Muscular system anna edited

Question 1

Entire muscle

Answer 1

Wrapped in epimysium
Runs from origin to insertion
Made of many fascicles

Question 2

Fascicles

Answer 2

Bundles of muscle fibers
Wrapped in perimysium

Question 3

Muscle fibers

Answer 3

• Individual muscle cells made of myofibrils
• Wrapped in endomysium
• multinucleated

Question 4

Sarcolemma

Answer 4

 Excitable plasma membrane
 Responds to electrical stimulus
 Membrane proteins that
conduct ions
 T-tubules that extend deep into cell

Question 5

Triad

Answer 5

contains t-tubule and 2 terminal cisternae of the SR

Question 6

Tendon

Answer 6

Extension of mysiums
Attaches muscle to bone

Question 7

myoblast

Answer 7

creates muscle cells

Question 8

Sarcoplasm

Answer 8

typical organelles + contractile proteins

Question 9

Terminal cisternae

Answer 9

large chambers in the SR that store calcium ions and release them to cause muscle contraction

Question 10

Sarcomere

Answer 10

basic unit of contractile muscle, composed of protein filaments actin and myosin

Question 11

Myofilaments

Answer 11

Contractile proteins within myofibrils
myosin and actin
tropomyosin and troponin

Question 12

actin

Answer 12

thin filaments
myosin binding sites

Question 13

myosin

Answer 13

thick filaments
myosin heads

Question 14

I band

Answer 14

Light regions of actin

Question 15

A band

Answer 15

Dark regions of myosin

Question 16

Z discs

Answer 16

• Hold sarcomeres together
• sarcomere boundrie

Question 17

Neuromuscular Junction

Answer 17

a synaptic connection between the terminal end of a motor nerve and a muscle. It is the site for the transmission of action potential from nerve to the muscle.

Question 18

resting membrane potential

Answer 18

-90mV
ECF positively charged, ICF negatively charged maintained by sodium-potassium pumps

Question 19

Neural Control of Skeletal Muscle

Answer 19

-Neuron fires
-Calcium channels on synaptic knob open
-Influx of calcium causes Ach to be released
-ACh diffuses across synaptic cleft
-ACh binds to receptors at motor end plate of sarcolemma

Question 20

Depolarization

Answer 20

• ACh triggers action potential along sarcolemma and t-tubules
• sodium gates open
• Sodium rushes into the muscle cell
• ICF becomes less negative (≤+30mV)

Question 21

Excitation-Contraction Coupling

Answer 21

• Action potential reaches triad
• calcium channels and calcium-release channels of SR open
• Calcium diffuses throughout muscle fiber.

Question 22

Sarcomere Crossbridge Cycling

Answer 22

• calcium binds to tropoin
• tropoin and tropomyosin shift off binding site of actin, exposing binding site. Myosin heads attach to binding sites of actin forming crossbridge.
  1. Crossbridge formation
  2. Power stroke
  3. Release
  4. Reset
  5. Cycling continues if calcium and ATP are available

Question 23

Repolarization

Answer 23

Sodium gates close
Potassium gates open (potassium rushes out of cell)
returns to -90mV

Question 24

Skeletal muscle contraction order

Answer 24

resting
motor neuron fires and releases ACh
ACh triggers motor end plate of sarcolemma
Depolarization
Excitation-contraction Coupling
Crossbridge cycling
Repolarization
Refractory period

Question 25

Skeletal Muscle Relaxation

Answer 25

1. Termination of nerve signal and ACh release; hydrolysis of residual ACh by acetylcholinesterase. 2. ACh receptors close; cessation of motor end plate potential. 3. No further action potential generated. 4. Closure of SR calcium channels and calcium release channels. 5. Return of calcium to SR via pumps. 6. Return of troponin and tropomyosin to original position, blocking actin’s binding sites. 7. Return of muscle to original length.

Question 26

Tetanus

Answer 26

- Spastic paralysis caused by toxin found in soil and feces - Results in overstimulation of muscles - Vaccination prevents symptoms

Question 27

Botulism

Answer 27

- Muscular paralysis - Prevents release of ACh - Recovery in 90% of cases

Question 28

Creatine phosphate

Answer 28

Phosphate group is transferred to ADP to form ATP Anaerobic, occurs in cytosol lasts for about 30 seconds

Question 29

Glycolysis

Answer 29

Breakdown of glucose by enzymes, releasing energy and pyruvic acid Anaerobic Fast; yields 2 ATP molecules/glucose molecule

Question 30

Aerobic Respiration

Answer 30

Slower; yields 32 ATP molecules/glucose molecule - uses oxygen

Question 31

Oxygen debt

Answer 31

Amount of oxygen needed after exercise to restore pre-exercise conditions

Question 32

Muscle Fiber Type I

Answer 32

 Slow-twitch oxidative fibers  High endurance; ATP supplied aerobically  Red due to myoglobin

Question 33

Muscle Fiber Type IIA

Answer 33

 “Intermediate”; aerobic/glycolytic  Faster, fatigue more quickly  Light red; some myoglobin

Question 34

Muscle Fiber Type IIB

Answer 34

 Fast-twitch glycolytic fibers  Fastest, fatigue quickest  White due to lack of myoglobin