Module 9 Muscular System Review Guide PDF

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Studyguide/review for module 9 which is all about the muscular system....

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Muscular System R eview Guide Re 1. List AND describe the functions of skeletal muscles. a. Movement, posture, supports soft tissue, guards entrances and exits, provides heat/maintains body temperature, storage of minerals 2. List AND describe the characteristics of skeletal muscle. a. Responsiveness (excitability)- to chemical signals, stretch and electrical change across the plasma membrane b. Conductivity- local electrical change triggers a wave of excitation that travels along muscle fiber c. Contractility-shortens when stimulated d. Extensibility- capable of being stretched e. Elasticity- returns to its original resting length after being stretched. 3. What are two other names for a muscle fiber? a. Myofiber, myocyte 4. Describe the number and location of nuclei in a myofiber. a. There are many nuclei b. Location: Nuclei are just below the sarcolemma-specialized cell membrane 5. Muscle cells are packed full of which type of protein filament? a. Actin and myosin. 6. Make sure you understand the difference between a myofiber and a myofibril! a. Myofiber= muscle fiber= myocyte-single muscle cell. Their cytoplasm is packed full of myofibrils. b. Myofibril- are bundle of protein filaments (actin and myosin) that cause contraction. 7. What is another name for the muscle cytoplasm? a. Sarcoplasm 8. What is another name for the plasma membrane of a myofiber? a. Sarcolemma= cell membrane 9. Describe the location of the T tubules, sarcoplasmic reticulum, and terminal cisternae. What is the function of each of these structures? a. Transverse tubules (T-tubules)- circles around myofibrils. Carry electric current to cell interior. Transmits signal to contract. b. SR: Network around each myofibril (spider webs), smooth ER, stores calcium c. TC: Part of the network around the myofibril, the end sacs, stores calcium 10. What is a “triad” referring to? a. 1 tubule and 2 tubule cisternae 11. Label the connective tissue wrappings of a skeletal muscle.  12. What is an aponeurosis? Where are some regions in the human body might you find one? How does an aponeurosis differ from a tendon? a. Aponeurosis- sheet-like structure b. You can find them at sites of muscle attachment, aponeurosis is a sheet-like structure and tendon is a cord-like structure c. Foot, shoulder, jaw 13. What is the name given to the contractile unit of muscle? a. Sarcomere 14. What protein is the thin filament made of? a. Actin filaments 15. What protein is the thick filament made of? a. Myosin filaments 16. What exactly is a cross bridge? a. The head aka extensions or cross bridges of Myosin filaments 17 17.. What is the function of a Titin protein? What two regions of the sarcomere does it connect? a. The titin protein is responsible for passive electricity of the muscles. It connects at the Z line and M line of the muscle fiber. 18. Label the following regions of a sarcomere:

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a. The thick filaments produce the dark A band. The thin filaments extend in each direction from the Z line. Where they do not overlap the thick filaments, they create the light I band. The H zone is that portion of the A band where the thick and thin filaments do not overlap. The entire array of thick and thin filaments between the Z lines is called a sarcomere. Which band of a sarcomere contains only actin? a. I band Which band of a sarcomere contains only myosin? a. A band Which zone of a sarcomere has only “bare” myosin? a. H Zone Which region of a myosin molecule attaches to actin? (Hint: Hint: it looks like a golf club head). a. Head/cross bridge Describe AND draw the relationship between the following proteins in a sarcomere during muscle contraction AND muscle relaxation:

24. What happens to the sizes of the following bands/regions of sarcomere during contraction AND relaxation? a. Distance between the Z-lines stays the same b. Size of I-Band becomes narrow (shortens) during contraction at maximum width at relaxation c. Size of A-Band remains unchanged d. Size of H-Zone Disappears almost (shortens) during contraction and at maximum width at relaxation 25. Explain, in detail, the concept of a motor unit. How would the arrangement of a motor unit differ for fine control vs. strength control? a. A motor neuron and the muscle fibers it innervates i. dispersed throughout the muscle, when contract together causes weak contraction over wide area, provides ability to sustain long-term contraction as motor units take turns resting (postural control) b. Fine control: mall motor units contain as ffew ew as 20 muscle fibers per nerve fiber (i.e. eye muscles) c. Strength control: gastrocnemius muscle has 1000 fibers per nerve fiber (recruitment) 26. Describe, in detail, all of the components of a neuromuscular junction (NMJ) including a. synaptic knob is the swollen end of the nerve fiber. b. Junctional folds: located on the sarcolemma, functions to increase surface area for ACh receptors and contains acetylcholinesterase to break down ACh and relax muscles. c. Synaptic cleft: tiny gap between nerve and muscle cell; function is a space for reactions to occurs

d. Basal Lamina: thin layer of glycoprotein and collagen all over muscle fibers e. Acetylcholine: chemical component released from neuron to produce a stimulus. f. Acetylcholine receptors sense the ACh being released into the synaptic gap and open channels to allow chemicals in for the muscle to contract. g. Acetylcholinesterase breaks down the ACh causing the muscle to relax 27 27.. Briefly summarize the four actions necessary for muscle contraction and relaxation. a. Excitation - action potentials in the nerve lead to formation of action potentials in a muscle fiber b. Excitation-Contraction Coupling - action potentials on the sarcolemma activate myofilaments. c. Contraction - shortening of a muscle fiber or at least the formation of tension. d. Relaxation - return of a muscle fiber to its resting length 28. Diagram AND explain in words ALL of the steps involved in muscle contraction AND relaxation. Yes, this will take you some time. You should know by now how you learn best, so choose a method that works for you. The more times you go through this and the more detail you include, the better off you will be! 

a. Contraction of a Muscle Fiber. A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten. b. Relaxation of a Muscle Fiber. Ca++ ions are pumped back into the SR, which causes the tropomyosin to reshield the binding sites on the actin strands. A muscle may also stop contracting when it runs out of ATP and becomes fatigued. 29. Discuss HOW some of the neuromuscular toxins covered in class affect the NMJ. a. Some of the toxins are cholinesterase which prevent acetylcholinesterase from degrading ACh, causes spastic paralysis and possible suffocation. Flaccid paralysis can occur when curare competes with ACh preventing a motor neuron from producing a stimulus. 30. Discuss HOW myasthenia gravis leads to progressive weakness. a. It is an autoimmune disease that binds to ACh receptors preventing ACh from stimulating a muscle and makes body less and less sensitive to ACh. 31. Explain, in detail, why an individual becomes rigid soon after death, but then days later, becomes floppy. Make sure to include the roles of ATP and calcium in your explanation. a. Occurs because muscle cells have a massive release of Ca2+ from sarcolemma causing muscles to contract and stiffen, muscles become floppy again because there is no more ATP being produced to reset the sarcolemma and proteins start breaking down.

32. Sketch the length tension curve and use it to describe the optimum length for a forceful muscle contraction. Make sure to explain what arrangement of actin and myosin is responsible for a forceful muscle contraction. a. Amount of tension generated depends on length of muscle before it was stimulated. 33. Explain the phenomenon of “all or none” when describing muscle contraction. a. In a muscle fiber in order for contraction all of the muscle fibers must be stimulated, or no contraction will take place i. All muscle fibers don’t fire at once, one goes, then another and another and so on till all fibers are contracting 34. What does recruitment mean in terms of muscle contraction? a. As muscle fibers are stimulated more are "recruited" and stimulated 35. Draw AND describe what twitch would look like on graph. a. One single curve, rather than multiple curves then lowers

36. What are the three phases of twitch AND what is happening on the molecular and cellular level during each of these phases? a. Latent period before contraction: action potential moves through sarcolemma causing Ca2+ to be released b. Contraction phase: calcium ions bind, tension builds to peak c. Relaxation phase: Ca2+ levels fall, active sites are covered, tension falls to resting levels 37 37.. Compare and contrast unfused and fused tetanus. Make sure to mention “treppe” and wave summation in your answer. a. fused tetanus: muscle contractions are short and close together; doesn’t allow for muscles to relax inbetween contractions, the treppe increases, treppe=increased stimulation b. Unfused tetanus, muscle contractions are further apart, allows muscles to relax between contractions 38. Compare and contrast isotonic and isometric muscle contraction. Give some examples of each. a. Isometric muscle contraction is when a muscle develops tension without changing length, important in posture function and joint stabilization. b. Isotonic muscle contraction is when muscle fiber tension increases and muscle fibers shorten and lengthen, lifting weights. 39. What is the difference between a concentric and eccentric isotonic contraction? a. Concentric is when tension exceeds resistance and muscles shorten. Eccentric is when resistance exceeds tension and muscle lengthens. 40. Explain what is meant by the statement that, “A muscle is never entirely relaxed.” Yes, this question is asking you to talk about muscle tone. a. A muscle is never entirely relaxed, some fibers react at different times to provide muscle tone, normal tension of a muscle at rest= muscle tone. 41. Review the processes of anaerobic and aerobic respiration. I briefly went over it in cla class ss this time around, but you may have to go back to your notes from sever several al weeks ago.

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a. Anaerobic- no oxygen required, produces lactic acid, little ATP produced b. Aerobic- oxygen required, produces H2O and CO2, more ATP produced Compare and contrast, in detail, what is occurring on a molecular and cellular level for immediate, short term, and long-term energy needs of a muscle. a. long: Aerobic respiration needed for prolonged exercise i. 36 ATPs/glucose molecule b. After 40 seconds of exercise, respiratory and cardiovascular systems must deliver enough oxygen for aerobic respiration c. oxygen consumption rate increases for first 3-4 minutes and then levels off to a steady state d. Limits are set by depletion of glycogen and blood glucose, loss of fluid and electrolytes What is creatine phosphate in terms of a supplement? Specifically, who is it going to benefit? Why? a. It is a molecule that produces more ATP, the more energy produced the more work a muscle fiber can do. b. Creatine kinase transfers Pi groups from creatine phosphate to make ATP (short burst) Describe on a molecular and cellular level what is occurring when a muscle becomes fatigued. a. ATP synthesis declines as glycogen is consumed, sodium-potassium pumps fail to maintain membrane potential and excitability, lactic acid inhibits enzyme function, accumulation of extracellular K+ hyperpolarizes the cell, motor nerve fibers use up their acetylcholine What types of things would an endurance athlete be concerned with? Explain! a. Oxygen uptake, for aerobic respiration, and nutrient availability for energy production and electrolyte balance to prevent muscle fatigue Describe what is occurring when a muscle goes into “oxygen debt.” Make sure to explain EPOC in your response. a. EPOC stands for excess posterities oxygen consumption, this is the heavy breathing occurring when you exercise, its purpose is to replenish phosphagen system, reconvert lactic acid, and to serve the elevated metabolic rate. Compare and contrast slow twitch and fast twitch muscle fibers. a. Slow- slow oxidative fiber (oxygen) smaller more mitochondria, myoglobin and capilla capillaries ries adapted for aerobic respiration and resistant to fatigue slow to contract soles and postural muscles of the back b. Fast- "Fast glycolytic fibers" larger, large glycogen reserves, few mitochondria, fast glycolytic rich in enzymes for phosphagen and gly glycogen-lactic cogen-lactic acid systems sarcoplasmic reticulum releases calcium quickly so contractions are quicker * extra ocular eye muscles, gastrocnemius and biceps brachii *fatigue faster How exactly do strength workouts increase muscle size? a. stimulates cell enlargement due to synthesis of more myofilaments b. Hypertrophy (increased muscle size) vs. increase in number of muscle cells What is DOMS? What exactly causes it? a. Delayed Onset Muscle Soreness b. This is caused by a buildup of lactic acid in the muscle tissue from strenuous activity. How does endurance training prepare an athlete for an Ironman triathlon? Explain what is going on at the molecular and cellular level! a. Aerobic exercise produces an increase in mitochondria, myoglobin, glycogen and density of capillaries. There is also less lactic acid production. Compare and contrast skeletal muscle, cardiac muscle, and smooth muscle making sure to include the following in your comparison. This question may be more appropriate for the lab portion of this course: a. Does it have one nucleus or is it multinucleated? i. Skeletal Muscle: More than one nucleus, multinucleated ii. Cardiac muscle: One nucleus per cell iii. Smooth muscle: One nucleus per cell b. What is the location of nucleus (central vs. peripheral)? i. Skeletal Muscle: Peripheral ii. Cardiac muscle: Peripheral iii. Smooth muscle: Central c. Striated or non-striated? i. Skeletal Muscle: Striated ii. Cardiac muscle: Striated iii. Smooth muscle: Non-striated d. Voluntary or involuntary? i. Skeletal Muscle: Voluntary ii. Cardiac muscle: Involuntary iii. Smooth muscle: Involuntary

e. Can it divide? i. Skeletal Muscle: No ii. Cardiac muscle: No iii. Smooth muscle: Yes f. Intercalated discs? i. Skeletal Muscle: Mo ii. Cardiac muscle: Yes iii. Smooth muscle: No g. Major function? i. Skeletal Muscle: moves the body ii. Cardiac muscle: to pump blood iii. Smooth muscle: changes shape to facilitate bodily functions h. Where in the human body is it found? i. Skeletal Muscle: the muscles; biceps, triceps, quads, etc. ii. Cardiac muscle: only in the heart iii. Smooth muscle: surrounds hollow organs and tubes (blood vessels, urinary bladder, respiratory and reproductive tracts) 52. Using your book AND notes, compare and contrast the PHYSIOLOGY of skeletal muscle and smooth muscle contraction. You will want to include the terms dense bodies, actin, myosin, intermediate filaments, myosin light chain, calmodulin, myosin light chain kinase, myosin light chain phosphatase, phosphorylation, dephosphorylation, plasticity, etc. in your explanation. DO NOT SIM SIMPL PL PLY Y DEFINE THESE TERMS! Instead create a “story.” a. The sequence for smooth muscle contraction is increased cytosolic calcium, which binds to calmodulin in cytosol, complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction. b. The sequence for skeletal muscle contraction is increased cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active sites on actin filament, which binds with myosin cross-bridges, resulting in contraction. c. Smooth muscle and skeletal muscle fibers both have their contractions triggered by calcium ions. Both smooth muscle contractions and skeletal muscle contractions involve thin (actin) filaments sliding over the thick (myosin) filaments....