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.