How can we answer these questions ? **Transcript:**Shirley was assigned to take Mr. Aletha to physical therapy. She helped Mr. Aletha into the wheelchair and took him down the hallway to the room where he was to receive strengthening exercises for his generalized muscle weakness. Mr. Aletha told Shirley that he often felt okay at the beginning of his therapy session but became weaker as the session progressed. Mr. Aletha was in the hospital because of this perplexing problem. One day Shirley went to Mr. Aletha’s room to take him to therapy, but Mr. Aletha told her that the sessions were canceled: The therapy would not help his condition because he had myasthenia gravis. Shirley had heard about this disease but did not understand the physiology. She went to her anatomy text and began to read the chapters on muscle contraction and nerve transmission. Help her answer the following questions so she can put this puzzling disease in perspective.**Diagram Explanation:**The diagram illustrates the process of nerve transmission and muscle contraction. Key components include:- **Motor Neuron**: The neuron that sends signals to muscle fibers.- **Synaptic End Bulb**: The enlarged end of the neuron where neurotransmitters are released.- **Axon**: The long fiber that conducts electrical impulses away from the neuron's cell body.- **Voltage-gated Ca²⁺ Channel**: Channels that open in response to voltage changes, allowing calcium ions to enter the synaptic end bulb.- **Synaptic Vesicles**: Membrane-bound vesicles containing neurotransmitters.- **Synaptic Cleft**: The small gap between the neuron and muscle fiber.- **Neurotransmitter**: Chemicals released by neurons that transmit signals across the synaptic cleft.- **Neurotransmitter Receptors**: Proteins on the muscle fiber that bind neurotransmitters.- **Muscle Fibers**: The target of neuronal signals, which contract in response.- **T-tubule**: Part of the muscle fiber involved in transmitting the electrical impulse further into the muscle. This detailed diagram provides essential insights into how nerve signals are transmitted and how muscles contract, helping to understand disorders like myasthenia gravis. ## Muscle Cell Function and Mechanisms### 4. Muscle cells are full of the actin and myosin proteins.**a. Briefly describe the arrangement of the actin and myosin molecules within the cell. How does the interaction between actin and myosin result in shortening of the muscle cell?**Actin and myosin are arranged in a repeating pattern of filaments within the muscle cell. Myosin acts as a thick filament with heads that attach to the actin, which is a thin filament. When these myosin heads bind to actin, they pull the filaments past each other, leading to shortening of the muscle cell—a process called the sliding filament theory.**b. Which molecule provides the energy to break the actin-myosin bond?**ATP (adenosine triphosphate) provides the energy needed to break the bond between actin and myosin, allowing the muscles to relax.**c. Would the muscle be able to contract if they run out of energy? Explain why.**No, muscles would not be able to contract if they run out of energy. ATP is essential for the detachment of myosin heads from actin, and without it, the muscle cannot relax or contract properly.**d. What happens to muscles in the case of death? Why do the muscles stay in a contracted state and relax only after a certain period of time?**After death, ATP is no longer produced, causing muscles to remain in a contracted state, known as rigor mortis. Eventually, natural biochemical processes lead to muscle relaxation.### 5. Myasthenia gravis is an autoimmune disease in which the body’s immune cells attack and destroy the acetylcholine (Ach) receptors in the motor end plates of muscles in the shoulder, neck, and face. When muscle do not contracts. Muscle atrophy (loss of muscle mass) is caused by not using the muscles enough. Why would Mr. Aletha experience a progressive weakening even if he tries to do more exercise?In myasthenia gravis, the destruction of acetylcholine receptors impairs nerve transmission to muscles, preventing effective contraction and leading to muscle atrophy despite exercise.### 6. Do aerobic (endurance) and resistance exercises produce the same effect on muscles? How do endurance and anaerobic exercises normally enhance your ability to contract muscles?Aerobic exercises primarily enhance muscular endurance and cardiovascular health, while resistance exercises increase muscle strength and size.

It has been inquired about the role of actin and myosin proteins in muscle contraction, the vitality…

Answered: 4. Muscle cells are full of the actin…

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,...