A new experimental drug is tested in muscle fibers and it is concluded that it blocks the calcium channels in the sarcoplasmic reticulum. Which of the following are expected consequences of the injection of this drug in skeletal muscles?

A new experimental drug is tested in muscle fibers and it is concluded that it blocks the calcium channels in the sarcoplasmic reticulum. Which of the following are expected consequences of the injection of this drug in skeletal muscles?

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter32: Structural Support And Movement

Section: Chapter Questions

Problem 2CT: After death, a person no longer makes ATP, so calcium stored in the sarcoplasmic reticulum diffuses...

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Figure 38.37 Which of the following statements about muscle contraction is true? The power stroke occurs when ATP is hydrolyzed to ADP and phosphate. The power stroke occurs when ADP and phosphate dissociate from the myosin head. The power stroke occurs when ADP and phosphate dissociate from the actin active site. The power stroke occurs when Ca2+ binds the calcium head.
Watch this video (http://openstaxcollege.org/l/micromacro) to learn more about macro- and microstructures of skeletal muscles. (a) What are the names of the junction points between sarcomeres? (b) What are the names of the subunits within the myofibrils that run the length of skeletal muscle fibers? (c) What is the â€œdouble strand of pearlsâ€� described in the video? (d) What gives a skeletal muscle fiber its striated appearance?
After death, a person no longer makes ATP, so calcium stored in the sarcoplasmic reticulum diffuses down its concentration gradient into the muscle cytoplasm. This result is rigor mortis----an unbreakable state of muscle contraction that stiffens the body for a few days until muscles begin to decay. Explain why this contraction occurs.
Every skeletal muscle fiber is supplied by a motor neuron at the NMJ. Watch this video (http://openstaxcollege.org/l/skelmuscfiber) to learn more about what happens at the neuromuscular junction. (a) What is the definition of a motor unit? (b) What is the structural and functional difference between a large motor unit and a small motor unit? Can you give an example of each? (c) Why is the neurotransmitter acetylcholine degraded after binding to its receptor?
What is the function of the sarcoplasmic reticulum in muscle cell contraction?
Explain why (a) calcium ions and (b) ACh are vital for muscle contraction.
In the diagram below, label the fine structure of a muscle, down to one of its myofibrils. Identify the basic unit of contraction in a myofibril.
Which of the following step(s) about the excitation of skeletal muscle is/are incorrect? 1. Acetylcholine is released and binds to motor end plate receptors 2. An action potential is created and moves down T-tubules 3. Calcium is released from the sarcoplasmic reticulum 4. Calcium ions bind to tropomyosin to shift troponin off the binding sites for cross-bridging 5. Myosin forms cross-bridges and binds with actin to pull it towards middle of sarcomere
During muscle isometric tension, the maximum tension occurs when: There is no overlapping between the actin and myosin O a. O b. None of these The myosin and actin overlap without crossing the center O d. The myosin and actin totally overlap Dilatant flow is characterized as a reverse phenomenon of: a. Newtonian flow O b. Plastic flow O c. Pseudoplastic flow O d. Rheopexy
Describe the contraction of a muscle fiber, starting with what events take place at the neuromuscular junction, explaining how depolarization along the length of the sarcolemma occurs, the role of calcium (where it is released, what it binds to, etc.), and the events that occur after calcium binds to troponin. Draw a few simple, labelled diagrams of a neuromuscular junction and sarcomere and outline the steps of excitation-contraction coupling, including power stroke, recovery stroke, formation of cross bridges, role of ATP, etc.
We've referred to alpha-motor neurons as the "decision making centre" for whether or not a muscle fibre contracts. Which of the following statements are true with regards to his concept? Select all that apply. O Alpha motor neurons receive input from many different sources, the balance of which determines whether or not the alpha-motor neuron fires an action potential O Alpha motor neurons are involved in conscious decision making in our central nervous system for planning and executing movements O When an action potential is initiated in an alpha-motor neuron, we are guaranteed an action potential in the muscle fibre, and hence contraction of that fibre. This means the muscle itself does not determine whether or not it contracts O Alpha motor neurons report information on where we are in space (proprioception) back to the central nervous system
When an action potential from a motor neuron arrives at the neuromuscular junction, a series of events occurs that leads to muscle contraction. Arrange following events in the correct order from first to last.