Power Point 1 Muscular System and Review Objective 1 Define and identify the anatomy of skeletal muscle and explain the sliding filament theory leading to muscle contraction account for roughly 80 of cellular volume and contain the contractile elements of Myofibrils Each fiber is composed of myofibrils arranged in a 3 D mosaic pattern the muscle cell Striations are due to a repeating series of dark A bands and light I bands Myofilaments make up the myofibrils and consist of thick and thin filaments Ultrastructure and Molecular Composition of the Myofilaments o Two types of myofilaments thick filaments composed of bundles of myosin and thin filaments composed of strands of actin Tropomyosin and troponin are regulatory proteins present in thin filaments Sarcolemma plasma membrane basement membrane fuses with tendon bone Sarcoplasm cytoplasm contains proteins minerals fats organnelles glycogen myoglobin Transverse Tubules transport system deep into fiber allows rapid conduction of impulse o T tubules are infoldings of the sarcolemma that conduct electrical impulses from the surface of the cell to the terminal cisternae The sarcoplasmic reticulum SR is a smooth endoplasmic reticulum surrounding each myofibril o SR membranous channel parallel to myofibril and storage site for Calcium Ca2 The link below is just an article but it has a lot of easy to understand figures and I think it is much easier to learn all the parts and pieces in context of what they actually do so do yourself a favor and actually read through this o http www thealevelbiologist co uk the sliding filament theory of muscle contraction He also mentioned that we should know the difference between myofibrils and myofibers so here ya go o As nouns the difference between myofibril and Myofiber is that myofibril is muscle cylindrical organelles found within muscle cells that are the contractile unit of muscles while myofiber is muscle fiber Objective 2 Define and distinguish between the types of muscle fibers and explain the possibilities or lack there of of fiber type morphology The different types of muscle fibers go in order of their increasing ATPase activity o Work and function the same These isoforms provide different energy transduction kinetics and crossbridge turnover rates during contraction Muscle fibers are organized into functional units called motor units o Motor unit defined one motor neuron and all of the muscle fibers it innervates Type I Slow Type IIa Fast fatigue resistance Type IIx or IIb Fast fatigable type 1 weight bearing sustained movements Slow motor units Fast oxidative motor units Fast glycolic motor units types IIa IIx sustained locomotion bike riding types IIb and IIx used for bursts of power Objective 3 State the different types of skeletal muscle contraction and the functions and characteristics of skeletal muscle The powerpoint goes over this but I found this website much more helpful and easier to follow http www ivyroses com HumanBody Muscles Types of Muscle Contractions php Objective 4 What are the different types of fascicle arrangements Also what determines a muscles power and ROM Fasicles are bundles of fibers that can be arranged differently Circular Convergent Fascicles arranged in rings Orbicularis Oris Eye Broad Origin and fascicles converge toward insertion o Example Pectoralis Major O sternum clavicle I tendon of humerus Converge toward humerus Example Sartorius fascicles run parallel along the AXIS Longest Muscle Parallel Spindle Shaped rectus femoris Fusiform Pennate Attach obliquely to the central tendon Featherlike Extensor Digitorum Longus Rectus Femoris o Unipennate o Bipennate o Multipennate Delts Arrangement of fascicles determines that muscle s ROM and power o Parallel Fascicle arrangement Muscles that shorten the most o Muscle s with greatest of fibers have most power i e Bipennate Rectus and multipennate Pound for Pound Strong Objective 5 Describe the 3 classes of levers and apply the knowledge to uses of mechanical advantage and muscle insertions to determine lever classes in the body Lever is a bar on a fixed point fulcrum o You have the load and effort applied force In your body o Joint Fulcrum o Muscle Insertion point at Bone Effort o Bone and weight Load whatever you are trying to move o Bone Lever Load is close to fulcrum and the effort is far from fulcrum In this case Power Lever a small effort over a large distance can move load Car Jack High mechanical advantage Speed Lever be greater mechanical disadvantage or low mechanical advantage Load is far from fulcrum and effort is close to fulcrum the effort must o First Class Lever Effort and load are on the ends and fulcrum is in the middle old school seesaw and scissors Example In the body Lifting your head off of your chest Load Facial Skeleton Fulcrum Atlanto Occipital Joint Effort Posterior Neck Muscles o Second Class Lever Effort applied at one end on the other end and the load in the middle Like wheelbarrow Example In the body Standing up on your toes Effort Triceps Surae Load Weight of Body Fulcrum Joints of the ball of the foot o Third Class Lever Effort is in the middle 3rd class are always at a mechanical disadvantage 1 and 2 vary Think of tweezers Effort btwn Load and fulcrum In the Body Biceps Curl Load Weight in hand Effort Insertion of Biceps brachii Fulcrum Elbow Joint Little summary When the effort is farther from the fulcrum than the load you have Mechanical Advantage When the effort is closer to fulcrum than load you have Mechanical Disadvantage Power Point 2 Spinal Cord Objective 1 Be able to draw and label the diagram of the entire CNS including labeling the direction impulses are sent for each system and division of the CNS The spinal cord is inside of the vertebral column extends from foramen magnum to L2 is a 2 Way conduction center sending messages to and from the brain and the major reflex center Contains neurons which route an afferent or an efferent stimulus to the inter neurons in the brain of the CNS o Afferent Sensory Efferent Motor o Efferent o Lateral Horns o Ganglia Controls ANS and Skeletal Muscle Ventral Horns ANS neurons and go to visceral organs not skeletal muscle groups of nerve cells forming a nerve center Picture below shows efferent afferent neurons and explaining the direction of impulses sent throughout the CNS Objective 2 Describe the basic anatomy of the spinal cord The meninges and all that goes with them o From outside to inside Dura Mater Arachnoid Mater and Pia
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