Chapter 4: muscular system

Question 1

males

Answer 1

• have faster contractile properties and a higher capacity for anaerobic metabolism
• generate more maximal power

Question 2

females

Answer 2

• more fatigue resistant; better for longer duration
• more susceptible to disuse atrophy

Question 3

skeletal muscle

Answer 3

moves skeleton, only type that is voluntary

Question 4

smooth muscle

Answer 4

around organs and involuntary movement

Question 5

cardiac muscle

Answer 5

heart, similar to smooth but only found in heart, involuntary

Question 6

contractile proteins

Answer 6

actin, myosin, troponin, and tropomyosin
80% protein

Question 7

water

Answer 7

75% water

Question 8

sarcomere

Answer 8

smallest functional unit of a muscle
one is defined as z-line to z-line
filled with myofilaments

Question 9

myofibril

Answer 9

several myofilaments or sarcomeres lined up and surrounded by endomysium

Question 10

muscle fascicle

Answer 10

several myofibrils bundled together surrounded by perimysium

Question 11

whole muscle

Answer 11

several fascicles grouped together and surrounded by epimysium

Question 12

tendon

Answer 12

the endomysium, perimysium, and epimysium follow the length of muscle and beyond the muscle creating the tendon

Question 13

sliding filament theory

Answer 13

• theory on why muscles contract
  1.) troponin and tropomyosin covers the binding sites on the actin
  2.) calcium binds to the troponin anf the tropomyosin moves to expose the binding sites
  3.) myosin attaches to the actin and a power stroke occurs
  4.) the myosin will stay attached until an ATP binds to it
  5.) once ATP binds to the myosin, this will disassociate the myosin from actin and get it ready for another power stroke
  6.) without ATP present, myosin is unable to disassociate from actin

Question 14

muscle nomenclature

Answer 14

based on size, shape, number of divisions, fiber orientation, location and function

Question 15

parallel muscles

Answer 15

aligned in the same direction as the tendon, the whole length of the muscle unit, and other fibers in the muscle
ex: speed

Question 16

pennate muscles

Answer 16

run at an angle to the tendon and are much shorter than parallel
ex: power

Question 17

anatomical cross-sectional area

Answer 17

measurement is what is reported in studies interested in how much muscle did a person gain
- measurement of the largest portion of muscle

Question 18

physiological cross-sectional area

Answer 18

measurement will give a more accurate measure of how much force production is available from a muscle
- measurement at perpendicular of the fibers regardless of tendon position

Question 19

uniarticular

Answer 19

muscle that only crosses one joint

Question 20

biarticular

Answer 20

muscle that crosses two joints

Question 21

multiarticular

Answer 21

muscle that crosses multiple joints

Question 22

eccentric

Answer 22

muscle is lengthening

Question 23

concentric

Answer 23

muscle is shortening

Question 24

isometric

Answer 24

muscle is static, no movement

Question 25

motor unit recruitment

Answer 25

increasing the number of neurons in a muscle to fire more of the muscle. more important for large, gross movements - size principle: amount of force required during movement

Question 26

rate coding

Answer 26

improving the precision of the firing rate. more important for precision of movement

Question 27

all or nothing principle

Answer 27

all the muscle fibers that are connected to a nerve will fire

Question 28

agonist

Answer 28

muscle for movement of action

Question 29

antagonist

Answer 29

opposite of the agonist (trying to stop)

Question 30

synergist

Answer 30

stabilizer of a joint associated with the primary movement but has no movement

Question 31

length-tension relationship

Answer 31

every muscle has it optimal length for maximal force production: optimal resting length if a muscle is contracted too much and is no longer able to produce force: active insufficiency if a muscle is stretched too much and is not able to produce force : passive insufficiency

Question 32

force-velocity relationship

Answer 32

concentric: indirectly related: eccentric: directly related

Question 33

proprioceptors

Answer 33

allow for muscles to contract at the appropriate time, with the appropriate force, and the appropriate muscles

Question 34

muscle spindles

Answer 34

sense changes in muscle length and rate of strecth and contract the muscle rapidly

Question 35

golgi tendon organs (GTOs)

Answer 35

in tendons, detect changes in muscle tension - too much sensed, the GTOs will deactivate the muscle to ensure no damage is caused by excessive tension

Question 36

pacinian corpuscles

Answer 36

located just below the skin around joints, detect rapid change to a joint angle and reports to CNS

Question 37

ruffini's corpuscles

Answer 37

located just below the skin mainly around the fingers, detect rapid change to a joint angle and reports to CNS