BIOL 235 Chapter 9, questions and answers with complete solutions

BIOL 235 Chapter 9, questions and answers with complete solutions What is an articulation? A joint (or arthrosis); a point of contact between 2 bones, a bone and cartilage, or bone and teeth What are the 2 main ways joints are classified? Structurally (based on anatomical characteristics) and functionally (based on type of movement) What are the different structural classifications of joints? Structural joints are classified based on presence or absence of a synovial cavity and tissue type Fibrous: no synovial cavity, dense irregular connective tissue (rich in collagen) Cartilaginous: no synovial cavity, cartilage Synovial: synovial cavity present, dense irregular connective tissue (of articular capsule and accessory ligaments) What are the different functional classifications of joints? Functional joints are classified by the degree of movement they permit Synarthrosis: an immovable joint Amphiarthrosis: a slightly movable joint Diarthrosis: a freely movable joint with a variety of shapes and sizes (all are synovial joints) What is a fibrous joint? A joint in which articulating bones are held very close together, permits little or no movement What are the 3 main types of fibrous joints? Suture: made of a thin layer of dense irregular connective tissue, only occur between skull bones where interlocking edges give strength and absorb shocks (synostosis: a bony joint with complete fusion of 2 bones with no movement; frontal/metopic suture: persists beyond age 6) Syndesmosis: dense irregular connective tissue arranged in a bundle with more distance between articulating surfaces, allows limited movement (gomphosis: dentoalveolar joint has no movement) Interosseous membrane: a substantial sheet of dense irregular connective tissue that binds long bones, permits slight movement (amphiarthrosis) What is a cartilaginous joint (2 types)? Articulating bones are tightly connected by hyaline or fibrocartilage Synchondrosis: hyaline cartilage connects joint (e.g. epiphyseal plate, an immovable joint) Symphysis: ends of articulating bones are covered with hyaline cartilage and fibrocartilage discs connect bones (e.g. pubic symphysis) What is a synovial joint? Has a synovial cavity between articulating bones, all joints are freely movable (diarthrosis) Articular cartilage: hyaline cartilage covers articulating surfaces of bones to reduce friction, but doesn't bind them Articular capsule: a sleeve-like joint capsule that encloses the synovial cavity and unites articulating bones (2 layers: outer fibrous membranes called ligaments, and synovial membranes with elastic fibres and sometimes articular fat pads) What is synovial fluid? Fluid secreted by synovial membrane that forms a thin film over articular capsule surfaces to reduce friction, absorb shocks, and supply nutrients/remove wastes (viscous when immobile) What are accessory ligaments? Extracapsular (lie outside articular capsule) or intracapsular (inside articular capsule but outside synovial cavity (e.g. ACL and PCL) What are articular discs (minisci)? Crescent-shaped pads of fibrocartilage that bind to the inside of fibrous membrane and divide the synovial cavity into 2 spaces to allow separate movements What is a labrum? A fibrocartilaginous lip that extends from the edge of a socket (prominent in ball & socket joints, helps deepen the socket) Describe the nerve and blood supply of synovial joints Nerve endings are distributed to the articular capsule and associated ligaments (convey pain and respond to stretch and reflexes) Arterial branches deliver oxygen and nutrients to synovial joints through ligaments and the articular capsule (veins remove carbon dioxide/wastes) Describe the structure and function of bursae Saclike structures filled with fluid, that alleviate friction in joints (have an outer fibrous membrane and inner synovial membrane) Found between skin, tendon, muscles, or ligaments and bones Describe the structure and function of tendon (synovial) sheaths Tube-like bursae that wrap around certain tendons with considerable friction where they pass through connective tissue or bone (in synovial cavities e.g. biceps brachii at shoulder) visceral layer: inner part attached to tendon parietal layer: outer part attached to bone What is gliding? Movement of nearly flat bone surfaces (back and forth or side to side) with no significant change in the angle between bones (can also be combined with rotation e.g. intercarpal/intertarsal joints) What are angular movements? Movements that involve an increase or decrease in the angle between articulating bones, include: flexion/extension, lateral flexion, hyperextension, abduction/adduction/circumduction What is flexion? Movement that decreases the angle between articulating bones, usually along the sagittal plane (lateral flexion: moving the trunk sideways at the waist along the frontal plane) What is extension? Movement that increases the angle between articulating bones (returns body parts to anatomical position after flexion), usually occurs along the sagittal plane (hyperextension: continuation of extension beyond anatomical position) What is abduction? Also called radial deviation; movement away from the midline, usually occurs along frontal plane (e.g. spreading fingers or toes) What is adduction? Also called ulnar deviation; movement toward the midline, usually occurs along frontal plane What is circumduction? Movement of the distal end of a body part in a circle (not an isolated movement: involves flexion, abduction, extension, adduction and rotation) What is rotation? Movement where a bone revolves around its own longitudinal axis (e.g. turning the head or trunk side-to-side) medial (internal) rotation: anterior surface of a limb (bone) turns toward the midline lateral (external) rotation: anterior surface of a limb (bone) turns away from the midline What are special movements? Occur only at certain joints, include: elevation/depression, protraction/retraction, inversion/eversion, dorsiflexion/plantar flexion, supination/pronation and opposition What is elevation? Superior movement of a body part (e.g. shrugging the shoulders) What is depression? Inferior movement of a body part (e.g. opening the mouth depresses the mandible) What is protraction? Movement of a body part anteriorly in the transverse plane (forward) (e.g. thrusting the mandible outward) What is retraction? Movement of a body part back to the anatomical position after it's been protracted What is inversion? Movement of the soles medially at intertarsal joints What is eversion? Movement of the soles laterally at intertarsal joints What is dorsiflexion? Bending the foot at the talocrural joint (ankle) in the direction of the dorsum (superior surface) (e.g. standing on your heels) What is plantar flexion? Bending the foot at the talocrural joint in the direction of the plantar (inferior surface) (e.g. standing on your toes) What is supination? Movement of the forearm at the proximal/distal radioulnar joints to turn the palm anteriorly What is pronation? Movement of the forearm at the proximal/distal radioulnar joints to turn the palm posteriorly What is opposition? Movement of the thumb where it moves across the palm to touch the fingers on the same hand What are the 6 subtypes of synovial joints? Plane, hinge, pivot, condyloid/ellipsoidal, saddle, ball & socket joints What is a planar joint? A synovial joint where articulating surfaces are flat, biaxial if they permit back and forth/side-to-side movements (triaxial if they also rotate against each other) (e.g. intercarpal/intertarsal joints) What is a hinge (ginglymus) joint? A synovial joint where the convex surface of a bone fits into the concave surface of another to produce an angular, flexion/extension (open/close) motion (uniaxial) (e.g. elbow, ankle) What is a pivot (trochoid) joint? A synovial joint where the rounded or pointed surface of a bone articulates with a ring formed by another bone or ligament, uniaxial (e.g. atlanto-axial joint in the head) What is a condyloid (ellipsoidal) joint? A synovial joint where the convex oval-shaped projection of one bone fits into the oval-shaped depression of another, allow flexion/extension and abduction/adduction (biaxial) (e.g. radiocarpal wrist joints) What is a saddle (sellar) joint? A synovial joint where the articular surface of one bone is saddle-shaped and the other bone fits on like a 'rider' (biaxial movement same as condyloid) (e.g. carpometacarpal joint) What is a ball & socket (spheroid) joint? A synovial joint where the ball-like surface of one bone fits into the socket-like depression of another (triaxial movement) (e.g. shoulders, hips) Explain the tibiofemoral joint Knee joint; largest and most complex in the body (a modified hinge joint with 3 joints in 1 synovial cavity) 1. lateral tibiofemoral joint 2. medial tibiofemoral joint 3. patellofemoral joint What is the articular capsule of the knee joint? A ligamentous sheath consisting of muscle tendons surrounds the joint (no independent capsule unites all bones in the knee joint) What is the patellar ligament? A continuation of the tendon of the quadriceps femoris muscle that extends from the patella to the tibial tuberocity (strengthens the anterior surface of the knee joint) What is the tibial collateral ligament? TCL; a broad, flat ligament on the medial surface of the knee joint that is firmly attached to the medial meniscus (extends from the medial condyle of the femur to the tibia) What is the fibular collateral ligament? FCL; a strong, rounded ligament on the lateral surface of the knee joint that strengthens the joint's lateral aspect (extends from the lateral condyle of the femur to the lateral side of the fibula head) What are the menisci? Two fibrocartilage discs between the tibial and femoral condyles on the knee that help compensate for the irregular shape of bones and circulate synovial fluid (includes C-shaped medial meniscus, and O-shaped lateral meniscus) What is the anterior cruciate ligament? ACL; extends from the anterior intercondylar area of the tibia to the medial posterior part of the femur's lateral condyle (front to back); limits hyperextension and prevents anterior sliding of the tibia on the femur (damaged in 70% of knee injuries) What is the posterior cruciate ligament? PCL; extends from a depression on the posterior intercondylar area of the tibia to the lateral anterior part of the femur's medial condyle (back to front); prevents posterior sliding of the tibia and anterior sliding of the femur when the knee is flexed (e.g. when walking down a steep incline) What is rheumatism? Any disorder of body's supporting structures (bones, ligaments, tendons, muscles) not caused by infection or injury (e.g. arthritis) What is osteoarthritis (OA)? A degenerative joint disease (progressive synovial joint disorder) where joint cartilage is lost (most common type); cartilage degenerates and exposed bone ends develop spurs which restrict joint movement Causes: aging, obesity, joint irritation, muscle weakness, wear and tear (affect large joints first) What is rheumatoid arthritis (RA)? An autoimmune disease where the body attacks cartilage and joint linings, causing joint inflammation (swelling, pain, loss of function); membrane thickens, fluid accumulates, which causes pressure; fibrous tissue ossifies over exposed bone ends, making joints immovable (can also cause finger distortion) What is gouty arthritis? Gout is an excess of uric acid in the body that causes sodium urate crystals to form and accumulate in joint cartilage (usually in the feet); these crystals erode cartilage until ends of joint bones fuse and become immovable Treatment: allopurinol (lowers uric acid levels) What is Lyme disease? Caused by Borrelia burgdorferi bacteria from ticks (usually causes a bull's-eye shaped rash at tick bite site); usually affects large joints Symptoms: joint stiffness (arthritis), fever/chills, headache, stiff neck, nausea, lower back pain Treatment: antibiotics (usually effective but symptoms may persist)