ebook_Muscular System

Myosin heads directly use ______________ to transition to their _____________________ conformation, which enables them ready to bind to actin.

-ATP; energized

Match the five properties of muscle tissue with their descriptions.

-Ability to extend in length. Extensibility -Ability to pass an electrical change along a cell's plasma membrane. Conductivity -Ability to return to original length. Elasticity -Ability to respond to stimuli. Excitability -Active generation of force. Contraction

Stand on both feet and bring one foot up to touch the heal of your foot to your buttocks. The hamstring muscles are acting as what?

-Agonist.

Check all that are a function of skeletal muscle tissue.

-Body movement. -Maintenance of posture. -Protection and support

True statement regarding cardiac and smooth muscle is that...

-Cardiac muscle cells can generate a muscle impulse without nervous stimulation.

Your school wins the homecoming football game against its biggest rival. You watch as the smallest cheerleader tries to lift up the heaviest linebacker in her excitement. As she strains against his 300 lb. load and does not move him, what type of muscle contraction are her muscles experiencing?

-Isometric

Match the type of muscle tissue with its brief description.

-Striated, multiple nuclei. Skeletal -Striated, autorhythmic. Cardiac -Unstriated, single nucleus. Smooth

Match the connective tissue with the component of skeletal muscle tissue that it surrounds.

-Surrounds the fascicles. Perimysium -Surrounds the whole skeletal muscle. Epimysium -Surrounds each muscle fiber. Endomysium

Check all that are proteins of thin filaments. -Myosin -Actin -Troponin -Titin -Tropomyosin

-Troponin. -Titin.

The area between the presynaptic nerve cell and the postsynaptic muscle cell is termed the synaptic cleft. (True or False)

-True.

When a motor unit is sufficiently stimulated, all of the muscle fibers in that motor unit will contract. (True or False)

-True.

The primary neurotransmitter at the neuromuscular junction is...

-acetylcholine.

The brachialis muscle is the prime mover of elbow flexion, while biceps brachii assists. In other words, during elbow flexion brachialis is the ______ and biceps brachii serves as the ________.

-agonist; synergist

After wearing a cast on your wrist for several weeks, you notice that your forearm muscles appear smaller and are weaker than before. This wasting of muscle tissue is termed muscle ______________.

-atrophy

In the gluteus maximus, each motor unit controls a(n) _____________ amount of muscle fibers than a motor unit in the eye muscles.

-greater

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the...

-motor end plate.

A motor neuron transmits the effect of a nerve impulse to the muscle fiber at a ________ _________.

-neuromuscular junction.

Acetylcholine causes an end-plate potential by triggering the ______________________.

-opening of sodium channels

Acetylcholine (ACh) is released from motor neurons and enters the __________________.

-synaptic cleft

At the ends of muscles, the connective tissues merge to form a __________, which attaches the muscle to other structures.

-tendon

The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the...

-transverse tubule (T-tubule).

Thin filaments connect to and extend from either side of a ___________. These thin filaments are composed largely of the myofilament ____________.

-z disc; actin

Place the events involved in muscle contraction in the correct order.

1. A nerve impulse causes ACh release at a neuromuscular junction. 2. ACh binds receptors on the motor end plate, initiating a muscle impulse. 3. Calcium ions bind to troponin, causing tropomyosin to move and expose active sites. 4.Myosin heads attach to actin and form crossbridges. 5. A cyclic "attach, pivot, detach, return" event occurs. 6. Calcium ions are moved back into the sarcoplasmic reticulum by ATP-driven pumps. 7. Myofilaments passively return to their original state.

Place the organizational level of muscle tissue in order, beginning with muscle and ending with the smallest component.

1. Muscle 2. Fascicle 3. Muscle Fiber 4. Myofibril 5. Myofilament

Arrange the following in the proper order in which they occur at the postsynaptic side of a neuromuscular junction. 1. Action potential is propagated over the muscle cell membrane 2. Depolarization of the post-synaptic membrane 3. Sodium ions move into muscle cell

3, 2, 1

The ability of a muscle cell to lengthen in response to antagonistic muscles contracting is referred to as...

extensibility.