Chapter 10: Muscle Tissue

Summa

A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation is called ____.

Sacomeres

A contracting skeletal muscle fiber typically shortens as all of its ____ shorten in length.

Tendon

A cord-like structure that attaches muscle to bone is a ____.

Synaptic knob, motor end plate, and synaptic cleft

A neuromuscular junction contains a(n) ____.

A. Body movement B. Posture C. Temperature regulation D. Storage and movement of material

A. Muscles contract and pull on the tendons that attach the muscles to the bones B. Contraction of specific skeletal muscles stabilizes joints C. Heat is produced as a waste product of energy usage D. Voluntary sphincter muscles of the gastrointestinal and urinary tracts can be kept closed or opened

Phosphate

ATP is generated when the enzyme creatine kinase transfers Pi from creatine ____ to ADP.

Diffusion

Acetylcholine moves across the synaptic cleft by ____.

Oxygen

Aerobic respiration requires the presence of what molecule?

Oxygen debt

After you stop running, you notice that you keep breathing heavily for some time. This is because your body is in ____.

Skeletal

Approximately 40-50% of your body weight is ____ muscle.

Closer together

As a result of muscle fiber contraction, thick filaments in neighboring sarcomeres move ____.

Recruitment

As you hold a barbell and begin to flex your arm in a curl, your biceps branchii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as ____.

Sarcoplasmic reticulum

At the end of contraction, when the stimulation from the nerve impulse ceases, calcium ions are pumped back into the ____.

Troponin

Calcium ion binds to what protein in a thin myofilament?

Troponin

Calcium ions bind to what protein in a thin myofilament?

Actin

Contraction of a muscle fiber requires that the myosin heads in the thick filament bind to active sites on ____ molecules within the thin filaments.

1. Calcium binds troponin; myosin binding site uncovered 2. Cross-bridge formation (attaching of myosin head to actin) 3. Power stroke (pulling thin filament by movement of myosin head) 4. Release of myosin head from actin 5. Resetting of myosin head

Cross-bridge cycling in order:

ATP

Energy to drive the myosin movement in the sliding filament process is provided in the form of ____.

1. Nerve impulse arrives at synaptic knob 2. Ca2+ enters and binds synaptic vesicles 3. ACh is released into synaptic cleft 4. ACh binds receptors on the motor end plate

Excitation of a skeletal muscle fiber:

Greater

In a muscle contraction, as increasing numbers of motor units are recruited ____ force is exerted.

Pushing a wall, holding weight while it does not move, holding baby in one position, attempting to move something that is too heavy, pushing on a locked door, sitting up very straight, holding a yoga pose

In which activities are muscles in an isometric contraction?

A. Latent period B. Contraction period C. Relaxation period

Match each stage of muscle twitch with the amount of tension generated. A. There is no tension B. Tension increase C. Tension decreases

A. Sarcolmella B. Muscle fiber C. Sarcoplasm D. Sarcoplasmic reticulum E. T-tubule

Match the name of the component of a muscle fiber: A. Plasma membrane of a muscle fiber B. A muscle cell C. Cytoplasm of a muscle fiber D. Smooth endoplasmic reticulum in a muscle fiber E. Narrow, tubular extensions of the sarcolmella into the sarcoplasm

Elasticity

Muscle tissue demonstrates the property of ____ when it is done contracting and returns to its resting length.

A. Muscle B. Fascicle C. Muscle cell

Muscle unit with connective tissue layer: A. Epimysium B. Perimysium C. Endomysium

1. Arrival of nerve signal at synaptic knob 2. Calcium entry at synaptic knob 3. Exocytosis of ACh into synaptic cleft 4. Binding of ACh at motor end plate

Neuromuscular junction in order:

1. ACh binds to receptors on the motor end plate 2. The resulting action potential moves down the sarcomella 3. The action potential moves down the t-tubules 4. The action potential reaches the terminal cisternae of the SR. 5. Calcium ions are released into the sarcoplasm

Occurrence once ACh diffuses across the synaptic cleft of a NMJ:

A. Immediate B. Short term C. Long term

Single muscle contraction with the source of ATP: A. B. C.

Half

Slow muscle fibers are about ____ the diameter of fast muscle fibers.

Thick

The H-band (or H-zone) is more lightly shaded because only ____ filaments are present.

Acetylcholine

The arrival of nerve impulse at the synaptic knob of a motor neuron causes synaptic vesicles to release ____ into the synaptic cleft.

Attachment

The connective tissue layers in muscle provide: protection, distribution sites for blood vessels and nerves, and a means of ____ to the skeleton.

Synaptic cleft

The enzyme acetylcholinesterase resides in the synaptic ____.

The entire skeletal muscle

The epimysium of a muscle surrounds ____.

Synaptic Knob

The motor end plate has folds and indentations to increase membrane surface area adjacent to the ____.

Motor neuron

The motor unit is composed of a single ____ and all of the muscle fibers it controls.

Sphincter

The muscle that surrounds the opening to your esophagus and opens reflexively to allow you to swallow food is what type of muscle?

Synaptic cleft

The narrow space separating the synaptic knob and the motor end plate is called the ____.

Sarcolmella

The plasma membrane of a skeletal muscle fiber is called the ____.

Neuromuscular

The point where a motor neuron meets a skeletal muscle fiber is called the ____ junction.

Calcium

The sarcoplasmic reticulum stores ____ ions needed to initate muscle contraction.

Thick and thin

The striated appearance in skeletal muscle cells is due to size and density differences between ____ and ____ filaments.

Cardiac

The wall of the heart is composed of ____ muscle.

Same length

Thick and thin filaments maintain their ____, whether the muscle is relaxed or contracted.

Myosin

Thick myofilaments are composed of bundles of what protein molecule?

Acetylcholine

To start a muscle contraction, a nerve impulse causes ____ release at a neuromuscular junction.

False

True or false: After diffusing across the synaptic cleft, ACh binds to receptors on the synaptic knob.

Isometric; isotonic

Two types of muscle contractions are: a. ____ contraction (when a muscle contracts but does not change length) and b. ____ contraction (when a muscle contracts and does change length).

Motor end plate

Upon release from the synaptic knob, acetylcholine attaches to receptors on the ____.

Smooth

What type of muscle forms the majority of the walls of the digestive tract?

Insufficient Ca2+, Na+ or K+ imbalances, build up of intracellular Pi

Which causes muscle fatigue?

Sarcomere

Within a myofibril, each ____ shortens as the muscle fiber contracts.