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BIO201-FINALREVIEW-1
BIO201 - Final Review 1 - Q & A's from Online Lessons & Labs - Muscle Tissue
Question | Answer |
---|---|
In the synaptic cleft of a neuromuscular junction, _____ is always present. | acetylcholinesterase |
Only ____ muscle cells branch. | cardiac |
The time in which cross bridges are active is called the period of _____. | contraction |
The end of the muscle that moves when a muscle contracts is called the ____. | insertion |
Claudication might more simply be called_____. | limping |
____ (color) fibers are slow (oxidative) fibers. | red |
Only _____ muscle cells are multinucleated. | skeletal |
A smooth, sustained contraction is called _____. | tetanus |
T/F Whereas skeletal muscle cells are electrically coupled, smooth muscle cells appear to be chemically coupled by gap junctions. | This is false. The gap junctions between smooth muscle cells are electrically coupled; and the skeletal muscles cells are chemically coupled. |
T/F - The more slowly a skeletal muscle is stimulated, the greater its exerted force becomes. | This is false. The more rapidly a skeletal muscle is stimulated, the greater its exerted force. |
T/F - A contraction in which the muscle does not shorten but its tension increases is called isometric. | True |
T/F Eccentric contractions are much more forceful than concentric contractions. | True |
T/F - The effect of the neurotransmitter on the muscle cell membrane is to modify its permeability properties temporarily. | True |
T/F - Once a nerve has fired, all the muscle fibers fire. | This is false. When a motor neuron fires, all of the muscle fibers contract. |
T/F - One of the important functions of skeletal muscle is production of heat. | True |
T/F - The thin filaments (actin) contain a polypeptide subunit G actin that seems to have no function. | This is false. G actin has a very important function, bearing the active sites to which the myosin heads attach during contraction. |
T/F - Oxygen debt refers to the oxygen required to make creatine phosphate. | his is false. Oxygen debt refers to the oxygen required to restore oxygen used by all of the processes involved in contraction. |
T/F - During isometric contraction, the energy used appears as movement. | This is false. In isometric contraction, the muscle neither shortens nor lengthens. |
T/F - Single-unit smooth muscle is found in the intestines. | True |
T/F - Peristalsis is characteristic of smooth muscle. | True |
T/F - Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments. | True |
T/F - A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell. | True |
T/F - During isotonic contraction, the heavier the load, the faster the velocity of contraction. | This is false. Once the load is overcome, the contraction is constant. |
T/F - The force of muscle contraction is controlled by multiple motor unit summation or recruitment. | True |
T/F - Muscle contraction will always promote movement of body parts regardless of how they are attached. | This is false. Some muscle contraction is used for maintaining posture, stabilizing joints, and generating heat. |
T/F - A nerve cell and all the muscle cells that it stimulates are referred to as a motor end plate. | This is false. This structure is called a motor unit. |
T/F - When a muscle fiber contracts, the I band diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length. | True |
Depends on oxygen delivery and aerobic mechanisms. | Slow (oxidative), fatigue-resistant fibers |
A high percentage are found in marathon runners. | Slow (oxidative), fatigue-resistant fibers |
Abundant in muscles used to maintain posture. | Slow (oxidative), fatigue-resistant fibers |
Red fibers, the smallest of the fiber types. | Slow (oxidative), fatigue-resistant fibers |
Contain abundant amounts of glycogen | Fast (oxidative or glycolytic), fatigable fibers |
Have very fast-acting myosin ATPases and depend upon anaerobic metabolism during contraction. | Fast (oxidative or glycolytic), fatigable fibers |
The myosin filaments are located in the: | A band |
Both actin and myosin are found in the: | A band |
he _____ contains only the actin filaments. | I band |
he thicker filaments are the ____ filaments | Myosin |
A sarcomere is the distance between two: | Z discs |
__ should affect the strength or force of skeletal muscle contraction. | The degree of muscle stretch. |
During muscle contraction, myosin cross bridges attach to which active sites? | Actin filaments |
Calcium ions bind to the __ molecule in skeletal muscle cells. | Troponin |
In an isotonic contraction, the muscle: | Changes in length and moves the "load". |
After nervous stimulation of the muscle cell has ceased, calcium: | Level in the cytoplasm drops |
The role of calcium ions in muscle contraction is to: | Bind to regulatory sites on troponin, changing the configuration. |
The mechanism of contraction in smooth muscle parallels that of skeletal muscle in the following ways except: | The site of calcium regulation differs. |
The first thing that stops a contraction after the nerve stops sending ACh is: | Acetylcholinesterase destroys the ACh, and they are removed from the membrane receptors. |
An anaerobic metabilic pathway that results int he rpoduction of two net ATPs per glucose plus two pyruvic acid molecules is: | Glycolysis |
The functional role of the T tubules is to: | Enhance cellular communication during muscle contraction. |
The major function of the sarcoplasmic reticulum in muscle contraction is to: | Regulate intracellular calcium concentration. |
__ do not act as a stimulus to initiate a muscle contraction? | A change in temperature. |
The sliding filament model of contraction involves: | Actin and myosin sliding past each other but not shortening. |
Which of the following is true about smooth muscle contraction? | Certain smooth muscle cells can actually divide to increase their numbers. |
When a muscle is unable to respond to stimuli temporarily, it is in which period? | Refractory period |
Mucle tension remains __ during isotonic contraction. | Constant |
Immediately following the arrival of the stimulus at a skeletal muscle cells, there is a short period called the __ period - events of excitation-contraction coupling occur. | Latent |
CT ensheathed in a bundle of muscle cells. | Perimysium |
Buncle of muscle cells | Fascicle |
Contractile unit of muscle | Sarcomere |
A muscle cell | Fiber |
Thin reticular CT investing each muscle cell | Endomysium |
Plasma membrane of the muscle fiber. | Sarcolemma |
A long filamentous organelle w/a banded appearance found within muscle cells. | Myofibril |
Actin- or myosin-containing structure. | Myofilament |
Cord of collagen fibers that attached a muscle to a bone. | Tendon |
Another name for a neuromusclular junction is? | Myoneural |
A motor neuron and all the skeletal muscle cells it stimulates is called a __. | Motor unit |
Within the axonal terminal are many small vesicles containing a neurotransmitter substance called __. | ACh - acetylcholine |
When the __ reaches teh ends of the axon, the neurotransmitter is released and diffuses to the muscle cell membrane to combine w/receptors there. | Nerve Impulse |
Neurotransmitter + muscle membrane receptors causes membrane to become permeable to sodium, which results in influx of sodium ions & __ of the membrane. | Depolarization |
Before a muscle cell can be stimulated to contract again, __ must occur. | Repolarization |
Which muscle cells have the greatest ability to regenerate? | Smooth |
Fatigued muscle cells that recover rapidly are the products of __. | Intense exercise of short duration. |
__ should affect the strength or force of skeletal muscle contraction. | The degree of muscle stretch. |
Myoglobin | Holds a reserve supply of oxygen in muscle cells. |
The giant protein titin maintains the organization of the __ assisting in muscle stretching. | A band |
Theoretically, if a muscle cell were stretched to the point where thick & thin filaments no longer overlapped __. | No muscle tension could be generated. |
If an individual ingested a chemical that binds irreversibly to ACh receptors in sarcolemma, __. | No contraction at all could occur by nervous mechanisms, but contraction could occur if stimulated by an external electrode. |