02 Articulations and intro to muscle tissue MJB PDF

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Functional Classification of Joints Synarthrosis * an immovable joint * common in the axial skeleton * Amphiarthrosis * a slightly movable joint * common in axial skeleton * Diarthrosis * a freely mobile joint * common in the appendicular skeleton *

Joints Based on Structure Based on * Type of connective tissue that binds the articulating surfaces of the bones * Whether a space occurs between the articulating bones

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Structural Classification of Joints Fibrous joint * bones are held together by dense regular (fibrous) connective tissue * no joint cavity

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doesn’t line the hyaline cartilage

Cartilaginous joint bones are joined by cartilage (classify by the type of cartilage) no joint cavity Synovial joint * has a fluid-filled synovial cavity; bones are enclosed within a capsule * bones are stabilized by various ligaments

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plane, hinge, pivot, etc.

Types of Joints (structural classification) * Fibrous * suture * gomphosis * syndesmosis *

Cartilaginous * synchondrosis * hyaline cartilage * symphysis 1

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* fibrocartilage Synovial * plane * hinge * pivot * condylar * saddle * ball-and-socket

Synovial Joint: Structural Characteristics Synovial Joint: Joint Cavity * * *

“Potential” space that holds synovial fluid Separates articulating bones Helps reduce friction

Synovial Joint: Articular Cartilage * Thin layer of hyaline cartilage covering all articulating bones in a synovial joint * Avoids direct bone-to-bone contact during compression of joint Synovial Joint: Articular Capsule * Surrounds entire joint * Double layered capsule * Fibrous layer (fibrous capsule) * Synovial membrane

Synovial Joint: Articular Capsule * Fibrous layer * outer layer * dense regular connective tissue to strengthen the joint

Synovial Joint: Articular Capsule * Synovial membrane * Inner layer * Composed primarily of areolar connective tissue * Lines joint cavity and covers surfaces not covered by articular cartilage

Synovial Joint: Articular Capsule Synovial membrane * Secretes synovial fluid * A viscous, oily fluid

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Lubricates the articular cartilages Provides nourishment to the articular cartilages Acts as a shock absorber during compression of the joint

Synovial Joint: Ligaments, Nerves and Blood Vessels * Ligaments * connect one bone to another bone * strengthen and reinforce most synovial membranes * Nerves * detect painful stimuli when the joint is stretched to an excess * Blood vessels * provide nourishment to the joint

Types of Synovial Joints * Classified by * The shapes of their articulating surfaces * Types of movement they allow

Types of Synovial Joints * Movement of a bone at a synovial joint * Uniaxial * bone moves in just one plane * Biaxial * bone moves in two planes * Multiaxial (or triaxial) * the bone moves in multiple planes

Types of Synovial Joints From least movable to most freely movable, the six specific types of synovial joints are * plane (gliding) joints * hinge joints * pivot joints * condylar (ellipsoid) joints * saddle joints * ball-and-socket joints

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Types of Movement at Synovial Joints (table  9.2) Gliding motion * Angular motion (mostly used when considering the lower extremeties) * Rotational motion *

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Special movements

Types of Movement at Synovial Joints: Angular Motion * Angle between articulating bones increases or decreases * Flexion * Extension * Hyperextension * Abduction * Adduction * Circumduction Angular Motion: Hip joint

Angular Motion: Knee Joint

Types of Movements at Synovial Joints: Special Movements * Dorsiflexion * movement of dorsum of foot toward anterior crest of tibia * Plantar Flexion * depressing the foot * Pointing the toes * standing on “tiptoe”

Special Movements * Eversion of the foot * turn sole of foot to face laterally * Inversion of the foot * turn sole of foot medially

Joints of the Pelvic Girdle and Lower Limbs * Anatomical name * Structural classification * Functional classification

Synovial Joints: Lower limb (table 9.5) Sacroiliac Coxal joint * Knee Joint * Patellofemoral * *

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Tibiofemoral Tibiofibular (superior) Talocrural Intertarsal Tarsometatarsal Metatarsophalangeal Interphalangeal

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Anatomical name: Sacroiliac joint * Structural classification * Synovial, plane *

Functional classification * diarthrosis

Sacroiliac joint * anterior sacroiliac jt. * synovial, plane *

posterior * fibrous, syndesmosis

Ligaments * sacrospinous * sacrum to ischial spine * sacrotuberous * sacrum to ischial tuberosities

Anatomical name: Pubic Symphysis * Structural classification * cartilaginous, symphysis * Functional Classification * amphiarthrosis

Anatomical name: Coxal Joint * the acetabular labrum is made up of cartilage that extends out of the coxal joint to allow for the socket to deepen *

Structural classification 5

synovial, ball and socket Functional Classification * diarthrosis *

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Knee Joint Anatomical name * Patellofemoral * Patella and femur * Tibiofemoral * Tibia and femur

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❖ A ligament will connect bone to bone

Anatomical name: patellofemoral Structural classification * Synovial, plane * Synovial, hinge

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Functional classification diarthrosis

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Anatomical name: tibiofemoral Structural classification * Synovial, hinge*

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Functional classification * diarthrosis

Unhappy triad * Injury to three structures in the knee * anterior cruciate ligament (ACL) * tibial collateral ligament (MCL) * medial meniscus 

Tibiofibular joint * Anatomical name * Superior Tibiofibular jt. * Head of fibula and lateral condyle of tibia *

Inferior Tibiofibular jt. Distal end of fibula and fibular notch of tibia

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Anatomical name: Superior tibiofibular * Structural classification * Synovial, plane Functional classification Diarthrosis

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Anatomical name: Inferior tibiofibular * Joint between distal end of fibula and fibular notch of tibia Structural classification Fibrous, syndesmosis

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Functional classification * amphiarthrosis

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Interosseous membrane * Structural classification * Fibrous, syndesmosis *

Functional classification * Amphiarthrosis

Epiphyseal plate Structural classification * Cartilaginous, synchondroses

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Functional classification Synarthroses

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Anatomical name: talocrural joint * Structural classification * Synovial, hinge * joint between distal end of tibia/medial malleolus and the talus * lateral malleolus of fibula and lateral aspect of talus * Functional classification * diarthrosis

Anatomical name: intertarsal * Structural classification * Synovial, plane 7

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Functional classification Diarthrosis

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Anatomical name: talocalcaneal Subtalar * Allows inversion and eversion of foot * Structural classification * Synovial, plane * Functional classification * Diarthrosis *

Anatomical name: tarsometatarsal Structural classification * Synovial, plane * Functional classification * Diarthrosis *

Anatomical name: metatarsophalangeal Structural classification * Synovial, condylar * Functional classification * Diarthrosis *

Anatomical name: interphalangeal * Structural classification * Synovial, hinge * Functional classification * Diarthrosis

Classification of Muscle Tissue * Types of Muscle * Skeletal * Cardiac * Smooth * Contraction mechanism is somewhat similar * Differences in appearance, location, physiology internal organization, and means of control by the nervous system

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Skeletal Muscle * Cells (muscle fibers) * long and cylindrical * can be as long as the entire muscle * Multinucleated * Needed to control and carry out cell functions * Striated * striped internal appearance * voluntary contractions * Neurons that stimulate contraction are motor neurons * Attached to bones of the skeleton

Smooth Muscle * Non-striated * Involuntary contractions * Location * walls of most internal organs * walls of blood vessels * Contraction causes movement of food, blood, sperm

Smooth Muscle Fibers * Short fusiform cells (widest in the middle and tapered and each end) * One centrally located nucleus * No striations

Cardiac Muscle * Cells are shorter than skeletal fiber cells * Branching cells, Y-shaped * Cells are connected to each other by strong gap junctions called intercalated discs * allow rapid passage of electrical current from one cell to the next during each heart beat * Contraction causes movement of blood * Striated and involuntary

Chapter 9 Skeletal Muscle Tissue and Muscle Organization Functional Properties of Muscle Tissue * Excitability * Contractility 9

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Elasticity Extensibility

Properties of Muscle Tissue * Excitability * Muscle cells are responsive to input from stimuli * Stimulus from environment results in electrical nerve impulse that stimulates the muscle cell to contract *

Contractility * long cells shorten and generate pulling force on bones or body specific body parts

Properties of Muscle Tissue * Elasticity * a muscle fiber’s ability to return to its original length when the tension of contraction is released * not the ability to stretch *

Extensibility capable of extending in length in response to the contraction of an opposing muscle * relates to flexion & extension

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Functions of Muscle Tissues * Smooth muscle * Squeezes fluids and other substances through hollow organs *

Cardiac muscle tissue Pump blood

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Functions of Muscle Tissue Skeletal Muscle * Body movement * Maintenance of posture * Temperature regulation * Storage and movement of materials * Support

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Functions of Skeletal Muscle Tissue Body Movement

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Bones of the skeleton move when muscle contract and pull on the tendons by which the muscles are attached to the bones Maintenance of posture * enables the body to remain sitting or standing; Joint stabilization Temperature generation * Heat generation * muscle contractions produce heat * Helps maintain normal body temperature *

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Functions of Skeletal Muscle Tissue * Storage and movement * Sphincters (circular muscle bands) * gastrointestinal and urinary * Support * Abdominal muscles * hold abdominal organs in place

Muscle Tissue Comprised of cells called fibers When stimulated by the nervous system, fibers shorten or contract The result of contraction is movement * voluntary and involuntary movement * movement of bones, blood, food, sperm

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Basic Features of Skeletal Muscle: Connective Tissue Components * Three layers of connective tissue * Encircle each individual muscle fiber * Encircle groups of muscle fiber * Encircle the entire muscle itself * Composed of collagen and elastic fibers * Function * Protection * Sites of distribution for nerves and blood vessels * Means of attachment to the skeleton Basic Features of Skeletal Muscle: Connective Tissue Components * Layers of connective tissue * Endomysium * Perimysium * Epimysium * Continuous with tendons 11

Basic features of skeletal muscle * Endomysium * Innermost connective tissue layer * Covers each muscle fiber (cell) * Areolar CT * type of loose CT * Reticular fibers help bind neighboring muscle fibers Basic features of skeletal muscle * Perimysium * Surrounds each fascicle * Dense irregular connective tissue * Contains numerous neurovascular bundles * extensive arrays of blood vessels and nerves * supply the fascicles Basic features of skeletal muscle * Epimysium * Covers the entire skeletal muscle * Dense irregular connective tissue Basic features of skeletal muscle * Deep fascia: (visceral or muscular fascia) * Covers the 3 layers of connective tissue * Separates individual muscles * Binds muscles with similar functions * Dense irregular connective tissue * Forms sheaths * Is deep to superficial fascia (i.e. subcutaneous layer or hypodermis)

Skeletal Muscle Attachments * At the ends of a muscle * the connective tissue layers merge to form a fibrous tendon * Tendons attach * Muscle to bone * Muscle to skin * Muscle to another muscle

Skeletal Muscle Attachments * Aponeurosis * a broad, flat tendon that attaches muscle to muscle Muscle Attachments 12

Most skeletal muscles extend over a joint have attachments to both articulating bones of that joint * Muscle contraction * one of the articulating bones moves and the other one doesn’t Muscle Attachments * Origin * The point of attachment to the bone that doesn’t move *

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Insertion * The point of attachment to the bone that does move Muscle Attachments * Biceps brachii (long head) * Origin = supraglenoid tubercle * Insertion = radial tuberosity * Action = flexes forearm *

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Triceps brachii (long head) * Origin = infraglenoid tubercle * Insertion = olecranon process of ulna * Action = extension of forearm

Actions of Skeletal Muscles * Skeletal muscles * Do not work in isolation * Work together to produce movements * Grouped according to their primary actions * Agonists * Antagonists * Synergists Actions of Skeletal Muscles Agonist (prime mover) * produces a specific movement when it contracts * biceps brachii * an agonist that causes flexion of the elbow joint * Antagonist * a muscle whose action opposes that of an agonist * triceps brachii * an antagonist to the biceps brachii * Synergist * a muscle that assist the agonist (i.e. prime mover)

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Gross Anatomy of Skeletal Muscle 13

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Muscle Fascicles Muscle fiber Myofibrils Myofilaments Actin and myosin

Naming of Skeletal Muscles Muscle action * Specific body regions * Muscle attachments * Orientation of muscle fibers * Muscle shape & size * Muscle heads/tendons of origin * Unusual features *

Naming of Skeletal Muscles * Muscle action * Adductor - adductor magnus * Abductor – abductor pollicis magnus * Specific body regions * Rectus femoris – thigh * Tibialis anterior – anterior surface of the tibia *

Muscle attachments Sternocleidomastoid * Origin on sternum and clavicle * Insertion on mastoid process of the temporal bone Orientation of muscle fibers * Rectus – straight * Oblique – angle * Orbicularis - circular

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Muscle shape & size Deltoid (triangular) – Deltoid muscle * The upper-case letter Δ * Quadratus (rectangular) – pronator quadratus * Trapezius (trapezoidal) - Trapezius Muscle heads/tendons of origin * Biceps (two heads) – biceps femoris * Triceps (three heads) – triceps brachii * Quadriceps (four heads) – quadriceps femoris *

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