Human Anatomy and Physiology: Muscular System PDF

HUMAN ANATOMY and PHYSIOLOGY Chapter 6 & 7: Joints and the Muscular System OBJECTIVES Identify the interactions of the skeletal muscles Recognize how to name skeletal muscles Recall the axial muscles of the head, neck and back List the axial muscles of the abdominal wall a...

HUMAN ANATOMY and PHYSIOLOGY Chapter 6 & 7: Joints and the Muscular System OBJECTIVES Identify the interactions of the skeletal muscles Recognize how to name skeletal muscles Recall the axial muscles of the head, neck and back List the axial muscles of the abdominal wall and thorax JOINTS Location where bones come together Joint stability and movement Structural Classification of Joints Functional Classification of Joints Synarthrosis ◦ Immobile or nearly immobile joints ◦ Provide a strong union between the articulating bones ◦ Provide protection for internal organs Amphiarthrosis ◦ Joint with limited mobility Diarthrosis ◦ Freely mobile joint ◦ All synovial joints of the body Diarthroses 1. Uniaxial joint – motion in a single plane 2. Biaxial joint – motion within two planes 3. Multiaxial joint – motion along three axes  Fibrous Joint Suture– to bind or sew Syndesmosis – fastened with a band Gomphosis – fastened with bolts Cartilaginous Joint  Synchondrosis – joined by hyaline cartilage  Symphysis – growing together ◦ Joined by fibrocartilage Synovial Joint Pivot Hinge Condyloid Saddle Plane Ball and socket Types of Body Movements  Flexion – Extension  Abduction – Adduction  Circumduction  Rotation  Supination – Pronation  Dorsiflexion – Plantar Flexion  Inversion – Eversion  Protraction – Retraction  Depression – Elevation  Excursion  Opposition - Reposition MUSCULAR SYSTEM Functions of Muscle: 1. Movement of Body 2. Maintenance of posture 3. Respiration 4. Production of Body heat 5. Communication 6. Constriction of organs and vessels 7. Contraction of heart Functional properties of muscle tissue Contractility  Ability to shorten forecefully Excitability  Respond to a stimulus Extensibility  Stretched beyond its normal resting length Elasticity  Ability to recoil to its original resting length Smooth Muscles Cardiac Muscles Duchenne Muscular Dystrophy Gross Anatomy of the Muscular System Skeletal Muscle Anatomy Muscle Attachments 1. Origin/ fixed end - Most stationary, proximal end 2. Insertion/mobile end -distal end undergoing the greatest movement ◦ Belly – part of muscle between the origin and insertion ◦ Aponeuroses – broad and sheetlike tendons Action– movement accomplished when muscles contract ◦ Agonist – muscle that accomplishes a certain movement ◦ Antagonist – muscle acting in opposition to an agonist  Synergists– group of muscles working together to produce a movement  Example: ◦ the biceps brachii and the brachialis are synergists in elbow flexion.  Prime mover – major role  Fixators – muscles that hold one bone in place while a usually more distal bone is moved.  Example: ◦ the muscles of the scapula act as fixators to hold the scapula in place while other muscles contract to move the humerus. Muscle Shapes Shape and size influence the degree of contraction and force generated 1. Circular – fasciculi arranged in a circle around an opening and act as sphincters to close the opening 2. Convergent – fascicles arrive at one comment tendon from a wide area, muscles are 3. Parallel – organized parallel to the long axis of the muscle but terminate on a flat tendon that spans the width of the entire muscle 4. Pennate – like feathers from a common tendon that runs the length of entire muscles  Unipennate, bipennate, multipennate 5. Fusiform – fibers run the length of the entire muscle and taper at each end to terminate at tendons Nomenclature Location - A pectoralis (chest) muscle is located in the chest, a gluteus (buttock) muscle is in the buttock, and a brachial (arm) muscle is in the arm. Size - gluteus maximus (large) is the largest muscle of the buttock, and the gluteus minimus (small) is the smallest. Shape - deltoid (triangular), quadratus (quadrate), teres (round) Orientation of fasciculi – rectus (straight), oblique Origin and insertion – sternocleidomastoid, brachioradialis Number of heads – biceps, triceps Function – abductor, adductor, masseter Movements accomplished by muscles Lever ◦ rigid shaft (bone) capable of turning about a hinge, or pivot point, called a fulcrum (joint) and transferring a force applied at one point along the lever to a weight (W), or resistance, placed at another point along the lever. -atlantooccipital joint - END OF CHAPTER