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Download Musculoskeletal System
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Musculoskeletal System • Why is locomotion essential to most organisms? • Motile vs. Sessile – Get food – Move away from harmful things and predators – Seek shelter – Seek out mates Skeletons • Humans and other vertebrates have endoskeletons – Made of bone and cartilage – Can grow along with animal • Insects and animals like crabs and lobsters have exoskeletons – – – – Made of chitin Jointed and flexible Muscles attached from inside Must be shed periodically for organism to grow larger Bone • Hard inflexible tissue • Made of living bone cells called osteocytes • Haversian Canals – inner cavities containing blood vessels and nerves Broken Bones – If bone is broken, osteocytes become active and produce new bone Bone • Function: – Site of attachment of skeletal muscles – Levers that make body parts move when muscles contract – Protect delicate structures like brain and spinal cord – Storage site for important minerals like calcium – Place where red blood cells and some white blood cells produced • Types of Bones: – Compact bone – Spongy bone • Marrow: – Tissue found in long bones – make RBC, platelets, some types of WBC Joints • Point where bones meet Types of Joints • Immovable – Bones tightly fitted together • Ex: skull • Movable – Hinge Joint • Ex: elbow and knee – Pivot Joint • Ex: base of skull – Ball and Socket Joint • Ex: Hip, shoulder – Saddle Joint • Allow Ex: wrists Cartilage • Found between joints • Found in nose and earlobe Cartilage • Provides support and flexibility • Allows bones to bend more easily • Cushions bones against impact or pressure • Makes up most of an embryo’s skeleton Ligaments • Tough elastic fibers • Hold bone to bone at the joints • http://www.youtube.com/watch?v=VsBJ4o Uff10&safe=active http://www.youtube.com/watch?v=YyfytTqbgUE&safe=active Types of Muscles Types of Muscles • Skeletal Muscle (striated) – Voluntary movement, locomotion – Bundles of muscle fibers – Appear striped or “straited” under microscope • Human locomotion is made possible by voluntary contractions of striated muscle. • Muscles operate in pairs: – Flexors: bend limb – Extensors: extend limb • Muscle Contraction – Muscle fibers contain contractile proteins – Require ATP (many mitochondria in muscle) Types of Muscles • Smooth Muscle (nonstriated) – Involuntary – Controlled by autonomic nervous system – Found in: • walls of digestive organs blood vessels, bladder Types of Muscles • Cardiac Muscle – Found in heart – Involuntary – Cells contract together as a unit Tendons • Inelastic connective tissue • Attaches muscle to bone Disorders of Muscular/Skeletal System • Tendonitis – Inflammation of connective tissue called tendons that connect muscles to joints • Arthritis – Inflammation of the joints – Deterioration of cartilage • Osteoporosis: – loss of bone due to calcium deficiencies Locomotion in Animals • Protists – Pseudopods (amoeba) – Cilia (paramecium) and flagella (euglena) • Hydra – Tends to be sessile but can glide along base, do somersault or use tentacles to pull itself • Earthworm – Uses muscles to burrow into soil – Has tiny bristles on each segment (setae) that hook onto earth to help it move http://www.youtube.com/watch?v=bFpblBf1dfE&safe=active http://www.youtube.com/watch?v=0Texxu3p7I8&safe=active • Grasshopper – Exoskeleton made of chitin divided into plates that have flexible joints – Muscles attached from the inside – Can walk jump, fly (3 pairs of legs and wings)
