10 31 14 Lecture 24 2 ways to classify joints Amrita Bhatt Functional based on amount of movement allowed at the joint o 3 types Synarthrotic joints synathroses immovable joints Amphiarthrotic joints ampliaarthroses slightly movable joints Diarthrotic joints diarthroses freely movable joints Cartilaginous joints o 2 types Synchondroses cartilaginous joints with bones connected by hyaline cartilage Symphyses Joints 3 Structural classes assign functional classes Fibrous joints joint cavity is absent and the bones are connected directly by fibrous connective tissue Dense Regular CT Fibrous Joints 3 Types Sutures present only in the skull connect cranial bones short fibrous material connecting adjacent cranial bones o Sutures in the skull of a child are ampiarthrotic important b c allow for the growth expansion of the brain to reach or attain the normal brain size 3 5 pounds o Once the average brain size is reached the sutures gradually ossify Dense Regular CT bone tissue o Ossified sutures are called synostoses synarthrotic joints o The cranial bones are not movable and the cranial bones form a cranial vault protect matured brain Gomphoses o Short fibrous cords called periodontal ligaments that connect the cemetum around the root of a tooth to the alveolar socket in the mandible or maxillae o Gomphoses in deciduous milk teeth in the child are amphiarthrotic joints allow for movement and eventually loss of deciduous teeth to allow for the permanent teeth to come through o Gomphoses of permanent teeth are synarthrotic joints o In periodontal diseases tooth loss may occur o Cord of dense fibrous CT ligament synarthrotic joints o Membranous dense fibrous CT interosseous membrane amphiarthrotic joint between ulna radius allows for pronation Syndesmoses 2 types 2nd structural class of joints cartilaginous joints Joint cavity absent and bones are connected by cartilage 2 types of cartilaginous joints Synchondroses synarthrotic Symphyses amphiarthrotic joints Synovial joints a joint cavity present which allows for more bones at the joint site all synovial joints are freely movable All are Diarthrotic joints Some are more movable than others 11 3 14 Lecture 25 Synovial Joints articulations Plane joint articulating surface of 1 flat 2 flat Hinge joint 1 trough 2 cylindrical projection Pivot joint in ppt Condyloid joint in ppt Saddle joint in ppt Ball and socket joint in ppt Amrita Bhatt Exam will ask for surfaces forming each of the joints what type of joint is the atlanto occipital joint and what do we use it for Ligaments reinforce synovial joints 3 types capsular intrinsic extracapsular intracapsular Only one area that s an example of a saddle joint carpometacarpal joint of thumb Flexion extension abduction adduction circumduction everything except rotations Arthritis a disease characterized by inflammation of synovial membranes that cause stiff and painful joints 3rd organ system Muscular System Joints are the functional system for the skeletal and muscular system 3 types of muscle tissues Skeletal muscle tissue o Elongated skeletal muscle o Cells fibers o Multinucleated o Striated Cardiac muscle tissue o Branched cells with intercalated discs o Uninucleated o Striated Smooth muscle tissue o Spindle shaped cells o Uninucleated o Non striated When each tissue type is organized with connective tissue blood vessels and nerve endings will form muscles organs Will form skeletal muscle cardiac muscle and smooth muscle Functional differences Skeletal muscle o Voluntary control Cardiac muscle o Involuntary control Smooth muscle o Involuntary control Skeletal muscle is attached to either bone or cartilage most of the time to bone Origin and insertion can give you an idea of the function Origin won t move much insertion will move when muscle contracts Skeletal Muscle the organ Attaches to structures in the skeletal system hence the name Each skeletal muscle o Insertion o Origin bones How do skeletal muscles attach to structures in the skeletal system o Indirect attachment epimysium of the skeletal muscle is extended by a tendon which attaches to the skeletal muscle to the surface of a bone 99 of skeletal muscles in the human body are attached indirectly o Direct attachment epimysium fuses directly with the fibrous layer of the periosteum of the bone Advantages of Indirect Attachment of Skeletal Muscles in the Human Body Allows for more skeletal muscles to be attached to the same bone better packaging of skeletal muscles allows for the function action of skeletal muscle agonistic synergistic muscles antagonistic muscles Allows for bones esp long bones to act as levers when hen the skeletal muscle contracts movement Prevents direct contact between the rough surface of the bone and the fleshy skeletal muscle protection Skeletal muscle the organ muscle the organ All the skeletal muscle fibers run the entire length of the skeletal Sarcolemma PM of skeletal muscle fiber Makes transverse tubules involutions of the sarcolemma in to the sarcoplasm Sarcoplasmic reticulum specialized smooth ER that stores releases calcium 11 5 14 Lecture 26 Amrita Bhatt Sarcolemma invaginations or inward folding structures called transverse tubules T tubules Fold into the sarcoplasm and each T tubule passes through 2 terminal cisternae expanded ends of the SR Terminal cisterna of SR1 t tubule terminal cisterna of SR2 o Order o As a whole it s a triad SRs Triad transverse tubule passes through 2 terminal cisternae of 2 Myofibrils occupy 80 of the volume of the skeletal muscle fiber Myofibrils run the entire length of the skeletal muscle fiber Each myofibril is composed of smaller units called myofilaments 2 types of myofilaments o Thin 8 nm diameter o Thick 16 nm wider diameter o Striated appearance of skeletal muscle thick and thin are alternating Myofibril thick filaments and the thin filaments are arranged in an alternating pattern Explains striations of skeletal muscle Thick filaments Composed of 300 molecules of the protein myosin Myosin o Rod like tail o Ends in 2 globular heads Globular heads are referred to as myosin globular heads Arrangement rod like tails of myosin molecules bundle to form the core of the thick filaments with the myosin globular heads exposed Exposed globular heads will have 2 binding sites Myosin globular heads contain the enzyme ATPase splits ATP into o Actin binding site o ATP binding site ADP and Pi o ATPase 2 isomers Slow acting ATPase Fast acting ATPase Actin o 2 binding sites Myosin
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