Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
PowerPoint® Lecture Slides prepared by Meg Flemming Austin Community College CHAPTER 7 The Muscular System © 2013 Pearson Education, Inc. Chapter 7 Learning Outcomes • 7-1: Specify the functions of skeletal muscle tissue. • 7-2: Describe the organization of muscle at the tissue level. • 7-3: Identify the structural components of a sarcomere. • 7-4: Explain the key steps involved in the contraction of a skeletal muscle fiber beginning at the neuromuscular junction. • 7-5: Compare the different types of muscle contractions. • 7-6: Describe the mechanisms by which muscles obtain the energy to power contractions. • 7-7: Relate the types of muscle fibers to muscle performance, and distinguish between aerobic and anaerobic endurance. • 7-8: Contrast the structures and functions of skeletal, cardiac, and smooth muscle tissues. • 7-9: Explain how the name of a muscle can help identify its location, appearance, or function. © 2013 Pearson Education, Inc. Chapter 7 Learning Outcomes • 7-10: Identify the main axial muscles of the body together with their origins, insertions, and actions. • 7-11: Identify the main appendicular muscles of the body together with their origins, insertions, and actions. • 7-12: Describe the effects of aging on muscle tissue. • 7-13: Discuss the functional relationships between the muscular system and other organ systems. © 2013 Pearson Education, Inc. Review Muscle Types • Elongated muscle cells or fibers that are highly specialized for contraction 3 types: a. Skeletal- most abundant, striated, large multinucleated, voluntary, cant divide b. Cardiac- only in heart, striated, single nucleus, intercalated discs, involuntary, cant divide c. Smooth- line organs, non striated, single nucleus, can divide, involuntary © 2013 Pearson Education, Inc. Five Skeletal Muscle Functions (7-1) 1. Produce movement of the skeleton • By pulling on tendons that then move bones 2. Maintain posture and body position 3. Support soft tissues • With the muscles of the abdominal wall and the pelvic floor 4. Guard entrances and exits • In the form of sphincters 5. Maintain body temperature • When contraction occurs, energy is used and converted to heat © 2013 Pearson Education, Inc. Checkpoint (7-1) 1. Identify the five primary functions of skeletal muscle. 1. Produce movement of the skeleton 2. Maintain posture and body position 3. Support soft tissues 4. Guard entrances and exits 5. Maintain body temperature © 2013 Pearson Education, Inc. Organization of Skeletal Muscle Tissue (7-2) Skeletal muscles – approximately 700, •Single skeletal muscle cells or muscle fibers Are organs that contain: 1. Skeletal muscle tissue (primary) 2. Connective tissue 3. Blood vessels 4. Nerves © 2013 Pearson Education, Inc. A. Three Layers of Connective Tissue (7-2) 1. Epimysium (ep-i-MIZ-e-um muscle) • Covers the entire muscle 2. Perimysium (per-i-MIZ-e-um around) • Divides the muscle into bundles called fascicles (FASi-kl) • Blood vessels and nerves are contained in the perimysium 3. Endomysium (en-do-MIZ-e-um- inside) • Covers each muscle fiber and ties fibers together • Contains capillaries and nerve tissue © 2013 Pearson Education, Inc. B. Tendons (7-2)Where the ends of all three layers of connective tissue come together and attach the muscle to a bone Aponeurosis (ap-o-noo-RO-sis) • A broad sheet of collagen fibers that connects muscles to each other, Similar to tendons, but do not connect to a bone © 2013 Pearson Education, Inc. C. Blood Vessels (7-2) • Extensive network of blood vessels in skeletal muscle provides high amounts of nutrients and oxygen to skeletal muscles which have high metabolic needs © 2013 Pearson Education, Inc. D. Nerves -Control of Skeletal Muscle (7-2) Mostly under voluntary control, Must be stimulated by the central nervous system; To control individual muscle fibers • Axons (nerve fibers) a) Push through the epimysium b) Branch through the perimysium c) And enter the endomysium © 2013 Pearson Education, Inc. Figure 7-1 The Organization of Skeletal Muscles. Skeletal Muscle (organ) Epimysium Perimysium Endomysium Nerve Muscle Muscle Blood fascicle fibers vessels Muscle Fascicle (bundle of fibers) Perimysium Epimysium Blood vessels and nerves Muscle fiber Endomysium Tendon Endomysium Muscle Fiber (cell) Capillary Myofibril Endomysium Sarcoplasm Perimysium Mitochondrion Stem cell Sarcolemma Nucleus Axon of neuron © 2013 Pearson Education, Inc. Checkpoint (7-2) 2. Describe the connective tissue layers associated with a skeletal muscle. A. epimysium is a dense layer of collagen fibers th at surrounds the entire muscle B. Perimuysium divides the skeletal muscle into a series of compartments, each containing a bundle of muscle fibers called a fascile C. Endomysium surrounds individual skeletal muscle cells (fibers) http://www.youtube.com/watch?v=f_tZne9ON7c © 2013 Pearson Education, Inc. Checkpoint (7-2) 3. How would severing the tendon attached to a muscle affect the muscle's ability to move a body part? Would prevent the muscle from moving the body part because the muscle would no longer be connected to the bone. © 2013 Pearson Education, Inc. Features of Skeletal Muscle Fibers/ cells(7-3) • Are specifically organized to produce contraction and have specific names for general cell structures • Can be very long and are multinucleated • Composed of highly organized structures, giving them a striped or striated appearance © 2013 Pearson Education, Inc. Features of Skeletal Muscle Fibers/ cells(7-3) 1. Sarcolemma 2. Transverse Tubules 3. Myofibrils 4. Sarcoplasmic Reticulum 5. Sarcomeres 6. Think and Thin Filaments © 2013 Pearson Education, Inc. The Sarcolemma and Transverse Tubules (7-3) The sarcolemma(Flesh, husk) • Specific name of muscle fiber plasma membrane • Has openings across the surface that lead into a network of transverse tubules, or T tubules • T tubules allow for electrical stimuli to reach deep into each fiber, coordinate contractions The sarcoplasm- Specific name for muscle fiber cytoplasm http://www.youtube.com/watch?v=F3ISlvNGTEg © 2013 Pearson Education, Inc. © 2013 Pearson Education, Inc. Myofibrils in Muscle Fiber (7-3) • Hundreds to thousands in each fiber • Are encircled by T tubules and are as long as the entire muscle fiber • Are bundles of thick and thin myofilaments • Actin molecules are found in thin filaments • Myosin molecules are found in thick filaments • Are the contractile proteins that shorten and are responsible for contraction • http://www.youtube.com/watch?v=DA7iOW7T-G4 © 2013 Pearson Education, Inc. The Sarcoplasmic Reticulum (SR) (7-3) • Specialized smooth endoplasmic reticulum • Expanded end that is next to the T tubule is the terminal cisternae, Contain high concentrations of calcium ions • Triad- A combination of two terminal cisternae and one T tubule © 2013 Pearson Education, Inc. Sarcomeres (7-3) • Smallest functional unit of skeletal muscle fiber • Formed by repeating myofilament arrangements • Each myofibril has about 10,000 sarcomeres • Thick and thin filament arrangements are what produce the striated appearance of the fiber • Overlapping filaments define lines and bands • http://www.youtube.com/watch?v=-9DmO-SRY3E © 2013 Pearson Education, Inc. Sarcomere Lines (7-3) x • Z lines • Thin filaments at both ends of the sarcomere • Another protein connects the Z lines to the thick filament to maintain alignment • M line • Made of connections between the thick filaments © 2013 Pearson Education, Inc. Sarcomere Bands (7-3)x • A band • Contains the thick filaments (dArk) • I band • Contains the thin filaments, including the Z line (Light) © 2013 Pearson Education, Inc. Figure 7-2 The Organization of a Skeletal Muscle Fiber. Terminal Sarcoplasmic T tubules cisterna reticulum Triad Sarcolemma Mitochondria Thick filament Thin filament Myofilaments MYOFIBRIL The structure of a skeletal muscle fiber. SARCOMERE Z line Zone of overlap M line Myofibril H band I band Zone of overlap A band The organization of a sarcomere, part of a single myofibril. M line Z line Z line A stretched out sarcomere. M line Z line Z line and thin filaments Myosin head Thick filaments Active site Actin molecules Myosin tail ACTIN STRAND Tropomyosin Thin filament The structure of a thin filament. Troponin © 2013 Pearson Education, Inc. Hinge MYOSIN MOLECULE The structure of a thick filament. Figure 7-2a The Organization of a Skeletal Muscle Fiber. Terminal Sarcoplasmic Triad Sarcolemma T tubules cisterna reticulum Mitochondria Thick filament Thin filament Myofilaments MYOFIBRIL The structure of a skeletal muscle fiber. © 2013 Pearson Education, Inc. Figure 7-2b The Organization of a Skeletal Muscle Fiber. SARCOMERE Z line Zone of overlap M line Myofibril I band H band A band The organization of a sarcomere, part of a single myofibril. © 2013 Pearson Education, Inc. Zone of overlap Figure 7-2c The Organization of a Skeletal Muscle Fiber. Z line M line Z line A stretched out sarcomere. Z line Z line and thin filaments © 2013 Pearson Education, Inc. M line Thick filaments Figure 7-2d The Organization of a Skeletal Muscle Fiber. Active site Actin molecules ACTIN STRAND Troponin Tropomyosin Thin filament The structure of a thin filament. © 2013 Pearson Education, Inc. Figure 7-2e The Organization of a Skeletal Muscle Fiber. Myosin head Myosin tail MYOSIN MOLECULE Hinge The structure of a thick filament. © 2013 Pearson Education, Inc. Thin and Thick Filaments (7-3) 1. Actin • A thin twisted protein, with specific active sites for myosin to bind to • At rest, active sites are covered by strands of tropomyosin, held in position by troponin 2. Myosin • A thick filament with tail and globular head that attaches to actin active sites during contraction © 2013 Pearson Education, Inc. Steps of Contraction (7-3)- calcium is the key 1. Calcium released from SR 2. Calcium binds to troponin 3. Change of troponin shape causes tropomyosin to move away from active sites 4. Myosin heads bind to active site, creating cross- bridges, rotate and cause actin to slide over myosin © 2013 Pearson Education, Inc. Sliding Filament Theory (7-3) • Based on observed changes in sarcomere • I bands get smaller • Z lines move closer together • H bands decrease • A bands don't change, indicating that the thin filaments are sliding toward the center • http://www.youtube.com/watch?v=Ct8AbZn_A8A • http://www.youtube.com/watch?v=sJZm2YsBwMY • http://www.youtube.com/watch?v=9BFvBRLDaQY © 2013 Pearson Education, Inc. Figure 7-3 Changes in the Appearance of a Sarcomere during Contraction of a Skeletal Muscle Fiber. I band Z line A band H band Z line A relaxed sarcomere showing locations of the A band, Z lines, and I band. © 2013 Pearson Education, Inc. I band A band H band Z line Z line During a contraction, the A band stays the same width, but the Z lines move closer together and the I band gets smaller. Checkpoint (7-3) 4. Describe the basic structure of a sarcomere. • The smallest contractile units of a skeletal muscle cell, are segments of myofibrils. • Have a Dark A Band and Light I Band. • Band A contains the M line, H band, and the zone of overlap. Each I Band contains thin filaments, but not thick filaments. Z lines mark the boundaries between adjacent sarcomeres © 2013 Pearson Education, Inc. Checkpoint (7-3) 5. Why do skeletal muscle fibers appear striated when viewed through a light microscope? The arrangement of the actin and myosin myofilaments within myofibrils produces a banded appearance © 2013 Pearson Education, Inc. Checkpoint (7-3) 6. Where would you expect the greatest concentration of calcium ions to be in a resting skeletal muscle fiber? In the terminal cisternae of the sarcoplasmic reticulum of a resting skeletal muscle fiber. © 2013 Pearson Education, Inc. The Neuromuscular Junction (7-4) http://www.youtube.com/watch?v=y7X7IZ_ubg4 ( Where a motor neuron communicates with a skeletal muscle fiber • Axon terminal of the neuron, An enlarged end that contains vesicles of the neurotransmitter • Acetylcholine (ACh) – chemical released by the neuron to communicate with other cells it is a neurotransmitter that will cross the synaptic cleft, space between axon terminal and sarcolemma Drawing video http://www.bing.com/videos/search?q=neuromuscular+junction&FORM=HDRSC3#view=detail&mid=A474BC69B34FDD © 2013 Pearson Education, Inc. 6752ADA474BC69B34FDD6752AD The Neuromuscular Junction (7-4) • ACh binds to the receptor on the motor end plate • Cleft and the motor end plate contain acetylcholinesterase (AChE), enzyme breaks down ACh • Neurons stimulate sarcolemma by generating an action potential, An electrical impulse © 2013 Pearson Education, Inc. Figure 7-8 Motor Units. Axons of motor neurons Motor nerve KEY Motor unit 1 Motor unit 2 Motor unit 3 © 2013 Pearson Education, Inc. SPINAL CORD Muscle fibers Figure 7-4 Skeletal Muscle Innervation. The cytoplasm of the axon terminal contains vesicles filled with molecules of acetylcholine, or ACh. Acetylcholine is a neurotransmitter, a chemical released by a neuron to change the permeability or other properties of another cell’s plasma membrane. The synaptic cleft and the motor end plate contain molecules of the enzyme acetylcholinesterase (AChE), which breaks down ACh. Vesicles ACh Synaptic cleft Motor end plate © 2013 Pearson Education, Inc. AChE Slide 1 Figure 7-4 Skeletal Muscle Innervation. Slide 2 The stimulus for ACh release is the arrival of an electrical impulse, or action potential, at the axon terminal. The action potential arrives at the NMJ after traveling along the length of the axon. Arriving action potential © 2013 Pearson Education, Inc. Figure 7-4 Skeletal Muscle Innervation. When the action potential reaches the neuron’s axon terminal, permeability changes in the membrane trigger the exocytosis of ACh into the synaptic cleft. Exocytosis occurs as vesicles fuse with the neuron’s plasma membrane. Motor end plate © 2013 Pearson Education, Inc. Slide 3 Figure 7-4 Skeletal Muscle Innervation. Slide 4 ACh molecules diffuse across the synaptic cleft and bind to ACh receptors on the surface of the motor end plate. ACh binding alters the membrane’s permeability to sodium ions. Because the extracellular fluid contains a high concentration of sodium ions, and sodium ion concentration inside the cell is very low, sodium ions rush into the sarcoplasm. ACh receptor site © 2013 Pearson Education, Inc. Figure 7-4 Skeletal Muscle Innervation. Slide 5 The sudden inrush of sodium ions results in the generation of an action potential in the sarcolemma. AChE quickly breaks down the ACh on the motor end plate and in the synaptic cleft, thus inactivating the ACh receptor sites. Action potential AChE © 2013 Pearson Education, Inc. Interference Paralysis • Botulism- bacterial toxin often found in canned or smoked foods, prevents the release of Ach at that axon terminals, leading to a potentially fatal muscular paralysis • Myasthenia gravis- progressive muscular paralysis, loss of Ach receptors at the motor end plate. Immune system attacks the receptors due to genetic factors. © 2013 Pearson Education, Inc. Rigor Mortis- body becoming stiff as a board • After a few hours ATP runs out • Muscle fibers are unable to remove calcium ions causing a sustained contraction • With out ATP the cross-bridges cannot detach from the active sites • Will last until the lysosomal enzymes released by autolysis break down the myofilaments, about 710 hours of death and end 1-6 days or during decomposition (environmental factors influence rate) © 2013 Pearson Education, Inc. The Contraction Cycle (7-4)- Key is Calcium • Involves the triads • Action potential travels over the sarcolemma, down into the T tubules • Causes release of calcium from the SR • Calcium binds to troponin and the contraction cycle starts © 2013 Pearson Education, Inc. Figure 7-5 The Contraction Cycle Slide 1 Contraction Cycle Begins Myosin head Troponin Tropomyosin © 2013 Pearson Education, Inc. Actin Figure 7-5 The Contraction Cycle Slide 2 Active-Site Exposure Sarcoplasm Active site © 2013 Pearson Education, Inc. Figure 7-5 The Contraction Cycle Slide 3 Cross-Bridge Formation © 2013 Pearson Education, Inc. Figure 7-5 The Contraction Cycle Slide 4 Myosin Head Pivoting © 2013 Pearson Education, Inc. Figure 7-5 The Contraction Cycle Slide 5 Cross-Bridge Detachment © 2013 Pearson Education, Inc. Figure 7-5 The Contraction Cycle Slide 6 Myosin Reactivation © 2013 Pearson Education, Inc. Table 7-1 Steps Involved in Skeletal Muscle Contraction and Relaxation © 2013 Pearson Education, Inc. Checkpoint (7-4) 7. Describe the neuromuscular junction. The link between a motor neuron and a muscle cell- allows for communication between the nervous system and skeletal muscle fiber. © 2013 Pearson Education, Inc. Checkpoint (7-4) 8. How would a drug that blocks acetylcholine release affect muscle contraction? It prevents muscle contraction © 2013 Pearson Education, Inc. Checkpoint (7-4) 9. What would you expect to happen to a resting skeletal muscle if the sarcolemma suddenly became very permeable to calcium ions? The muscles would contract and may not relax completely © 2013 Pearson Education, Inc. Contraction Produces Tension (7-5) • Individual fibers (cells) surround by connective tissue, Are either contracted or relaxed, "On" or "off" • Tension is a product of the number of cross-bridges a fiber contains, pulling towards, active force Variation in tension can occur based on: 1. The amount of overlap of the myofilaments 2. The frequency of stimulation, The more frequent the stimulus, the more Ca2+ builds up, resulting in greater contractions © 2013 Pearson Education, Inc. Contraction Produces Tension (7-5) Resistance- passive force, opposed movement Depends on: 1.Objects weight 2.Shape 3.Friction 4.Other Compression- push applied to object, tends to force the object away fro the source of compression (muscle cells can only contract- shorten and generate tension) they cannot actively lengthen and generate compression) © 2013 Pearson Education, Inc. Contraction Produces Tension (7-5) Whole skeletal muscle organ Contracts with varying tensions based on: 1. Frequency of muscle fiber stimulation 2. Number of fibers activated © 2013 Pearson Education, Inc. A Muscle Twitch (7-5) • A single stimulus-contraction-relaxation cycle in a muscle fiber or whole muscle • Represented by a myogram © 2013 Pearson Education, Inc. Three Phases of a Muscle Twitch (7-5) 1. Latent period • Starts at the point of stimulus and includes the action potential, release of Ca2+, and the activation of troponin/tropomyosin 2. Contraction phase • Is the development of tension because of the cross-bridge cycle 3. Relaxation phase • Occurs when tension decreases due to the re-storage of Ca2+ and covering of actin active sites © 2013 Pearson Education, Inc. Figure 7-6 The Twitch and Development of Tension. Tension Maximum tension development Stimulus Time (msec) 0 5 10 Resting Latent Contraction phase period phase © 2013 Pearson Education, Inc. 20 30 Relaxation phase 40 Summation and Tetanus (7-5) • Summation • Occurs with repeated, frequent stimuli that trigger a response before full relaxation has occurred • Incomplete tetanus • Near peak tension with little relaxation • Complete tetanus • Stimuli are so frequent that relaxation does not occur PLAY ANIMATION Frog Wave Summation © 2013 Pearson Education, Inc. Figure 7-7 Effects of Repeated Stimulations. Maximum tension (in tetanus) Tension = Stimulus Time Summation. Summation of twitches occurs when successive stimuli arrive before the relaxation phase has been completed. © 2013 Pearson Education, Inc. Time Incomplete tetanus. Incomplete tetanus occurs if the stimulus frequency increases further. Tension production rises to a peak, and the periods of relaxation are very brief. Time Complete tetanus. During complete tetanus, the stimulus frequency is so high that the relaxation phase is eliminated; tension plateaus at maximal levels. Varying Numbers of Fibers Activated (7-5) • Allows for smooth contraction and a lot of control • Most motor neurons control a number of fibers through multiple, branching axon terminals © 2013 Pearson Education, Inc. Motor Unit (7-5) • A single motor neuron and all the muscle fibers it innervates • Motor units are dispersed throughout the muscle • Fine control movements • Use motor units with very few fibers per neuron • Gross movements • Motor units have a high fiber-to-neuron ratio © 2013 Pearson Education, Inc. Recruitment (7-5) • A mechanism for increasing tension to create more movement • A graded addition of more and more motor units to produce adequate tension © 2013 Pearson Education, Inc. Figure 7-8 Motor Units. Axons of motor neurons Motor nerve KEY Motor unit 1 Motor unit 2 Motor unit 3 © 2013 Pearson Education, Inc. SPINAL CORD Muscle fibers Tetanus- Clostridium tetani • Bacteria that can be found everywhere • Thrive in low O2 • Powerful toxin that is released will affect the CNS • Inhibits motor neuron activity causing a sustained powerful contraction of the skeletal muscles through out the body • Incubation period is less than 2 weeks • Headache, muscle stiffness and difficulty swaloling, lockjaw • 40-60% mortality • Immunization and booster shots every 10 yrs , antitoxins can be administered if detected early, but will not reduce symptoms if have already appeared. © 2013 Pearson Education, Inc. Muscle Tone and Atrophy (7-5) Muscle tone- muscle that is firm and solid • Some muscles at rest will still have a little tension • Primary function is stabilization of joints and posture Atrophy – loss of muscle tone • Occurs in a muscle that is not regularly stimulated • Muscle becomes small and weak • Can be observed after a cast comes off a fracture © 2013 Pearson Education, Inc. Types of Contraction (7-5) 1. Isotonic contraction • When the length of the muscle changes, but the tension remains the same until relaxation • For example, lifting a book 2. Isometric contraction • When the whole muscle length stays the same, the tension produced does not exceed the load • For example, pushing against a wall © 2013 Pearson Education, Inc. Elongation of Muscle after Contraction (7-5) • No active mechanism for returning a muscle to a pre-contracted, elongated state Passively uses a combination of: 1. Gravity 2. Elastic forces 3. Opposing muscle movement © 2013 Pearson Education, Inc. Checkpoint (7-5) 10. What factors are responsible for the amount of tension a skeletal muscle develops? a. The frequency of muscle fiber stimulation b. Number of muscle fibers activated © 2013 Pearson Education, Inc. Checkpoint (7-5) 11. A motor unit from a skeletal muscle contains 1500 muscle fibers. Would this muscle be involved in fine, delicate movements or in powerful, gross movements? Explain. powerful, gross movements such as moving your leg would require large amounts of muscle fibers. © 2013 Pearson Education, Inc. Checkpoint (7-5) 12. Can a skeletal muscle contract without shortening? Explain. Yes in an isometric contraction. The muscle does not shorten even thought tension increases. (isotonic shortens) © 2013 Pearson Education, Inc. ATP and CP Reserves (7-6) • At rest, muscle cells generate ATP, some of which will be held in reserve • Some is used to transfer high energy to creatine forming creatine phosphate (CP) © 2013 Pearson Education, Inc. ATP and CP Reserves (7-6) • During contraction each cross-bridge breaks down ATP into ADP and a phosphate group • CP is then used to recharge ATP • The enzyme creatine phosphokinase (CPK or CK) regulates this reaction • It lasts for about 15 seconds • ATP must then be generated in a different way © 2013 Pearson Education, Inc. Aerobic Metabolism (7-6)- provides 95% ATP/ Cellular Respiration • Occurs in the mitochondria • Using ADP, oxygen, phosphate ions, and organic substrates from carbohydrates, lipids, or proteins • Substrates go through the citric acid cycle • A series of chemical reactions that result in energy to make ATP, water, and carbon dioxide • Oxygen supply decides ATP aerobic production © 2013 Pearson Education, Inc. Glycolysis (7-6)- alone is insufficient • Breaks glucose down to pyruvate in the cytoplasm of the • If pyruvate can go through the citric acid cycle with oxygen, it is very efficient • Forming about 34 ATP • With insufficient oxygen, pyruvate yields only 2 ATP • Pyruvate is converted to lactic acid • Potentially causing a pH problem in cells causing fatigue © 2013 Pearson Education, Inc. Muscle Fatigue (7-6) • Caused by depletion of energy reserves or a lowering of pH, Muscle will no longer contract even if stimulated • Endurance athletes, using aerobic metabolism, can draw on stored glycogen and lipids (carb loading) • Sprinters, functioning anaerobically, deplete CP and ATP rapidly, and build up lactic acid • PLAY ANIMATION Frog Fatigue © 2013 Pearson Education, Inc. The Recovery Period (7-6) • Requires "repaying" the oxygen debt by continuing to breathe faster, Even after the end of exercise, and recycling lactic acid • Heat production occurs during exercise, Raising the body temperature • Blood vessels in skin will dilate; sweat covers the skin and evaporates, Promoting heat loss © 2013 Pearson Education, Inc. Checkpoint (7-6) 13. How do muscle cells continuously synthesize ATP? By utilizing creatine phosphate (CP) and metabolizing glycogen and fatty acids. Most cells generate ATP through aerobic metabolism. (cellular respiration/ aerobic respiration) © 2013 Pearson Education, Inc. Checkpoint (7-6) 14 What is muscle fatigue? Reduced ability to contract due to low ATP levels, low pH (lactic acid buildup and dissociation) © 2013 Pearson Education, Inc. Checkpoint (7-6) 15. Define oxygen debt. Amount of oxygen required to restore normal, preexertion conditions in muscles © 2013 Pearson Education, Inc. Muscle Performance (7-7) Measured in force • The maximum amount of tension produced by a muscle or muscle group Measured in endurance • The amount of time a particular activity can be performed Two keys to performance: 1. Types of fibers in muscle 2. Physical conditioning or training http://www.youtube.com/watch?v=HpyRkoL42w0 © 2013 Pearson Education, Inc. Fast Fibers (7-7) • The majority of muscle fibers in the body • Large in diameter • Large glycogen reserves • Few mitochondria • Rely on glycolysis • Are rapidly fatigued © 2013 Pearson Education, Inc. Slow Fibers (7-7) • About half the diameter of, and three times slower than, fast fibers Are fatigue resistant because of three factors: 1. Oxygen supply is greater due to more perfusion(network capillaries) 2. Myoglobin stores oxygen in the fibers 3. Oxygen use is efficient due to large numbers of mitochondria © 2013 Pearson Education, Inc. Percentages of Muscle Types Vary (7-7) • Fast fibers appear pale and are called white muscles (chicken breast, wings short burst energy/ anaerobic process) • Extensive vasculature and myoglobin in slow fibers cause them to appear reddish and are called red muscles (legs dark meat, chickens walk around all day/ aerobic) • Human muscles are a mixture of fiber types and appear pink • Hands and eyes only have white(quick movement), calf is red (standing) © 2013 Pearson Education, Inc. Muscle Conditioning and Performance (7-7) Physical conditioning and training Can increase power and endurance 1. Anaerobic endurance • Is increased by brief, intense workouts • Hypertrophy of muscles results (enlargement) 2. Aerobic endurance • Is increased by sustained, low levels of activity © 2013 Pearson Education, Inc. Checkpoint (7-7) 16. Why would a sprinter experience muscle fatigue before a marathon runner would? Sprinters require large amounts of energy for a relatively short burst of activity. To supply this energy , the sprinter’s muscles switch to anaerobic metabolism. Anaerobic metabolism is less efficient in producing energy than aerobic metabolism and produces acidic waste products; this combination contributes to muscle fatigue. Marathon runners derive most of their energy from aerobic metabolism, which is more efficient and produces fewer waste products than anaerobic metabolism. © 2013 Pearson Education, Inc. Checkpoint (7-7) 17. Which activity would be more likely to create an oxygen debt in an individual who regularly exercises: swimming laps or lifting weights? Activities that require short periods of strenuous activity produce a greater oxygen debt, because such activities rely heavily on energy production by anaerobic metabolism. Weight lifting © 2013 Pearson Education, Inc. Checkpoint (7-7) 18. Which type of muscle fibers would you expect to predominate in the large leg muscles of someone who excels at endurance activities such as cycling or long-distance running? They would have a higher than normal percentage of slow muscle fibers. © 2013 Pearson Education, Inc. Cardiac Muscle Tissue (7-8) • Found only in heart • Cardiac muscle cells • Relatively small with usually only one central nucleus • Striated and branched • Intercalated discs, which connect cells to other cells • Communicate through gap junctions, allowing all the fibers to work together © 2013 Pearson Education, Inc. 1. Cardiac Pacemaker Cells (7-8) • Exhibit automaticity • Make up only 1 percent of myocardium • Establish rate of contraction © 2013 Pearson Education, Inc. 2. Cardiac Contractile Cells (7-8) • 99 percent of myocardium • Contract for longer period than skeletal muscle fibers • Unique sarcolemmas make tetanus impossible • Are permeable to calcium • Rely on aerobic metabolism © 2013 Pearson Education, Inc. Smooth Muscle Tissue (7-8) • Found in the walls of most organs, in the form of sheets, bundles, or sheaths • Lacks myofibrils, sarcomeres, or striations • Smooth muscle cells • Also smaller than skeletal fibers • Spindle-shaped and have a single nucleus © 2013 Pearson Education, Inc. Smooth Muscle Tissue (7-8) • Thick filaments are scattered throughout sarcoplasm • Thin filaments are anchored to the sarcolemma • Causing contraction to be like a twisting corkscrew • Cells are bound together • Resulting in forces being transmitted throughout the tissue © 2013 Pearson Education, Inc. Smooth Muscle Tissue (7-8) • Different from other muscle types • Calcium ions from the extracellular fluid are needed to trigger a contraction mechanism that is different from other muscle tissues • Function involuntarily • Can respond to hormones or pacesetter cells © 2013 Pearson Education, Inc. Figure 7-10 Cardiac and Smooth Muscle Tissues. Cardiac muscle cell Intercalated discs Cardiac muscle tissue LM x 575 A light micrograph of cardiac muscle tissue. T L Circular muscle layer Longitudinal muscle layer Smooth muscle tissue LM x 100 © 2013 Pearson Education, Inc. Many visceral organs contain several layers of smooth muscle tissue oriented in different directions. Here, a single sectional view shows smooth muscle cells in both longitudinal (L) and transverse (T) sections. Table 7-2 A Comparison of Skeletal, Cardiac, and Smooth Muscle Tissues © 2013 Pearson Education, Inc. Checkpoint (7-8) 19. How do intercalated discs enhance the functioning of cardiac muscle tissue? © 2013 Pearson Education, Inc. Checkpoint (7-8) 20. Extracellular calcium ions are important for the contraction of what type(s) of muscle tissue? © 2013 Pearson Education, Inc. Checkpoint (7-8) 21. Why can smooth muscle contract over a wider range of resting lengths than skeletal muscle? © 2013 Pearson Education, Inc. Skeletal Muscle System Names (7-9) • Based on: • Action • What they do • Origin • The end that stays stationary • Insertion • The end that moves © 2013 Pearson Education, Inc. Actions (7-9) • Described as relative to the bone that is moved • Example, "flexion of the forearm" • Described as the joint that is involved • Example, "flexion at the elbow" © 2013 Pearson Education, Inc. Primary Actions of Muscles (7-9) • Prime mover, or agonist • The muscle that is chiefly responsible for producing a movement • Antagonist • A muscle that opposes another muscle • Synergist • A muscle that helps the prime mover • Example, flexion of the elbow • The biceps brachii is the prime mover, the triceps brachii is the antagonist, and the brachialis is the synergist © 2013 Pearson Education, Inc. Table 7-3 Muscle Terminology (1 of 2) © 2013 Pearson Education, Inc. Table 7-3 Muscle Terminology (2 of 2) © 2013 Pearson Education, Inc. Muscle Terminology (7-9) • Combining the various terms in Table 7-3, anatomists name the muscles using: • Location, direction of fibers, number of origins, and/or function • Muscles are organized into two groups 1. Axial muscles (mostly stabilizers) 2. Appendicular muscles (stabilizers or movers of the limbs) © 2013 Pearson Education, Inc. Figure 7-11a An Overview of the Major Skeletal Muscles. Frontalis Temporalis Trapezius Clavicle Deltoid Masseter Sternocleidomastoid Pectoralis major Sternum Latissimus dorsi Serratus anterior External oblique Rectus abdominis Extensor carpi radialis Brachioradialis Flexor carpi ulnaris Biceps brachii Triceps brachii Brachialis Pronator teres Palmaris longus Flexor carpi radialis Flexor digitorum Tensor fasciae latae Vastus lateralis Rectus femoris Patella Tibia Tibialis anterior Extensor digitorum Gluteus medius Iliopsoas Adductor longus Gracilis Sartorius Vastus medialis Fibularis Gastrocnemius Soleus Anterior view © 2013 Pearson Education, Inc. Figure 7-11b An Overview of the Major Skeletal Muscles. Sternocleidomastoid Trapezius Deltoid Infraspinatus Teres minor Teres major Latissimus dorsi Brachioradialis Extensor carpi radialis Tensor fasciae latae Semitendinosus Biceps femoris Gastrocnemius Occipitalis Triceps brachii Rhomboid major Flexor carpi ulnaris External oblique Extensor digitorum Extensor carpi ulnaris Gluteus medius Gluteus maximus Adductor magnus Semimembranosus Gracilis Sartorius Soleus Calcaneal tendon © 2013 Pearson Education, Inc. Calcaneus Posterior view Checkpoint (7-9) 22. Identify the kinds of descriptive information used to name skeletal muscles. © 2013 Pearson Education, Inc. Checkpoint (7-9) 23. Which muscle is the antagonist of the biceps brachii? © 2013 Pearson Education, Inc. Checkpoint (7-9) 24.What does the name flexor carpi radialis longus tell you about this muscle? © 2013 Pearson Education, Inc. Axial Muscles (7-10) • Muscles of the head and neck • Muscles of the spine • Muscles of the trunk • Muscles of the pelvic floor © 2013 Pearson Education, Inc. Checkpoint (7-10) 25. If you were contracting and relaxing your masseter muscle, what would you probably be doing? © 2013 Pearson Education, Inc. Checkpoint (7-10) 26. Which facial muscle would you expect to be well developed in a trumpet player? © 2013 Pearson Education, Inc. Checkpoint (7-10) 27. Damage to the external intercostal muscles would interfere with what important process? © 2013 Pearson Education, Inc. Checkpoint (7-10) 28. If someone were to hit you in your rectus abdominis, how would your body position change? © 2013 Pearson Education, Inc. Appendicular Muscles (7-11) • Muscles that position the pectoral girdle • Muscles that move the arm, forearm, and wrist • Muscles that move the hand and fingers • Muscles of the pelvic girdle • Muscles that move the thigh and leg • Muscles that move the foot and toes © 2013 Pearson Education, Inc. Muscles That Position Pectoral Girdle (7-11) • Trapezius • Diamond-shaped muscle, has many actions depending on the region • Rhomboid • Adducts and rotates scapula laterally • Levator scapulae • Adducts and elevates scapula • Serratus anterior • Abducts and rotates scapula • Pectoralis minor and subclavius • Depress and abduct shoulder © 2013 Pearson Education, Inc. Figure 7-17 Muscles That Position the Pectoral Girdle. Superficial Dissection Deep Dissection Muscles That Position the Pectoral Girdle Trapezius Muscles That Position the Pectoral Girdle Levator scapulae Rhomboid muscles Scapula Serratus anterior Triceps brachii Posterior view Muscles That Position the Pectoral Girdle Trapezius Levator scapulae Subclavius Pectoralis minor Muscles That Position the Pectoral Girdle Pectoralis minor (cut) Serratus anterior Pectoralis major (cut and reflected) Internal intercostals Biceps brachii External intercostals Anterior view © 2013 Pearson Education, Inc. T12 vertebra Table 7-8 Muscles That Position the Pectoral Girdle © 2013 Pearson Education, Inc. Muscles That Move the Arm (7-11) • Deltoid • Abducts arm, supraspinatus assists • Subscapularis, teres major, infraspinatus, and teres minor • Form the rotator cuff • Pectoralis major • Flexes the arm at the shoulder • Latissimus dorsi • Extends the arm at the shoulder PLAY A&P FLIX™ Rotator cuff muscles: An overview (a) PLAY A&P FLIX™ Rotator cuff muscles: An overview (b) © 2013 Pearson Education, Inc. Figure 7-18 Muscles That Move the Arm. Deep Dissection Superficial Dissection Sternum Clavicle Ribs (cut) Muscles That Move the Arm Deltoid Pectoralis major Muscles That Move the Arm Subscapularis Coracobrachialis Teres major Biceps brachii Vertebra T12 Anterior view Deep Dissection Superficial Dissection Muscles That Move the Arm Supraspinatus Deltoid Latissimus dorsi Vertebra T1 Muscles That Move the Arm Supraspinatus Infraspinatus Teres minor Teres major Triceps brachii Posterior view © 2013 Pearson Education, Inc. Table 7-9 Muscles That Move the Arm © 2013 Pearson Education, Inc. Muscles That Move the Forearm and Wrist (7-11) • Biceps brachii • Flexes the elbow and supinates forearm • Triceps brachii • Extends elbow • Brachialis and brachioradialis • Flex elbow • Flexor carpi ulnaris, flexor carpi radialis, and palmaris longus • Flex wrist • Extensor carpi radialis and extensor carpi ulnaris • Extend wrist • Pronators and supinators • Rotate radius © 2013 Pearson Education, Inc. Muscles That Move the Hand (7-11) • Extensor digitorum • Extends fingers • Flexor digitorum • Flexes fingers • Abductor pollicis • Abducts thumb • Extensor pollicis • Extends thumb PLAY A&P FLIX™ The elbow joint and forearm: An overview © 2013 Pearson Education, Inc. Figure 7-19 Muscles That Move the Forearm and Wrist. Humerus Coracobrachialis Triceps brachii Biceps brachii Brachioradialis Extensor carpi radialis Brachialis Flexor carpi Extensor radialis carpi ulnaris Flexor Extensor digitorum digitorum superficialis Abductor pollicis Flexor Extensor retinaculum pollicis Extensor retinaculum Flexor carpi ulnaris Ulna Pronator teres Brachioradialis Palmaris longus Flexor carpi ulnaris Pronator quadratus Supinator Pronator teres Ulna Radius Posterior view of right upper limb © 2013 Pearson Education, Inc. Anterior view of right upper limb Anterior view of the muscles of pronation and supination when the limb is supinated Table 7-10 Muscles That Move the Forearm, Wrist, and Hand (1 of 2) © 2013 Pearson Education, Inc. Table 7-10 Muscles That Move the Forearm, Wrist, and Hand (2 of 2) © 2013 Pearson Education, Inc. Checkpoint (7-11) 29. Which muscle do you use to shrug your shoulders? © 2013 Pearson Education, Inc. Checkpoint (7-11) 30. Sometimes baseball pitchers suffer rotator cuff injuries. Which muscles are involved in this type of injury? © 2013 Pearson Education, Inc. Checkpoint (7-11) 31.Injury to the flexor carpi ulnaris would impair which two movements? © 2013 Pearson Education, Inc. Muscles That Move the Thigh (7-11) • Gluteal group • Includes gluteus maximus, the largest and most posterior; is a hip extensor • Adductors • Include the adductor magnus, adductor brevis, adductor longus, the pectineus, and the gracilis • Largest hip flexor is the iliopsoas • Made up of the psoas major and the iliacus PLAY A&P FLIX™ Anterior muscles that cross the hip joint © 2013 Pearson Education, Inc. Figure 7-20 Muscles That Move the Thigh. Iliac crest Gluteus medius (cut) Gluteus maximus (cut) Sacrum Gluteal region, posterior view Gluteal Group Gluteus medius Gluteus maximus Gluteus minimus Tensor fasciae latae Iliotibial tract Vastus lateralis Sartorius Rectus femoris Biceps femoris Semimembranosus Plantaris Head of fibula L5 Patella Patellar Lateral ligament view Iliopsoas Group Psoas major Iliacus Adductor Group Pectineus Adductor brevis Adductor longus Adductor magnus Gracilis Anterior view of the iliopsoas muscle and the adductor group © 2013 Pearson Education, Inc. Table 7-11 Muscles That Move the Thigh (1 of 3) © 2013 Pearson Education, Inc. Table 7-11 Muscles That Move the Thigh (2 of 3) © 2013 Pearson Education, Inc. Table 7-11 Muscles That Move the Thigh (3 of 3) © 2013 Pearson Education, Inc. Muscles That Move the Leg (7-11) • Knee flexors are the hamstrings • Biceps femoris, semimembranosus, semitendinosus, and the sartorius • Knee extensors are the quadriceps femoris • Which include the rectus femoris and the three vastus muscles • Popliteus muscle • Unlocks the knee joint © 2013 Pearson Education, Inc. Figure 7-21 Muscles That Move the Leg. Iliac crest Gluteus medius Tensor fasciae latae Gluteus maximus Iliacus Psoas major Iliopsoas Tensor fasciae latae Pectineus Adductor longus Gracilis Adductor magnus Sartorius Gracilis Iliotibial tract Flexors of the Knee Extensors of the Knee (Quadriceps muscles) Rectus femoris Biceps femoris Vastus lateralis Semitendinosus Vastus medialis Vastus intermedius (deep to above muscles) Semimembranosus Quadriceps tendon Sartorius Patella Popliteus Patellar ligament Hip and thigh, posterior view © 2013 Pearson Education, Inc. Quadriceps and thigh muscles, anterior view Table 7-12 Muscles That Move the Leg © 2013 Pearson Education, Inc. Muscles That Move the Foot and Toes (7-11) • The gastrocnemius of the calf is assisted by the underlying soleus • They share a common calcaneal tendon, and are both plantar flexors • Fibularis muscles • Produce eversion and plantar flexion • Tibialis • Cause inversion of the foot • Tibialis anterior is largest and produces dorsiflexion © 2013 Pearson Education, Inc. Figure 7-22a Muscles That Move the Foot and Toes. Superficial Dissection Deep Dissection Ankle Extensors Plantaris Head of fibula Gastrocnemius Soleus Popliteus Ankle Extensors (Deep) Tibialis posterior Fibularis longus Fibularis brevis Digital Flexors Gastrocnemius (cut and removed) Flexor digitorum longus Flexor hallucis longus Calcaneal tendon Tendon of flexor hallucis longus Calcaneus Tendons of fibularis muscles Posterior views © 2013 Pearson Education, Inc. Tendon of flexor digitorum longus Figure 7-22b Muscles That Move the Foot and Toes. Iliotibial tract Head of fibula Ankle Extensors Gastrocnemius Ankle Flexors Fibularis longus Tibialis anterior Soleus Fibularis brevis Digital Extensors Extensor digitorum longus Tendon of extensor hallucis longus Calcaneal tendon Retinacula Lateral view © 2013 Pearson Education, Inc. Figure 7-22c Muscles That Move the Foot and Toes. Patella Medial surface of tibial shaft Patellar ligament Ankle Flexors Ankle Extensors Tibialis anterior Gastrocnemius Soleus Digital Extensors Tibialis posterior Tendon of extensor hallucis longus Calcaneal tendon Retinacula Tendon of tibialis anterior Medial view © 2013 Pearson Education, Inc. Table 7-13 Muscles That Move the Foot and Toes (1 of 2) © 2013 Pearson Education, Inc. Table 7-13 Muscles That Move the Foot and Toes (2 of 2) © 2013 Pearson Education, Inc. Checkpoint (7-11) 32. You often hear of athletes suffering a "pulled hamstring." To what does this phrase refer? © 2013 Pearson Education, Inc. Checkpoint (7-11) 33. How would you expect a torn calcaneal tendon to affect movement of the foot? © 2013 Pearson Education, Inc. Four Effects of Aging on Skeletal Muscle (7-12) 1. Muscle fibers become smaller in diameter 2. Muscles become less elastic and more fibrous 3. Tolerance for exercise decreases due to a decrease in thermoregulation 4. Ability to recover from injury is decreased © 2013 Pearson Education, Inc. Checkpoint (7-12) 34. Describe general age-related effects on skeletal muscle tissue. © 2013 Pearson Education, Inc. Exercise Engages Multiple Systems (7-13) • Cardiovascular system • Increases heart rate and speeds up delivery of oxygen • Respiratory system • Increases rate and depth of respiration • Integumentary system • Dilation of blood vessels and sweating combine to increase cooling • Nervous and endocrine systems • Control of heart rate, respiratory rate, and release of stored energy © 2013 Pearson Education, Inc. SYSTEM INTEGRATOR Skeletal Removes excess body heat; synthesizes vitamin D3 for calcium and phosphate absorption; protects underlying muscles Provides mineral reserve for maintaining normal calcium and phosphate levels in body fluids; supports skeletal muscles; provides sites of attachment Muscular System Body System Skeletal muscles pulling on skin of face produce facial expressions Provides movement and support; stresses exerted by tendons maintain bone mass; stabilizes bones and joints (Page 138) Muscular System Integumentary Integumentary Body System Skeletal (Page 188) Figure 7-23 Endocrine (Page 376) Reproductive (Page 671) Urinary (Page 637) Digestive (Page 572) Respiratory (Page 532) Lymphatic (Page 500) Cardiovascular (Page 467) The muscular system performs five primary functions for the human body. It produces skeletal movement, helps maintain posture and body position, supports soft tissues, guards entrances and exits to the body, and helps maintain body temperature. Nervous (Page 302) The MUSCULAR System © 2013 Pearson Education, Inc. Checkpoint (7-13) 35. What major function does the muscular system perform for the body as a whole? © 2013 Pearson Education, Inc. Checkpoint (7-13) 36. Identify the physiological effects of exercise on the cardiovascular, respiratory, and integumentary systems, and indicate the relationship between these physiological effects and the nervous and endocrine systems. © 2013 Pearson Education, Inc.