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Ch 9 muscles/tissues
Ch 9 practice exam muscles and muscle tissues
Question | Answer |
---|---|
What are the characteristics of slow (oxidative), fatigue-resistant fibers? | They depend on oxygen delivery and aerobic mechanisms. They are RED FIBERS, the smallest of the fiber types. Are abundant in muscles used to maintain posture. high % found in marathon runners. |
What are the characteristics of Fast (oxidative or glycolytic), fatigable fibers? | They have very fast-acting myosin, ATPases and depend upon anaerobic metabolism during contraction. Contain large amounts of glycogen. |
What is maximal stimulus? | The stimulus above which no strongest contraction can be elicited, because all motor units are firing in the muscle. |
What is the phenomenon where the contraction strength of a muscle increases due to increase in Ca2+ availability and enzyme efficiency during the warm up? | Treppe |
What is tetanus? | Continued sustained smooth contraction due to rapid stimulation |
Whats the name of the situation in which contractions become stronger due to stimulation before complete relaxation occurs? | Wave summation |
How is a smooth increase in muscle force produced? | Multiple motor unit summation. |
What is a sarcomere? | The distance between 2 Z-discs |
What does the I-band contain? | It only contains the actin filaments |
What are the Thicker filaments called? | Myosin filaments |
What is found in the A-Band? | Actin and myosin |
Where are myosin filaments located? | they are located in the A-band |
What serves as a "trigger" for muscle contraction by removing the inhibition of troponin molecules? and is also stored in the terminal cisternae of the sarcoplasmic reticulum? | Calcium Ions |
What is Acetylcholine? | A neurotransmitter released at motor end plates by the axon terminals. |
What is Aerobic respiration? | A metabolic pathway that provides lots of ATP per glucose, because oxygen is used. Products are water, CO2, and ATP. |
What does Creatine phosphate do? | converts ADP to ATP by transfer of high-energy phosphate group. a reserve high energy compound. |
What does Acetylcholinesterase do? | It destroys ACh. |
Once a motor neuron has fired, all the muscle fibers in a muscle contract. T OR F? | False |
The thin filaments (actin) contain a polypeptide subunit G actin that bear active sites for myosin attachment. T OR F? | True |
The force of muscle contraction is controlled by multiple motor unit summation or recruitment. T OR F? | True |
Eccentric contractions are more forceful than concentric contractions. T OR F? | True |
A motor neuron and all the muscle plates are referred to as a motor end plate. T OR F? | False |
Peristalsis is characteristic of smooth muscle. T OR F? | True |
A contraction in which a muscle does not shorten but its tension increases is called isometric. T OR F? | True |
During isotonic contraction, the heavier the load, the faster the velocity of contraction. T OR F? | False |
During Isometric contraction, the energy used appears as movement. T OR F? | False |
One of the important functions of skeletal muscle contractions is to produce heat. T OR F? | True |
Oxygen debt refers to the oxygen required to make creatine phosphate, T OR F? | False |
Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments. T OR F? | True |
Whereas skeletal muscle cells are electrically coupled, smooth muscle cells appear to be chemically coupled by gap junctions. T OR F? | False |
Single unit smooth muscle is found in the intestines. T OR F? | True |
A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell. T OR F? | True |
The effect of a neuro transmitter on the muscle cell membrane is to modify its ion permeability properties temporarily. T OR F? | True |
When a muscle fiber contracts, the I-Bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length. T OR F? | True |
The more slowly a skeletal muscle is stimulated the greater its external force becomes. T OR F? | False |
Contractures are a result of a total lack of ATP. T OR F? | True |
Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions. T OR F? | True |
Recruitment is an option of a single unit smooth muscle cell. T OR F? | False |
What is the major function of the sarcoplasmic reticulum in muscle contractions? | To regulate intracellular calcium concentration. |
What is muscular dystrophy? | when muscle fibers degenerate and atrophy. |
Which muscle cells have the greatest ability to regenerate? | Smooth |
What do most muscles contain? | A mixture of fiber types. |
Fatigued muscle cells that recover rapidly are products of what? | Intense exercise of short duration. |
What will increasing the stimulation up to maximal stimulus achieve? | The strongest muscle contractions. |
What is recruited later in muscle stimulation when contractile strength increases? | Motor units with larger, less excitable neurons. |
What is NOT a usual result of resistance exercise? | Increase in the number of muscle cells |
In skeletal muscle contraction, what does calcium do? | Remove the blocking action of tropomyosin. |
What molecules do calcium ions bind to in skeletal muscle cells? | Calcium Ions bond to troponin molecules. |
What does myoglobin do? | Myoglobin stores oxygen in muscle cells. |
An elaborate network of membranes in skeletal muscle cells that functions in calcium storage is called: | The sarcoplasmic reticulum |
Immediately after the stimulus arrive at the skeletal muscle cell there is a short period called the LATENT period, during which the events of ________ occur. | Excitation-contraction coupling occurs |
How does Creatine phosphate function in the muscle cell? | It stores energy that will be transferred to ADP to resynthesize ATP. |
What happens to to calcium after nervous stimulation of the muscle cell has ceased? | The calcium level in cytoplasm drops. |
what is the major function of the sarcoplasmic reticulum in muscle contraction? | To regulate intracellular calcium concentration. |
What is produced mainly by the arrangement of myofilaments? | The striations of a skeletal muscle cell are produced |
What are thick filaments composed of? | Myosin |
What active sites do myosin cross bridges attach to during muscle contraction? | Actin filaments |
What surrounds the individual muscle cell? | Ensomysium |
What are smooth muscles that act like skeletal muscles and are controlled by autonomic nerves and hormones called? | Multiunit muscles |
Why does Rigor mortis occur? | Because there is no ATP available to release attached actin and myosin molecules. |
What does NOT act as stimulus to initiate muscle contraction? | a change in temperature. |
What does Aponeurosis refer to? | a sheetlike indirect attachment to a skeletal element |
What is the oxygen-binding protein found in muscle cells? | Myoglobin |
Whats the name of the contractile units in skeletal muscles? | Myofibrils |
What is the site of calcium regulation in the smooth muscle cell called? | Calmodulin |
One functional unit of skeletal muscle is___: | a sarcomere |
What is the functional role of T Tubules? | to enhance cellular communication during muscle contraction. |
What is the role of calcium ions in muscle contraction? | to bind to regulatory sites on troponin, changing the configuration. |
The warm-up period required of athletes in order to bring their muscles to peak performance is called___: | TREPPE |
Main effect of warm-up of athletes as muscle contractions increase in strength is to_____: | Enhance the availability of calcium and the efficiency of enzyme systems. |
During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. What is the Pyruvic acid converted to? | LACTIC ACID |
When a muscle is unable to respond to stimuli temporarily, which period is it in? | Refractory Period. |
What happens during an isotonic contraction? | the muscle changes in length and moves the load |
What is the SARCOLEMMA? | the muscle cell membrane. |
what is one way that smooth muscle is different from striated muscle? | Smooth muscle contracts in a twisting way. |
The mechanism for smooth muscle is different from skeletal muscle because: | the site of calcium regulation differs. |
What type of cells exhibit spontaneous action potentials? | the cells of single unit visceral muscle. |
What is not true about the developmental aspects of muscle? | there is no biological basis for the difference in strength between women and men. |
What is true about smooth muscle contraction? | certain smooth muscle cells can actually divide to increase their numbers. |
Muscle tissues has all the following properties (Contractability, excitability, extensibility) EXCEPT: | Secretion |
What maintains the organization of the A-Band assisting in muscle stretching? | the giant protein TITIN |
What is true about striated muscle cells? | They are long and cylindrical w/ many nuclei |
An anaerobic metabolic pathwya that results in the production of 2 ATPs per glucose plus 2 pyruvic acid molecules is______: | Glycolysis |
What is muscle tone? | A state of sustained partial contraction |
What does the sliding filament model of contraction involve? | Actin and Myosin sliding past eachother and partially overlap. |
what is true about isotonic contraction? | Muscle tension remains relatively constant. |
What is the most distinguishing characteristic of muscle tissue? | Its ability to transform chemical energy into mechanical energy. |
3 discrete types of muscle fibers are identified based on size, speed, and endurance. wich would best represent the use of red fibers? | a Long relaxing swim |
Which muscle type has has only 1 nucleus, NO sarcomeres, and rare gap junctions? | Multiunit smooth muscle |
Hypothetically if a muscle were stretched to the point where thick and thin filaments no longer overlapped what would happen? | No muscle tension could be generated. |
If a person has ingested a chemical that binds to ACh receptors in the sarcolemma, ignoring effects on other systems what would happen to the skeletal muscle system? | there would be co contractions at all. by nervous mechanisms, but contractions if stimulated by an external electrode. (cigs) |
What are caveoli? | folds on surface of smooth muscle cells that correspond with T Tubules in skeletal muscle cells |