Muscular System #1

Question 1

What is the function of the muscular sytem?

Answer 1

Movement, Posture, Heat production

Question 2

What do muscles help move?

Answer 2

Skeleton, Internal organs, Heart

Question 3

What are muscles?

Answer 3

Muscular tissue held together by connective tissue

Question 4

What attaches the muscle to the bone?

Answer 4

Tendons

Question 5

What are aponeurosis.

Answer 5

a sheet of pearly white fibrous tissue that takes the place of a tendon in flat muscles having a wide area of attachment

Question 6

What makes up a muscle fiber?

Answer 6

Sarcolemma, sarcoplasm, myofibrils, sarcomere, and myofilaments (actin, myosin)

Question 7

What is sarcolemma?

Answer 7

a specialized membrane which surrounds striated muscle fiber cells.

Question 8

What is sarcoplasm?

Answer 8

the cytoplasm of striated muscle cells

Question 9

What are myofibrils?

Answer 9

very fine contractile fibers, groups of which extend in parallel columns along the length of striated muscle fibers. The myofibrils are made up of thick and thin myofilaments, which help give the muscle its striped appearance

Question 10

What is sarcomere?

Answer 10

the functional unit of striated muscle

Question 11

What are myofilaments?

Answer 11

the filaments of myofibrils, constructed from proteins, principally myosin or actin

Question 12

What is actin?

Answer 12

a protein that forms the contractile filaments of muscle cells, thin

Question 13

What is myosin?

Answer 13

a protein that forms the contractile filaments of muscle cells, thick

Question 14

What is a myosatellite cell?

Answer 14

differentiate and fuse to augment existing muscle fibers and to form new fibers

Question 15

What is an I band?

Answer 15

Light band, only has thin filaments and is found between the A bands, centered around the Z line (border between sarcomere)

Question 16

What is an A band?

Answer 16

Dark band, has both thin and thick filaments

Question 17

What is an M line?

Answer 17

A line down the A bands comprised of multiple M enzymes responsible for energy metabolism

Question 18

What is the H zone?

Answer 18

Area of A band with only thick filaments

Question 19

How do myosin and actin work together?

Answer 19

Myosin heads bind to the actin and pull on it, which is the sliding filament theory

Question 20

How does a muscle contract?

Answer 20

a muscle fiber contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber. When all the sarcomeres in a muscle fiber shorten, the fiber contracts.

Question 21

What other proteins are contained in actin?

Answer 21

Tropomyosin, Troponin

Question 22

What does tropomyosin do?

Answer 22

changes position to reveal actin attachment sites when calcium binds to troponin

Question 23

What does troponin do?

Answer 23

Binding site for calcium, causing movement in tropomyosin when bound to calcium

Question 24

What does calcium do in the muscles?

Answer 24

Calcium binds to the troponin, causing a position change in tropomyosin, exposing the actin sites that myosin will attach to for a muscle contraction

Question 25

What is the sarcoplasmic reticulum?

Answer 25

a complex network of specialized smooth endoplasmic reticulum that is important in transmitting the electrical impulse as well as in the storage of calcium ions

Question 26

How does a sarcomere shorten?

Answer 26

the actin is pulled along myosin toward the center of the sarcomere until the actin and myosin filaments are completely overlapped

Question 27

What is the neuromuscular junction?

Answer 27

is a synaptic connection between the terminal end of a motor nerve and a muscle

Question 28

What is the motor end plate?

Answer 28

specialized chemical synapses formed at the sites where the terminal branches of the axon of a motor neuron contact a target muscle cell

Question 29

What neurotransmitter activates muscles?

Answer 29

acetylcholine

Question 30

What is depolarizaiton?

Answer 30

Na enters the cell, K leaves the cell, changing the membrane potential and continuing the AP down the fiber/nerve

Question 31

What is rigor mortis?

Answer 31

Rigor mortis is defined by the decline of ATP to zero, 0% extensibility, an ultimate pH that is reached, and the production of lactic acid that has plateaued.

Question 32

What is related to muscle fiber contraction strength?

Answer 32

Nerve impulse stays the same, more calcium can cause a stronger contraction, fatigue in muscles results in weaker contractions

Question 33

What is an isometric contraction?

Answer 33

A muscular contraction in which the length of the muscle does not change

Question 34

What is an isotonic contraction?

Answer 34

A muscular contraction in which the length of the muscle changes