Muscular Physiology

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1. Move Them Bones2. Shared Excitement 3. Uniquely Structured4. Myofilaments Function 5. Short Comings 6. Relax Those Muscle Cells7. Feel The Burn8. How My Motor Runs9. Run Run Run10. Combined As A Unit11. Death12. How To Contract13. Twitch Twitch14. Sweat

Move Them Bones1. Explain how skeletal muscles provide movement, heat, and posture. Are all of these functions unique to muscles? Explain your answer.

Skeletal muscle moves bones by receiving from a motor nerve that triggers an action potential across the muscle fibers. Muscle fibers contain actin and myosin, which are the function components of muscle contraction. Essentially, movement of a bone occurs when the muscle attached is being shortened. The chemical reactions that cause muscle contraction generate heat. Energy conversion always generates “useless,” energy. .

Shared Excitement

2. The characteristics of excitablility is shared by what other system? Relate contractility and Extensibility to the concept of agonist and antagonist discussed in chapter 10.

The characteristics of excitability are the responsibility are the response to stimuli. The excitability and the nervous system share the same characteristics. This is an anagonist concept because the pain that you receive will go against the muscle direction that is was originally going until the response says otherwise.

Uniquely Structured3. What structures are unique to skeletal muscle fibers? Which of the structures involved primarily in contractility and which are in involved in excitability?

• A myofiber is a single muscle cell, the cell is densely packed with contractile proteins, energy stores and signaling mechanisms.

• Excitation- The contraction signal is spread rapidly along the fiber by means of the T-tubule system, which signals the rapid release of calcium ions from the sarcoplasm reticulum.

• Contraction- Within each myofibril are a network of myofibrils. These fibers contain the proteins that do the actual force production.

Myofilaments Function

4. Explain how the structure of the myofilaments is related to their function.

Cancer treatment may generate a need for a bone marrow transplant. Osteoporosis is a condition characterized by an excessive loss of calcium in bone. These 2 conditions are disruptions or failures of 2 bone functions. Identify these 2 functions and explain what their normal function should be.– 1. Creation of blood cells– 2. Calcium helps the bones to grow normally and develop

better.

Short Comings

5. Explain why a bone fracture along the epiphyseal plate may have serious implications among children and young adults.– 1. It can have serious implications because the

bone is still growing. It needs space to grow and if it is fractured it will stop the process.

Relax Those Muscle Cells

6. Compare and contrast the role of Ca++ in excitation, contraction, and relaxation of a muscle cell.

• During the aging process, adults face the issue of a changing skeletal framework. Describe these changes and explain how these skeletal framework changes affect the health of older adults.– 1. Osteoporosis is one change, as you increase in age

the bone density decreases which will result in osteoporosis and bone breakage.

Feel The Burn

7. People who exercise seriously are sometimes told to work a muscle until they "feel the burn". In terms of how muscle is able to release energy, explain what is going on in the muscle early in the exercise and when the muscle is "burning."• While exercising, your muscles are building up lactic acid

and releasing energy, which causes that tingling, heavy, or burning sensation, and lets you know when your muscles have had enough. It's definitely a good thing that you're feeling this sensation, because it's a sign that your muscles are being challenged, which makes them stronger. Just be sure to listen to your body. That burning sensation is a warning, and if you ignore it, you could be risking an injury.

How My Motor Runs

8. Describe the anatomical arrangement of a motor unit. Contrast fine and gross motor units• A motor unit is made up of a large anterior horn cell, its

motor axon, and the skeletal muscle fibers innervated by that axon. The larger the cell body of the motorneuron, the higher the conduction velocity of its axon. It is a single α-motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type (either fast twitch or slow twitch). When a motor unit is activated, all of its fibers contract. Groups of motor units often work together to coordinate the contractions of a single muscle.

• Gross motor skills are walking, running, throwing and catching a ball, etc.

Run Run Run

9. Using fiber types, design a muscle for a marathon runner. and a different muscle for a 100-yard-dash Sprinter. Explain our choice.• A marathon runner would need the majority of his

muscle fibers to be type one, also know. As slow twitch muscles, they are not as powerful, but can fire for a longer period of time with less fatigue.

• A sprinter in the 100 yard dash would need type 2B or fast twitch muscles, new which are the most powerful, but fatigue the fastest and need the most recovery

Combined As A Unit

10. Explain the meaning of a "unit of combined cells" as it relates to cardiac Muscle. How does the structure arrangement affect its function?• The cardiac muscle contracts as a syncytium, or in definition

A multinucleated mass of cytoplasm that is not separated into individual cells. The muscle Is then synchronized electrically to help keep it beating in rhythm with the correct pace. A cardiac muscle also contains more mitochondria than the usual body muscle cell. The mitochondria is responsible for creating energy for the cell. These extra mitochondria keep the muscle from becoming fatigued and keep the heart beating.

Death

11. Describe Rigor Mortis.- Rigor Mortis refers to the stiffness of skeletal

muscles sometimes observed shortly after; the permanent contraction of muscle tissue after death caused by the depletion of ATP during the actin-myosin reaction, preventing myosin releasing actin to allow relaxation of the muscle.

How To Contact

12. Describe in detail the 4 factors that influence the strength of muscle contractions. • - The number of muscle fibers stimulated. The more muscle

fibers there are the more able the muscle will be able to contract.

• - The relative size of the fibers. The larger the fiber the easier it will be for them to contract.

• - Frequency of stimulation. The more frequently the muscles are stimulated the stronger the contraction will appear to be due to the fact that the muscle is contracting more often.

• - The degree of muscle strength.

Twitch Twitch

13. What are the phases of a twitch contraction? What molecular events occur during each of these phases? • - The three phases of a twitch contraction are called, the latent

period, the contraction phase, and the relaxation phase. During phase one, the impulse initiated by the stimulation travels through the sarcolemma and T tubules to the SR, where it triggers the release of calcium ions into the sarcoplasm. When the calcium binds to troponin and the myofilaments begin to slide then the contraction starts. After a few milliseconds, the sliding stops and the relation phase kicks in. When the last phase is complete all of the myosin-actin reactions in all the fibers have ceased.

Sweat

14. How does the treppe effect relate to the warm-up exercises of athletes?• - Treppe is a gradual increase in the extent of

muscular contraction following rapidly repeated stimulation; the staircase phenomenon. It affects athletes warm-up exercises because it increases warmth and causes the efficiency of muscle enzyme system to increase.