I Study of Skeletal Systems A) Current Issues - Bone and Joint Pathology 1) Rheumatoid arthritis - autoimmune disease, affects smaller joints (e.g., hands) 2) Osteosarcoma - malignant bone tumor 3) Osteoporosis - porous bones 4) Scoliosis - lateral bending of the vertebral column 5) Gout - deposition of sodium urate crystals 6) Osteoarthritis - wear and tear arthritis, major joints (e.g., knees) B) Function 1) Support 2) Movement 3) Protection 4) Mineral reserve (in vertebrates) 5) Blood cell production (in vertebrates) C) Types of Skeletons 1) Hydrostatic - water-filled skeleton a) Unicellular organisms and starfish 2) Exoskeleton - chitin (carbohydrates) a) arthropods (insects and lobsters) 3) Endoskeleton - vertebrates D) Human Skeleton - generic example of a vertebrate 1) Axial skeleton = skull, vertebral column 2) Appendicular skeleton a) Forelimb 1) girdle = scapula, clavicle 2) humerus, radius, ulna, carpals, metacarpals, digits=phalanges b) Hindlimb 1) girdle = ilium, ischium and pubis 2) femur, tibia, fibula, tarsals, metatarsals, digits=phalanges 3) joints where bones meet suture hinge ball and socket E) Study of Adaptation - Feeding, Skulls and Teeth Carnivores - canines, carnassial molars Canids (Dogs) Coyote Felids (Cats) Lynx Bobcat Cougar Ursids (Bears) Black Bear Mustelids and other Predators Wolverine Fisher Badger Herbivores - diastema, grinding molars Mule Deer Llama Cow Pocket Gopher Beaver F) Study of Adaptation - Movement 1) Adaptations for flight a) wing = elongations of the fingers or digits in bats, Pterosaurs b) wing = modification of forelimb in birds c) hollow bones of birds 2) Adaptations of limbs for swimming a) Flattened skulls for swimming mammals - fusiform shape b) limb bones are flattened, elongation of digits and additional bones in the digits 3) Adaptations for terrestrial movement - walking and running a) plantigrade stance - entire foot on ground human, armadillo b) digitgrade stance - animal is standing on it digits, heel off the ground most mammalian predators c) unguligrade stance - animal is standing on one foot horse G) Microscopic examination of bone structure a) bone tissue 1) Spongy bone and marrow a) marrow = site of blood cell production 2) Compact bone 3) Haversian systems (osteocytes in lacunae, connected to Haversian canal by canaliculi) II - Muscular systems A) Function = movement accomplished by contractile systems B) Primitive contractile systems 1) Cilium and flagellum - 9 + 2 arrangement of contractile elements, movement of unicellular organisms C) Primitive Muscular Systems 1) Roundworms - single layer 2) Segmented worms - double layer D) Vertebrate Muscle - different types and arrangements 1) 3 Types of muscle a) Skeletal or striated muscle 1) contains striations, found in close contact with bones, under voluntary control b) Cardiac muscle 2) heart muscle, contains striations and intercalated discs, discs involved in spreading electric impulses through heart, involuntary control c) Smooth muscle 3) no striations, lining viscera and vessels, involuntary control 2) Antagonistic arrangement of most skeletal muscles:Human Muscular System Schematic a) Extensors - open the angle between bones and the body b) Flexors - closes the angle between bones and the body 3) Movement and contraction a) Movement is accomplished by contractions of muscle tissue b) Contractions - result of movement of filaments across each other c) Filaments - thin are actin, thick are myosin, Ca++ entering the muscle cells involved in pulling actin across myosin elements III Practical Applications A) Use of muscle 1) Strength training - leads to hypertrophy of muscles a) muscle mass increases due to an increase in the number of myofibrils and mitochondria B) Disuse of muscle 1) Muscle mass decreases due to lack of use (occurs in elderly or bedridden patients) 2) Leads to atrophy of muscles - muscle tissue is replaced by fat C) Rigor mortis - my friend the squirrel 1) Death results in an uncontrolled leakage of Ca++ into the cells which stimulates permanent muscle contraction D) Genetic Disease - Duchenne's Muscular Dystrophy (information from the MDA) 1) genetic disease that affects boys, individuals can not produce dystrophin protein (provides support for muscle cells), leads to muscle weakness, degeneration of muscle tissues, loss of muscle cells (atrophy), progressive disease, early signs of lack of coordination, 8-11 years old unable to walk, short life expectancy E) Muscle injuries and Remedies 1) Spasm and Cramps - rapid and involuntary contractions of muscles a) Spasm - rapid, involuntary contraction of muscle, very painful b) Cramp - rapid and sustained contraction of muscle, very painful 2) Muscle damage a) muscle tear due to strenuous exercise - leads to cell damage 3) RICE - remedy for sports injuries a) R - rest, I - ice, C - compression, E - elevation F) Aerobic exercise 1) indirectly affects the muscular system 2) actually increases size and strength of the heart which increases blood flow to the muscles, able to bring more O2, take away CO2
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