We control muscle force using motor unit recruitment. When we recruit more motor units, what is happening at the organ/cell/molecular level? more myofibrils within a muscle cell are activated more muscle cells are excited the rate of crossbridge cycling is increased the number of myosin heads bound to actin within a muscle cell is increased more Ca++ is released into the cyoplasm of the muscle cell

We control muscle force using motor unit recruitment. When we recruit more motor units, what is happening at the organ/cell/molecular level? more myofibrils within a muscle cell are activated more muscle cells are excited the rate of crossbridge cycling is increased the number of myosin heads bound to actin within a muscle cell is increased more Ca++ is released into the cyoplasm of the muscle cell

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Match the following regarding muscle contractions: The final chemical messenger and "trigger" for muscle contraction. It binds to troponin A neurotransmitter released at motor end plates by the axon terminals It diffuses across the cell membrane resulting in depolarization Activates synaptic vesicles in axon terminals to fuse with plasma membrane of axon terminal Used to convert ADP to ATP by transfer of a high-energy phosphate group. A reserve high-energy compound Breaks down ACh into its building blocks, rendering it ineffective [Choose] [Choose] [Choose] [Choose] [Choose] [Choose ]
What do the calcium ions that are released into the cytoplasm during contraction bind to? tropomyosin actin the Z-line myosin O troponin
A bands: Dark areas that correspond to the areas where thick filaments are present. • I hands: Light areas that contains only thin filaments. . Z line: A protein disk within the I band that anchors the thin filaments and connects adjacent myofibrils. • H zone: Located in the middle of each A band, this lighter stripe appears corresponding to the region between the thin filaments. • M line: Protein fibers that connect neighboring thick filaments. Sarcomeres: The region of the myofibril between two Z lines. ** Keep in mind, this information is crucial for your understanding of the sliding filament theory.
Why is sarcoplasmic hypertrophy a limitation with size training? It adds more actin and myosin. It decreases glycogen content of the muscle cell. It adds mass that is not able to produce force. It results in greater stores of intracellular fat.
Classify characteristics of skeletal muscle energy metabolism by dragging each statement to its correct metabolic pathway for ATP synthesis. Allows time for the other two pathways to increase their ATP production Reaction is catalyzed by creatine kinase Blood glucose and fatty acids become fuel for this pathway after 10 minutes of exercise Lactic acid is a waste product produced by this pathway Rapid means of forming ATP during the first few seconds of muscle contraction Very rapid, requiring only a single enzymatic reaction Produces ATP used during moderate, prolonged levels of muscular activity This pathway requires oxygen Produces a significant fraction of ATP during high-intensity Produces ATP from glucose quickly in the absence of охудen Uses glycogen broken down into glucose during the first 5-10 minutes of moderate exercise Produces only small quantities of ATP for each metabolized glucose molecule exercise Oxidative Phosphorylation Creatine Phosphate Glycolysis Reset
Why does continuouns calcium release within a muscle fiber cause greater tension? Acticates more calcium pump Activates myofibrils continuously Increase action potential frequency Lengthens sarcomere
In the absence of O Ca2+; Tropomyosin and Tropomodulin the myosin binding sites in the actin microfilament are masked by O ATP: Tropomyosin and Troponin ATP: Cofilin and Profilin OCa2+; Tropomyosin and Troponin Previous
What contains troponin, is involuntary and intracellular calcium is necessary in muscle contraction? Multi-unit smooth muscle Unitary smooth muscle O Cardiac muscle fiber Red skeletal muscle fiber White skeletal muscle fiber
How is the list below to be properly put in order to describe a muscular contraction? 1. Calcium causes exocytotic release of Acetylcholine into the synaptic gap; all this happens at an area called the neuromuscular junction2. ATP is consumed which allows myosin to "pivot" the myosin head, which pulls actin toward it.3. This process is repeated multiple times and is called the "sliding filament theory".4. Myosin filaments perform "crossbridging".5. Calcium is released and circulated throughout the muscle cell6. The brain predicts the action necessary and decides which muscles and how many "motor units" are needed to perform that action.7. Tropomyosin moves to reveal the active site of the F-Actin strand8. Upon reception of a calcium ion, the Troponin complex becomes activated9. Proteins embedded in the Sarcolemma receive enough of the ACH neurotransmitter to generate an electrical impulse.10. The electrical impulse is perpetuated throughout the muscle fiber.11. A nervouse impulse is…
Compare the rate of Ca2+ release from the sarcoplasmic reticulum to the rate of Ca2+ return back to the sarcoplasmic reticulum. Which of the following is true? The rate of ca2+ returns is faster than the rate of ca2+ release The rate of ca2+ release is faster than the rate of ca2+ return Rates of Ca2+ release from and return to the sarcoplasmic reticulum are the same.
During the cross bridge cycle, what is the first event that occurs after ATP binds myosin? the power stroke occurs myosin releases actin myosin binds actin to form another cross bridge myosin enters its energized state
Which of the following would NOT occur as a result of regular exercise to a specific muscle group (assume you are resting now, but have been working this muscle group)? more capillaries will grow into the area the muscle cells will build more mitochondria O the muscle cells will build fewer contractile proteins O the muscle cells will increase their glycogen stores