F Muscular System M

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Summer 2005 F.1

Unit F: Muscular System

Program Area: Health Occupations Education

Course Title: Medical Sciences I Number : 7221

Unit Title: Muscular System

SuggestedTime for Instruction: 5 class periods (90 minute classes)

11 class periods (55 minute classes)

Course Percent: 6 %

Unit Evaluation: 100 % Cognitive

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Competency : MD06. Analyze the anatomy and physiology of the muscles.

Specific Objectives:

MD06.01 Describe the structure of the muscles.

MD06.02 Analyze the function of the muscular system.

MD06.03 Analyze characteristics and treatment of common muscledisorders.



Summer 2005 F.2

Unit F Master Outline

F. Muscular System

MD06.01 Describe the structu re of the muscles A. Muscles

1. Nearly half our weight comes from muscle tissue2. There are 650 different muscles in the human body3. Muscles give shape and form4. Muscles produce body heat

B. Types of muscles1. Voluntary

a. Skeletal – muscles attached to boneb. The sarcolemma is the cell membrane

2. Involuntarya. Smooth (visceral) – found in internal organsb. Cardiac – found in heart

3. Sphincter – circular muscles in openings between esophagus andstomach, anus and urethra

C. Principal skeletal muscles1. Biceps brachii2. Brachioradialis3. Buccinator 4. Deltoid5. Diaphragm6. External oblique7. Hamstrings8. Gastrocnemius9. Gluteus maximus

10. Gluteus medius11. Intercostal muscles12. Latissiumus dorsi13. Masseter 14. Pectoralis major 15. Quadriceps femoris16. Rectus abdominus17. Rectus femoris18. Sartorius19. Soleus major 20. Sternocleidomastoid21. Tibialis anterior 22. Trapezius

23. Triceps brachii24. Vastus lateralis25. Vastus medialis

MD06.02 Analyze the func tion of the muscular system A. Responsible for:

1. Body movement2. Posture3. Body heat



Summer 2005 F.3

B. Characteristics1. Contractibility – muscle becomes shorter and thicker causing muscle

movement2. Excitability – respond to stimuli3. Extensibility – ability to stretch muscles4. Elasticity – ability to return to original length

C. Movement1. Muscles move bones by pulling on them2. Groups of muscles usually contract to produce a single movement

1. Motor unit – a motor neuron plus all the muscle fibers it stimulates2. Neuromuscular junction – junction between the motor neuron’s fiber

which transmits the impulse, and the muscle cell membrane3. Acetylcholine – chemical neurotransmitter, diffuses across the

synaptic cleft (carries impulse across synaptic cleft)4. Muscle fatigue – caused by the accumulation of lactic acid in the

muscles5. Oxygen debt – after exercise, the amount of oxygen needed by the

muscle to change lactic acid back to glucose3. Diaphragm – dome-shaped muscle, separates abdominal and thoracic

cavity, aids in breathing

D. Muscle tone – muscles slightly contracted and readyE. Exercise and training

MD06.03 Identify characteris tics and treatment of common musc le

disorders A. Conditions

1. Atrophy – wasting away of muscle due to lack of use2. Hypertrophy – an increase in the size of the muscle cell3. Contracture – tightening or shortening of a muscle4. Flat feet (talipes) – weakening of leg muscles that support arch,

downward pressure on foot flattens arches, Rx with exercise, massageand corrective shoes.

5. Hernia – organs protrude through weak muscle6. Muscular dystrophy – group of diseases in which muscle cells

deteriorate7. Myasthenia gravis – progressive muscular weakness and paralysis,

sometimes death, cause unknown, fatal when respiratory muscles areparalyzed

8. Tetanus (Lockjaw) Infectious disease, continuous spasms of voluntarymuscles, bacteria enters body through puncture wound, prevent by anti-toxoid vaccine

9. Torticollis (Wry neck) – inflammation of trapezius and/or sternocleidomastoid muscle

B. Injury and overuse1. Strain – muscle tear, symps are pain and swelling, Rx – ice packs2. Muscle spasm (cramp) – sustained contraction of muscle

3. Myalgia – muscle pain4. Tendonitis – inflammation of tendon

C. Treatment1. Massage2. IM injections



Summer 2005 F.4


Competency MD06: Analyze the anatomy and physio logy of themuscles.

Materials/Resources

Scott, Ann Senisi and Elizabeth Fong. Body Structures & Functions. Delmar Publishers, 9th Edition,1998. www.DelmarAlliedHealth.com

National HOSA Handbook: Section B. Published by HOSA, Flower Mound, Texas. Current Edition.www.hosa.org

Teaching/Learning Indicators: The following letters are used to indicate specific

skills/areas required in the instructional activity.

R Reading SS Social StudiesW Writing S ScienceM Math A The ArtsH Health professional/parent/community involvement



Summer 2005 F.5

Objective MD06.01 Descr ibe the structure of the muscles.

Teaching/Learning Activ ities

• Basic Skills S

Working alone, in pairs, and in small groups, have students complete theactivities on the “Reading Guide” (Appendix MD06.01B) for the Muscular System.Students are to work at their own pace. Pairs and teams need to be assigned prior to starting the activities.

• Cognitive S Have students color the muscle diagram (Appendix MD06.01C).

• Basic Skills S, R, A Have students write a story about their favorite hobby or sports activity using the termsfrom the Muscle System terminology list. (Appendix MD06.01A) Students should NOTtell what the activity is, but should write a short story that describes the muscles they use

as they do their activity.

Then, have students read their stories in class, and see if classmates can guess whattheir hobby is.

• HOSA S Have each student write five fill-in-the-blank questions related to the structure of themuscles. Then, using HOSA Bowl guidelines, play HOSA Bowl.Note: If you do not have a buzzer system you may substitute a bell.

• Cognitive S Have students use 10 of 30 given terms (Appendix MD06.01A) to form a crosswordpuzzle. Use definitions as the clues and terms as the answers.

• Special Needs Each student will reach the highest level of mastery in the least restrictive environment asrecommended in the student’s IEP.



Summer 2005 F.6

Objective MD06.02 Analyze the funct ion of the muscular system.


• Cognitive S

Have students participate in a teacher-led discussion of the function of the muscular system. (Transparency masters)

Have students complete the “Muscle Function Matching”. (Appendix MD06.02A)

• Critical Thinking S Have students create a game dealing with the topic “muscular function.” Includedin the game should be instructions and materials necessary to play the game.Upon completion, students will bring the game to class for fellow classmates to play.

• Basic Skills S, M Answer the muscle math worksheet found in the appendix. (Appendix MD06.02B)

• Team Work S Working in pairs, have students perform exercises as listed in “The Power System.”(Appendix MD06.02C) Students should alternate reading and performing tasks.

• Critical Thinking S, A Teacher or students can take a dance and write the instructions using movement terms,muscles, and bones. It works out well for students or teachers to write the instructionsand then cut up the instructions giving each student a different step or movement of thedance. Each student demonstrates their movement. Finally you put the steps in order,add the music and dance!

( An example of th is wi th the Macarena is inc luded in Appendix MD06.02D)




Summer 2005 F.7

Objective MD06.03 Analyze characterist ics and treatment of commonmuscle disorders.


• Employability S, H Invite a chiropractor, massage therapist, physical therapist or local health sparepresentative to speak to your class. Discuss common muscle disorders.

• Teamwork S, W Divide students into teams of 4 and provide time for teams to visit the media center tofind information on genetic testing and muscular dystrophy.

Allow students to debate the topic in class, with 2 teams to debate at a time. One teamwill be pro and one will be con. Debate the following topic: According to genetic testing,you carry the defective gene for muscular dystrophy. Gene manipulation costs $100,000and is experimental. What do you do? What if this person was a family member?

• Critical Thinking S Divide students into groups of 2-3 members. Assign each group one of the followingmuscular system diseases/conditions:

Sprain Muscular dystrophy Tennis elbowStrain Myalgia Shin splintsMuscle spasm Rotator cuff disease

Give groups an assigned amount of time to review their disease/condition. Then, let onegroup at a time go in front of the class. Allow the class at large to ask them 5 questionsof the yes/no variety. The class may not ask for the name of the disease/condition, butquestions should lead to discovery of disease. For example: Are you an injury?

• Technology S Take students to the school’s technology lab to review the MDA web site and completethe Muscular Dystrophy review worksheet. (MD06.03A)

• HOSA S, W, H Have students research various careers related to the muscular system (physicaltherapist, orthopedist, athletic trainer, chiropractor, exercise physiologist, occupationaltherapist, massage therapist, etc.)

Using the HOSA Competitive Events Guidelines, have student work in pairs andcreate a career health display, This display should have information aboutthe education, duties, job opportunities, etc. of the selected career.




Summer 2005 F.8

Daily Lesson Plans

Unit F: Muscular SystemLessons: 5Hours: 7 1/2 clock hours

Steps Lesson #1 Lesson #2 Lesson #3Focus andReview

In groups, have studentsbrainstorm the relationshipbetween the skeletal andmuscular systems. (This is athinking activity.)

Go around the room and havestudents ask the questions theywrote down at the end of classyesterday. See if fellowstudents can figure out thecorrect answers. Help andclarify as necessary.

Use the “Muscle FunctionMatching” assignment as aquiz.

Correct the quiz in class.

Collect index card assignment.

Statementof Objectives

Objective MD06.01 Describethe structure of the muscles.

Objective MD06.02 Analyzethe function of the muscular system.

Objective MD06.03 Analyzecharacteristics and treatment of common muscle disorders.

Teacher Input Assign students in pairs. Havepairs complete the ReadingGuide for the muscular system.

When all teams are finishedwith their reading guide, theteacher should use theoverheads to review themuscular system while studentscorrect their work.

Using the overheads, reviewmuscle anatomy. Studentsshould follow along with themodel they illustrated for homework. If there is a musclechart or model in theclassroom, students should beasked to point out muscles asthey are discussed.

Review major diseases anddisorders of the muscular system using overheadtransparency masters.

GuidedPractice

When teams complete theReading Guide assignment,have them begin work on themuscle ID assignment.(MD06.01C)

Have students write anexplanation of their favoritesport or hobby, using muscleanatomy and physiology todescribe the movements. Let

them read their short stories inclass while classmates guessthe sport or hobby.

Go to the school’s Internet lab.Have students complete theMuscular Dystrophy WebReview assignment.

IndependentPractice

Complete the muscle IDassignment.

Write 10 fill-in-the blankquestions from this unit or fromthe skeletal system. Thesequestions should be written onone side of a 3X5” index cardwith the correct answer on theback.

Assign groups in pairs to usethe HOSA CHD guidelines andresearch a health career related to the muscular system.In their presentation, theyshould talk about how thechosen professional treatsmuscular disorders.

Closure Ask students to think aboutwhat they learned today, andwrite down one question theyhave about the muscular system.

Have students stand and pointto a muscle as the teacher callsout the muscle term.

Tell students they will be havinga guest speaker tomorrow.Have each student write 3questions they expect to haveanswered about the guestspeaker’s profession.

Materials Handouts – Reading Guide andMuscle IDColored pencilsOverheads

Overheads Handouts – Muscle FunctionMatching and MD Web Review

AssignmentCHD Guidelines



Summer 2005 F.9

Unit F: Muscular System (Continued)

Steps Lesson #4 Lesson #5Focus and

Review

Ask questions from index cardsthat students created duringlesson #2.

Ask 5 review questions fromthe speaker.

Statementof Objectives



Teacher

Input

Guest speaker for approximately 30 minutes.

Allow a student to introduce thespeaker.

Students should have thequestions they wrote in front of them, and fill in the answers asthey are given by the speaker.They may ask any questionsnot answered following thespeakers presentation.

Allow students to give CHDpresentations modified to allowfor a 5 minute explanation of the career and relatedmuscular disorders. (This willtake the first half of class.)

GuidedPractice

Allow students remaining classtime to work on Career HealthDisplays.

TEST – Muscular System

If time permits, grade test inclass.

IndependentPractice

Allow students remaining classtime to work on Career HealthDisplays.

Allow students to correct testand turn it in for a reward or bonus points.

Closure Remind students about Career Health Display presentationsand Test.

If time permits, play HOSABowl with index card questions.

Materials Guest speaker intro information TestCHD rating sheet



Summer 2005 F.10

Unit F: Muscular SystemTerminology List

1. acetylcholine2. biceps brachii3. brachioradialis4. buccinator 5. cardiac muscle6. contractability7. deltoid8. diaphragm9. elasticity10. excitability11. extensibility12. external oblique13. hamstrings14. gastrocnemius15. gluteus maximus16. gluteus medius17. intercostal muscles18. involuntary19. latissimus dorsi20. masseter 21. motor unit

22. muscle fatigue23. muscle tone24. neuromuscular junction25. oxygen debt26. rectus femoris27. pectoralis major 28. quadriceps femoris29. rectus abdominis30. sarcolemma31. sartorius32. skeletal muscle33. smooth muscle34. soleus major 35. sphincter 36. sternocleidomastoid37. tibialis anterior 38. trapezius39. triceps brachii40. vastus lateralis41. vastus medialis42. voluntary

Disorders and Related Terminology

1. atrophy2. contractures3. flat feet (talipes)4. hernia5. hypertrophy6. intramuscular injection7. massage8. muscular dystrophy

9. myalgia10. myasthenia gravis11. spasm12. strain13. tendonitis14. tetanus15. torticollis

Appendix MD06.01A



Summer 2005 F.11

Name ___________________________________________ Date _________________

Reading Guide: The Muscular System

∗ Alone + Pairs

χ Small Groups ∼ Whole Class

∗ Skim quickly through pages 92 - 111 in your Body Structures and Functions book. Lookat pictures and headings. Write down what you think this section will be about. (10 pts.)

+ Discuss and write down all you already know about the following topics before you

began your reading.

1. What are the 3 types of muscle? (2 pts.)

2. How are the types of muscles alike and how are they different? (2 pts.)

3. How do skeletal muscles work? (2 pts.)

+ Whisper read (read softly together) pages 93 to the top of page 97 (stop when you get to

the section “ Sources of Energy and Heat.”) (4 pts.)

∗ With your hand on your biceps, bend your arm upward at the elbow. Describe what youfeel related to the biceps muscle. (5 pts.)



Summer 2005 F.12

χ Design your own skeletal muscle on a piece of 8” x 10” white paper. Label and define itsparts including: origin, insertion, body, and tendons. Describe what movements your muscle will cause. (20 pts.)

∗ Read pages 97 to the top of page 99. (5 pts.)

+ Review with your partner information on these pages. Be sure to have a clear understanding of the following vocabulary words: (2 pts. each)

motor unit

neuromuscular junction

acetylcholine

muscle fatigue

muscle tone

isotonic contractions

isometric contractions

∗ Jake has decided to improve his appearance by exercising. He would like to build up hischest and shoulder muscles so he looks better in the tank tops he is fond of wearing.He has decided to play racquetball everyday as his primary training program because heknows that he will use his upper body muscles in this sport. After his first game of racquetball, you ask him how he likes his new sport and he can hardly answer you - heseems out of breath.

Is Jake’s plan likely to help him meet his goal? How do you explain his breathingdifficulties? (10 pts.)



Summer 2005 F.13

+ One of you needs to stand in a doorway and with your palms against the doorjamb for 2

minutes. After the 2 minutes is up, have your partner step away and relax their arms (letthem go limp.) What happened and why do you think it did happen? (10 pts.)

∼ Congratulations! The four or five of you at the Muscular Moving Ad Agency have beenhired to produce a brochure which will provide a luxury tour through the Muscular System. You must highlight the trendy spots, spotlight the exciting activities, and alsowarn the prospective guest of any dangers or special precautions they might need totake. You may us drawings, computer graphics, photographs from magazines, etc.

Whenever possible, type all written parts of the brochure. BE CREATIVE! You will

present you brochure to the class and they will vote on which team gets the contract.Include a lot of your vocabulary words. (20 pts.)

Appendix MD06.01B



Summer 2005 F.14

Muscle Anatomy

Color the following structures – and be sure to identifyyour color scheme.

Vastus medialis Tibialis anterior Trapezius Sartorius Biceps brachii Triceps brachii Rectus femoris Rectus abdominis Deltoid Pectoralis major Sternocleidomastoid Brachioradialis External oblique Vastus lateralis Gastrocnemius Soleus major

Appendix MD06.01C



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Muscle Function Matching

1._____Extends femur and rotates it A. gluteus medius

2._____Flexes thigh and extends leg B. sartoris

3._____points toes and flexes lower leg C. rectus abdominis

4._____Helps with breathing D. deltoid

5._____Raises ribs and helps with breathing E. biceps brachii

6._____Flexes and rotates thigh and leg F. gluteus maximus

7._____Extends the lower arm G. sternocleidomastoid

8._____Abducts the upper arm H. diaphragm

9._____Abducts and rotates thigh I. rectus femoris

10.____Compresses abdomen J. gastrocnemius

11.____Flexes upper arm and helps abduct it K. trapezius

12.____Compresses and closes lips L. intercostals

13._____Flexes and rotates the head M. orbicularis oris

14.____Moves the shoulder and extends the head N. triceps brachii

15.____Flexes lower arm O. pectoralis major

Appendix MD06.02A



Summer 2005 F.16

Answer Key to Muscle Funct ion Matching Exercise

1. F

2. I

3. J

4. H

5. L

6.B

7. N

8. D

9. A

10. C

11. O

12. M

13. G

14. K

15. E



Summer 2005 F.17

Muscle Math

Round answers to the nearest whole number.

1. What percentage of muscle weight would you have if 60 pounds out of 140pounds is muscle weight?

2. If you know out of 140 pounds, 60 pounds is muscle weight, what is the muscleweight of a 200 pound male?

3. What would the muscle weight be on an 80 pound female? (Use informationfrom #1)

4. If muscle weight is 90 pounds, how much does the person weigh?

5. If muscle weight is 45 pounds, how much does the person weigh?

Appendix MD06.02B



Summer 2005 F.18

Answers to Muscle Math

1. 451

2. 86 pounds

3. 34 pounds

4. 210 pounds

5. 105 pounds



Summer 2005 F.19

The Muscular System“ The Power System”

Working in pairs, perform the following exercises. Alternate onereading the task and the other performing it . Make sure both of youcould demonstrate these tasks in front of the class if asked to. Youmay use your

textbook if you need a reference for the muscles.

1. Abduct fingers. 12. Extend foot.2. Flex right forearm 13. Flex pectoralis major.

3. Adduct arm 14. Contract gastrocnemius.4. Flex leg. 15. Contract tib ialis anterior.5. Extend leg. 16. Extend quadriceps.6. Flex fingers 17. Flex biceps.7. Contract diaphragm. 18. Contract abdominal muscles8. Contract diaphragm. 19. Flex and rotate sartor ius.9. Contract masseter. 20. Extend/contract gluteal

maximus.

10. Flex masseter. 21. Extend trapezius.11. Flex foot. 22. Contract/abduct deltoid.

Appendix MD06.02C



Summer 2005 F.20

Skeletal System and Muscle System ReviewThe Macarena

1. Extend right Latissimus Dorsi and Triceps and abduct to the front of your body.Metacarpals , carpals, and phalanges should be pronated.

2. Extend left Latissimus Dorsi and Triceps and abduct to the front of your body.Metacarpals, carpals, and phalanges should be pronated.

3. Extend right Latissimus Dorsi and Triceps and abduct to the front of your body.Metacarpals, carpals, and phalanges should be in supination.

4. Extend left Latissimus Dorsi and Triceps and abduct to the front of your body.Metacarpals, carpals, and phalanges should be in supination.

5. Flex right Biceps and place right phalanges and metacarpals on left scapula.

6. Flex left Biceps and place left phalanges and metacarpals on right scapula.

7. Rotate right arm about 90 degrees, flex right biceps, and place right metacarpals andphalanges on occipital bone.

8. Rotate left arm about 90 degrees, flex left biceps, and place left metacarpals andphalanges on occipital bone.

9. Extend right Latissimus Dorsi and with right Biceps slightly flexed, adduct and place rightmetacarpals and phalanges on left ilium.

10. Extend left Latissimus Dorsi and with left Biceps slightly flexed, adduct andplace leftmetacarpals and phalanges on right ilium.

11. Extend right Latissimus Dorsi and with right Biceps slightly flexed, rotate the right Deltoid90 degrees and place right metacarpals and phalanges on right gluteus medius.

12. Extend left Latissimus Dorsi and with left Biceps slightly flexed, rotate the left Deltoid 90degrees and place left metacarpals and phalanges on left gluteus medius.

13. Rotate gluteus maximus and gluteus minimus as well as the entire pelvis three times.

14. Plantar-flex bilateral metatarsals and phalanges. Flex hamstring muscles bilateral while

rotating self a quarter turn to the side. Extend quadriceps group and start over.

Appendix MD06.02D



Summer 2005 F.21

Web ReviewMuscular Dystrophy

Go to the web site of the Muscular Dystrophy Association at www.mda.org

1. How many types of Muscular Dystrophy are there? ___________

2. Which type is also known as Pseudohypertrophic MD? _____________________________________________________

3. What causes congenital muscular dystrophy? ________________________________

4. What are some recent research developments that have occurred as a result MDAcontributions?

______________________________________________________________________

____________________________________________________________________

5. What is the national magazine for MDA? ____________________________________

6. What MDA clinic is nearest to your home? ___________________________________

7. What type of Muscular Dystrophy occurs usually in adults over age 40? _____________________________________________________________________

8. What symptom do all types of Muscular Dystrophy have in common? _____________________________________________________________________

9. Marilla is 19 years old and is diagnosed with a type of Muscular Dystrophy that causesweakness in her shoulders and hips. Her physician assures her that she will likely livelong enough to join the AARP. Is that possible? If so, what type of MD does she have?

_______________________________________________________________

10. Carlotta is a 21 year old college student who has been diagnosed with Becker Muscular Dystrophy. What health professional can be helpful in helping her stay in school andmeet the demands of her college schedule?

________________________________________________________________

11. True or False? Muscular Dystrophy is incurable? ______________________________

12. True or False? Muscular Dystrophy is untreatable? ____________________________

13. What are the goals of rehabilitation for someone with Muscular Dystrophy? ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ __________________________________________________________________

MD06.03A



Summer 2005 F.22

Web Review Answer KeyMuscular Dystrophy

1. How many types of Muscular Dystrophy are there? 9

2. Which type is also known as Pseudohypertrophic MD? Duchenne Muscular Dystrophy

3. What causes congenital muscular dystrophy? genetic

4. What are some recent research developments that have occurred as a result MDAcontributions? Answer varies

5. What is the national magazine for MDA? Quest

6. What MDA clinic is nearest to your home? Answer varies

7. What type of Muscular Dystrophy occurs usually in adults over age 40? Distal Muscular Dystrophy

8. What symptom do all types of Muscular Dystrophy have in common? Muscle weakness

9. Marilla is 19 years old and is diagnosed with a type of Muscular Dystrophy that causesweakness in her shoulders and hips. Her physician assures her that she will likely livelong enough to join the AARP. Is that possible? If so, what type of MD does she have?Yes – Limb-Girdle MD

10. Carlotta is a 21 year old college student who has been diagnosed with Becker Muscular Dystrophy. What health professional can be helpful in helping her stay in school andmeet the demands of her college schedule? Occupational Therapist

11. True or False? Muscular Dystrophy is incurable? True

12. True or False? Muscular Dystrophy is untreatable? False

13. What are the goals of rehabilitation for someone with Muscular Dystrophy?

The goals of rehabilitation in patients with neuromuscular disease (NMD) are tomaximize and prolong independent function and locomotion, inhibit physical deformity,and provide access to full integration into society



Summer 2005 F.23


OVERHEAD TRANSPARENCY M ASTERS



Summer 2005 F.24

MUSCULAR SYSTEM“ the power system”

• Nearly half our weight comes from muscle tissue.

• There are 650 different muscles in the human body.

• Muscles give us form and shape.

• Muscles produce most of our body heat.

THREE MAIN FUNCTIONS

1. Responsible for all body movement.

2. Responsible for body form and shape (posture)

3. Responsible for body heat and maintaining bodytemperature.

SKELETAL

TYPES OF MUSCLES SMOOTH

CARDIAC



Summer 2005 F.25

Skeletal Muscle

• Attached to bone

•

Striated (striped) appearance• VOLUNTARY

• Multinucleated muscle cell bundles (muscle cells= muscle fibers)

• SARCOLEMMA = cell membrane

• Contract quickly, fatigue easily, can’t maintaincontraction for long period of time

Smooth Muscle

• Visceral (organ) muscle

• Found in walls of digestive system, uterus andblood vessels

• Cells small and spindle-shaped

• INVOLUNTARY

• Controlled by autonomic nervous system• Act slowly, do not tire easily, can remain

contracted for long time

Cardiac Muscle

• Found only in the heart

•

Striated and branched• Involuntary

• Cells are fused – when one contracts, they allcontract

• Involuntary



Summer 2005 F.26

= special circular muscles in openings

of esophagus and stomach, stomach

and small intestine, anus, urethraand mouth.

CHARACTERISTICS OF MUSCLES

• CONTRACTIBILITY – the ability of a muscle to

reduce the distance between the parts of itscontents or the space it surrounds.

• EXCITEABILITY (IRRITABILITY) – the ability torespond to certain stimuli by producing impulses.

• EXTENSIBILITY – the ability to be stretched.

• ELASTICITY – ability of muscle to return to its

original length when relaxing.



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MOVEMENT

1. Muscles move bones by pull ing on them.

As a muscle contracts, it pulls the insertion bonecloser to the origin bone. Movement occurs at the

joint between the origin and the insertion.

Rule: A muscle’s insertion bone moves toward itsorigin bone.

2. Groups of muscles usually contract toproduce a single movement.

• MOTOR UNIT – a motor neuron plus all the musclefibers it stimulates.

•

NEUROMUSCULAR JUNCTION – the junctionbetween the motor neuron’s fiber which transmitsthe impulse – and the muscle cell membrane.

• ACETYLCHOLINE – chemical neurotransmitter,diffuses across the synaptic cleft (carries impulseacross synaptic cleft)

• MUSCLE FATIGUE – caused by the accumulationof lactic acid in the muscles.



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• OXYGEN DEBT – after exercise, the amount of oxygen needed by the muscle to change lacticacid back to glucose.

• MUSCLE TONE - When muscles are slightlycontracted and ready to pull.

• DIAPHRAGM – Dome-shaped muscle thatseparates the abdominal and thoracic cavities,aids in breathing

Diaphragmflattens when you

breathe in.



Summer 2005 F.29



Summer 2005 F.30



Summer 2005 F.31

Disorders and Related Terminology

ATROPHY – wasting away of muscle due to lack of use.

HYPERTROPHY – an increase in the size of themuscle cell.

STRAIN – tear in the muscle result ing from excessive

use. Bleeding inside the muscle can result in pain andswelling. Ice packs will help stop bleeding and reduceswelling.

MUSCLE SPASM (cramp) – sustained contraction of the muscle, usually because of overuse.

MYALGIA – muscle pain

HERNIA – organs can protrude through this weekmuscle.

FLAT FEET (TALIPES) – weakening of leg musclesthat support the arch, downward pressure on the footeventually flattens out the arches. Condition can be

helped by exercise, massage and corrective shoes.



TETANUS (lockjaw) – Infectious disease, continuousspasms of voluntary muscles, caused by a toxin fromthe bacillus clostr idium tetani, enters the body

through puncture wound. Prevented by an anti-toxoidvaccine.

TORTICOLLIS (wry neck) – may be due to aninflammation of the trapezius and/or sternocleidomastoid muscle.

MUSCULAR DYSTROPHY – group of diseases in

which muscle cells deteriorate. Most common isDuchenne Muscular Dystrophy, caused by a geneticdefect.

MYASTHENIA GRAVIS – progressive muscular weakness and paralysis, sometimes death. Causeunknown. Fatal when respiratory muscles are

paralyzed.

TENDONITIS – inflammation of a tendon

CONTRACTURE – tightening or shortening of amuscle.

F Muscular System M

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