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

1. sodium
2. potassium
3. chloride

The resting membrane is permeable to:

1. sodium
2. potassium
3. large anions (A-)

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

1. axon
2. dendrite
3. nucleus

The resting membrane potential is:

1. –70 mV (more negative inside)
2. +30 mV (more positive outside)
3. 0 mV

The diagram below depicts the neuron in:

1. resting state
2. peak of action potential going to +50 mV

c. declining phase of action potential returning to –70 mV

The diagram below is a picture of:

1. a macrophage
2. a sarcomere
3. a Schwann cell

The action potential is when:

1. the membrane potential rapidly becomes more negative –100 mV
2. the membrane potential rapidly becomes more positive +30-50 mV then returns to a negative value
3. the membrane potential doesn’t change.

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

1. threshold potential, opening of voltage gated sodium channels, opening of voltage gated potassium channels
2. opening of voltage gated sodium channels, threshold potential, opening of voltage gated potassium channels
3. threshold potential, opening of voltage gated potassium channels, opening of voltage gated sodium channels

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

1. myosin cannot bind to actin in this state
2. myosin can bind to actin in this state
3. this state is what occurs when calcium levels are high in the muscle cell

Tetrodotoxin blocks:

1. calcium from entering the cells
2. voltage gated potassium channels
3. voltage gated sodium channels

Propagation of action potentials can be increased in speed by:

1. adding tetrodotoxin
2. having schwann cells and nodes in between them
3. making axon diameter smaller

the speed of action potentials is as fast as:

1. the speed of light
2. 225 mph
3. diffusion

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

1. vesicles containing neurotransmitter to release into the synaptic cleft
2. voltage gated calcium channels to close
3. nothing to happen

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

1. increased calcium
2. increased sodium
3. decreased potassium

Binding of the neurotransmitter to the post synaptic cell can result in:

1. depolarization
2. hyperpolarization
3. all of the above

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

1. the T tubules to release calcium
2. the T tubules to take up calcium
3. the T tubules to release myosin

The sarcomere is comprised of two major proteins

1. insulin and glucagon
2. myosin and myoglobin
3. myosin and actin

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

1. myosin
2. tropomyosin
3. ATP

The binding of calcium to calmodulin causes:

1. tropomyosin to pull away from actin
2. an action potential to be generated
3. the muscle fiber to stop shortening

ATP causes:

1. myosin to bind to actin
2. actin to bind to calcium
3. myosin to detach from actin

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

1. actin pulling on myosin
2. the Z line pulling on actin
3. myosin pulling on actin

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

1. type I
2. type II
3. type III

Smooth muscle:

1. has well defined sarcomeres
2. is found in the heart
3. is an involuntary muscle found in organs like the small intestine

The thick filament is made of:

1. actin
2. myosin
3. lipid

The picture below is of:

1. smooth muscle
2. cardiac muscle
3. striated (skeletal) muscle

Low serotonin is linked to:

1. clinical depression
2. schizophrenia
3. spastic behavior

Dopamine is linked to:

1. clinical depression
2. schizophrenia
3. spastic behavior

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

1. type I
2. type IIa
3. type IIx