Exam 3 Material_ Notes from pages 73-87
Exam 3 Material_ Notes from pages 73-87 BIOL 2140
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This 10 page Class Notes was uploaded by Kourtney Edwards-Campbell on Tuesday March 1, 2016. The Class Notes belongs to BIOL 2140 at East Carolina University taught by Elizabeth Jones in Winter 2016. Since its upload, it has received 32 views. For similar materials see Human Anatomy and Physiology in Biology at East Carolina University.
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Date Created: 03/01/16
Fracture- a bone that has been broken or cracked Types of Fractures: Non-aligned fracture- bone that has fractured but is still aligned. Displaced fracture- bone that has fractured but is out of alignment. Complete fracture- bone broken completely through. Incomplete fracture- bone not completely broken, part of it is still attached, may be referred to as a crack. Linear fracture- bone fractured in same direction as the bone/ parallel to the long axis. Transverse fracture- perpendicular to the long axis/ bone fractured on a transverse plane. Open/ Compound fracture- when the bone fractures and penetrates the skin. May cause infection, surgery is needed. Closed/ Simple- bone fractures but doesn’t penetrate the skin. Comminuted fracture- bone fragments into three or more pieces. Particularly common in the aged, whose bones are more brittle. Compression fracture- bone is crushed. Common in porous bones subjected to extreme trauma, as in a fail. Spiral fracture- ragged break occurs when excessive twisting forces are applied to a bone. Common in sports fractures. Epiphyseal fracture- epiphysis separates from the diaphysis along the epiphyseal plate. Tends to occur where cartilage cells are dying and calcification of the matrix occurring. Depressed fracture- broken bone is pressed inward. Typical of skull fractures Greenstick fracture- bones break incompletely. Only one side of the shaft breaks and the other side is bent. Bone Disorders Osteomalacia- soft bones, calcium is not deposited so bones are weak. This leads to pain. Rickets- bones such as pelvis, hips and ribcage deform. The legs may bow because of a lack of vitamin D and/or calcium. Occurs in children. Osteoporosis- bone mass is reduced. Leading to them being porous and lighter. The spongy bone of the spine is most vulnerable. Occurs mostly in older men and women and more so in women. Sex hormones restrain the osteoclast activity. Joint Articulation Functional classification- amount of movement Synarthroses- immovable Ampiarthroses- slightly moveable Diarthroses- freely moveable Structural classification- material binding bones together Fibrous- immovable/ slightly moveable Cartilaginous- rigid/ slightly moveable Synovial- freely moving Joints Fibrous joints Bones joined by fibrous tissue No joint cavity Most immovable 3 types Sutures Only skull bones Wavy edged interlock Filled with minimal amount of very short connective tissue Short connective tissue fibers continuous with periosteum Tightly bind bones but allow growth Ossifies as adult , bones fuse to single unit Now called syntoses (bony junction) Syndesmoses Bones connected by a ligament of fibrous tissue Vary in length Length determines movement Ex: ligaments connecting tibia and fibula Gomphoses A peg-in-socket fibrous joint Tooth in bony alveolar socket only Held by short periodontal ligament Cartilaginous Joint- cartilage attaching bone together Synchondroses Bones to bone joint Hyaline cartilage unites bones Virtually all are immovable (synarthrosis) Are temporary joints, become ossified; completely fused (synostoses) Ex: epiphyseal plates Symphyses Hyaline/ articular cartilage is fused to a pad of fibrocartilage Allows limited movement of joint (amphiarthrotic) Designed for strength, shock, absorption, flexibility Synovial Joints Articulating bones are separated by a fluid-filled joint cavity Allows a lot of movement (diarthrotic) All limb joints 5 distinguishing features Articular cartilage Glassy smooth hyaline cartilage Absorbs compression-protective Synovial cavity Unique to synovial cavity Filled with synovial fluid Articular capsule 2 layers External layer- tough, fibrous dense irregular connective tissue Strengthens the joints Inner layer is synovial membrane composed of loose connective tissue Covers all internal joint surfaces that are not hyaline cartilage Synovial Fluid Occupies the joint capsule Is a blood filtrate ( viscous, viscosity decreases as joint warms) Also found in articular cartilage As joint compresses it oozes out When pressure relieved synovial fluid gets soaked back up into cartilage; weeping lubrication Contains phagocytic cells Removal of cell debris Reinforcing Ligament Strengthen joints Most are intrinsic or capsular Are thickening of fibrous capsule Extracapsular- outside capsule Intracapsular- not really within as these ligaments covered with synovial membrane Bursa and tendon sheaths Often closely associated with synovial joints Are bags of lubricants Bursa Flattened sacs Lined with synovial membrane Contain synovial fluid Provide lubrication and padding Bunion is an enlarged bursa Bursitis- painful inflamed bursa Tendon Sheath- an elongated bursae that wraps completely around a tendon Muscle Function of muscle tissue: convert chemical energy into mechanical energy/ force Types: 1. Skeletal 2. Cardiac 3. Smooth How do they differ? Cell structure Body location Function Source of contraction Skeletal muscle is a discrete organ- made of several types of tissue Muscle fibers Blood vessels Nerve fibers Connective tissue Muscle Structure Epimysium- covering that surrounds whole muscle, made of dense irregular connective tissue Fascicle- a group of muscle fibers. For example, skeletal muscle is made of multiple fascicles Perimysium- covering around fascicle Muscle fibers-muscle cells Long, cylindrical, multinucleate Plasma membrane of muscle fibers is called the sarcolemma. The sarcoplasm is similar to cytoplasm of other cells except: 1. Sarcoplasm has large amount of stored glycogen in glycosomes 2. Myoglobin, is a muscle fibers. Similar to hemoglobin in red blood cells; stores oxygen 3. Contain myofibrils alongside the usual organelles Endomysium- connective tissue that surrounds each muscle fiber. Epi, peri, endomysium are all continuous with one another and with tendons Extra glucose goes to the liver and skeletal muscle by the use of insulin The liver stores glucose as glycogen and glyosomes in skeletal muscles Nerve and Blood Supply Each muscle has an: Nerve Artery One or more veins Enter/exit in center Branch extensively The muscle needs: A continuous supply of O and nu2rients Capillaries- are contorted when muscle is relaxed or contracted Straighten- when muscle stretched Myofibrils Contractile element of muscle cell Each muscle fiber contains 100s-1000s of myofibrils Run parallel and fill entire cell , it’s 80% of the cell volume Myofibril Anatomy Skeletal muscle is striated because of actin and myosin fiber of myofibril. Striations- made from repeating series of A bands, light I band. What gives skeletal muscle it’s striated appearance? The A band and I band of every myofibril line up. This is very important to the function of the skeletal muscle. H-zone-lighter stripe in middle of A band (relaxed muscles only) M-line-bisects H zone and A band Z disc- bisects I bands Sarcomere- region between Z-disc, it’s the functional contractile unit, sarcomere units end to end are what form a myofibril. Myofilaments- fibers within the sarcomere Thick filaments (myosin)- form length of A band Thin filaments (actin)-form I band and extend into A band Nebulin- protein that forms Z discs, anchor thin filaments, connects adjacent myofibrils Desmin- fine protein strands that form M line, hold adjacent thick filaments together Elastin Filaments- composed of giant protein, titin, runs from z disc to myosin and on to M line, holds thick filaments in place, extensible when the muscle is stretching, recoils when returns to original length. Myosin- is the protein that makes up the thick filaments, has two heads and long tail. The tail is two twisted heavy polypeptide chains. The head is the business end of myosin. With two light polypeptide chains. They link thick and think filaments together during contraction. Thick Filament Structure Myosin tails bundle together (forming thick filament) Myosin heads poke outwards Myosin heads in contact with thin filaments (Are binding sites for actin /ATP) Thin Filament Structure Subunit is globular actin (G) Attached in a long polypeptide chain (F actin) F actin folds back on itself to make a twisted double strand Stiffened by 2 strands of tropomyosin In a relaxed muscle tropomyosin blocks active site of actin Troponin Three polypeptide complex TnI- bonds actin TnT-binds to tropomyosin and positions it on actin TnC- binds calcium ions Shape of troponin determines position of tropomyosin Position of tropomyosin determines ability of muscles to contract Sarcoplasmic Reticulum Is the endoplasmic reticulum of the muscle Surrounds each myofibril Network of tubules A-I junction tubules thicker (Terminal Cisternae) Between term. Cis are T-tubules T-tubule Transverse tubules Formed from SR Are tubes that wrap around each myofibril Lumen is continuous with extra cellular space Conduct nerve impulses deep inside muscle cells Contraction of Skeletal Muscle (Sliding Filament Theory) During contraction the actin/myosin overlap increases When stretched the actin/ myosin overlap minimal Muscle Contracting Story Step 1: Exposure of binding sites on actin An action potential brings about the release of calcium ions from the terminal cisternae of the sarcoplasmic reticulum Calcium ions flood into the cytosol and bind to the troponin, causing a change in conformation of the troponin-tropomyosin complex Thus conformational change exposes the binding sites on actin Step 2: Binding of myosin to actin When a binding site on actin is exposed an energized myosin head can bind to it forming a cross bridge Step 3: Power stroke of the cross bridge The binding of myosin to actin brings about change in the conformation of the myosin head, resulting of ADP and inorganic phosphate All the same time, the myosin head flexes, pulling thin filament inward toward the center of the sarcomere. This movement is called the power stroke Step 4: Disconnecting the myosin head from actin In order to disconnect the myosin head from actin, an ATP molecule must bind to its site on the myosin head Step 5: Re-energizing and repositioning the myosin head The release of myosin head from actin triggers the hydrolysis of the ATP molecule into ADP and P 1 Energy is transferred from ATP to myosin head, which returns to its high-energy conformation Step 6: Removal of Calcium Ion Calcium is actively transported from the cytosol into the sarcoplasmic reticulum by ion pumps As the calcium is removed the troponin-tropomyosin complex again covers the binding sites on actin