119thLectureFri 27 Feb 2009Vertebrate PhysiologyECOL 437 (MCB/VetSci 437)Univ. of Arizona, spring 2009Kevin Bonine & Kevin OhMovement & MuscleChapter 182Housekeeping, Fri 27 February 2009ReadingsToday: Ch 18Mon: Ch 19Wed: Ch 19 & 20LAB Wed 04 Mar: Dickinson et al. 2000Fri 06 Mar: Ch 21 (gas transport)Lab discussion leaders: 04 Mar1pm – Deedra, Franz3pm – AJ, KareemLab discussion leaders: 25 Mar1pm – Sam3pm – Karri, JasonFri 13 Feb = Exam 13Movement and BehaviorNervous System and Muscleintegration, control, feedback4DipsosaurusdorsalisCallisaurusdraconoidesPhrynosomaplatyrhinosThanks to Duncan Irschick and Steve Reilly5~Behavior InitiationBring together nervous, endocrine, muscular systems, etc.ComplexReflexes / Learned / PlasticityRespond to situation(s)Parallel ProcessingComplicatedNeuronalCircuitryAnimal Behavior,Neurobiology6Simple Reflexes – basis of neuronal circuitryReflex Arc, Stereotypic Behaviore.g., stretch reflex (patellar tendon)- Tonic tension in muscle- Important for maintenance of posture via negative feedback-Only 2 neurons required- monosynaptic reflexStretch receptor activates1a-afferent neuronAlpha-motor neuron activates quadricepsSherwood 1997 (see 11-1 in Eckert)(ventral)7Simple ReflexesStretch receptor = muscle spindle organ-containsintrafusal fibers(as opposed to extrafusal)- Sensitive to stretch (stretch -> APs)-Need to be reset for new muscle length-Gamma-efferent neurons innervate spindle81. 1a-afferent neuron2. Alpha-motor neuron3. Gamma-motor neuronc. Contracted musclewithout ‘reset’ musclespindleSherwood 1997 (see 11-1 in Eckert)9Simple Reflexes +Other neurons become involved as well:-1a-afferentsinhibit antagonist muscle(Knee flexor ~hamstring)- Conscious decision to bend leg etc.-LimbFig. 11-2Randall et al. 200210Silverthorn 2001Stretch Reflex11Hill et al. 2004 Fig 18.712Hill et al. 2004 Fig 18.713Silverthorn 200114Silverthorn 2001Golgi Tendon Reflex:15Law of Nerve-Specific EnergyventraldorsalAction Potentials and Graded Potentials don’t convey specific information.Rather, the geographic connections, summation of different inputs, and modulation are important for correct responseFig. 11-12Randall et al. 200216CPG = central pattern generator-neuronal network producing repetitive outputWalking, swimming, flying, breathingToad walking with no afferents -awkward- flaccid musclesSensory feedbackHigher centers can overrideSome patterns at level of spinal cord if stimulateinitially (cats on treadmill)Peripheral vs. Central Control17Silverthorn 200118Hill et al. 2008 Fig 18.11Central Pattern Generators in Cat Spinal Cord19Design of a robot salamander that walks and swims Figure 18.1220Activating musclesNERVOUS SYSTEM CONTROL:•cerebral cortex•frontal, parietal,temporal, occipital lobes•Cerebellum•basal ganglia•brain stem•spinal cord•peripheral nerves21Silverthorn 200122Major Motor Areas,IncludingPRIMARY MOTOR CORTEXHill et al. 2004, Fig 18.15&1623Basal Ganglia(plans&initiates movement)Cerebellum(fine-tunes execution)Hill et al. 2004, Fig 18.19Parkinson’s Disease(akinesia, too much inhibition of motor function, mediated by dopamine)Huntington’s Disease(chorea, not enough inhibition of motor function)24http://salmon.psy.plym.ac.uk/year1/ETHEXPT.HTM#Egg%20retrievalHerring Gull Egg Retrieval-prefer the larger of two eggs of the same colour-prefer the speckled egg over an unspeckled egg of the same colour- prefer natural coloured(brown speckled) eggs over brown unspeckled eggs - prefer green speckled eggs over green unspeckled eggs -prefer green eggs over brown eggs (Baerends & Kruijt) Fixed Action Patterns…Greater preference25Research Proposal Tips:-Physiology and science should be subject, not researchers and experiments-Having interesting question or problem helps give direction and focus-More physiology-Subheadings often helpful-Synthesize, not serial book reports-Abstract, role is summary of entire paper, not an intro to the intro-Avoid Pronouns (its, these, this, …which, there are)-Passive voice to be avoided (e.g., Avoid passive voice)-Leading and following zeroes (0.5, .5, .50)-Page numbers-Citation format (J. of Physiology, instructions to authors, [full journal names])-Turn in old, graded work with each new version-Peer editing (read quickly, then read for content and writing, comments helpful)26MuscleA. SarcomereB. Cross-bridge cyclingC. Length-tension relationshipD. Excitation-contraction couplingE. Force-Velocity curves, PowerF. Fiber TypesG. Motor Units/RecruitmentH. EnergeticsI. FatigueJ. Repair and RegenerationVertebrate Physiology 437- Smooth and Cardiac introduction27Uses: - most observable animal behavior - most visceral function- generally act by shorteningMuscleClassification: -striated- smoothskeletal or cardiacAll muscle movement based on myofilaments (actin and myosin) sliding past each other…Utilize: ATP, Ca2+, ~APswalls of hollow organs(Myo-, Sarco-= musclerelated)28Structure:Skeletal Muscle- muscle attached to bone(skeleton) via tendons- muscle comprises elongate,multinucleate, muscle fibers- multinucleate muscle fibersderived from combination of manymyoblasts (embryonic muscle cells)- within each muscle fiber are many parallel myofibrils- each myofibril contains sarcomeresarranged in series (end-to-end)- sarcomere is functional unit ofmuscle29SarcomereZ-disk at each end of sarcomereSarcomeres in adjacent myofibrils are alignedleading to striated appearanceActin thin myofilaments attachedto each Z-diskMyosin thick myofilaments in between actins (6,3)Actin and Myosin overlap is what allows muscle contraction(6,3)30SarcomereZ-disk (actin attaches)Areas within sarcomere given names:I-band (actin only) A-band (myosin length)H-zone (myosin only)M-line (midpoint of myosin)During muscle contraction, myosin thick filaments slide past actin thin filaments toward Z-lines31Which regions change length and which remain the same as the sarcomere shortens?Z-disk (actin attaches)I-band (actin only) A-band (myosin length)H-zone (myosin only)M-line (midpoint of myosin)During muscle contraction, myosin thick filaments slide past actin thin filaments toward Z-lines32Sarcomere CompositionActin composed of:individual molecules of G-actin (globular)united into chains called F-actin (filamentous) which form a two-stranded helixIn the groove of the two F-actin strands is tropomyosin,which also has globular troponin molecules attached to it33Sarcomere CompositionMyosin composed of:2 heavy chains withglobular heads2