Bio notes 2 - The Skeletal System Axial Skeleton Protects...

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The Skeletal System Axial Skeleton - Protects our internal organs - 80 bones - Skull - Vertebral column - Ribs and sternum Skull - Cranial bones o Enclose and protect brain - Facial bones o Front of skull o Support sensory structures Vertebral Column - Supports head - Protects spinal cord - Column of 33 irregular vertebrae o Cervical 7 o Thoracic 12 o Lumbar 5 o Sacrum (5 fused) o Coccyx (4 fused) Ribs - 12 pairs - Attach at back to the thoracic vertebrae - Top 10 pairs attach to sternum at front Sternum - Breastbone - Flat blade-shaped bone Ribcage - Ribs, sternum and vertebral column - Surround and shield heart and lungs Appendicular Skeleton - Pectoral girdle (shoulders) - Pelvic girdle (pelvis) - Limbs (arms and legs) Pectoral girdle and arm - Pectoral girdle o Supportive frame for the upper limbs
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o Collarbones (clavicles) o Shoulder blades (scapulae) - Arm Pelvic girdle and leg - Pelvic girdle o More rigid than pectoral girdle o Pelvic (coxal) bones - Leg o Femur o Patella o Tibia o Fibula o Tarsals o Metatarsals o Phalanges Joints - Juncture between bones - Classified based on components and structure o Fibrous o Cartilaginous o Synovial Which type of joint allows the most movement? - Synovial Fibrous Joints - Immovable o Do not permit movement - No joint cavity - Held together by fibrous connective tissue - Sutures o Joints between skull bones Cartilaginous Joints - Allow very little movement (slightly movable) - Bones connected by cartilage - Vertebral column - Ribs and sternum Synovial Joints - Most joints - Freely movable - Bones separated by thin fluid-filled cavity
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- Cavity surrounded by two-layered joint capsule o Synovial membrane o Cartilage - Joint reinforced by ligaments - Hinge joint o Allows movement in one plane o Knee, elbow - Ball-and-socket joint o Permit wider range of movement in all planes o Rounded head of one bones fits into socket of another o Shoulder, hip The Muscular System Functions - Produces movement - Maintains posture o Resisting force Gravity - Produces heat o Shivering Structure - 3 types of muscle o Skeletal 75% of muscle o Cardiac Found in heart o Smooth Hollow organs and tubes Which type(s) of muscle is/are striated? - Skeletal and cardiac Muscle: Characteristics - Excitable o Respond to stimuli - Contractile o Have ability to shorten - Extensible o Have ability to stretch - Elastic o Return to original length Skeletal Muscle - Muscles responsible for moving body
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- Interact with skeleton and cause bones to move relative to each other - More than 600 - Attached to bones by tendons - Muscle origin o End of muscle attached to the bone that remains relatively stationary during movement Proximal - Muscle insertion o End of muscle attached to the bone that moves Distal - Most work in pairs or groups - Synergistic muscles o Work together to create the same movement - Antagonistic muscles o Oppose each other Which branch of the nervous system is responsible for controlling the skeletal muscle? -
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This note was uploaded on 04/22/2009 for the course BIO 309D taught by Professor Jessicawandelt during the Spring '08 term at University of Texas at Austin.

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Bio notes 2 - The Skeletal System Axial Skeleton Protects...

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