BIOL 152 1st Edition Lecture 19 Outline of Last Lecture I. Nerves and nervous systemsa. CNS vs. peripheralb. Autonomici. Sympatheticii. ParasympatheticII. Reflexes: not all signals go to brainIII. Sensory receptor typesIV. Sensory system examplesV. Evolution of the eye and visionOutline of Current Lecture I. HomunculusII. Different muscle typesIII. How muscles worka. Sliding filament theoryb. Cross-bridge cycleIV. Fast twitch vs. slow V. SkeletonsVI. Intro to hormonesCurrent LectureReceptors (cont.)Magnetoreceptors- Pigeons use this to navigateSensing respondingMovementMuscle types (37.2)- Striated (main focus)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.- Smooth- CardiacMuscle organization (37.3)- Muscle muscle bundle muscle fiber (cell) myofibril- Myofibril- contains actin, myosin and other proteins, smallest unit- Muscle fibers- multinucleate cells Thick and thin filaments (37.4)- Myosin-thick- Actin-thino Both involved in sliding filament theory- Tropomyosin- sits on binding sites of actin, must move away in order for muscle to contract- Sarcomere- basic contracting unit of a skeletal muscle- Z-discs- separate each sarcomere, shrink during contraction- ACTIN AND MYOSIN ALWAYS WORK TOGETHERSliding filament theory (37.6)- Size of actin and myosin do not change, they slide together to contractCross bridge cycle (37.7)*Motor neurons stimulate muscle cells to contractMotor neuron end plates- Attachment point of neuron to muscle fiber, signals can be sent resulting in movement (acetylcholine released)Excitation-contraction coupling (37.8)- Calcium released in cell- Binds with troponin (on tropomyosin)o Moves tropomyosin so actin binding site is openNeuron action potential> acetylcholine release> calcium release> binds to troponin> moves tropomyosin away from actin binding site> contractionSmooth muscle- Controls internal organs- Activatorso Autonomic nervous systemo Muscle stretcho Hormoneso pHo Oxygeno Carbon Dioxideo Nitric OxideAntagonist muscles (37.11)- Flexion vs. extension Motor unit (37.13)- One neuron + all muscle cells it controlso One muscle cell interfaces with just one neurono One nerve cell controls one to hundreds of muscle cells- Graded response, depending on:o Number and size of motor units and rate of stimulationTypes of muscles (37.14)- Slow-twitch= aerobic respiration (oxidative)- Fast-twitch= glycolosisMuscle fibers affect speedAnimal skeleton (3 types)- Hydrostatic - Endoskeleton- ExoskeletonSignaling- Nervous and endocrine system- Endocrine=HORMONESo Can be responses to internal or external environmentInvolvement in growth and development (refer to 38. 1)Growth and development control (refer to
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