HTHS Mod 10

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  1. four functions of muscle tissue
    • Producing body movements
    • stabilizing body positions
    • storing and moving substances within the body
    • generating heat
  2. Examples of muscles storing and moving substances with in the body
    • digestive enzymes are kept in pancreas by specialized circular muscle called sphincter. When meal arrives and is detected by sphincter, it relaxes and releases it's cargo of digestive juices
    • Lymph fluid is pushed around by muscular action, having no pump of it's own
  3. Three types of muscle tissue
    • skeletal
    • cardiac
    • smooth
    • *all depend on interactions btwn actin and myosin to change cell length
  4. skeletal muscle
    • also called voluntary muscle, under our voluntary control
    • striated
    • controlled by nervous system
    • moves body at joints
    • made up of long tubes formed from fusion of syncytium
    • dozens or hundreds of nuclei, along outside of fused muscle cell
    • *# of cells is set at birth. Cells can get bigger, but no more are created
  5. syncytium
    • (mature skeletal muscle cells) are formed by fusion of many embryonic m. cells
    • the resulting multinucleated, incredibly long cell of skeletal muscle
    • nuclei remain along outside of long tube that is formed (called eccentrically placed nuclei)
  6. eccentrically placed nuclei
    nuclei which are away from the center of the tube in skeletal muscles
  7. cardiac muscle
    • in some ways resembles skeletal muscle
    • striated
    • single cells, branched, connected at intercalated discs
    • single nucleus along outside of branched muscle cell
    • *nuclei are in center of cell, the fusion of embryonic cells has produced a branched structure instead of long tubes
    • not under voluntary control
  8. what makes a muscle striated
    the proteins of striated muscle are arranged in a regular, repeating pattern that gives it the appearance of tiger stripes
  9. smooth muscle
    • not striated
    • made up of single spindle-shaped cells, unbranched
    • single nucleus in center of cell
    • contractile proteins stick out in all directions
    • Involuntary
  10. structure of muscle cells
    • like all cells, muscle cells have thin filaments made up of globular shaped actin strung together like beads on a string to make long rods
    • contain 3 proteins: contractile proteins, regulatory proteins and structural proteins
  11. myosin & actin
    • contractile proteins, interact to contract
    • Myosin = thick filament
    • Actin = thin filament
  12. regulatory proteins
    • control how actin and myosin deal w each other
    • Ex: one key regulatory protein keeps myosin away from actin until just the right moment, and then allows them to join together
  13. structural proteins
    • keep the actin filaments and myosin filaments in the correct orientation so they can interact when needed
    • is the framework constructed by these proteins that give striated muscle it's appearance
  14. sarcomere
    • the basic functional unit of muscle cell necessary for contraction
    • each strip is sarcomere
    • The repeating sarcomeres give muscle it's striated appearance
    • *When muscle is relaxed, sarcomeres are at maximum width
    • *When sarcomeres collapse on themselves and become shorter, the entire muscle becomes shorter
    • **If one shortens, they all do
  15. how is skeletal muscle controlled?
    by a nerve cell that makes synaptic (cell to cell) contact w the muscle fiber
  16. Cardiac muscle
    • has sarcomeres; contracts due to combined action of millions of sarcomeres working together
    • has it's own electrical signaling system
    • *heart rate controlled for entire muscle, not for individual muscle fibers
    • is involuntary
  17. cardiac pacemaker
    • the hearts own electrical signaling system
    • sends an electrical spike every 0.8 seconds to cause the heart to contract 72 times a min.
  18. similarities btwn cardiac and skeletal muscle
    • striated in appearance due to sarcomeres
    • elaborate system of T tubules and sarcoplasmic reticulum to regulate contractility
  19. Differences from cardiac and skeletal muscle
    Cardiac has branched fibers, single nucleus per cell, cells joined by intercalated discs, and not under voluntary control
  20. How is the cardiac muscle controled
    • In response to stress, the nervous system can send a signal to increase the heart rate using epinephrine
    • The nervous system can also slow the heart rate using acetylcholine
  21. Contractions of cardiac muscle
    • All parts of muscle must fire together
    • uses gap junctions to transmit electrical impulses btwn cells, through out the entire muscle simultaneously, to ensure coordinated firing of muscle contraction
  22. intercalated discs
    • bind cells together and allow signals to move btwn cells
    • are regions in cardiac muscle with multiple desmosomes holding muscle together
    • insures that muscle isn't torn by force of contraction
  23. Gap junctions
    • used in cardiac muscle
    • allow rapid movement of ions (ions that tell heart to contract) from one cell to another so that all the muscle in that area of heart contracts (beats) at the same time
    • *can also close off if one cell gets sick or dies. Ca++ increases and seals door
  24. Recall desmosomes
    • "spot-welds" that give tissue structural integrity and strength
    • uses cadherin plus intermediate filament, hooking to cytoskeleton. Gives strength to physical connection btwn cardiac cells
  25. Where is smooth muscle found
    lining blood vessels, lining airways, lining the gut tube throughout the digestive system, and in a number of there places
  26. Why is smooth muscle called smooth muscle
    • doesn't have striations like cardiac and skeletal muscle
    • have one nucleus per cell, spindle shaped
    • does have gap junctions, but no desmosomes like skeletal & cardiac
    • the actin and myosin filaments are there, but are arranged in a meshwork like a vegetable bac, and not in sarcomeres

  27. controlling smooth muscle
    • nerves that innervate smooth muscle are there to regulate contraction rather than control it
    • the nerve cells release chemicals that increase or decrease the overall activity level, but don't control individual muscle cells
  28. Similarities btwn smooth muscle and skeletal muscle
    • uses actin and myosin for contraction
    • actin: thin filaments
    • myosin: thick filaments
  29. Differences btwn smooth muscle and skeletal muscle
    • Organization of proteins in smooth muscle is a bit different
    • smooth muscle is small cells, single nucleus per cell, spindle-shaped cells, not under voluntary control, no electrical or Ca++ management
  30. Levels of muscle organization
    • Going from largest to smallest:
    • muscle
    • Fascicle
    • muscle fiber (muscle cell)
    • myofibril
    • sacromere
  31. smallest unit of muscle?
    sarcomere: a regular arrangement of interdigitated strands of actin (small filaments) and myosin (thick filaments) plus structural proteins to hold things in place
  32. myofibril
    a long strand of (thousands) of sarcomeres arranged end to end
  33. muscle fiber
    • also called muscle cell
    • contains several dozen myofibrils bordered by sarcolemma
    • is the syncytium that results when embryonic muscle cells fuse to form a long tube
    • inside are sacs and tubules and dozens of myofibrils divided into sarcomeres
  34. sarcolemma
    the plasma membrane of a muscle cell, surrounds & borders each muscle fiber
  35. fascicle
    several dozen muscle fibers bounded together by a connective tissue sheath
  36. connective tissue sheaths
    • three connective tissue sheaths surround muscle cells, muscle fascicles, and entire muscle:
    • epimysium, perimysium, endomysium
    • *think of his shovel story, these would be the outer plastic coating of the wires
  37. epimysium
    a dense irregular connective tissue which surrounds the entire muscle

    connected to, and continuous with, tendon and then periosteum of bone
  38. perimysium
    a dense irregular connective tissue which covers (surrounds) each fascicle
  39. endomysium
    an areolar connective tissue sheath which surrounds each muscle fiber (muscle cell syncytium)
  40. What does muscle function start with?
    • a wave of electrical potential that arrives at the surface of the muscle cell
    • releases Calcium ions
  41. transverse tubules
    • also called T tubules
    • help electrical potentials (voltage changes) rapidly penetrate into the center of the cell
  42. sarcoplasmic reticulum
    • a specialized form of smooth endoplasmic reticulum which stores Ca++ and releases them when needed
    • "bags of calcium"
  43. triad
    • formed by 1 transverse tubule spur plus 2 sacs of sarcoplasmic reticulum
    • *T tubule brings electrical charge inside cell; SR releases Ca++ in response to electrical signal
    • *when action potential hits triad, calcium is released into cytoplasm of muscle cell
  44. What is critical for muscle function
    • wave of electrical potential on surface of muscle cell
    • calcium ion concentration
  45. sarcolemma
    membrane which covers the muscle fiber
  46. polarized light
    • a special kind of light used before the invention of the electron microscope to see things better
    • *some structures of myofibrils are named after there appearance in polarized light
  47. organization of myofibrils
    • made up of many sarcomeres
    • 1 sarcomere consists of Z disc, H zone, I band and A band
    • nearest Z line: Only Actin (thin) filaments center of sarcomere: only myosin (thick) filaments
    • *the actin and myosin are proteins within the filaments
  48. Z disc
    • defines the borders of the sarcomere
    • where actin filaments are held together
  49. I band
    • isotropic band
    • actin filaments ONLY
    • by Z band
    • does not bend polarized light (appears lighter)
  50. A band
    • anisotropic: myosin and myosin + actin
    • Includes H band
    • part of sarcomere that bends polarized light
  51. H zone
    • myosin thick filaments only
    • in middle of A band
  52. How do neurons work?
    • by releasing chemical substances (neurotransmitters)ONTO other cells 
    • causes electrical change in the cell that receives the message
  53. neuromuscular junction
    • the point of contact btwn the nervous system and muscular system
    • neurons in the spinal cord send out a cable-like axon which ends at this junction
    • the signal sent at the junction (which happens by the release of acetylcholine) triggers contraction of the entire muscle fiber
  54. neurotransmitters
    • chemical substances which allow neurons to work
    • they transmit info from neurons, cause an electrical change in cell that receives message
  55. What controls the muscular system
    Neurons (nerve cells), which are the thinking and info processing cells of the nervous system
  56. acetylcholine
    • (ACh)
    • the neurotransmitter which causes muscle cell contraction
  57. How do motor neurons work
    • when it receives the proper stimulus, it releases acetylcholine onto the sarcolemma of muscle fiber
    • there, specialized receptors turn chemical signal into electrical signal
    • called nicotinic acetylcholine receptors
  58. nicotinic acetylcholine receptors
    • specialized receptors which turn the chemical signal into an electrical signal which spreads over the entire surface of the muscle fiber, penetrating into T tubules where they meet the sarcoplasmic reticulum in triads. 
    • This causes calcium release from it's stors in the SR
    • best respond to nicotine, hence the name
  59. synaptic release
    • the way neurotransmitters are released from nerves
    • understand that an electrical signal in both nerve and muscle is what triggers events in both cells
  60. motor neuron
    • brain cells (or nerve cell) that controls movement (muscle tissue)
    • they receive input through the spinal cord
    • generate an electrical impulse (action potential) which travels along a "cable" (axon) to its end (axon terminal)
    • releases acetylcholine - receiving cell is skeletal muscle cell
    • single motor neuron branches several times & contacts muscle fibers
  61. alpha motor neuron
    the last neuron in the motor neuron chain, has it's cell body and dendrites (info receivers) INSIDE SPINAL CORD
  62. action potential
    • the electrical impulse generated by motor neurons, as long as a certain combination of events occur
    • is a change in voltage that lasts for just a brief period of time and makes things happen (from neg to pos to neg.. as neg charge is normal)
    • *remember scientists use the word "potential" to mean "voltage"
    • *the motor neuron action potential releases acetylcholine from the end of the motor neuron
  63. axon
    part of the nerve cell that takes signals away from the nerve body; therefore the action potential travels from the spinal cord to the muscle, using the axon of the cell for the journey
  64. axon terminal
    • the end of the axon, where action potential triggers the release of acetylcholine
    • *attached to the synaptic end bulb 
  65. synaptic end bulb
    • at the end of the axon terminal
    • Where the exchange or signal, passing from neuron to the muscle cell to allow for a series of events to take place to get contraction
  66. how does muscle cell action potential actually happen?
    • after the ACh (acetylcholine) is released from the axon terminal, it diffuses across tiny gap btwn nerve and muscle and binds to receptors on muscle cell.
    • these receptors allow the flow of Na+ (sodium) and K+ (potassium); which cause the voltage inside muscle cell to change from neg. to pos.
    • This "flip" in voltage is the muscle cell action potential
  67. order of events which occur in motor neuron and at neuromuscular junction
    • 1. motor neuron action potential arrives at neuromuscular junction, triggers release of acetylcholine in synapse btwn neuron & muscle
    • 2. Acetylcholine binds up with acetylcholine receptors, which then sends that electrical impulse (action potential) along muscle surface (on plasma membrane of sarcomere)
    • 3. When this impulse reaches T tubules, initiates release of Ca++ from sarcoplasmic reticulum
    • 4. Once acetylcholine is no longer needed (no need for constant contraction), cleared away by acetylcholinesterase
  68. nerve agent intoxication
    makes the ACh keep binding to receptors and opening ion channels; making the muscle stay w positive voltage forever
  69. Sequence of events that link muscle cell action potential to release of calcium from sarcoplasmic reticulum
    • Again, action potential travels along surface of muscle
    • Penetrates into the interior muscle cell at transverse tubules (T tubules)
    • The action potential in T Tubule initiates release of Ca++ from sarcoplasmic reticulum
    • Ca++ interacts w proteins to help contraction btwn myosin and actin
  70. From Ca++ Release to Contraction
    • The Ca++ released from SR then binds w troponin (a regulatory protein)
    • troponin then changes it's shape, which causes the tropomyosin to move aside and expose binding site for myosin on the actin filament
  71. AChE
    • acetylcholinesterase ~ an enzyme used to stop the action of ACh
    • breaks apart the ACh molecule at it's ester linkage, into acetate and choline - nether of these can bind to receptors
    • the action potential ends and leftover pieces of ACh are taken up into the presynaptic axon terminal for recycling
  72. troponin
    • a special protein found only in muscle cells
    • binds which calcium (which is released from the SR) and changes shape
    • moves tropomyosin aside and exposes binding sites for myosin on the actin filament
  73. tropomyosin
    • normally covers a myosin binding site on the actin molecule; keeps myosin (which wants to bind actin very much) from being able to reach it's binding site on actin
    • therefore, when troponin shoves tropomyosin out of the way, myosin can grab actin
  74. cross-bridge cycle
    • series of events referring to the link btwn myosin and actin forming, then breaking, the forming, etc
    • 1 - calcium binds to troponin, which shoves tropomyosin & exposes myosin binding site on actin
    • 2 - as soon as sites are exposed, myosin heads bind to actin sites, creating "crossbridges"
    • 3 - once attached, the myosin heads pull the actin fiber and Z disk inward (this motion is called the powerstroke)
    • 4 - Myosin head then picks up fresh 
    • ATP , which causes it to drop actin and reset to again form "crossbridges"
  75. Role of ATP and ADP/P in cross-bridge cycle
    • After troponin shoves tropomyosin and exposes the myosin binding site on actin, myosin wants to bind - brings an ATP molecule
    • As myosin binds to actin (requiring energy), the ATP is split into ADP & a loose P
    • When myosin heads move to pull actin (powerstroke), releases ADP and open site for ATP to bind again
    • Once ATP binds to myosin, it can let go of the actin, and start the cycle over by binding to a new site on actin, w it's ATP
  76. power stroke
    • step in the cross-bridge cycle
    • the movement of the myosin heads pulling the actin inward
  77. rigor mortis
    • what happens when ATP is absent, 
    • Myosin remains permanently bound to actin, muscles cannot move (they stay contracted) - they are locked in position
    • When a person dies, they no longer make more ATP.  A  dead person uses up the rest of their ATP in a matter of mins or hours, depend on temp (usually 3-4 hrs after death)
    • Later (again, depending on temp) enzymes and microbes destroy/break down muscle tissue (usually 24 hrs later) and corpse becomes "loose" again
  78. Steps that bring an end to contraction of muscle
    • For RELAXATION, requires calcium clean-up
    • Calcium pump proteins (found in the SR) sponge up the free calcium in muscle cell cytoplasm & stores it for next action potential
    • When Ca is absent, troponin-tropomyosin slides back to original places and 
    • No cross-bridges are formed, muscle relaxes
  79. extraction-contraction coupling
    • The entire process of muscle contraction, from the brain sending first impulse to relaxation of muscle
    • *action potentials are all-or-none, either happen or they don't
    • if enough ACh is released, action potential which results always spreads over ENTIRE surface of muscle
    • entire muscle cell contracts at once & always contracts "all the way"
  80. What would make the excitation-contraction coupling not result in muscle contraction
    • if actin and myosin filaments were not precisely aligned in skeletal and cardiac muscle
    • because they are, excitation leads to contraction through shortening of the sarcomere
  81. titin
    the protein that holds myosin molecules in a bundle, with the heads sticking out where they can interact with actin
  82. α-actinin
    protein that holds the actin filaments in place at the Z line (Z disc)
  83. the sliding filament model
    • as myosin heads flex (in cross-bridge cycle), they move actin filaments (sliding past the myosin thick filaments)
    • as actin filaments move, the Z lines are brought together and the sarcomere shortens
    • as thousands of sarcomeres shorten, the entire muscle fiber shortens
    • As muscle fibers shorten, the muscle contracts
  84. Length-tension relationship
    • refers to the location of the myosin & actin filaments and the strength of the contraction
    • the amount of tension that muscles generate varies as a function of their length
    • *Relaxed muscles can't generate much force
    • *Partially contracted muscles generate max force
    • *fully contracted muscles can't generate much force
  85. what does force depend on
    • the overlap btwn myosin and actin
    • At maximum stretch (relaxation) or maximum contraction, fewer actin-myosin interactions ↦ less force generated
  86. motor unit
    • one motor neuron and all the muscle fibers that it's connected to (all the muscle fibers which the motor neuron forms neuromuscular junctions)
    • *note that when one motor unit sends impulse for contraction, all the muscle fibers it innervates will contract
  87. Explain concept of "all or none"
    • recall muscle contraction is "all-or-none", that once muscle fiber contracts, it contracts as much as possible. But how can you have small movements?
    • *While individual muscle fibers contract fully, not all the muscle fibers in a muscle contract.
    • most of the time, very few contract at all. they take turns
    • *other half of answer is existence of motor units
  88. sizes of motor units
    • important for the wide range of movements
    • Precise control of muscles = small motor units
    • More force from a single motor neuron = large motor units
  89. size principle
    • makes movements more smooth
    • the small motor units are recruited first, than larger units, until finally largest motor units are recruited last
    • *amount of force generated is directly proportional to the number of muscle fibers that contract
  90. myogram
    a graph showing the time it takes to move through the process of contraction to relaxation
  91. Latent period (of a myogram)
    the time it takes for an action potential to travel from the motor neuron to when action potentials spread over a few, or many, muscle fibers
  92. contraction period (of myogram)
    time period from when the action potentials penetrates the T tubules & releases calcium; when troponin shoves tropomyosin, which results in more and more force generated by the muscle fiber until max. force is reached
  93. relaxation period (of myogram)
    • time period when calcium is packed back into sarcoplasmic reticulum, myosin releases actin, and muscle relaxes
    • final segment of graph
  94. refractory period
    • both muscle and nerve have this
    • depending on type, it may take a few milliseconds up to a 2nd of a second for the muscle to be ready to contract again
  95. Contraction period vs relaxation period
    roughly the same length of time
  96. If multiple action potentials arrive...
    • force increases - up to a point
    • when one action potential fires, the muscle starts to contract. If we receive another action potential before the muscle can relax from the first impulse, it increases the force
  97. wave formation
    • referring to a graph of action potentials
    • the process of firing multiple action potentials & having the small bumps begin adding together
    • looks almost like a wave
  98. unfused tetanus
    • when the waves on the muscle graph increase in the frequency of the stimulation
    • show discernable bumps or steps
  99. treppe
    • the name of the pattern you get on the graph
    • when you get multiple action potentials firing, and the graph "waves" start looking like steps
  100. tetanus
    • when the action potentials come so rapidly that the individual bumps fuse into one big ridge (on the myogram graph) - also called fused tetanus
    • describes a muscle that is contracting as forcefully as possible
  101. isotonic contractions
    • greek word tonos means "tension"; "iso-" means equal
    • those muscle contractions that use equal tension (or equal force, equal strength) to move objects
    • 2 subcategories: concentric and eccentric contractions
  102. concentric contraction
    • subcategory of isotonic contractions
    • involves moving a muscle against gravity
    • Ex: picking up a book
  103. eccentric contractions
    • subcategory of isotonic contractio
    • think of lowering a dumbbell
    • occur when gravity is stretching a muscle (increasing it's length) at the same time you are trying to shorten the muscle (to control the decent of the dumbbell)
    • great for building muscle, but make muscle prone to injury
  104. delayed onset muscle soreness
    • associated w eccentric contractions
    • happens about 24 to 72 hours after exercise
    • Ex: running downhill means the muscle is in relaxed state when ur foot hits the ground
  105. isometric contractions
    • involve holding things in place against gravity
    • Position is being maintained
    • no movement takes place; keep muscle at same length or measurement
  106. sources of muscle energy
    • oxygen for glucose is in blood via hemoglobin or from myoglobin in muscle fibers
    • Pyruvic acid from glycolysis (glucose breakdown)
    • Fatty acids liberated from adipose cells
    • Amino acids from protein breakdown
  107. sources of glucose in muscle
    • blood glucose
    • muscle stores glycogen, which can easily be converted to glucose
    • *remember, it's important to have oxygen to use glucose
  108. sources of oxygen in muscle for glucose breakdown
    • blood oxygen
    • myoglobin w/in muscles (an oxygen-binding protein similar to hemoglobin in blood)
  109. If we are anaerobic, and don't have enough oxygen, but plenty of glucose
    • metabolism is anaerobic
    • Prob 1. anaerobic glycolysis is inefficient
    • Prob 2. anaerobic glycolysis produces lactic acid, which lowers blood pH (acidosis)
  110. sources of muscle energy from fatty acids and amino acids
    • bad choice; not easily utilized
    • fatty acids produce acid (lowering blood pH) and ketones; cannot increase glucose rapidly
    • Proteins can be used, but actin and myosin are proteins and muscle breakdown to operate muscle is counterproductive
  111. creatine
    • an additional energy source not used in other tissues
    • when energy is plentiful, phosphate groups are stored on muscle creatine, creating creatine phosphate
    • When energy it needed, these phosphates can be transferred to ADP to make ATP
  112. Three types of muscle fibers
    • each with it's own metabolic strategy:
    • slow oxidative, fast glycolytic, and fast oxidative-glycolytic
    • *all muscles are a mix of all three fiber types, but dominated by one of the three types
    • *each type tends to be innervated by different motor unit, so when one unit fires, only activates one type
  113. slow oxidative fiber
    • in postural muscles, like strong muscles of lower extremity
    • comparatively weak, but have stamina
    • aerobic glycolysis predominates
    • slower to respond to activation
    • use a steady supply of ATP
    • tend to use oxidative metabolism, meaning they have lots of myoblobin
  114. fast glycolytic
    • muscles used for fine movement, like extraocular muscles moving eye of small muscles move fingers to thread needle
    • anaerobic glycolysis predominates
    • quick to respond to activation
    • use ATP in brief bursts; very strong, but short endurance
    • don't need to store glycogen or oxygen to work
    • have little myoglobin
    • since they only need to work for a few twitches, they don't need to rely on stored energy as much
    • "white meat" in turkey
  115. fast oxidative-glycolytic fibers
    • those fibers that combine both strategies
    • more common in muscles which need both endurance and speed
    • mid level for both strength and endurance
  116. two sources of muscle fatigue
    • depletion of energy sources & a few metabolic factors
    • *also can involve central fatigue
  117. central fatigue
    • when the nervous system "shuts down" and will not activate motor neurons (the person "quits")
    • that point the your body says "no more" 
    • Ex: doing pushups
  118. muscle fatigue due to depletion of energy sources
    • glucose and glycogen
    • creatine phosphate and ATP
    • blood oxygen and oxygen bound in myoglobin
  119. metabolic factors in muscle fatigue
    • ADP & phosphate directly interfere w calcium release from sarcoplasmic reticulum
    • lactic acid accumulation reduces pH and inhibits key muscle enzymes
    • extracellular potassium builds up, reducing ability of muscle to fire an action potential
    • glycogen is depleted
    • *no one knows which of these, or something else, is the "most" important factor
  120. recovery from muscle fatigue
    consists of replenishing ATP, creatine, oxygen (bound to myoglobin), glycogen, Ca stores, and restoring pH to normal levels
  121. Cardiac muscle compared to skeletal muscle...
    • Cardiac muscle is adapted to be fatigue-resistant:
    • higher number of mitochondria (energy producing factory)
    • higher myoglobin content
    • higher creatine phosphate (ready source of high-energy phosphate for ATP) content
    • ample blood supply
    • *w/o oxygenated blood, heart muscle can not work. if it is deprived of oxygen at all, it fails
  122. What is the effort, fulcrum, and load represent regarding lever systems?
    • Effort/energy is the muscle force
    • Fulcrum is the joint
    • Load is the weight or object being moved
  123. first-class lever system
    • arranged in the order Energy, Fulcrum, Load
    • analogous to tee-ter-taw-ter
    • Ex: neck muscles (E) are using the atlanto-occipital joint (F) as a fulcrum to support the weight of head (L) from falling forward
  124. second-class lever system
    • order is Fulcrum, Load, Energy
    • analogous to wheelbarrow
    • Ex: metacarpophalangeal joints (F) are used as a fulcrum to support the weight of the body (L) through the contraction of the calf muscles (E)
  125. Third class lever system
    • order is Fulcrum, Energy, Load
    • analogy is to tweezers
    • by far the most common levers in body but lack stability (hard to hold heavy weight w tweezers)
    • Ex: elbow joint (F) is used as a fulcrum so that the arm muscles (E) can support a weigh in the hand (L)
  126. Names of muscle parts
    origin, insertion, and action
  127. origin of a muscle
    • theoretically where it begins
    • in general, origin is more proximal part
  128. insertion
    • place where the muscle "ends"
    • theoretically attached to the part being moved
    • usually the distal end of muscle
  129. action of muscle
    what it does when it contracts
  130. names of muscle function
    • prime mover (agonist)
    • antagonist
    • synergist
    • fixator
  131. Prime mover
    • agaonist
    • the muscle that does most of the work
  132. antagonist
    muscle opposes the agonist
  133. synergist
    muscle that helps the agonist muscle do it's job
  134. fixators
    muscles which stabilize the origin of the muscle to make the agonist more effective
  135. different terms used to name muscles
    • Location: Ex=extraocular
    • Shape: deltoid, trapezius, rectus abdominis
    • Number of origins: biceps brachii, triceps brachii
    • Location and/or dirrection of fibers: transversus abdominis
    • Origin and insertion: sternocleidomastoid
    • Muscle action: adductor hallucis
  136. naming muscles by shape
    • deltoid: after the greek letter delta (Δ)
    • trapezius : cause it has 4 sides like a trapezoid
    • rectus (straight) abdominis; rectus (straight) femoris
  137. extraocular muscles
    • six eye muscles
    • Origin: skull (eye socket or orbit)
    • Insertion: eyeball
    • Action: eye movements
  138. masseter
    • in head & neck group
    • "chewer" or closing of mouth. 
    • origin: maxilla zygomatic arch
    • insertion: mandible
    • action: closes the mouth
  139. sternocleidomastoid muscle
    • named after origins and insertion; head and neck group
    • Origin: clavicle & sternum
    • insertion: temporal bone (mastoid process)
    • Action: tilt head towards ipsilateral shoulder
    • **NOTICE origin is inferior to insertion point!
  140. trapezius muscle
    • part of the pectoral girdle and shoulder
    • It's the big muscle on the upper back; when looking at both sides, forms a trapezoid
    • Origin: occipital bone, cervical spine
    • Insertion: clavicle & scapula
    • Action: move scapula or shoulders (like shrugging shoulders)
  141. pectoralis major muscle
    • part of the pectoral girdle and shoulder
    • it's the "big chest (boob) muscle"
    • Origin: clavicle & upper ribs
    • Insertion: humerus
    • Action: adduct arm (some medial rotation of arm) *brings arms toward midline of body
  142. Latissimus Dorsi muscle
    • In the pectoral girdle/shoulder group
    • "wide muscle of back" 
    • Origin: thoracic vertebrae, lumbar vertebrae, and iliac bone of pelvis
    • Insertion: humerus
    • Action: pulls arm inferiorly & posteriorly (as in butterfly swim stroke) *notice origin is inferior to insertion
  143. Deltoid Muscle
    • In pectoral girdle and shoulder group
    • "deltoid" = shaped like greek letter delta Δ
    • the top shoulder muscle
    • Origin: clavicle & scapula
    • Insertion: humerus
    • Action: abduct, flex, medially rotate upper arm
  144. Biceps Brachii muscle
    • upper extremity
    • "two-headed muscle of arm"
    • Origin: scapula
    • Insertion: radius (radial tuberosity)
    • Action: Flexes forearm at elbow
  145. Triceps Brachii muscle
    • upper extremity muscle
    • "three-headed muscle of arm"
    • Origin: scapula (long head); humerus (lateral/medial heads)
    • Insertion: ulna (olecranon process - "funny bone")
    • Action: extends arm and forearm
  146. Brachialis muscle
    • upper extremity
    • "arm muscle" on front
    • Origin: humerus
    • Insertion: ulna
    • Action: flexes forearm at elbow
  147. Brachioradialis
    • upper extremity
    • "rod in arm"
    • Origin: humerus
    • Insertion: radius
    • Action: supinates foreman
  148. diaphragm
    • breathing muscle
    • "partition wall"
    • Origin: ribs 7 - 12, sternum, lumbar vertebra
    • Insertion: central tendon
    • Action: breathing (also separates thoracic & abdominal cavities
  149. intercostal muscles
    • btwn ribs
    • internal and external intercostals aid in breathing:
    • External elevate ribs - inhalation
    • internal depress ribs - forced exhalation
    • *normal exhalation is from elasticity of lungs
    • Origin: lower surface of ribs
    • Insertion: upper surface of ribs
  150. rectus abdominis
    • "straight abdominal muscle"
    • Origin: pubic bone of pelvis
    • Insertion: ribs 5-7 & sternum
    • Action: flexes vertebral column and compresses abdomen
  151. linea alba
    • "white line" 
    • thin strip of connective tissue along the midline
  152. external oblique muscle
    • abdominal muscle
    • Latin: "outside diagonal muscle"
    • Origin: ribs 5-12
    • Insertion: iliac crest of pelvis & linea alba
    • Action: flexes vertebral column and compresses abdomen
  153. internal oblique muscle
    • abdominal muscle
    • "inside diagonal muscle"
    • origin: iliac crest of pelvis
    • Insertion: ribs 7-10, linea alba
    • Action: flexes vertebral column and compresses abdomen
  154. transversus abdominis
    • abdominal muscle
    • "perpendicular abdominal muscle"
    • Origin: iliac crest of pelvis & ribs 5-10
    • Insertion: rib 12, L1-L4
    • Action: flexes vertebral column and compresses abdomen
  155. gluteus maximus
    • buttock large muscle
    • Origin: iliac crest of pelvis, sacrum, coccyx
    • insertion: femur, greater trochanter
    • Action: extension of thigh, lateral rotation of thigh
  156. compartments of the thigh muscles
    • 3 compartments:
    • anterior contains femur + quadriceps group
    • posterior contains hamstring group
    • medial compartment (don't need to know)
    • blood vessels and nerves run in "seams' btwn compartments
  157. Quadriceps group
    • rectus femoris
    • vastus lateralis
    • vastus intermedius
    • vastus medialis
    • *recall that thigh is the proximal part of lower extremity, leg is distal
  158. origin, insertion and action of quadriceps group
    • Origin: iliac spine of pelvis, femur
    • Insertion: quadriceps tendon, patella, patellar ligament, and tibia
    • Action: flexes thigh, extends leg
  159. gastrocnemius muscle
    • "calf muscle"
    • Origin: femur
    • Insertion: calcaneus (heel) via calcaneal tendon
    • Action: flexes foot
  160. Soleus muscle
    • "sandal" - under Gastrocnemius 
    • Origin: fibula & tibia
    • Insertion: calcaneus via calcaneal tendon
    • Action: flexes foot
  161. muscles of the hamstring group
    • biceps femoris - 2 headed muscle of femur
    • semitendinosus
    • semimembranosus - 1/2 tendon/membrane muscle
    • Origin: ischial tuberosity of pelvis
    • insertion: fibula/tibia
    • action: extends thigh/flexes leg
Card Set
HTHS Mod 10
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