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Muscular System

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<strong>Muscular</strong> <strong>System</strong>


Goals<br />

Content: Students will refresh over the<br />

muscular system as well as learn how<br />

muscles get their names (nomenclature).<br />

The students will be able to categorize the<br />

various muscles of the human body based<br />

on their nomenclature.<br />

Language: Students will learn and utilize<br />

correct anatomical vocabulary to describe<br />

and label the different muscle types of the<br />

human body.


Muscle Functions<br />

• Movement<br />

• Protection<br />

• Posture and Support<br />

• Heat


Muscle<br />

• Over 600 muscles<br />

• 40 – 50 % of total body weight<br />

• 215 pairs of muscles<br />

– Aggregate muscle action


Muscle Nomenclature<br />

• Appearance<br />

• Location<br />

• Function


Muscle Nomenclature<br />

• Shape<br />

– Deltoid<br />

– rhomboid


Muscle Nomenclature<br />

• Size<br />

– Gluteus Maximus<br />

– Teres Minor


Muscle Nomenclature<br />

• Number of Divisions<br />

– Biceps Brachii


Muscle Nomenclature<br />

• Direction of fibers<br />

– External Oblique


Muscle Nomenclature<br />

• Location<br />

– Rectus femoris<br />

– Palmaris longus


Muscle Nomenclature<br />

• Points of Attachement<br />

– Coracobrachialis<br />

– Flexor Digitorum Longus


Muscle Nomenclature<br />

Action<br />

– Erector spinae


Muscle Nomenclature<br />

Action and Shape<br />

Pronator quadratus<br />

Action and Size<br />

Adductor magnus<br />

Shape and Location<br />

Serratus anterior


Muscle Nomenclature<br />

Location and Attachment<br />

Brachioradioalis<br />

Location and Number of Divisions<br />

Biceps femoris


Muscle Nomenclature<br />

Groups of muscles<br />

Shape<br />

hamstrings<br />

Number of Divisions<br />

quadriceps<br />

triceps


Muscle Nomenclature<br />

Groups of muscles<br />

Location<br />

peroneals<br />

abdominal<br />

shoulder girdle<br />

Action<br />

hip flexors<br />

rotator cuff


Myofilaments<br />

• Actin – thin proteins<br />

• Myosin – thick proteins


Myofilaments<br />

Sarcomere<br />

Contractile unit of a muscle fiber


What fiber joins muscles to bones?<br />

Tendons


• Flexibility<br />

• Strength<br />

Muscle-tendon Functions<br />

• <strong>Muscular</strong> power<br />

Joints ROM<br />

• <strong>Muscular</strong> endurance<br />

Maximum force on a unit<br />

Rate of muscular force applied<br />

to move a load<br />

Ability of a muscle to exert a<br />

force repeatedly or constantly<br />

Muscle fatigue, soreness, pain – build-up of lactic acid in<br />

the muscles


Structural Damage<br />

in Muscle Fibers<br />

• The vertical lines are the “z -<br />

lines” that define the<br />

boundaries of the muscle<br />

sarcomere<br />

• Microscopic damage can<br />

lead to disruption of the z-<br />

lines and contribute to<br />

soreness


Relative Strength<br />

• The amount of weight lifted relative to the<br />

person's body weight<br />

• Measured as a ratio:<br />

Relative Strength =<br />

weight lifted (lb.)<br />

body weight (lb.)


Fibers and Shape<br />

• Determine a muscle’s ability to exert force<br />

– Cross section diameter<br />

• Greater = greater<br />

• Determine range through which it can exert<br />

force onto the bone it is attached<br />

– Ability to shorten<br />

• Longer muscles shorten through a greater range = more<br />

effective moving joints through large ranges of motion


Classification by Fiber Arrangement<br />

• Parallel<br />

run longitudinally or somewhat<br />

parallel with the muscle’s long axis<br />

• Pennate<br />

(feather-like) tendons run down the<br />

muscle’s long axis, and fibers run obliquely to<br />

the tendon


Parallel Structures<br />

• Fibers are longer<br />

• Run parallel to the length of the muscle<br />

• Pull bones through a greater ROM


• Flat<br />

– Thin and broad<br />

• Fusiform<br />

Parallel Structures<br />

• Rectus abdominus<br />

• External oblique<br />

– Spindle shaped with a central belly that tapers to<br />

tendons on the ends<br />

• Strap<br />

• Brachialis<br />

• Brachioradialis<br />

– More uniform<br />

• Sartorius


Parallel Structures<br />

• Radiate (triangular or fan-shaped)<br />

– Combo of flat and fusiform<br />

• Pectoralis major<br />

• Trapezius<br />

• Sphincter (circular)<br />

– Endless strap around openings<br />

• Orbicularis oris<br />

• Orbicularis oculi


Pennate Structures<br />

• Shorter fibers run oblique to tendons<br />

• Greater cross section = greater force<br />

• Most muscles in the body<br />

• To provide more force than fusiform, but less<br />

ROM<br />

Example: sit-ups


Pennate Structures<br />

• Types<br />

– Unipennate . . . Biceps femoris<br />

– Bipennate . . . Rectus femoris<br />

– Multipennate . . . Deltoid


• Scavenge the room.<br />

Class Activity<br />

• Find something that would be considered<br />

fusiform.<br />

• Find something that would be considered<br />

pennate


Class Activity<br />

• Classify the following items as:<br />

fusiform<br />

unipennate<br />

bipennate<br />

multipennate


Skeletal Muscle Tissue Properties<br />

• Irritability or<br />

Excitability<br />

• Conductivity<br />

• Contractility<br />

• Distensibility or<br />

Extensibility<br />

• Elasticity<br />

responds to nervous stimuli<br />

wave of excitement<br />

pulling ends together<br />

stretched<br />

recoil from a stretch


Reciprocal Inhibition or Innervation<br />

• Agonists<br />

muscles that cause or help cause motion<br />

• Antagonists<br />

perform opposite to the movement being<br />

done<br />

Example: hip flexors & hip extensors


• Synergistic Muscles – same function, work<br />

together


Presentations<br />

You may utilize the following website or any others you find<br />

useful (do not use Wikipedia) to chose a muscle.<br />

http://www.ptcentral.com/muscles/index.html<br />

For the muscle use the internet or other resources to find<br />

the following:<br />

1. State the anatomical and if pertinent the “everyday”<br />

name of the muscle.<br />

2. Identify the muscle’s prime movement if possible<br />

(ex. It is the agonist of flexing the upper arm)<br />

3. State the muscle(s) that is(are) the antagonist(s) for the<br />

muscle’s prime movement.<br />

4. State if there are any synergists acting in conjunction<br />

with the muscle for this action.


Presentations<br />

5. State the muscle fiber arrangement type ( Ex. fusiform,<br />

unipennate, bipennate, or multipennate)<br />

6. State how the muscle received its name or classification.<br />

7. Give an example of a movement that has this muscle<br />

utilizing an isometric contraction.<br />

8. Give an example a movement that has this muscle<br />

utilizing both isotonic contractions (eccentric and<br />

concentric).<br />

9. Make a hypothesis regarding the fiber type this muscle<br />

would most likely have. Also give logical reasoning as to<br />

why you believe this to be so.<br />

10.State a possible “lab” that you could perform to test your<br />

hypothesis in #9.


11. Construct or draw (paint) a figure showing the muscle fiber<br />

arrangement as well as it correct anatomical position.<br />

12. Provide a table that distinguishes the 5 muscle properties<br />

for the muscle by a picture-graph. You may forego the table<br />

and create a slide for each property and picture-graph if<br />

desired.<br />

contractibility<br />

( Ex. )<br />

13. Find or create a video showing the muscle at work<br />

(contracting/extending)

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