Exam 2 Muscle Structure

Question 1

how many muscles in a carcass

Answer 1

over 600

Question 2

tendon

Answer 2

• bind muscle to bone

- skeletal muscle

Question 3

ligaments

Answer 3

• bind bone to bone

- joint capsule

Question 4

connective tissue layers

Answer 4

• endomysium covered by the
• perimysium covered by the
• epimysium

Question 5

what is the most abundant muscle protein

Answer 5

myosin

Question 6

thick filament

Answer 6

myosin (yellow inside)

Question 7

thin filament

Answer 7

actin (black horizontal line)

Question 8

sarcoplasmic reticulum

Answer 8

organelle that regulates calcium

Question 9

sarcolemma

Answer 9

membrane covering a muscle fiber

Question 10

t-tubules

Answer 10

invaginations that allow depolarization of the membrane

Question 11

motor neurons

Answer 11

axons that control muscle

Question 12

blood vessels

Answer 12

transports blood/ oxygen to the muscles

Question 13

action potential

Answer 13

• a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls
• so electrical current travels down an axon of a neuron

Question 14

acetylcholine

Answer 14

a chemical compound that acts as a neurotransmitter and delivers the message for contraction

Question 15

what is resting membrane potential

Answer 15

-70 mV (maintained by ATP pump)

Question 16

depolarization

Answer 16

• rising membrane potential
• sodium ion channels open allowing sodium to flow into the cell
• becomes more positive

Question 17

repolarization

Answer 17

• decreasing membrane potential (after hitting 33 mV)
• positively charged K ions flow out of the cell
• becomes more negative
• results in hyperpolarization

Question 18

hyperpolarization

Answer 18

• more negative membrane potential (-90 mV)

- regaining resting membrane potential after repolarization

Question 19

what % is actin and myosin bound in normal muscle

Answer 19

20% bound together

80% not bound together

Question 20

what % is actin and myosin bound together post mortem (no ATP produced)

Answer 20

100% actin and myosin bound together (forms actomyosin)

Question 21

actomyosin

Answer 21

complex protein forms by the cross bridge of actin and ,myosin

Question 22

red muscle fiber

Answer 22

• more myoglobin content
• tonic (locomotive)
• slow contractions
• not easily fatigued
• distance runner
• smaller
• high capillary density (2:1)

Question 23

white muscle fiber

Answer 23

• less myoglobin content
• phasic (supportive)
• fast contractions
• easily fatigued
• sprinter
• larger
• low capillary density (1:1)

Question 24

why do muscles burn when exercising

Answer 24

• not enough oxygen delivered to muscles

- leads to breakdown of glycogen into lactic acid

Question 25

how can a marathon runner get more energy production and high endurance

Answer 25

• oxidative metabolism
• more mitochondria
• more myoglobin
• smaller diameter so that and waste dissipate faster
• more lipid for energy storage

Question 26

red vs. white muscle in face

Answer 26

eyes = white (rapid blink)
lips = red (long chewing)

Question 27

epimysium

Answer 27

• surrounds muscle

- prevents friction

Question 28

perimysium

Answer 28

-surrounds muscle bundles

Question 29

endomysium

Answer 29

-surround the individual muscle fibers in the muscle bundle

Question 30

order of muscle makeup from smallest to largest

Answer 30

• muscle
• muscle bundle
• muscle fiber
• myofibril
• myofilament (actin + myosin)