Anatomy & Physiology I - Quiz 5 & 6

Smooth muscle and cardiac muscle are similar in that they both

are under involuntary control

List the following structures in order from smallest to largest 1) muscle fiber 2) myofilament 3) myofibril 4) muscle fascicle

2, 3, 1, 4

An action potential

occurs when the local potential reaches threshold level

when repolarization of the plasma membrane is complete, the

original polarity of the cell is restored

Muscles exhibit the property of excitability. This means that the muscle

responds to stimulation by the nervous system

Which type of muscle tissue is autorhythmic?

Both cardiac and smooth muscle are correct.

Which of the following connective tissue layers is outside all the others?

Epimysium

Synaptic vesicles in the neuromuscular junction contain

acetylcholine

When an action potential reaches the presynaptic terminal...

calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels

Muscle myofibrils

contain myosin and actin myofilaments

Which of the following changes would have the most dramatic effect on the membrane potential?

increased permeability of the membrane to Na+

The electrical properties of cells are the result of

ion concentration differences across the plasma membrane

The length of the resting sarcomere is

longer than the length of a contracted sarcomere.

Which of the following actions is caused by contraction of skeletal muscle?

moving your feet in walking

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called...

neuromuscular junctions

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

size of muscle fibers

A sarcomere is the

structural and functional unit of the skeletal muscle fiber

Which of the following is NOT a property of the myosin head?

the bind to troponin

The plasma membrane of an excitable cell is more permeable to K+ because

there are more leak ion channels for K+ than Na+

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called

voltage-gated ion channels