Anatomy MIDTERM > Muscles > Flashcards

Muscles Flashcards

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1
Q

degree of movement depends on…

A

Origin and insertion create movement of body parts when the contract across joints. The type and degree of movement achieveed depends on how much movement the joint allows and where the muscle is located in relation to the joint.

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2
Q

Movement of Wrist Extensors

A
  • Appendicular
  • arm/forearm
  • finger and wrist extension
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3
Q

sarcolemma

A

cell membrane

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4
Q

what happens in the muscle cells when a muscle contracts?

A
  • when the sarcomere shortens, it means that the muscle is contracting
    • why muscles are multinucelated –> to move at the same
  • muscles contract –> absence of ATP
    • for a muscle to contract, ATP must be present and be partially hydrolyzed
  • muscles relax –> presence of ATP
    • ATP needed to pump calcium ions out so that the muscle fibers can unlatch
  • least energy to stay contracted
  • (muscles contract when things die)
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5
Q

extended sub-maximal effort (marathon)

A
  • depletion of all energy stores lead to a failure of calcium release
  • repetitive overuse damages muscle fibers
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6
Q

aponeurosis

A
  • sheetlike fibrous membrane
  • binds muscles together or msucles to bone
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7
Q

explain the cause of the banding pattern visible in striated muscle

A

caused by the overlap pattern of the thick and thin filaments

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8
Q

Movement of Trapezius

A
  • Axial
  • Neck
  • extension and abduction of head
  • rotation, adduction, and fixation of scapula
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9
Q

When a muscle contracts (steps and bio shit)

A
  1. neuron releases electrical impulses
    • transported thorugh T-tubules of sarcolema
    • causes sarcoplasimic reticulum to release calium ions
  2. calcium ions attach to trpomysoin and reveal actin
  3. myosin attaches to actin and pulls
  4. etc
  • if you constantly flush muscle with calcium ions –> contract and then twitch
  • tryposmyosin only moves if calcium ions attach to it
    • blocks myosin from attaching actin
    • stays on top of actin
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10
Q

why are the reasons for fatigue in a long distance race different to those in a sprint?

A
  • in a long distance race, ATP continues to be prduced aerobically until all energy supplies are exhausted
  • in a sprint, ATP is produced anaerobically until the o2 debt has been repaid
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11
Q

Movement of Masseter

A
  • Facial
  • Head
  • Axial
  • closes mandible
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12
Q

Movement of Brachioradialis

A
  • appendicular
  • arm/forearm
  • flexion of forearm
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13
Q

cross bridges

A
  • ends of the thick myosin filaments are studded with head or cross bridges that can link to the thin filaments next to them
  • when the cross bidges of the thick filaments connect to the thin filaments, a shape change moves one filament past the other
  • two things are necessary for cross bridge formation:
    • calcium ions, which are released from the sarcoplasmic reticulum when the muscle receives an action potential
    • atp, which is hydrolyzed by ATPase enzymes on the myosin
  • when cross bridges attach and detach in sarcomores throughout the muscle cell, the cell shortens
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14
Q

Muscles of Head and Neck

A
  • orbicularis oculi - orbits eye; voluntary and involuntary
  • levator labii superioris - action on a piece of skin
  • zygomaticus minor and major - smile
  • sternocaleidomastoid - sternum and clavicle
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15
Q
A
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16
Q

neuromusclular junction

A
  • muscle fibers are innervated by the branches of motor neurons
  • once an electrical impulse is received, it travels through the T tubules and then passes through entire sarcoplasmic reticulum
  • NMJ is place where electricity passes to stimulate Ca ion release
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17
Q

Movement of Wrist Flexors

A
  • appendicular
  • arm/forearm
  • wrist flexion, radial deviation
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18
Q

fixator muscles

A
  • stabilizing
  • don’t want to hyperextend
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19
Q

Movement of Brachialis

A
  • appendicular
  • arm/forearm
  • flexion of forearm
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20
Q

short term maximal exertion (sprint)

A
  • lactic acid build up lowers pH
  • depletion of creatine phosphate
  • buildup of phosphate affects the sensitivity of muscle to Ca
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21
Q

muscle fatigue

A
  • decline in muscle’s ability to maintain force in a proglonged or repeated contraction
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22
Q

Movement of Levator labii superioris

A
  • Axial
  • Head
  • sneering expression
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23
Q

describe the purpose of the connective tissue sheaths surrounding the muscle and its fascicles

A
  • protect the msucle from friction and give structureal integrity to the tissue
  • the perimysium (surrounding the fascicles) may also be involved in transmitting contractile movements across the muscle
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24
Q

explain the change in appearance of a myofibril during contraction

A
  • I band: becomes narrower as more filaments overlap and the area of non overlap decreases
  • H zone: disappears as overlap becomes maximal (no region of only thick filaments)
  • the sarcomere: shortens progressively as the overlap becomes maximal
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25
muscle fibers/cell
multinucleated
26
duchenne's muscular dystrophy
* x-linked disorder caused by a mutation in the gene DMD, which codes for dystrophin * causes rapid deterioration of muscle, eventually leading to loss of function and death * most prevalent type of muscular dystrophy and affects only males * muscle fibers die and are replaced with adipose and connective tissue
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t-tubules
invaginations of cell membrane to conduct electricity
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Muscle Groups
* prime mover * antagonist * synergists * fixator muscles
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31
effects of aerobic training on body
* improved oxidation of glycogen * increases the capacity of skeletal muscle to generate ATP aerobically * increased capacity of muscle to oxidize fates * allows muscle and lvier glycogen to be used at a slower rate * body becomes more efiicient at mobilizing free fatty acids from adipose tissue for use as fuel * increased myoglobin (which stores oxgyen in muscle cells and aids o2 deliverly to the mitochondria) content * increase in lean muscle mass and decrease in body fat * size of slow twich fibers increases * increase in size and density of mitochondria in skeletal muscles * increase in number of capillaries surrounding each muscle fiber * oxygen is limited and more of muscles energy needs must be met through anaerobic metabolism * lactic acid
32
prime mover/agonist
* biggest movement * produces the most force * primarily responsible for the movement
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fascia
* thinner than aponeurosis * covering of the muscle --\> fuses to form tendon
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Movement of Sternoceidomastoid
* Axial * Neck * adduction, rotation, and flexion of head * turns your head
36
sliding filament theory
Muscle contraction requires calcium ions and energy in the form of ATP in order for the thick and thin filaments to slide past eachother 1. the binding sites of the actin molecule (to which myosin 'heads' will locate) are blocked by a complex of two protein molecules: tropomysoin and troponin 2. prior to muscle contraction, ATP binds to the heads of the myosin molecules, priming them in an erect high energy state. arrival of an action potential causes a release of calcium from the sarcoplasmic reticulum. the calcium binds to the troponin and causes the blocking complex to move so that the myosin binding sites on the actin filament become exposed 3. the heads of the cross-bridging myosin molecules attach to the binding sites on the actin filament. release of energy from the hydrolysis of ATP accompanies the cross bridge formation 4. the energy released from ATP hydrolysis causes a change in shape of the mysoin cross bridge, resulting in a bending action. this cases the actin filaments to slide past the myosin filaments towards the centre of the sarcomere 5. fresh ATP attaches to the myosin molecules, releasing them from the binding sittes and repriming them for a repeat movement. they become attached further along the actin chain as long as ATP and calcium are available
37
Movement of Occipitalis
* Cranial * Head * Axial * draws back scalp
38
insertion
the attachement to the movable bone
39
myofibril
thin and thick filament bundles
40
all or none law of muscle contraction
* the response of a signle muscle fiber to stimulation is to contract maximally or not at all * if the stimulus is not strong enough to produce an action potential, the muscle fiber will not respond * however, skeletal muscles as a whole are able to produce varying levels of contractile force --\> graded responses * achieved by changing the frequency of stimulation and by changing the number and size of the motor units recruited
41
Movement of Orbicularis oculi
* frontal * Head * axial * closes eyelid
42
Slow Twitch Muscle Fibers
* efficient in using oxygen * delayed muscle firing * do not fatigue easily * best suited for: endurance sports, including cycling, marathon running, and long distance triathalons * have more red muscle fibers and less white muscle fibers * aerobic metabolism * slow twitch fibers contian more mitochondria and myoglobin than fast twitch fibers, so they are more efiicient at using oxygen to generate ATP without lactate build up --\> which is why they can fuel repeated muscle contractions such as those required for endurance
43
Movement of Biceps Brachii
* appendicular * arm/forearm * flexion, supination
44
mixed aerobic and anaerobic extertion
* lactate accumulation in the muscle * build up of ADP and phosphate * decline in calcium release affetcs the ability of the muscle to contract
45
Movement of Temporalis
* Cranial * Head * Axial * closes mandible
46
sarcoplasmic reticulum
* covers everything * endoplasmic reticulum * specifically modified to **store calcium** * **​**network of membranous tubules containing a store of calcium ions
47
Movement of Platysma
* Axial * Neck * pulls skin of the jaw down
48
sarcoplasm
cytoplasm --\> where mitochondria are
49
describe relationship between muscles and joints
Muscles have an origin on one (less moveable) bone and an insertion on another (more moveable) bone. When the muscle contracts across the joint connecting the two bones, the insertion moves towards the origin, therefore moving the limb. To raise a limb, the flexor (prime mover in this case) contracts pulling the limb bone up (extensorlantagonist relaxed). To lower the limb, the extensor contracts, pulling the limb down (flexor relaxed). * joint acts as fulcrum/pivot, the muscles exert the force, and the weight of the bone being moved is the load
50
antagonist
* extension * stabilizing and extending * opposes the prime mover * ex: when prime mover contracts, it relaxes * responsible for not overstretching the prime mover during contraction * triceps make sure your biceps don’t overextend
51
one sarcomere
* single, contractile unit within a muscle * thin and thick filaments * boundaries --\> z line * When Z-lines are far apart: muscles are relaxed * opposite means contraction * thin and thick filaments slide past each other
52
explain why the muscles that cause movement of body parts tend to operate as anagonistic pairs
* muscles can only contract and relax --\> they can only pull on a bone, cannot push * to move, two muscles must work as antagonistic pairs to move a bone from different positions
53
Movement of Orbicularis Oris
* Facial * Head * Axial * closes lips
54
origin
the attachement to the less movable bone
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Movement of Deltoid
* appendicular * arm/forearm * adduction, flexion/extension, and rotation
57
Movement of Zygomaticus(minor/major)
* Facial * Head * Axial * smile
58
thin and thick filaments
* cause striations in muscle * when you exercise * these don't grow in number, but they do get thicker and more efficient * proteins * thin: actin * thick: myosin * holds atp * has extensions that are responsible for hooking onto actin
59
fast twitch muscle fibers
* do not burn oxygen to create energy * fast to fire; best for explosive body movements * tire out quickly * best suited for: short bursts of activity, including sprinting races, pole vaulting, and cross fit style events * makes the most lactate * Fast twitch muscles don’t have a lot of oxygen * Sprinters have wider and more fast twitch muscles * anaerobic metabolism
60
Movement of Frontalis
* Cranial * Head * Axial * raises eyebrows and draws scalp anteriorly
61
muscle groups of forearm
synergist - brachialis
62
Movement of Triceps Brachii
* Appendicular * arm/forearm * extension, adduction
63
dystrophin
* important structural component within muscle tissue * connects muscle fiibers to the extracellular matrix through a protein complex on the sarcolemma
64
synergists
* support * assists the prime mover by fine tuning the direction of the limb movement
65
muscle cell
Anatomy MIDTERM
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