BIOL 152 1st Edition Lecture 19 Outline of Last Lecture I Nerves and nervous systems a CNS vs peripheral b Autonomic i Sympathetic ii Parasympathetic II Reflexes not all signals go to brain III Sensory receptor types IV Sensory system examples V Evolution of the eye and vision Outline of Current Lecture I Homunculus II Different muscle types III How muscles work a Sliding filament theory b Cross bridge cycle IV Fast twitch vs slow V Skeletons VI Intro to hormones Current Lecture Receptors cont Magnetoreceptors Pigeons use this to navigate Sensing responding Movement Muscle 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 Cardiac Muscle 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 thin o 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 TOGETHER Sliding filament theory 37 6 Size of actin and myosin do not change they slide together to contract Cross bridge cycle 37 7 Motor neurons stimulate muscle cells to contract Motor 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 open Neuron action potential acetylcholine release calcium release binds to troponin moves tropomyosin away from actin binding site contraction Smooth muscle Controls internal organs Activators o Autonomic nervous system o Muscle stretch o Hormones o pH o Oxygen o Carbon Dioxide o Nitric Oxide Antagonist muscles 37 11 Flexion vs extension Motor unit 37 13 One neuron all muscle cells it controls o One muscle cell interfaces with just one neuron o One nerve cell controls one to hundreds of muscle cells Graded response depending on o Number and size of motor units and rate of stimulation Types of muscles 37 14 Slow twitch aerobic respiration oxidative Fast twitch glycolosis Muscle fibers affect speed Animal skeleton 3 types Hydrostatic Endoskeleton Exoskeleton Signaling Nervous and endocrine system Endocrine HORMONES o Can be responses to internal or external environment Involvement in growth and development refer to 38 1 Growth and development control refer to 38 2
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