Chapter 9 Worksheet - muscle answers PDF

Preview

Summary

worksheet for chapter 9...

Description

Outline 8 Chapters 9: Muscles 1. Fill in the following table to describe, compare and contrast the three types of muscle: Voluntary Cell Shape Location or and Involuntary appearance On bones, Skeletal Voluntary Short to attached to Muscle very long the filaments skeleton

Function

Striations present?

Movement Of the skeleton

yes

Smooth involuntary Muscle

Spindle shaped

Walls of hollow organs, blood vessels, digestive tract, respiratory tract, etc.

Help organs move contents through

no

Cardiac involuntary Muscle

Y shaped

heart

Pump blood

yes

2. What are the four functions of muscle tissue? • Produce movement • Maintain posture and body position • Stabilize joints • Generate heat 3. How does muscle tissue generate heat? Muscles generate heat as they contract, which plays a role in maintaining normal body temperature 4. Explain how muscles relate to bones and movement. Skeletal muscles are attached to the skeleton and by contracting and relaxing they allow locomotion 5. What does it mean to say that a muscle cell is excitable? Is the ability of a cell to receive and respond to a stimulus by changing its membrane potential; this is also called responsiveness. 6. Given any muscle, how would you determine its origin and insertion points? The origin attaches on the least movable bone, in the limbs this is usually proximal. The insertion attaches to the most movable bone, again in the limbs this is usually distal. 7. Does muscle tissue have nerve and blood supply? yes 8. What is the epimysium? Where it is? What kind of tissue is it?

Is an overcoat of dense irregular CT that surrounds the whole muscle. Sometimes it blends with the deep fascia that lies between neighboring muscles or the superficial fascia of the skin. 9. What is the perimysium? What kind of tissue is it made out of? Where would you find it? Within each skeletal muscle, the muscle fibers are grouped into fascicles, that resemble bundles of sticks; surrounding each fascicle is a layer of dense irregular CT called perimysium. 10. What is the endomysium? What type of tissue is it and where would you find it? Is a wispy sheath of connective tissue that surrounds each individual muscle fiber. It consists of fine areolar connective tissue. 11. In the limbs, is the origin of a muscle proximal or distal to the insertion? The origin is proximal to the insertion. 12. What are tendons made out of? They are made of connective tissue that has strong collagen fibers 13. What’s the difference between a tendon and a ligament? A tendon serves to move a bone structure, a ligament is a fibrous CT that attaches bone to bone, and usually serves to hold structures together keeping them stable. 14. What’s the sarcolemma? Sarcoplasm? Sarcolemma is a plasma membrane; sarcoplasm is the cytoplasm of a muscle cell, it contains unusually large amounts of glycosomes 15. How does the size of a muscle cell compare to other cells in the body? It can be up to tens times larger than an average body cell. 16. What are glycosomes? What is it an advantage for muscle tissue to house glycosomes? Granules of stored glycogen that provide glucose during muscle cell activity for ATP production. 17. What is myoglobin? Red pigments that store oxygen. 18. What are three organelles you might find in a muscle cell, but not in other cells? Myofibrils, sarcoplasmic reticulum, and t tubules. 19. What is a myofibril? Organelles that are inside a muscle cell, they are made up of a chain of sarcomeres linked end to end 20. What is a sarcomere? If you link sarcomeres end to end, what do you get? Is the region of a myofibril between two successive Z discs; if we linked them together end to end, we would get a myofibril 21. What are myofilaments? There are two types of myofilaments. What are they? They are the muscle equivalent of the actin-containing microfilaments and myosin motor proteins. The two types are: thick filaments and thin filaments.

22. How many actin filaments make a thin filament? How many myosin filaments create a thick filament? Two intertwined actin filaments. A thin filament is made of three proteins (actin, troponin, tropomyosin). Thick filaments are about 300 myosin molecules bundle together. They are made up of six proteins. 23. Diagram a sarcomere. Include the H zone, Z disc, thick filaments, thin filaments, I band, A band, M line.

24. Diagram myosin and actin up close. Include myosin heads, actin-binding site, tropomyosin, troponin, and myosin-binding sites.

25. What is the energy source for muscle contraction? Adenosine triphosphate (ATP) 26. What is the main function of tropomyosin? Troponin? Tropomyosin spiral about the actin core and help stiffen and stabilize it.

Troponin is a globular protein, together with the tropomyosin they both help control the myosin-actin interactions involved in contraction. 27. What are the three things that troponin binds to during contraction? Actin, tropomyosin, and calcium ions. 28. What is the function of the sarcoplasmic reticulum? It regulates intracellular levels if ionic calcium. It stores calcium and releases it on demand when the muscle fiber is stimulated to contract. 29. What is the main function of the T-tubules. Describe their anatomy. They conduct impulses to the deepest regions of the muscle cell and every sarcomere. They resemble elongated tubes. 30. Describe what happens in one sarcomere during contraction. (The 4 steps of the sliding filament model of contraction). • The I band shorten • The distance between successive Z discs shortens. • The H zone disappear • The contiguous A bands move closer together, but their length doesn’t change. 31. What is the main fuel source for muscle contraction? ATP 32. What is the function of acetylcholine? To relate the message to skeletal muscle to contract from the motor neurons. 33. Look at page 79 (chapter 3 on membrane potentials and voltages). What is membrane potential? What creates a voltage across a membrane? Is the inside of most cells more negative or more positive compared to outside the cell? Membrane potential (voltage) is electrical potential energy resulting from the separation of oppositely charged particles. The selective permeability creates that voltage. The inside of the cells is usually more negatively charged than the outside. 34. What role do the somatic motor neurons play in muscle contraction? The axions of these neurons branch through the muscles innervating them, so they can signal the muscle fibers voluntarily 35. What is a motor end plate? Axon terminal? Synaptic cleft? Synaptic vesicles? Motor end plate or neuromuscular junctions are curling branches of the axon that divides again and again. Axon terminals are the most distal portion of a neuron’s axon. Synaptic cleft is the space that separates the muscle fibers and the axon terminal. Synaptic vesicles are small membranous sacs containing the neurotransmitter acetylcholine. 36. Describe what happens at the neuromuscular junction (this explains how a neuron stimulates a muscle to begin contracting)? The ACh comes down the nerve cell and when it gets to the end of the nerve (the axon terminal) it stimulates the calcium channels to open, then calcium

enters in a greater concentration into the nerve cell, once it enters it stimulates the synaptic vesicles to release the acetylcholine or excrete it into the synaptic cleft and then binds to the sodium channels which opens up, letting the sodium rush into the muscle cell, making the cell depolarize. 37. Explain what happens during excitation-contraction coupling. Include, T tubules, SR, Ca++ release channels, troponin, tropomyosin, active transport. The EPP triggers an action potential that travels across the entire sarcolemma. The AP in the sarcolemma propagates along the T tubules and causes release of Ca2+ from the terminal cisterns of the SR. Ca2+ is the final trigger for contraction. It is the internal messenger that links AP to contraction. Ca2+ binds to troponin and this causes the myosin-binding sites on actin to be exposed so that myosin heads can bind to actin. 38. Explain the cross bridge cycle. Include: actin myosin cross bridge, calcium, ADP and P, ATP, low-energy myosin head state, high-energy myosin head state. The muscle contracts as a result of a repeating cycle of steps that cause myofilaments to slide relative to each other. 39. What is muscle tension and load? Tension is the force exerted by a contracting of the muscle on an object. The opposing force exerted on the muscle by the weight of the object to be moved is called the load. 40. What is an isometric contraction? Isotonic? Give examples. Isometric contraction is a concentration that is not associated with any movement, the muscle does not shorten. An example would be to carry an object in front of you, the weight of the object would be pulling downward, but your hands and arms would be opposing the motion with equal force going upward. Isotonic contraction is when the muscle tension developed overcomes the load and muscle shortening occurs. Lifting a dumbbell using your biceps is an example of this. 41. What’s a motor unit? What control do they have over fine motor function/control? Gross motor control? A motor unit consists of a motor neuron and all the muscle fibers it innervates. Muscles that exert fine control (such as fingers and eyes) have small motor units, each neuron is communicating to less muscles, having more specific control. Gross motor control is when you need less precise movement. 42. What is temporal summation? What is the outcome? Is the additional stimulation delivered before relaxation is completed, the outcome is that the second contraction is greater because the muscle is already partially contracted. 43. What happens when the frequency of muscle stimulation increases? Higher stimulation frequency results in unfused tetanus.

44. What is recruitment? What is the outcome? Also called multiple motor unit summations, controls the force of contraction more precisely. 45. What’s tetanus? At even higher frequency there is no relaxation between stimuli . this is fused (complete) tetanus.

46. What is the function of creatine phosphate? To help us regenerate ATP 47. What happens during anaerobic respiration? How many ATP are generated? What types of exercise produce anaerobic respiration? Glycolysis is the first step in breaking glucose into ATP. Next, if there isn’t enough oxygen around, then pyruvic acid molecules are converted into lactic acid. This is lactic acid fermentation, which is a type of anaerobic respiration. Then the lactic acid is diffused into the blood, and can be used as an energy source, or be converted by the liver back into glucose. This can sustain heavy muscle use for about a minute. Only 2 ATP/glucose. This would happen in a moderately long activity in which the oxygen we obtain through breathing cant keep up with the use, for example snowboarding downhill for several minutes. 48. Give the equation for glycolysis. Explain why fermentation happens if oxygen isn’t present. 2 Pyruvic Acid + 2 NADH ----→ 2 NAD+ + Lactic Acid

Fermentation happens when the pyruvic acid is converted into lactic acid; if there was oxygen the pyruvic acid would go back to the mitochondria and finishes aerobic respiration 49. What is the chemical equation for aerobic respiration? How many ATP are generated? What types of exercise produce aerobic respiration? Glucose + oxygen -----→ carbon dioxide + water + ATP (36-38 ATP total per glucose) Lower intensity exercise would be powered by aerobic respiration for a longer period of time 50. How do muscles respond to aerobic endurance exercise? the number of capillaries surrounding the muscles increase, the number of mitochondria also increases, the fiber synthetizes more myoglobin 51. How do muscles respond to resistance exercise? Muscles increase in size; each cell increases in size and some might split. Mitochondrial count increases Cells form more myofilaments. Myofibrils, store more glycogen and develop more CT between muscle cells

52. Where is smooth muscle found in the body? In the walls of hollow organs, except the heart. 53. In most places there are two layers of smooth muscle. What are they and what is the function of each? Longitudinal layer: to move the contents through Circular layer: it gives the contents access to the cells surrounding the lumen...