muscles 1

Question 1

Skeletal muscle functions

Answer 1

• Produce skeletal movement
• Maintain posture and body position
• support soft tissues
• guard entrances and exits
• maintain body temperature
• nutrient reserves

Question 2

origin

Answer 2

attached to bone that remains relatively stationary during movement

Question 3

insertion

Answer 3

attached to the bone that moves

Question 4

synergistic muscles

Answer 4

work together for a common thing

Question 5

antagonistic muscles

Answer 5

flexors and extensors

Question 6

endomysium

Answer 6

covers individual muscle fibers

Question 7

perimysium

Answer 7

sheathes bundles of muscle fibers (muscle fasicles)

Question 8

What do endomysium and perimysium contain

Answer 8

blood vessels and nerves

Question 9

epimysium

Answer 9

surrounds a muscle

Question 10

deep fascia

Answer 10

wrap groups of cooperating muscles together

Question 11

muscle cell=

Answer 11

muscle fiber

Question 12

The muscle cell is how long?

Answer 12

as long as the muscle is

Question 13

How are skeletal muscle cells formed?

Answer 13

formed during embryogenesis by end-to-end fusion of uni-nucleate myoblasts

Question 14

Where do skeletal muscle cells come from?

Answer 14

Stem cells called satellite cells

Question 15

thin myofilaments

Answer 15

actin

Question 16

thick myofilaments

Answer 16

myosin

Question 17

Bundles of myofilaments

Answer 17

myofibrils

Question 18

muscle cell cytoplasm

Answer 18

sarcoplasm

Question 19

cell membrane

Answer 19

sarcolemma

Question 20

modified ER

Answer 20

sarcoplasmic reticulum

Question 21

transverse tubules

Answer 21

narrow tubes of sarcolemma extend into cell at right angles to cell surface

Question 22

what do transverse tubules do?

Answer 22

• conduct action potential deep into cell

- come in close contact w/sarcoplasmic reticulum

Question 23

What does the sarcolemma do?

Answer 23

an excitable membrane that conducts action potentials

Question 24

What does the sarcoplasmic reticulum do?

Answer 24

• similar to ER
• Forms a tubular network around each myofibril
• terminal cisternae form triads w/ T tubules
• Stores high concentration of ions needed for muscle contraction

Question 25

What are myofilaments made of?

Answer 25

Thick=myosin | thin=actin

Question 26

what are myofibrils?

Answer 26

bundles of myofilaments

Question 27

what do myofibril's do?

Answer 27

- can actively shorten | - anchored to inner surface of sarcolemma at either end of cell

Question 28

what are sarcomeres?

Answer 28

repeating units of myofilaments in myofibril

Question 29

I bands

Answer 29

light bands which contain only thin filaments

Question 30

A bands

Answer 30

Dark bands that contain thick filaments and some overlap w/ thin filaments

Question 31

H bands

Answer 31

only thick filaments

Question 32

Z disk

Answer 32

line that borders sarcomeres

Question 33

What interactions are responsible for muscle contraction?

Answer 33

thin filaments and thick filaments

Question 34

What slides over what to shorten the sarcomere?

Answer 34

thin slides over thick

Question 35

sliding filament model of muscle contraction

Answer 35

1) thin filaments slide over thick filaments 2) z lines are pulled closer together 3) I bands and H band narrow 4) A band stays the same width

Question 36

When is the maximum shortening of the sarcomere

Answer 36

When sarcomere is the width of the A ban, no I band or H band are visible

Question 37

What causes thin and thick myofilaments slide across each other?

Answer 37

- Myosin filaments have projections extending out of the filament - projections bind to sites on actin filaments forming cross bridges - cross bridges pull the actin past the myosin using ATP - convert chemical energy to mechanical energy

Question 38

shape of myosin molecules

Answer 38

golf club shape

Question 39

which chemical prevents myosin head and actin interactions

Answer 39

tropomyosin

Question 40

tropomyosin cover the active sites of which filament?

Answer 40

actin

Question 41

what attaches tropomyosin strands to actin?

Answer 41

troponin

Question 42

How do cross bridges form?

Answer 42

- Ca bonds to troponin - troponin moves, moving tropomyosin and exposing actin active site - myosin head form cross bridge to actin - bends to center, pulling actin - atp allows release of cross bridge

Question 43

how much Ca is around the sarcomere at rest?

Answer 43

low amounts

Question 44

Ca causes troponin to do what?

Answer 44

pull tropomyosin off of actin active sites