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Human Muscular System SVHS Adv, Biology Biology Unit #6 2011-12

Human Muscular System SVHS Adv, Biology Biology Unit #6 2011-12. Normal or Not???. Tortora pages 154. Muscular System. Study of muscle is known as myology . 40-50% of body weight is muscle. Tortora pages 154. Muscle Tissue Types. Smooth Involved in internal processes.

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Human Muscular System SVHS Adv, Biology Biology Unit #6 2011-12

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  1. Human Muscular System SVHS Adv, Biology Biology Unit #6 2011-12

  2. Normal or Not???

  3. Tortora pages 154 Muscular System • Study of muscle is known as myology. • 40-50% of body weight is muscle.

  4. Tortora pages 154 Muscle Tissue Types • Smooth • Involved in internal processes. • Makes up the walls of hollow internal structures. • Involuntary

  5. Tortora pages 154 Muscle Tissue Types • Cardiac • Forms wall of the heart and major vessels leading from the heart

  6. Tortora pages 154 Muscle Tissue Types • Skeletal • Attached to skeleton. • Responsible for skeletal movement.

  7. Tortora pages 154 Functions of Muscle Tissue • Producing body movement • Movement of substances in body. • Stabilizing body position. • Regulating organ volume. • Heat production.

  8. Tortora pages 154-155 Striated Muscle Connective Tissue. • Connective tissues • Superficial facia • Contains fat and is just below the skin. • Deep facia • Connective tissue • Holds muscles together. • Separates muscle bundles • Extends to form tendons

  9. Tortora pages 154-155 Striated Muscle Connective Tissue. • The entire muscle is wrapped in the epimysium

  10. Tortora pages 154-155 Striated Muscle Connective Tissue. • Muscle bundles fasicles are surrounded by facia called perimysium

  11. Tortora pages 154-155 Striated Muscle Connective Tissue. • Each muscle fiber (cell) is covered by facia called endomysium.

  12. Tortora pages 154-155 Striated Muscle • Blood supply • Muscle contraction requires large amounts of energy and so requires large amounts of nutrients and oxygen.

  13. Tortora pages 154-155 Striated Muscle Nervous Tissue Nerve tissue • Motor neuron • Motor units • Muscle must receive a stimulus in order to contract. • Role of muscle action potential.

  14. Homework Quiz - Activity A 1- T or F Smooth muscle is voluntary and found in the walls of blood vessels. 2- T or F Cardiac muscle is not under conscious control. 3- T or F Striated muscle is voluntary and is also called skeletal muscle. 4- Which of the following is not a function of the muscular system? • A) Creating motion • B) Moving substances in the in the body. • C) Creating body heat. • D) Sustaining the body’s posture. • E) Producing hormones for growth.

  15. 5- Which of the following is not a characteristic of muscle tissue? A) Ability to return to it’s original shape. B) Ability to respond to a stimuli. C) Ability to push bones to create movement. D) Ability to shorten. E) Ability to stretch. 6- The ability of muscle to stretch is referred to as ? 7- Muscle making up the wall of the heart is known as ? 8- Muscle making up the walls of the intestine is known as ?

  16. Answers 1) True 2) True 3) True 4) E (producing hormones for growth) 5) C (ability to push bones) 6) Extensibility (ability to stretch) 7) Cardiac (makes up wall of heart) 8) Smooth (makes up wall of intestines)

  17. Muscles + Bones = Lever Systems • Class I lever • fulcrum between resistance and energy. • Class II lever • Resistance between energy and fulcrum. • Class III lever • Energy is between fulcrum and resistance.

  18. Tortora pages 156 Skeletal Muscle Structure Each muscle fiber or cell is composed of subunits called myofibrils

  19. Tortora pages 156-157 Striated Muscle Structure • Structure of striated muscle cell. • Sarcolemma • Sarcoplasm • Sarcoplasmic reticulum • Transverse tubules

  20. Tortora pages 156 Striated Muscle Structure • Proteins of muscle are called myofilaments. • Thin protein filament is composed of: • Actin • Tropomyosin. • Thick protein myofilament is myosin. • Myosin has cross bridges.

  21. Tortora pages 156 Striated Muscle Structure • Actin • Contains myosin binding site. • Site is covered by tropomyosin. • Myosin • Contains actin binding site. • Contains a binding site for ATP.

  22. Striated Muscle Structure Tortora pages 156 • Sarcomeres are contracting units in muscle. • Each fiber has many myofibrils. • Each myofibril is composed of many sarcomeres. • Z lines • A band • I band • H zone

  23. Tortora pages 156

  24. C & D Quiz • Which lever type is a distance multiplier? • Which lever type has the force exerting between the fulcrum and the load? • A muscle that decreases the angle of a joint. • A muscle that moves a bone away from the midline of the body. • A muscle that decreases the size of an opening. • A muscle that produces a downward movement. • A muscle that turns the palm downward or posteriorly.

  25. Striated Muscle Structure • Motor units • Motor neuron • Muscle cell • 10-500 fibers per motor neuron. • Neuromuscular junctions • Motor end plate. • Synaptic cleft. • Sarcolemma

  26. Neuromuscular Junctions • Starting a muscle contraction. • Nerve impulse reaches axon terminal. • Ca++ enters the synaptic end bulb. • Vesicles move to and fuse with membrane. • Vesicle releases ACH into the synaptic cleft.

  27. Neuromuscular Junctions • 5) ACH diffuses across cleft and binds to ACH receptors in sarcolemma. • 6) Muscle action potential is created. • 7) Within 1/500 of a second ACHe inactivates ACH. • 8) Muscle prepares for next muscle action potential.

  28. Physiology of Contraction • Muscle action potential spreads across sarcolemma. • Reaches into the transverse tubules. • Spreads to the sarcoplasmic reticulum. • Sarcoplasmic reticulum releases Ca++

  29. Physiology of Contraction • Calcium binds to tropomyosin, changing its shape. • Myosin and actin bind. • ATP is broken down to ADP . • Powerstroke occurs.

  30. Striated Muscle & Relaxation • Two changes cause relaxation. • ACh broken down by Ache. • Results in no muscle action potential. • Ca++ is rapidly removed from the sarcoplasm. • Results in tropomyosin covering the myosin binding sites on the actin.

  31. Tortora Pages 160, 162-163 Striated Muscle & and Energy • ATP is needed as energy source for muscle contraction. • ATP attaches to ATP binding site on myosin head. • ATP is broken down to ADP + P. • Myosin cross bridge is energized.

  32. Tortora Pages 160, 162-163 Striated Muscle & and Energy • Ca++ removes tropomyosin. • Actin & myosin engage. • Cross bridge changes shape. (Powerstroke) • ADP is released. • ATP again attaches to binding site causing actin & myosin to disengage. • ATP is broken down causing myosin head to return to normal position. • Powerstroke repeated.

  33. Tortora Pages 160, 162-163 Energy for Muscle Contraction • Contraction is powered initially by ATP stored in the muscle. • 5 second supply. • 40 yards into 400 meter race.

  34. Tortora Pages 160, 162-163 Energy for Muscle Contraction • Creatine Phosphate • Energy is released from CP. • Used to make more ATP from ADP and Pi. • Supplies 15 seconds worth of energy. • 22 seconds or 220 yards into race.

  35. Tortora Pages 160, 162-163 Energy for Muscle Contraction • Glycolysis • Glucose is broken down to pyruvic acid. • Occurs in sarcoplasm. • Anaerobic (does not require oxygen) • Results in lactic acid if no oxygen available. • Lactic acid causes fatigue feeling. • Provides 30 seconds worth of muscle contraction. • You are now 300 yards into race.

  36. Tortora Pages 160, 162-163 Energy for Muscle Contraction • Aerobic respiration. • Occurs in mitochondria. • Breaks down pyruvic acid. • Requires oxygen. • Results in H2O and CO2 as wastes. • Makes 36 ATP molecules. • Now you can run a marathon!!

  37. Tortora Pages 160, 162-163 Energy for Muscle Contraction • Greg LeMond’s career ended due to a mitochondrial condition. • What is he doing today?

  38. Still Racing!! Tortora Pages 160, 162-163

  39. Tortora Pages 160, 162-163 Oxygen Debt • Occurs when oxygen does not get to muscles. • Glycolysis results in L.A. • Must acquire oxygen to pay back debt. • Heavy breathing after exercise!

  40. TortoraPage 163-164 All-or-None Principle • Any given motor unit will be fully contracted or not at all. • Threshold stimulus causes contraction. • Subthreshold will not create a contraction. • Some motor units are contracted while others are not.

  41. TortoraPage 164 Homeostasis • Oxygen Debt • Due to lactic acid. • Paid back with oxygen. • Muscle Fatigue • Due to L.A. • Decrease in pH. • Heat production • 85% of energy is released in form of heat.

  42. TortoraPage 164 Types of Contraction • Different types of contractions depending on how often stimulation occurs. • A muscle twitch is a brief contraction of all muscle fibers in a motor unit due to a single nerve impulse.

  43. TortoraPage 164 Types of Contraction • Phases of a muscle twitch • Latent phase • Action potential spreads across sarcolemma • Ca++ released.

  44. TortoraPage 164 Types of Contraction • Contraction phase • Power stroke. • Actin and myosin slide over one another. • Muscle becomes shorter.

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