1. ____ Chapter 49 ~ Sensory and Motor Mechanisms ( Just focusing on motor mechanisms ) Motor Mechanisms

2. Vertebrate Skeletal Muscle Contract/relax: antagonistic pairs w/skeleton Muscles: bundle of….  Muscle fibers: single cell w/ many nuclei consisting of…. Myofibrils: longitudinal bundles composed of….  Myofilaments:  Thin~ 2 strands of actin protein and one strand of a regulatory protein  Thick~ staggerd arrays of myosin protein http://entochem.tamu.edu/MuscleStrucContractswf/index.html

3. Vertebrate Skeletal Muscle Sarcomere: repeating unit of muscle tissue, composed of…. Z lines~ sarcomere border I band~ only actin protein A band~ actin & myosin protein overlap H zone~ central sarcomere; only myosin http://www.sumanasinc.com/webcontent/animations/content/muscle.html

4. Sliding-filament model Theory of muscle contraction Sarcomere length reduced Z line length becomes shorter Actin and myosin slide past each other (overlap increases) http://www.blackwellpublishing.com/matthews/myosin.html

5. Actin-myosin interaction 1- Myosin head hydrolyzes ATP to ADP and inorganic phosphate (Pi); termed the “high energy configuration” 2- Myosin head binds to actin; termed a “cross bridge” 3- Releasing ADP and (Pi), myosin relaxes sliding actin; “low energy configuration” 4- Binding of new ATP releases myosin head Creatine phosphate~ supplier of phosphate to ADP

6. Muscle contraction regulation, I Relaxation: tropomyosin blocks myosin binding sites on actin Contraction: calcium binds to toponin complex; tropomyosin changes shape, exposing myosin binding sites http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__action_potentials_and_muscle_contraction.html

7. Muscle contraction regulation, II Calcium (Ca+)~ concentration regulated by the…. Sarcoplasmic reticulum~ a specialized endoplasmic reticulum Stimulated by action potential in a motor neuron T (transverse) tubules~ travel channels in plasma membrane for action potential Ca+ then binds to troponin

8. Materials Muscle model/chicken wing The following is needed for each student: 4 red/black licorice strands (the thick twisted type) 10 red licorice strands (the thin type) a paper towel; toothpicks one raw chicken wing one dissection tray; dissection tools, gloves.

9. Muscle cell simulation: contraction/relaxation Procedure: Two thin pieces of licorice intertwined to represent thin actin filaments Thick licorice to represent thick myosin fibers Toothpicks represent the Z lines where thin filaments attach