Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Muscular System  Muscles are responsible for all types of body movement  Three basic muscle types  Skeletal muscle  Cardiac muscle  Smooth muscle

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Muscles  Muscle cells are elongated (muscle cell = muscle fiber)  Contraction is due to the movement of microfilaments

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Characteristics  Most are attached by tendons to bones  multinucleate  Striated  Voluntary  Cells surrounded by connective tissue

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Attachments SS ites of muscle attachment BB ones CC artilages CC onnective tissue coverings

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Smooth Muscle Characteristics  no striations  Spindle-shaped cells  Single nucleus  Involuntary  Found in walls of hollow organs Figure 6.2a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Characteristics  Has striations  single nucleus  Involuntary  Found only in the heart Figure 6.2b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Function of Muscles  Produce movement  Maintain posture  Stabilize joints  Generate heat

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Skeletal Muscle  Cells are multinucleate  Nuclei are just beneath the sarcolemma Figure 6.3a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6.3b Microscopic Anatomy of Skeletal Muscle  Myofibril  Bundles of myofilaments  Myofibrils are aligned to give distinct bands  I band = light band  A band = dark band

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Skeletal Muscle  Sarcomere  Contractile unit of a muscle fiber Figure 6.3b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Actin and Myosin are protein filaments

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Stimulus to Muscles  Skeletal muscles must be stimulated by a nerve to contract Figure 6.4a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Stimulus to Muscles  Synaptic cleft – gap between nerve and muscle Figure 6.5b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscles and Body Movements  Movement is attained due to a muscle moving an attached bone Figure 6.12

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscles and Body Movements  Muscles are attached to at least two points  Origin – attachment to a immoveable bone  Insertion – attachment to an movable bone Figure 6.12

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscles and Body Movements Muscles are classified by their movements Flexor – a muscle that bends a joint Extensor – a muscle that straightens a joint

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscular Contraction  Requires energy in the form of ATP  One ATP is needed for each movement of the myosin heads.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Response to Strong Stimuli  Muscle force depends upon the number of fibers stimulated  More fibers contracting results in greater muscle tension  Muscles can continue to contract unless they run out of energy

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Head and Neck Muscles Figure 6.15

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Trunk Muscles Figure 6.16

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Deep Trunk and Arm Muscles Figure 6.17

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscles of the Pelvis, Hip, and Thigh Figure 6.19c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscles of the Lower Leg Figure 6.20

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Superficial Muscles: Anterior Figure 6.21

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Superficial Muscles: Posterior Figure 6.22

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Quiz Review  Be able to locate and label on a given diagram:  Biceps brachii, Triceps brachii, Trapezius, Latissimus dorsi, Deltiod, Pectoralis major,  Biceps femoris, Rectus femoris, Sartoris, Gastronemius & Gluteus maximus   Gastrocemius