is linked to:

a. clinical depression


Dopamine is linked to:


b. schizophrenia


Which of the following is the type of myosin in slow twitch muscle fibers:

a. type I