AHP Chapter 10 Review Questions PDF

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AHP Review Chapter 10...

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1. Define the terms sarcolemma, sarcoplasm, and sarcoplasmic reticulum. Sarcolemma - cell membrane of muscle fiber Sarcoplasm - cytoplasm of the muscle fiber Sarcoplasmic Reticulum - the muscle fiber's version of smooth endoplasmic reticulum; function is to temporarily store calcium 2. Describe the function of the sarcoplasmic reticulum - The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions 3. How are acetylcholine, Ca++, and adenosine triphosphate (ATP) involved in excitation and contraction of skeletal muscle? acetylcholine is the neurotransmitter that stimulates the sarcolemma and initiates the contraction. The result of that stimulus is the release of Ca++ from the sarcoplasmic reticulum. The calcium causes the troponin to pull the tropomyosin away from the binding sites on the actin. ATP supplies the energy to the cross bridges of the myosin, so that the actin fiber can be pulled to the center of the sarcomere, causing the muscle to contract 4. Describe the general structure of ATP and tell how It relates to it’s function - ATP consists of a molecule of adenine, a molecule of ribose sugar, and three molecules of phosphate. The last two phosphates are joined to the molecule by high-energy bonds. When the high-energy bonds are broken, the energy stored in the bonds is used for cell work. 5. How does ATP provide energy for muscle contraction - ATP transfers the energy from the high-energy bonds to the myosin cross bridges. The energy is stored in the myosin until it is released when the myosin binds with the actin during muscle contraction 6. Describe the anatomical arrangement of motor unit. A single motor neuron—plus all the muscle fibers it stimulates—is called a motor unit. Motor units can include many muscle fibers for less precise movement or few fibers for more delicate movement. 7. Explain the difference between an isotonic contraction and an isometric contraction – Isotonic contraction - the tension within the muscle remains the same. As the muscle contraction begins, the sarcomeres actually shorten and move the load on the muscle Isometric contraction - the muscle length remains the same, but the tension on the muscle increases. The sarcomeres do not shorten, and the muscle is unable to move the load on the muscle. 8. Define the terms endomysium, perimysium and epimysium Endomysium - The endomysium, meaning within the muscle, is a wispy layer of areolar connective tissue that ensheaths each individual myocyte (muscle fiber, or muscle cell). It also contains capillaries and nerves. It overlies the muscle fiber's cell membrane: the sarcolemma. Perimysium - the sheath of connective tissue surrounding a bundle of muscle fibers. Epimysium - a sheath of fibrous elastic tissue surrounding a muscle. 9. Give an example of muscle named by location function, shape, fiber direction & number of heads. Rectus abdominis, transversus abdominis, external oblique, etc, Deltoid, trapezius, serratus anterior, rhomboid major, orbicularis oculi, pectineus, piriformis, platysma, quadratus femoris, gracilis, etc. Temporalis. 10. Give examples of the muscles of the back, chest, abdomen, neck, shoulder, upper part of the arm, lower part of the arm, thigh, buttocks, leg and pelvic floor.

Sternocleidomastoid, trapezius, deltoid, biceps brachii, gluteus maximus, sartorius, latissimus dorsi & gastrocnemius. 11. Give examples of the muscles that flex , extend, abduct and abduct the upper arm; that raise and lower the shoulder.

Deltoid

12. Give examples of the muscles that flex and extend the lower part of the arm; that flex and extend the wrist and hand - The muscles that extend the hand at the wrist include the extensor carpi radialis longus and brevis along with the extensor carpi ulnaris. The muscles that flex the fingers include the flexor digitorum superficialis and profundus, while the muscles that extend the fingers include the extensor digitorum 13. Give examples of the muscles that flex, extend, abduct and adduct the thigh; that flex and extend the lower part of the leg and thigh ; that flex and extend the foot- Pectineus adducts, flexes, and assists in medial rotation of the thigh. Iliopsoas made up of the psoas major and minor, and the iliacus come together to flex the hip joint as well as stabilize this joint during standing. Sartorius helps the flex, abduct and laterally rotate the thigh at the hip joint. 14. Give examples of the muscles that flex, extend, abduct and adduct the head - The

sternocleidomastoid flexes the head, the semispinalis capitis extends the head, the splenius capitis extends, adducts, and abducts, and the longissimus capitis extends. 15. Give examples of muscles that move the abdominal wall; that move the chest wall The external and internal oblique and the transverse abdominis. The diaphragm and external and internal intercostals move the chest wall. 1. Explain how skeletal muscles provide movement, heat and posture - The general functions of skeletal muscles are movement, heat production, and posture. Muscle contractions cause the joints to bend and the body to move. Heat is produced by the large number of contracting muscle cells. The continuous partial contraction of many skeletal muscles produces the relatively stable positions of the body when standing or sitting; this is known as posture. 2. What structures are unique to skeletal muscle fibers? Which of the structures are involved primarily in contractility and which are involved in excitability? - Myofibrils are unique to muscle cells; they are primarily involved in contraction. T tubules and sarcoplasmic reticula are also unique to muscle cells; they are primarily involved in excitability. 3. Explain how the structure of the myofilaments is related to their function - The structure of the myofilament consists of thousands of smaller subunits called myofibrils. Each myofibril consists of thick and thin filaments lying parallel to one another. Four kinds of proteins make up the myofilament: actin, troponin, and tropomyosin make up the thin filaments; myosin makes up the thick filaments. The tropomyosin twists around the actin filament and is held in place by troponin. In this position the tropomyosin is blocking the binding sites between the actin and myosin. When the muscle is stimulated to contract, Ca++ are released from the sarcoplasmic reticulum. When Ca++ attach to the troponin, they cause the troponin to move the tropomyosin away from the binding sites, allowing the myosin to pull the actin so that the muscle fiber shortens.

4. Explain how the sliding – filament model allows for shortening of a muscle fiber - The sliding-filament theory explains how the excitation of the muscle fiber begins with the neurotransmitter acetylcholine, causing the stimulation of the sarcolemma, T tubule, and sarcoplasmic reticulum. When the sarcoplasmic reticulum is stimulated, it releases Ca++ into the sarcomere. The Ca++ attach to the troponin, which causes the troponin to move the tropomyosin away from the actin binding site. When this happens, the myosin forms cross bridges with the actin and pulls it toward the center of the sarcomere. The muscle shortens as a result of the filaments sliding past one another. Energy for the contraction is supplied by ATP. When the calcium is transported back to the sarcoplasmic reticulum, the tropomyosin returns to the blocking position, which prevents the joining of actin and myosin. 5. Compare and contrast the role of a Ca++ in excitation, contraction, and relaxation of a skeletal muscle. - The Ca++ is released into the sarcomere as a result of excitation of the sarcoplasmic reticulum. When the Ca++ binds to the troponin, it moves the tropomyosin, allowing the cross bridges to form, which causes the muscle to contract. When the calcium is transported back into the sarcoplasmic reticulum, the troponin returns the tropomyosin to its blocking position, causing relaxation. 6. People who exercise seriously are sometimes told to work a muscle until they “feel the burn”. In terms of how the muscle is able to release energy, explain what is going on in the muscle early in the exercise and when the muscle is “burning” - Early in the exercise, the muscle is able to keep up with the energy demands by using aerobic respiration. When the muscle cannot keep up with the energy demand because of a lack of oxygen, it must resort to anaerobic respiration. The end product of anaerobic respiration is lactic acid. An accumulation of lactic acid will cause a burning sensation in the muscle. 7. Using fiber types, design a muscle for a marathon runner and a different muscle for a 100-yard dash sprinter. Explain your choice - The marathon runner would want muscles with a high proportion of slow fibers. These muscles can maintain contractions over a long period without fatigue. A sprinter would want a muscle with a high proportion of fast fibers. Fast fibers can respond much more rapidly; however, they use so much energy that they fatigue quickly. 8. Explain the meaning of a “cardiac syncytium” as it relates to cardiac muscle. How does this structural arrangement affect its function- The cardiac syncytium is a network of cardiomyocytes connected by intercalated discs that enable the rapid transmission of electrical impulses through the network, enabling the syncytium to act in a coordinated contraction of the myocardium. The cardiac muscles do not taper at the ends like skeletal muscles but branch and form strong electrically coupled junctions with other fibers. This allows cardiac muscle fibers to form a continuous electrically coupled mass. This allows for the efficient conduction of electrical impulses necessary for coordinated pumping action. 9. Identify the muscles of facial expression. What muscles facilitate smiling and frowning?

Zygomaticus Major and Minor (smile) these muscles pull up the corners of your mouth. Orbicularis Oculi (smile)&(frown) causes eyes to crinkle Levator Labii Superioris

(smile) pulls u the corner of lip and nose Levator Anguli Oris (smile) helps to raise the angle of mouth Risorius (smile) pulls the corners of mouth to the side of face Platysma (frown) pulls down lip and wrinkles lower skin Corrugator Supercilii and procerus (frown) furrows the brow Orbicularis oris (frown) closes the mouth and puckers lip Mentalis (frown) causes wrinkling of chin Depressor Anguli Oris (frown) pulls corner of mouth down 10. How do the origin and insertion of a muscle relate to reach other in regard to actual movement? - The contraction of skeletal muscles allows the movement at synovial joints. ... The fixed end is called as “origin” and the freely movable end is known as “insertion.” The contraction of the muscle thus causes movement of the joint by pulling the insertion towards the origin. 11. When the biceps brachii contracts, the elbow flexes, when the triceps brachii contracts, the elbow extends. Explain the role of both muscles in terms of agonist and antagonist in both of these movements. - Agonist muscles and antagonist muscles refer to muscles that cause or inhibit a movement. Agonist muscles cause a movement to occur through their own activation. For example, the triceps brachii contracts, producing a shortening contraction, during the up phase of a push-up (elbow extension) 12. Describe how the body maintains posture. - Several muscle groups, including the hamstrings and large back muscles, are critically important in maintaining good posture. While the ligaments help to hold the skeleton together, these postural muscles, when functioning properly, prevent the forces of gravity from pushing us over forward. 13. Baseball players, particularly pitches, often incur rotator cuff injuries. List the muscle that make up the rotator cuff and explain the importance of these muscles and their role in joint stability. Four muscles make up the rotator cuff: the subscapularis, teres minor, supraspinatus, and infraspinatus. Together they assist in stabilizing the shoulder joint as well as in performing various arm movements. Four muscles and their attached tendons make up the rotator cuff. 1. A 2. D...