The Muscular System Chapter 9

I. Introduction

 All movements require ________ (Chemical energy causes contraction)  Muscles:   Move fluids such as _____ & ______ Produce heat which warms the body  Three types of muscle in the body are _______, _______, and ______

Types

 _______ Muscle  __________ muscles lining the organs (stomach, bladder, uterus, and blood vessels)   __________ – (wave like contractions) moves substances through these (smooth) muscles ________ to contract and relax, but are _________ to fatigue

Types cont…

  Cardiac  ___________ muscle of the ______  Does _____ fatigue Skeletal  __________ muscle used for movement that are _______ to bones  The rest of this chapter will mainly focus on skeletal muscle

II. Structure of Skeletal Muscle

 Each muscle is an _______  All are comprised of skeletal muscle tissue, connective tissues, nervous tissues, and blood

Structure cont…

 Connective Tissue Coverings  Layers of ______ surround and separate each muscle  Extends beyond the ends of the muscle  WHY?

 Gives rise to ______ that are fused to the _______ of the skeletal system (bones)

Structure cont…

 Around each whole muscle is the __________  The ___________ surrounds individual bundles (_________) within each muscle  Each muscle cell (_____) is covered by an ____________

Structure cont…

 Within muscle fibers are many cylindrical tubes called _____________  contain _____ and _____ filaments (striations)   ______ – made of the protein Myosin ______ – made of the protein Actin

STUDY ANALOGY

Take 100 pencils (muscle fibers) -Wrap each pencil in tissue paper (endomysium) -Take 100 pencils in a bundle (a fascicle) and wrap them in paper (perimysium) -Then take all the bundles and wrap them in gift wrap (epimysium) -Wrap all of it up in brown paper (Fascia)

III. Muscles & The Nervous System  ______________ – site where a motor _______ and ______ ______ meet  End of muscle fiber forms a motor end plate  Motor neuron stores _______________ (chemicals)

Muscles & Nervous cont…

 Motor Units  A motor _______ and the ______ fiber it controls  When stimulated to do so, the muscle fiber of the motor unit contract all at once (___________________)

IV. Skeletal Muscle Contraction

  The pulling of a muscle against its attachments _______(energy) is needed from ___________________  The ______________, _______________, is released at the neuromuscular junction

Contraction cont…

 _________ (Ca) ions are released into the muscle fibers  ______ and _______ slide together

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V. Skeletal Muscle Relaxation

 The lengthening and relaxing of a muscle from its attachments    ___________ is decomposed Calcium ions _______ muscle fibers ______ and ________ slide apart

Major Skeletal Muscles

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Major Skeletal Muscles

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VI. Skeletal Muscles of the Human Body   _______ – immovable end of a muscle _______ – moveable end of the muscle  _________ – always occurs to move point of insertions to its point of origin

Muscles cont…

 Of a group of muscles, the one doing the majority of the work is the ______________  Helper muscles are called _________  Opposing muscles are called __________

Muscles cont…

  Face  _________ – lifts eyebrows    ___________ ____ – moves lips _____________ – “Smile” muscle, lifts cheeks ___________ _____ – Moves skin around the eyes Neck  __________________ – Turns neck/head

Muscles cont…

 Trunk  Trapezius        Pectoralis Major Pectoralis Minor Serratus anterior Intercostal Muscles Rectus Abdominis External Abdominal Obliques Latissimus Dorsi

Muscles cont…

 Upper Extremities  Deltoid   Biceps Brachii Triceps Brachii

Muscles cont…

 Lower Extremities   Upper leg: Gluteus medius & maximus Sartorius Gracilis Rectus Femoris Vastus medialis, intermediate and lateralis Biceps femoris Lower leg: Tibialis anterior Soleus Gastrocnemius

VII. Oxygen Debt

    During rest or moderate activity, there is enough oxygen to support ________ respiration Oxygen _____________ develop during strenuous exercise __________ acid (feeling of pain or muscle burning) builds up as an end product of anaerobic respiration “Repaying” oxygen debt may take ____________.

VIII. Muscle Fatigue

   Muscle losses its ability to ________ during strenuous exercise, from accumulation of ______ acid in the muscle. _______ acid prevents muscle from contracting A ____________ occurs due to a lack of ______ required to get rid of the ___________ so muscle fibers can ________

Fatigue cont…

 Other causes of muscle fatigue  .

 .

 .

 .

IX. Muscle Function

 _____________ is achieved by sustained contraction within a muscle, and is needed for normal posture

Function cont…

 Slow Fibers  Muscle fibers that are __________ to fatigue  Use causes them to develop more _____________ (running, swimming, etc.)

Function cont…

 Fast Fibers  Forceful exercise (___________) causes muscles to ________    New ____ and ______ develop _______ of muscle fibers increase Entire muscle enlarges (_____________________________!)

Function cont…

 Use/Disuse  Muscular ___________   Decrease in ____ and ________ of muscles due to disuse (accidents, etc.) Less mitochondria, actin, and myosin  Muscular ____________  ____________ muscles due to increased ______/__________

Function cont…

 Muscle strain/Pull  ______ – few fibers injured, fascia still in tact, little loss of function  ______ – many fibers and fascia injured and torn, loss of function, pain, discoloration, swelling of tissues

Function cont…

 __________________ – sustained, forceful contraction that lacks relaxation  _________________ – Muscle contraction at time of death    Muscles run out of _____, and Ca can NOT be removed Constant state of contraction for ____ hours or more ____ and ______ remain linked until muscle cells decompose

X. Life Span Changes

 myoglobin, ATP, and creatine phosphate decline  by age 80, half of muscle mass has atrophied  adipose cells and connective tissues replace muscle tissue  exercise helps to maintain muscle mass and function

XI. Clinical Applications

Myasthenia Gravis

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autoimmune disorder receptors for acetylcholine on muscle cells are attacked weak and easily fatigued muscles result difficulty swallowing and chewing ventilator needed if respiratory muscles are affected treatments include

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drugs that boost acetylcholine

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removing thymus gland immunosuppressant drugs antibodies