Human Anatomy and Physiology Eleventh Edition Chapter 10 PDF

Human Anatomy and Physiology Eleventh Edition Chapter 10 The Muscular System PowerPoint® Lectures Slides prepared by Karen Dunbar Kareiva, Ivy Tech Community College...

Human Anatomy and Physiology Eleventh Edition Chapter 10 The Muscular System PowerPoint® Lectures Slides prepared by Karen Dunbar Kareiva, Ivy Tech Community College Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  10.1 Muscle Actions and Interactions Muscles can only pull; never push What one muscle group “does,” another “undoes” 3 main functional groups: – Prime mover (agonist)  Has primary responsibility for a movement – Antagonist  Opposes or reverses particular movement – Prime mover and antagonist are located on opposite sides of joint across which they act – Synergist helps prime movers  Adds extra force to same movement  Reduces undesirable or unnecessary movement  Fixators: type of synergist that immobilizes bone or muscle’s origin rather than enhancing movement of prime movers – Gives prime mover stable base on which to act Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Remember! Muscle attachment sites (origin and insertion) Origin- stationary end Insertion- movable end Action- movement that occurs when muscle contracts. (Most often insertion is pulled toward the origin) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 10.4 Lever Systems Most skeletal muscles move using leverage Components of lever system – Lever: rigid bar (bone) that moves on a fixed point called fulcrum (joint) – Effort: force (supplied by muscle contraction) applied to lever to move resistance (load) – Load: resistance (bone + tissues + any added weight) moved by the effort Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Levers: Power Versus Speed Levers allow given effort to move heavier load or to move load farther or faster – Depends on fulcrum position relative to load and effort Mechanical advantage (power lever): load is close to fulcrum, with effort far from fulcrum – Small effort can move large load Mechanical disadvantage (speed lever): load is far from fulcrum, with effort close to fulcrum – Load moved rapidly over large distance; offers wider range of motion Power Speed Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Lever Systems Operating at a Mechanical Advantage and a Mechanical Disadvantage Figure 10.2 Lever systems operating at a mechanical advantage and a mechanical disadvantage. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Classes of Lever Systems (123 FLE) Three classes of levers are based on relative position of effort, fulcrum, load First-class lever – Fulcrum is between load and effort – Example: seesaw, scissors Second-class lever – Load is between fulcrum and effort – Example: wheelbarrow, standing on toes Third-class lever – Effort is applied between fulcrum and load – Example: tweezers, forceps, most skeletal muscles Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Summary of lever systems In mechanical disadvantage (speed levers) force is lost, but speed and range of movement are gained Systems operating under mechanical advantage (power levers) are slower, but more stable – Used where strength is a priority Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Range of motion (ROM) and power output for whole muscles Fiber length determines ROM – Longer muscles provide greater ROM (fibers shorten to 70% of resting length when contracting) Cross-sectional area determines power output – Greater cross-sectional area provides greater force of contraction Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 10.5 Major Skeletal Muscles of the Body Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Head: Facial Expression Facial expression muscles are different because they insert into skin, not bone – Origin is in fascia or on skull bones Important in nonverbal communication Occipitofrontalis (Epicranium)- raises eyebrows, wrinkles forehead Orbicularis oculi- closes eyes (blink) Orbicularis oris- purses lips (kiss) Zygomaticus major and minor- raises corner of mouth (smile) Platysma- draws angle of mouth downward (pout) Nasalis- flares nose Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Lateral View of Muscles of the Scalp, Face, and Neck Figure 10.6b (continued) Lateral view of muscles of the scalp, face, and neck. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Head: Mastication Masseter- elevates and protracts mandible Temporalis- elevates and retracts mandible Buccinator- compresses cheeks Medial pterygoid- elevates mandible, moves mandible side to side Lateral pterygoid- depresses and protracts mandible (pulls on mandibular condyle), moves mandible side to side Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Promoting Mastication Figure 10.8a Muscles of mastication and tongue movement. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Promoting Mastication Figure 10.8b Muscles of mastication and tongue movement. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Neck: Head movement Sternocleidomastoid – rotates the head, flexes and laterally flexes the neck, elevates the sternum (aiding in inhalation) Splenius capitis – rotates head, extends and laterally flexes neck Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Deep Muscles of the Thorax: Breathing Two phases of breathing: inspiration (inhaling) and expiration (exhaling) Diaphragm and external intercostals Inspiratory muscles – Contraction of these muscles enlarges rib cage – Diaphragm divides thoracic and abdominal cavities Internal intercostals Expiratory muscles – Relaxation of inspiratory muscles too! (decreases size of rib cage) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of Respiration Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Abdominal Wall Four paired muscles: their fasciae and aponeuroses form lateral and anterior abdominal wall – Rectus abdominis compresses abdomen, flexes lumbar spine – External obliques and internal obliques Compresses abdomen, rotates trunk – Transversus abdominis compresses abdomen Help promote urination, defecation, childbirth, vomiting, coughing, and screaming Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Abdominal Wall Figure 10.12a Muscles of the abdominal wall. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Abdominal Wall Figure 10.12b Muscles of the abdominal wall. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Thorax and Shoulder: Movements of the Pectoral girdle Trapezius – rotates, retracts, elevates and depresses scapula (depresses shoulder); also extends neck Rhomboid major – retracts, elevates, rotates scapula Rhomboid minor – retracts and elevates scapula Levator scapulae – elevates scapula Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Thorax and Shoulder: Movements of the Pectoral girdle Pectoralis minor- pulls scapula forward and downward, elevates ribs Serratus anterior – pulls scapula anteriorly and downward Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Shoulder Joint: Movements of the Arm (Humerus) Nine muscles cross shoulder joint Insert on and move humerus Seven originate from scapula; pectoralis major and latissimus dorsi originate on axial skeleton – Pectoralis major – flexes and adducts arm, medial rotation of arm – Latissimus dorsi – extends and adducts arm, rotates arm medially, rotates trunk – Deltoid - abducts, extends, and flexes arms Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Shoulder Joint: Movements of the Arm (Humerus) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Shoulder Joint: Movements of the Arm (Humerus) Rotator cuff muscles act as synergists and fixators; originate on scapula; reinforce shoulder capsule; prevent dislocation – Supraspinatus – abducts arm – Infraspinatus – rotates arm laterally – Teres minor – rotates arm laterally – Subscapularis - rotates arm medially Coracobrachialis and teres major: synergists (assist) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Shoulder Joint: Movements of the Arm (Humerus) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Shoulder and Elbow Joints: Movements of the Radius and Ulna Most muscles that move the forearm cause flexion/extension at the elbow Biceps brachii – flexes elbow, flexes and abducts arm, supinates radioulnar joint Triceps brachii –extends elbow, extends and adducts arm Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Forearm: Movements of the Wrist, Hand, and Fingers Extrinsic muscles of the hand originate outside of the hand and insert within it Tendons entering the hand are held close to the bones by fascial bands (flexor and extensor retinaculum) Thumb is positioned at a right angle to the other digits Anterior compartment (Flexors) – Flexor carpi radialis – flexes and abducts wrist – Flexor carpi ulnaris – flexes and adducts wrist – Flexor digitorum superficialis – flexes fingers (digits 2-5) and wrist – Flexor digitorum profundus- flexes distal finger joints Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Forearm: Movements of the Wrist, Hand, and Fingers Figure 10.16a Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Muscles of the Forearm: Movements of the Wrist, Hand, and Fingers Posterior compartment (Extensors) – Extensor carpi radialis longus- extends and abducts wrist – Extensor carpi unlaris – extends and adducts wrist – Extensor digitorum – extends fingers Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Neck and Vertebral Column That Move the Head and Trunk Extensors – Erector spinae muscles- extend spine and influence flexion, lateral flexion, rotation  Iliocostalis  Longissimus  Spinalis – Splenius muscles – extend cervical spine, laterally flex cervical spine, rotate head Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Neck and Vertebral Column That Move the Head and Trunk \ Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Hip and Knee Joints: Movements of the Thigh Thigh flexors pass in front of hip joint – Iliopsoas (iliacus and psoas major)- Flex thigh – Gluteus maximus – extend thigh – Gluteus medius- abducts and rotates thigh medially – Tensor fasciae latae – abducts, flexes, and rotates thigh medially Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Hip and Knee Joints: Movements of the Thigh Figure 10.20a Anterior and medial muscles that move the thigh and leg. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Muscles Crossing the Hip and Knee Joints: Movements of the Thigh Adductors (also medially rotate thigh) are used in movements that press thighs together Overstretched thigh muscles are referred to as “pulled groin” – Adductor magnus – adducts thigh, extends and flexes thigh – Adductor longus – adducts, flexes, and rotates thigh laterally – Adductor brevis – adducts, flexes and rotates thigh laterally – Gracilis – adducts thigh, flexes knee Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Hip and Knee Joints: Movements of the Leg Quadriceps group (anterior thigh muscles) All insert on or near the quadriceps tendon Rectus femoris – extends knee, flexes thigh Vastus lateralis, vastus medialis, and vastus intermedius – extend knee Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles Crossing the Hip and Knee Joints: Movements of the Leg Hamstring group (posterior thigh muscles) Bicep femoris – flexes knee, laterally rotates flexed knee, extends thigh Semitendinosus and semimembranosus - flexes knee and extends thigh Sartorius – flexes knee and thigh, abducts and rotates thigh laterally Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Leg: Movements of the Foot Dorsal Flexor – Tibialis anterior – dorsiflexion, inversion of the foot Plantar flexors – Gastrocnemius – plantar flexion, flexes knee – Soleus – plantar flexion Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Leg: Movement of the Foot Figure 10.22a Muscles of the anterior compartment of the right leg. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Muscles of the Leg: Movement of the Foot Figure 10.24a Muscles of the posterior compartment of the right leg. 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