4 IntroductionThe skeletal system provides the framework for the body; the system that allows for movement and locomotion is the muscular system.In addition to external motion of the arms and legs, the muscular system also moves things inside the body. This internal motion includes the movement of the digestive system, the cardiovascular system, and the respiratory system.Different types of muscles allow for both external and internal movement.
5 Learning Objectives Differentiate the three major muscle types. Explain the difference between voluntary and involuntary muscles.Identify and explain the components of a muscle cell.Describe the cellular activities required for muscle movement.Identify specific skeletal muscles.
6 Pronunciation Guide acetylcholine (AS eh till KOH leen) actin (ak TIN) Click on the megaphone icon before each item to hear the pronunciation.acetylcholine (AS eh till KOH leen)actin (ak TIN)adenosine triphosphate (ah DEN oh sin)ataxia (ah TAK see uh)atrophy (AT roh fee)diaphragm (DYE ah fram)electromyography (ee LEK troh my OG rah fee)fibromyalgia (FIE broh my AL jee uh)flaccid (FLAS sid)
7 Pronunciation Guide flexion (FLEK shun) glycogen (GLIE co jin) Click on the megaphone icon before each item to hear the pronunciation.flexion (FLEK shun)glycogen (GLIE co jin)Guillian-Barré syndrome (GEY yan bar RAY)hypertrophy (high PER troh fee)intercalated discs (in TER kuh LATE ed)muscular dystrophy (MUS kyoo lahr DISS troh fee)myalgia (my AL jee uh)myasthenia gravis (my as THEE nee uh)myofibril (my oh FIE bril)
8 Pronunciation Guide myosin (MY oh sin) rigor mortis (RIG er MORE tiss) Click on the megaphone icon before each item to hear the pronunciation.myosin (MY oh sin)rigor mortis (RIG er MORE tiss)sarcomeres (SAR koh meres)sphinters (SFING terz)tetanus (TET ah nuss)tonus (TONE us)
9 Overview Muscle is a general term for all contractile tissue. The contractile property of muscle tissue allows it to become short and thick as a result of a nerve impulse and then to relax once that impulse is removed. This alternative contraction and relaxation causes movement.The cells of muscle tissue are called muscle fibers.Muscle tissue is constructed of bundles of these fibers, each approximately the size of a human hair.
10 Types of Muscles The body has three major types of muscles Skeletal SmoothCardiac
11 Skeletal MuscleSkeletal muscles are voluntary muscles that attach to bones of the skeletal system.The fibers appear striped, so they are sometimes called striated muscle.These muscles allow external movement and are developed through exercise.
12 Smooth Muscle Smooth muscles are involuntary muscles. They are called smooth because they don’t have the striped appearance of skeletal muscles.These muscles are found within certain organs, blood vessels, and airways, and allow for internal movement.Change in blood vessel diameter is one example.
13 Cardiac MuscleCardiac muscle is a specialized muscle with a striated appearance.It is found solely in the heart.Cardiac muscle is completely involuntary.The contraction of this muscle causes your heart beat, an internal movement.
14 Figure 7-1 The three types of muscle: skeletal, cardiac, and smooth.
15 Skeletal MusclesSkeletal muscles are attached to bones and provide movement for your body.Tendons are fibrous tissues that attach skeletal muscles to bones, while ligaments attach bone to bone. Some muscles attach directly to a bone or soft tissue without a tendon.
16 Skeletal MusclesSkeletal muscle is also called voluntary because movement is controlled by conscious thought.The numerous skeletal muscles are responsible for movement and maintaining posture.Heat is also produced by skeletal muscles.
17 Figure 7-2 Anterior and posterior view of major muscles.
18 Contraction and Relaxation Movement of the body is the result of contraction (shortening) of certain muscles while there is relaxation of others.The primary mover (or agonist) is the chief muscle causing movement. As the muscle contracts it pulls the bone, causing movement.Point of origin – The end of the muscle that is attached to the stationary bonePoint of insertion – Muscle end attached to the moving bone
19 Contraction and Relaxation Synergistic muscles assist the primary mover.Antagonist muscles cause movement in the opposite direction of the agonist.All movement is a result of contraction of primary movers and relaxation of opposing muscles.
20 Figure 7-3 Coordination of antagonist muscles to perform movement.
21 The Diaphragm The primary mover of breathing is the diaphragm. This dome-shaped muscle separates the abdominal cavity from the thoracic cavity and is responsible for performing the major work of bringing atmospheric air into our lungs.This muscle is under both voluntary and involuntary control.
22 Figure 7-4 The diaphragm: The major muscle of breathing.
23 Movement TerminologyRotation describes circular movement that occurs around an axis.Circumduction describes circular movement of the end of a limb.Abduction means to move away from the midline of the body.Adduction occurs when you produce a movement toward the midline.
24 Movement TerminologyExtension is a term used for increasing the angle between two bones connected at a joint. The muscle that straightens a joint is called the extensor muscle.Flexion is the opposite of extension, decreasing the angle between two bones. The muscle that bends the joint is called the flexor muscle.
25 Figure 7-5 The types of skeletal movement Figure The types of skeletal movement. (A) Flexion and extension of left forearm.
26 Figure 7-5 (continued) The types of skeletal movement Figure 7-5 (continued) The types of skeletal movement. (B) Flexion and extension of the leg.
27 Muscle FibersEach muscle cell is an elongated fiber known as the muscle fiber, and can be up to 12 inches in length.Several muscle fibers can be bundled together to form a specific muscle segment.Each muscle fiber is composed of several myofibrils.
28 SarcomeresSarcomeres are the functional contractile units of each fiber.Each sarcomere has two types of threadlike structures called thick and thin myofilaments.Thick myofilaments are made up of the protein myosin.
29 Sarcomeres Thin myofilaments are made up of the protein actin. The sarcomere has actin and myosin filaments arranged in repeating units separated from each other by dark bands called Z lines which give the striated appearance to skeletal muscle.Z lines are the borders of each sarcomere.
30 Muscle ContractionContraction of a muscle causes the two types of myofilaments to slide toward each other and shorten each sarcomere, and therefore the entire muscle.Muscle contraction requires that temporary connections of cross-bridges are formed between the myosin head and the actin. These pull the sarcomere together.
32 Figure 7-6 (continued) (B) The muscle segment with sarcomere.
33 Figure 7-6 (continued) (C) Relaxed and contracted sarcomeres.
34 ATP and CalciumEnergy is needed for contraction and relaxation. This energy comes from ATP (adenosine triphosphate) which help the myosin heads form and break the cross-bridges with actin.Calcium is stored away from the actin and myosin in the sarcoplasmic reticulum (SR) during relaxation of the muscle.
35 ATP and CalciumDuring contraction, the calcium is released from the SR and causes actin, myosin, and ATP to interact, which causes the contraction. When calcium leaves the muscle and returns to the SR, the cross-bridge attachments are broken and the muscle relaxes.
36 ATP and CalciumWhen the nervous system tells a muscle to contract, the signal causes the muscle fiber to open sodium ion channels.Sodium ions flow into the muscle fiber, exciting it.When the muscle becomes excited, calcium is released from the SR.It is the calcium that causes the muscles to contract.Calcium is then pumped back into the SR.This slide also had the old incorrect info. I fixed it as best I could without having a copy of the final version of the chapter
37 Applied Science: Inter-Relatedness of the Neuromuscular System Contraction of skeletal muscle requires the coordination of both the muscular and nervous systems.The initiation of a skeletal muscular contraction requires an impulse from a motor neuron of the nervous system to cause a release of a neurotransmitter substance called acetylcholine, which sets the process of muscle contraction into motion.
38 Applied Science: Inter-Relatedness of the Neuromuscular System It is the acetylcholine which opens sodium channels, exciting the muscle fibers.This all occurs at the neuromuscular junction.
39 From the Streets: Neuromuscular Blockade Rapid Intubation Sequence (RSI)A procedure used in emergency situations to place an ET tube.Involves use of medications that act on the neuromuscular junction.There are two ways to block neuromuscular junction.
40 Muscular FuelMuscles, like all tissue, need fuel in the form of food and oxygen to survive and function.The body stores glycogen in the muscle, where it waits to be converted to a useable energy source. When needed, glycogen is converted to glucose which releases energy.Muscles with very high demands also store fat and use it as energy. Energy release causes heat production. That is why an exercising athlete gets overheated.
41 Muscular FuelHigher demand muscles also have a greater blood supply to carry much-needed oxygen.The greater blood supply gives them a darker color.An example of this is a chicken which has white and dark meat.
42 Click here to view an animation on the topic of muscle contraction. Back to Directory
43 Rules for Naming Muscles Muscles can be named based on any of the following criteriaMuscle location (Example: Biceps brachii is in the arm. Brachii = arm.)Number of origins (Example: Biceps brachii has two origins. Biceps = two heads.)Action (Example: Adductor longus adducts the thigh.)Size (Example: Gluteus maximus. Maximus = biggest.)
44 Rules for Naming Muscles Muscles can be named based on any of the following criteriaLocation of attachments (Example: Brachioradialis. Radialis refers to the radius.)Shape (Example: Deltoid is triangular. Delta = triangle.)Direction of fibers (Example: Rectus abdominis. Rectus = straight.)Combination (Example: Pectoralis major. Pectoral = shoulder, major = big.)
48 Figure 7-8 Skeletal muscles of the posterior and anterior trunk.
49 Figure 7-9 Skeletal muscles of the shoulder, arm, and hand.
50 Figure 7-10 Skeletal muscles of the hip and leg.
51 Click here to view an animation on the topic of forearm and hand muscles. The animation may need a moment to being playing.Back to Directory
52 Click here to view an animation on the topic of head and neck muscles Click here to view an animation on the topic of head and neck muscles. The animation may need a moment to being playing.Back to Directory
53 Click here to view an animation on the topic of hip and thigh muscles Click here to view an animation on the topic of hip and thigh muscles. The animation may need a moment to being playing.Back to Directory
54 Click here to view an animation on the topic of leg and foot muscles Click here to view an animation on the topic of leg and foot muscles. The animation may need a moment to being playing.Back to Directory
55 Click here to view an animation on the topic of lower limb muscles Click here to view an animation on the topic of lower limb muscles. The animation may need a moment to being playing.Back to Directory
56 Click here to view an animation on the topic of female pelvic muscles Click here to view an animation on the topic of female pelvic muscles. The animation may need a moment to being playing.Back to Directory
57 Click here to view an animation on the topic of shoulder and arm muscles. The animation may need a moment to being playing.Back to Directory
58 Click here to view an animation on the topic of trunk and abdomen muscles. The animation may need a moment to being playing.Back to Directory
59 Click here to view an animation on the topic of upper arm muscles Click here to view an animation on the topic of upper arm muscles. The animation may need a moment to being playing.Back to Directory
60 Smooth MuscleSmooth muscle, also called visceral muscle, is found in the organs, except for the heart.It can also be found in blood vessels and bronchial airways.The ability of smooth muscle to contract and relax is essential to the internal processes of our body, like digestion and regulation of blood pressure.
61 Smooth MusclesSmooth muscles are involuntary muscles and don’t contract as rapidly as skeletal muscles (skeletal muscles contract 50 times faster).Smooth muscle receives a smaller blood supply, resulting in poor repair of injured tissue.
62 Vasodilation and Vasoconstriction Enlarging the diameter of a blood vessel is called vasodilation.Decreasing the diameter of a blood vessel is called vasoconstriction.Vasodilation can lead to a decrease in blood pressure due to smooth muscle relaxation in the blood vessel, while vasoconstriction increases blood pressure.
63 Respiratory Smooth Muscle Smooth muscle is also found in the airways of the respiratory system. Excess constriction of smooth muscle in the respiratory system occurs during an asthma attack.
64 Respiratory Smooth Muscle A special type of smooth muscle is called a sphincter and can be found throughout the digestive system. These donut-shaped muscles act as doorways to let material in and out. Contraction closes the door while relaxation opens it.
65 Cardiac MuscleThe walls of the heart are made mostly of cardiac muscle. When the muscle fibers contract, they force blood from the heart causing it to circulate through the blood vessels in your body.Cardiac muscle is involuntary.Cardiac muscle fibers are shorter, and receive a richer supply of blood than any other muscle in the body.
66 Cardiac MuscleThe cardiac muscle fibers are connected by intercalated discs, causing one fiber to contract and then pull the next one into a contraction creating a domino effect. This wave of motion squeezes blood out very efficiently.Cardiac muscle does not repair itself. Damage to cardiac muscle always leaves a scar. Scar tissue doesn’t contract like normal tissue because it is rigid. This decreases cardiac output.
68 From the Streets: Laboratory Testing in Heart Attack Heart attack occurs when an artery that supplies blood to the heart is blocked.Left untreated, the affected are of the heart muscle will die (myocardial infarction).Because of this, it is important for emergency personnel to recognize heart attacks, now referred to as acute coronary syndrome.
69 From the Streets: Laboratory Testing in Heart Attack Ultimate goal is provide treatment and restore blood flow before a significant mass of the heart muscle is permanently damaged.Several diagnostic tools are routinely used to determine whether a heart attack has occurred.Electrocardiogram (ECG)X-raysLaboratory tests
70 Clinical Application: Muscle Tone Have you ever had a cast on for an extended period of time? When removed, the arm or leg is much smaller and weaker than the limb without the cast. Why?Normally all muscles exhibit muscle tone (tonus), which is the partial contraction of a muscle with resistance to stretching. The muscle fibers in an athlete increase in diameter (hypertrophy) and become stronger.
71 Clinical Application: Muscle Tone Hypertrophy refers to increased growth. In the clinical setting, as muscles are used less and less, they begin to lose their tone and become flaccid (soft and flabby), as in a bedridden patient.Muscles may waste away (atrophy) from lack of use. One of the reasons patients are gotten out of bed as soon as possible is to prevent atrophy from occurring.While skeletal muscle can regenerate from damage, extensive damage results in scarring.
72 Common Muscular System Disorders Myalgia – pain or tenderness in a muscleFibromyalgia– affects women under 40, but is not fully understood; symptoms include aches, pains, and muscle stiffness with specific tender points; the cause is unknown, but is linked with chronic fatigue syndrome.Ataxia – irregular muscle action with lack of coordination
73 Common Muscular System Disorders Paralysis – partial or total loss of function in voluntary musclesSpasm or cramp – involuntary sudden and violent contraction of a muscle for a prolonged period of timeSprains – tears or breaks in ligaments
74 Common Muscular System Disorders Strains – actual tears in muscles or tendonsShin splints – inflammation of the extensor muscles and surrounding tissues of the lower leg, found in runners
75 Common Muscular System Disorders Hernia – tear in the muscle wall with an organ protruding through the openingTendonitis – inflammation of tendonsElectromyography – a diagnostic test in which a muscle, or group of muscles, is stimulated with an electrical impulse, causing contraction, allowing the strength of the contraction to be measured
76 From the Streets: Musculoskeletal Back Disorders Back pain is one of the most common complaints in modern emergency medical practice.EMS personnel particularly vulnerable to back injury.Minimize chance of injury using proper lifting techniques and requesting assistance when needed.
77 Figure 7-12 There are many physical demands in EMS Figure There are many physical demands in EMS. Lifting and moving patients and equipment can cause low back injury if not performed properly.
78 Figure 7-13 EMS personnel should always use proper lifting techniques Figure EMS personnel should always use proper lifting techniques. By lifting with the legs the large paraspinous muscles are not overstressed.
79 Figure Back strains in EMS personnel usually occur when a team member moves awkwardly during a lift. Twisting, turning, or other movements can place stress on the large back muscles and result in back strain.
80 Neuromuscular Disorders These disorders involve both the nervous and muscular systems.Myasthenia gravis – gradually increasing profound muscle weakness, with drooping of the eyelid as the first symptomMuscular dystrophy – inherited muscular disease in which muscle fibers degenerate and there is progressive muscular weakness
81 Neuromuscular Disorders Guillain-Barré syndrome is a disorder of the peripheral nervous system that causes flaccid paralysis and the loss of reflexes, ascending from the feet and progressing to the head. Paralysis peaks in 10–14 days and then subsides gradually.Tetanus – creates rigid paralysis, and any minor stimulus causes muscles to go into a major spasm. It is a result of toxins produced by a bacteria found in the ground and can result from any puncture wound, not just a rusty nail.
82 Click here to view a video on the topic of myofacial massage. Back to Directory
83 Click here to view a video on the topic of neuromuscular massage. Back to Directory
84 Click here to view a video on the topic of western massage. Back to Directory
85 Click here to view a video on the topic of muscle atrophy. Back to Directory
86 Click here to view a video on the topic of muscular dystrophy. Back to Directory
87 Click here to view a video on the topic of physical therapy. Back to Directory
88 Click here to view a video on the topic of occupational therapy. Back to Directory
89 Click here to view a video on the topic of massage therapy. Back to Directory
90 Click here to view a video on the topic of kinesiology. Back to Directory
91 Snapshots from the Journey The three main types of muscles are skeletal, smooth, and cardiac. Skeletal muscle is striated, or striped, voluntary muscle that allows movement, stabilizes joints, and helps maintain body temperature.
92 Snapshots from the Journey Smooth muscle is a non-striated involuntary muscle found in the organs of the body and linings of vessels; it facilitates internal movement within the body. Cardiac muscle is involuntary, striated muscle found only in the heart.
93 Snapshots from the Journey All movement is a result of contraction of primary movers and relaxation of opposing muscles.Large muscles consist of many single muscle fibers comprised of myofibrils. The smallest functional contractile unit is called a sarcomere. Each sarcomere unit contains the two threadlike contractile proteins myosin and actin.
94 Snapshots from the Journey Muscles contract as the actin and myosin protein filaments, in the presence of ATP and calcium, form crossbridges that cause the filaments to slide past each other, thereby causing the muscle to contract or shorten.
95 Snapshots from the Journey There is a relationship between the nervous and muscular systems in which the motor neuron of the nervous system initiates the activity of muscle contraction through the release of a neurotransmitter.
96 Snapshots from the Journey There are many common diseases and conditions of the muscles, and because the nervous system is so closely related, there are also many common neuromuscular diseases.
97 Case StudyA 30-year-old patient complains of ascending flaccid paralysis that began with tingling in the toes and muscle weakness. This individual presented to the emergency department after the leg weakness became so profound that he could barely walk, and now he notices his arms weakening. Loss of reflexes were also noted.
98 Case Study Questions What disease do you think this is? Knowing that the patient is losing the ability to use skeletal muscles, what life-threatening condition could occur?What vital signs would you need to monitor?Why is muscle atrophy a problem?
99 Case Study Questions What areas of patient care need to be addressed? What is the likely prognosis?
100 From the StreetsYou respond to a 70 year-old female experiencing a gastrointestinal bleed. She appears lethargic and is hypotensive, tachycardic, and has pale, cool, & clammy skin.
101 From the Streets Questions Why does the patient have pale & cool skin?
102 From the Streets Questions Why does the patient have pale & cool skin? This is due to peripheral vasoconstriction
103 From the StreetsA patient is experiencing neurogenic shock after falling 20 feet out of a deer stand. The patient transected his spinal cord at T-5 and is hypotensive with pink & warm skin below the level of the injury.
104 From the Streets Questions Why does this patient have pink & warm skin?
105 From the Streets Questions Why does this patient have pink & warm skin? This is due to vasodilation
106 End of Chapter Review Questions Another name for voluntary muscle is:SkeletalSmoothCardiacNon-striated
107 End of Chapter Review Questions Which structure does not contain smooth muscle?Blood vesselsHeartDigestive tractBronchi
108 End of Chapter Review Questions Most skeletal muscles attach to bones via:LigamentsJointsFlexorsTendons
109 End of Chapter Review Questions The state of partial skeletal muscle contraction is known as:HomeostasisMuscle tonePartialus contractusFlexerus
110 End of Chapter Review Questions Cardiac muscle:Is a voluntary muscleHas intercalated discs to assist contractionRegenerates after injuryLines the blood vesselI onlyI and IIII onlyI, II, III, and IV
111 End of Chapter Review Questions Jill falls and twists her ankle. Later she cannot dorsiflex her foot. Her doctor tells her she has torn a tendon and must have surgery. Which tendon?PatellarCalcanealRotator cuffAnterior cruciate
112 End of Chapter Review Questions Sam wakes up one morning unable to move his toes. Within a few hours he can’t move his legs and call 911. By morning he is completely paralyzed. What has happened to him?TetanusGuillain BarreMuscular dystrophyMuscular atrophy
113 End of Chapter Review Questions A sudden or violent muscle contraction is a _________.Partial or total loss of voluntary muscle use is _________.A tear in the muscle wall through which an organ can protrude is a __________.The body stores a carbohydrate called ___________ in the muscle; it can be converted to a usable energy source.
114 End of Chapter Review Questions _____ means pain or tenderness in the muscle.Elbow flexion is the action of the _______ muscle.
115 End of Chapter Review Questions List the three major muscle types and give an example of each.Explain the relationship between origin, insertion and action of skeletal muscle.List the criteria for naming muscles and give an example of each criteria.Explain the steps needed in a skeletal muscle contraction.Considering the knee, list the major muscles involved in control of the joint, their attachments and their actions.