PET 3322C Study Guide Exam 1 Muscular System and Review Skeletal Muscle o Components Multi nucleated 75 water 5 inorganic material 20 mix of proteins voluntary muscle cells Atrophy decrease muscle mass Hypertrophy increase muscle mass Area 2000 micrometers 2 to 7500 micrcometers 2 o Structure of Muscle Muscle ex bicep brachii wrapped in epimysium Group of fascicles bundle of muscle fibers o Fascicle wrapped in perimysium Muscle Fiber Myofiber bundle of myofibrils wrapped in Endomysium Myofibril bundle of myofilaments o Components of Myofibril Account for 80 cellular volume Appears striated due to alternation dark A bands and light I bands Made of myofilaments thick and thin o Structure of Myofibril Wrapped in sarcolemma Sarcoplasm surrounding all myofibrils in the Myofiber Transverse T Tubules Allows transportation deep into fiber causing rapid impulse conduction Sarcoplasmic Reticulum surrounds each myofibril and is the storage site for calcium Ca2 o Sarcomere functional unit of muscle contraction o Structure of Sarcomere ZAAAAAAAA m AAAAAAAZ Z MMMMmMMMM Z ZAAAAAAAA m AAAAAAAZ I band A band H zone A band I band 2 Types of filaments Smallest contractile unit of skeletal muscle fiber Thin Thick are Actin A are Myosin M M line m is where the myosin filaments are attached Only contains thin filaments with accessory proteins Z disk Z is where the actin filaments are attached Sarcomere length is from one Z disk to the next Bands and Zones I band only thin filaments A band thick and thin filaments H zone only thick filaments o Other structures Satellite cells responsible for muscle growth and regeneration Make up 5 15 of muscle mass Located between the plasma membrane and the basement membrane 200 300 nuclei mm muscle length Muscles only grow in cross sectional area of muscle fiber increasing number of myofibrils Myofiber proteins Regulatory active site Structural o Tropomyosin covers binding site on actin o Troponin binds calcium to pull topomyosin off of actin o C protein part of thick filament that hold myosin tails in correct arrangement o Titin links ends of thick filament to Z disk 1 Signal travels down the T tubules and reaches the sarcomeres 2 Signal causes release of Ca2 which binds troponin and causes it to pull tropomyosin off of the active site on actin 3 ATP enters the ATP pocket on the myosin heavy chain MHC and causes the head of myosin to bind the actin active site 4 ATPase breaks down ATP 5 New ATP the actin filaments closer to the M line binds to MHC and causes the head to cock power stroke pulling Sliding filament theory aka Muscle Contraction 6 Process repeats until actin thin filaments reach the M line Types of Muscle Fibers aka MHC isoforms o Slow Type I o Common type of muscle for running marathons Speed of contraction 0 20 Lowest ATPase activity Smallest in size Lowest force production Low fatigue o Fast Type IIa Speed of contraction 21 40 Type IIx Speed of contraction 41 60 Type IIb not found in humans Speed of contraction 61 80 Largest in size Highest force production Highest ATPase activity o Means it can quickly remove old ATP so that a new one can enter the MHC site and have another power stroke faster Fatigue the fastest o Motor Unit one neuron and all of the fiber types that it innervates o Common type of muscle for sprinting Types of Skeletal Muscle Contraction o Isotonic 2 types Concentric Eccentric Muscle actively shortening Ex bicep curl Muscle actively lengthening Ex triceps extension Muscle actively held at a fixed length Ex carrying a puppy o Isometric Functions of muscles o Produce movement o Stabilize o Maintain posture o Generate heat joints Characteristics of muscles o Excitability can be stimulated o Contractility can shorten o Extensibility can extend o Elasticity can stretch without ripping Fascicle Arrangements o Circular aka circle aka in a ring Ex around eyes o Convergent aka converge aka come together to an insertion point Ex toward humerus o Parallel o Fusiform spindle shaped o Pennate aka feather like Ex Sartorius runs parallel to axis of body Attached obliquely to central tendon Ex Bipennate rectus femoris Muscle Power and Range of Motion o Determined by the fascicle arrangement Parallel short muscles wider than it is long because several fibers are parallel to each other Larger cross section More fibers more power and smaller length Move slowly but produce a lot of power o Ex Gastrocnemius calf muscle Long Muscles long and skinny so have less density to contract Small cross section Move very quickly but have very little power and large length o Ex Sartorius allows you to cross your legs o Bone lever joint fulcrum muscle insertion at bone effort bone and muscle Levers in the body weight load o 3 classes of Levers 1 First Class a Effort and loads are on the end and fulcrum is in middle i Ex seesaw ii Ex lifting head off of chest 2 Second Class 3 Third Class a Load is in the middle and effort is applied at one end i Ex wheelbarrow ii Ex standing up on your toes calf raises a Effort is between the load and the fulcrum b Always at a mechanical disadvantage effort close to fulcrum i So this is a speed lever and not a power lever 1 Ex tweezers 2 Ex Bicep curl Spinal Cord KNOW WELL ENOUGH TO DRAW Central Nervous System Diagram Brain 88888888 8888888 Cervical Spinal Nerves Cervical Enlargement drink Coffee at 8 8 cervical spinal nerves Lumbar Enlargement drink Tea at 12 12 thoracic spinal nerves Thoracic spinal nerves Conus Medularis Cauda Equina horse tail drink Lagers at 5 5 lumbar spinal nerves Lumbar spinal nerves Sacral Nerves 6 Filum Terminale Total Spinal Nerves 31 pairs Motor Neurons Signals Exit Efferent brain and go to muscle to cause movement Damage to upper motor neurons results in Spastic paralysis Sensory Neurons Signals come At Afferent the brain from the body to register a stimulus Anatomy of the Spinal Cord o 2 way conduction to and from brain o Located inside the vertebral column extending from the foramen magnum base opening of skull to L2 lumbar vertebrae o Meninges coverings Epidural Space fat and veins Dura Mater tough mother o Arachnoid mater spider like matrix Cerebrospinal Fluid CSF Pia Mater soft mother o Posterior dorsal Structures Posterior Median Sulcus Split left and right Dorsal Root Dorsal root ganglion halves Cell bodies of sensory neurons o Middle Structures Central Canal Grey matter Dorsal Horn o Contain interneurons o Receive Afferent info Lateral Horn thoracic upper lumbar only o ANS neurons and send
View Full Document
Unlocking...