the muscular system: movement for the journey

CHAPTER

ESSENTIALS OF A&PFOR EMERGENCY CARE

Copyright ©2011 by Pearson Education, Inc.All rights reserved.

Essentials of A&P for Emergency CareBruce J. Colbert • Jeff Ankney • Karen T. Lee • Bryan E. Bledsoe

The Muscular System: Movement for the Journey

7



Multimedia Asset Directory

Slide 42Muscle Contraction AnimationSlide 51Forearm and Hand Muscles AnimationSlide 52Head and Neck Muscles AnimationSlide 53Hip and Thigh Muscles AnimationSlide 54Leg and Foot Muscles AnimationSlide 55Lower Limb Muscles AnimationSlide 56Female Pelvic Muscles AnimationSlide 57Shoulder and Arm Muscles AnimationSlide 58Trunk and Abdominal Muscles AnimationSlide 59Upper Arm Muscles AnimationSlide 82Myofacial Massage VideoSlide 83Neuromuscular Massage Video



Multimedia Asset Directory

Slide 84Western Massage VideoSlide 87 Physical Therapy VideoSlide 88 Occupational Therapy VideoSlide 89 Massage Therapy VideoSlide 90 Kinesiology Video



Introduction

• The 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.



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.



Pronunciation GuideClick 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)




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)




myosin (MY oh sin)rigor mortis (RIG er MORE tiss)sarcomeres (SAR koh meres)sphinters (SFING terz)tetanus (TET ah nuss)tonus (TONE us)



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.



Types of Muscles

• The body has three major types of muscles– Skeletal – Smooth – Cardiac



Skeletal Muscle

• Skeletal 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.



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.



Cardiac Muscle

• Cardiac 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.



Figure 7-1 The three types of muscle: skeletal, cardiac, and smooth.



Skeletal Muscles

• Skeletal 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.



Skeletal Muscles

• Skeletal 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.



Figure 7-2 Anterior and posterior view of major muscles.



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 bone

• Point of insertion – Muscle end attached to the moving bone



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.



Figure 7-3 Coordination of antagonist muscles to perform movement.



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.



Figure 7-4 The diaphragm: The major muscle of breathing.



Movement Terminology

• Rotation 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.



Movement Terminology

• Extension 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.



Figure 7-5 The types of skeletal movement. (A) Flexion and extension of left forearm.



Figure 7-5 (continued) The types of skeletal movement. (B) Flexion and extension of the leg.



Muscle Fibers

• Each 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.



Sarcomeres

• Sarcomeres 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.



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.



Muscle Contraction

• Contraction 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.



Figure 7-6 (A) The muscle segment.



Figure 7-6 (continued) (B) The muscle segment with sarcomere.



Figure 7-6 (continued) (C) Relaxed and contracted sarcomeres.



ATP and Calcium

• Energy 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.



ATP and Calcium

• During 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.



ATP and Calcium

• When 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.



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.



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.



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.



Muscular Fuel

• Muscles, 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.



Muscular Fuel

• Higher 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.



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Rules for Naming Muscles

• Muscles can be named based on any of the following criteria– Muscle 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.)



Rules for Naming Muscles

• Muscles can be named based on any of the following criteria– Location 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.)



Figure 7-7 Skeletal facial muscles.



Figure 7-8 Skeletal muscles of the posterior and anterior trunk.



Figure 7-9 Skeletal muscles of the shoulder, arm, and hand.



Figure 7-10 Skeletal muscles of the hip and leg.



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Smooth Muscle

• Smooth 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.



Smooth Muscles

• Smooth 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.



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.



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.



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.



Cardiac Muscle

• The 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.



Cardiac Muscle

• The 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.



Figure 7-11 Heart and intercalated discs.



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.



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-rays– Laboratory tests



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.



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.



Common Muscular System Disorders

• Myalgia – pain or tenderness in a muscle• Fibromyalgia– 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




• Paralysis – partial or total loss of function in voluntary muscles

• Spasm or cramp – involuntary sudden and violent contraction of a muscle for a prolonged period of time

• Sprains – tears or breaks in ligaments




• Strains – actual tears in muscles or tendons

• Shin splints – inflammation of the extensor muscles and surrounding tissues of the lower leg, found in runners




• Hernia – tear in the muscle wall with an organ protruding through the opening

• Tendonitis – inflammation of tendons• Electromyography – 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



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.



Figure 7-12 There are many physical demands in EMS. Lifting and moving patients and equipment can cause low back injury if not performed properly.



Figure 7-13 EMS personnel should always use proper lifting techniques. By lifting with the legs the large paraspinous muscles are not overstressed.



Figure 7-14 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.



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 symptom

• Muscular dystrophy – inherited muscular disease in which muscle fibers degenerate and there is progressive muscular weakness



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.



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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.




• 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.




• 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.




• 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.




• 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.




• 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.



Case Study

• A 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.



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?



Case Study Questions

• What areas of patient care need to be addressed?

• What is the likely prognosis?



From the Streets

You respond to a 70 year-old female experiencing a gastrointestinal bleed. She appears lethargic and is hypotensive, tachycardic, and has pale, cool, & clammy skin.



From the Streets Questions

• Why does the patient have pale & cool skin?




• Why does the patient have pale & cool skin? This is due to peripheral vasoconstriction



From the Streets

• A 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.




• Why does this patient have pink & warm skin?




• Why does this patient have pink & warm skin? This is due to vasodilation



End of ChapterReview Questions

1. Another name for voluntary muscle is:a. Skeletalb. Smooth c. Cardiacd. Non-striated




2. Which structure does not contain smooth muscle?a. Blood vesselsb. Heart c. Digestive tractd. Bronchi




3. Most skeletal muscles attach to bones via:a. Ligamentsb. Joints c. Flexorsd. Tendons




4. The state of partial skeletal muscle contraction is known as:a. Homeostasisb. Muscle tonec. Partialus contractusd. Flexerus




5. Cardiac muscle:I. Is a voluntary muscleII. Has intercalated discs to assist contractionIII. Regenerates after injuryIV. Lines the blood vessel

a. I onlyb. I and II c. II onlyd. I, II, III, and IV




6. 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?a. Patellarb. Calcanealc. Rotator cuffd. Anterior cruciate




7. 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?a. Tetanusb. Guillain Barrec. Muscular dystrophyd. Muscular atrophy




1. A sudden or violent muscle contraction is a _________.

2. Partial or total loss of voluntary muscle use is _________.

3. A tear in the muscle wall through which an organ can protrude is a __________.

4. The body stores a carbohydrate called ___________ in the muscle; it can be converted to a usable energy source.




5. _____ means pain or tenderness in the muscle.

6. Elbow flexion is the action of the _______ muscle.




1. List the three major muscle types and give an example of each.

2. Explain the relationship between origin, insertion and action of skeletal muscle.

3. List the criteria for naming muscles and give an example of each criteria.

4. Explain the steps needed in a skeletal muscle contraction.

5. Considering the knee, list the major muscles involved in control of the joint, their attachments and their actions.

the muscular system: movement for the journey

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