Biol 3401 1st Edition Lecture 5Current Lecture- Accessory structures associated with synovial joints o Tendon: attaches muscle to bone Most important structures in stabliazing a joint o Ligament: similar tissue that attaches bone to bone o Bursa: a fibrous sac filled with synovial fluid  Cushions muscles  Helps tendons slide over joints  In joint cavity, Modifies direction of tendon pull- Exercise and articular cartilage o Exercise warms up synovial fluid  Becomes less viscous (thick) and more easily absorbed by articular cartilageo Cartilage then swells and provides a more effective cushion against compression Warm up period before vigorous exercise helps protect cartilage from undo wear and tear- Repetitive compression cycle provides circulation to nonvascular cartilage  Impact squeezes fluid and metabolic waste out of cartilage  Hen weight removed, cartiage absorbs synovial fluid taking in oxygen and nutrientsSkeletal muscle fiber Sarcoplasmic reticulum (SR)- a calcium reservoir Calcium activates the muscle contraction process Traid- a T tubule and two terminal cisternsMyofilaments These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Contractile proteins Myosin (thick)Actin (thin)Not connected to one another Nervous impulse- calcium- binds triponen- causes shape change- opens binding site- myosin binds to actin (power stroke) - slide over one another- contractionMotor neurons and motor units Motor unit- one nerve fiber and all the muscle fibers innervated by it Not one to one ratio, branching that connects to multiple fibersMultiunit Smooth MuscleSingle nerve fiber that innervates multiple muscle fibersOccurs in largest arteries, aorta Single unit Smooth Muscle Occurs in, blood vessals, digestive tract, respiratory tract, urinary tract Gap junction Run along the middle of fibersLarge number of cells contact as a single