The Muscular System PDF

PowerPoint® Lecture Slides prepared by Vince Austin, University of Kentucky The Muscular System Part A 10 Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb Copyright © 2004 Pearson Ed...

PowerPoint® Lecture Slides prepared by Vince Austin, University of Kentucky The Muscular System Part A 10 Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Interactions of Skeletal Muscles ▪ Skeletal muscles work together or in opposition ▪ Muscles only pull (never push) ▪ As muscles shorten, the insertion (I) generally moves toward the origin (O) ▪ Whatever a muscle (or group of muscles) does, another muscle (or group) “undoes” Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscle Classification: Functional Groups ▪ Prime movers – provide the major force for producing a specific movement ▪ Antagonists – oppose or reverse a particular movement ▪ Synergists ▪ Add force to a movement ▪ Reduce undesirable or unnecessary movement ▪ Fixators – synergists that immobilize a bone or muscle’s origin Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Naming Skeletal Muscles ▪ Location of muscle – bone or body region associated with the muscle ▪ Shape of muscle – e.g., the deltoid muscle (deltoid = triangle) ▪ Relative size – e.g., maximus (largest), minimus (smallest), longus (long) ▪ Direction of fibers – e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis) Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Naming Skeletal Muscles ▪ Number of origins – e.g., biceps (two origins) and triceps (three origins) ▪ Location of attachments – named according to point of origin or insertion ▪ Action – e.g., flexor or extensor, as in the names of muscles that flex or extend, respectively Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Arrangement of Fascicles ▪ Parallel – fascicles run parallel to the long axis of the muscle (e.g., sartorius) ▪ Fusiform – spindle-shaped muscles (e.g., biceps brachii) ▪ Pennate – short fascicles that attach obliquely to a central tendon running the length of the muscle (e.g., rectus femoris) ▪ Convergent – fascicles converge from a broad origin to a single tendon insertion (e.g., pectoralis major) ▪ Circular – fascicles are arranged in concentric rings (e.g., orbicularis oris) Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Arrangement of Fascicles Figure 10.1 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Bone-Muscle Relationships: Lever Systems ▪ Lever – a rigid bar that moves on a fulcrum, or fixed point ▪ Effort – force applied to a lever ▪ Load – resistance moved by the effort Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Lever Systems: Classes ▪ First class – the fulcrum is between the load and the effort ▪ Second class – the load is between the fulcrum and the effort ▪ Third class – the effort is applied between the fulcrum and the load Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Lever Systems: First Class Figure 10.3a Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Lever Systems: Second Class Figure 10.3b Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Lever Systems: Third Class Figure 10.3c Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Major Skeletal Muscles: Anterior View The 40 superficial muscles here are divided into 10 regional areas of the body Figure 10.4b Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Major Skeletal Muscles: Posterior View ▪ The 27 superficial muscles here are divided into seven regional areas of the body Figure 10.5b Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles: Name, and Action ▪ Name and description of the muscle – be alert to information given in the name ▪ Origin and insertion – there is always a joint between the origin and insertion ▪ Action – best learned by acting out a muscle’s movement on one’s own body Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles of the Scalp ▪ Epicranius (occipitofrontalis) –consisting of the: ▪ Frontalis ▪ Occipitalis ▪ Cranial aponeurosis connecting above muscles ▪ These two muscles have alternate actions of pulling the scalp forward and backward Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles of the Face ▪ 11 muscles are involved in lifting the eyebrows, flaring the nostrils, opening and closing the eyes and mouth, and smiling ▪ Usually insert in skin (rather than bone), and adjacent muscles often fuse Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles of the Face Figure 10.6 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles of Mastication ▪ The main muscles involved in mastication ▪ Prime movers – temporalis and masseter Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Muscles of Mastication Figure 10.7a Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings