Anps Lab Exam 3 Part 1

Front 1

T/F myofibrils are composed of protein filaments called actin and myosin

Back 1

true

Front 2

a bundle of muscle fibers is known as a

Back 2

fascicle

Front 3

A skeletal muscle fiber (cell) contains a single nucleus (T/F)

Back 3

false

Front 4

the muscle cell membrane is called the

Back 4

sarcolemma

Front 5

which connective tissue wrapping separates individual muscle fibers

Back 5

endomysium

Front 6

Name the compartments of muscle cells

Back 6

Front 7

label the parts of a muscle cell

Back 7

Front 8

skeletal muscles are composed of hundreds of muscle cells called

Back 8

muscle fibers

Front 9

at the ends of muscles, the connective tissues merge to form a _____ which attaches the muscle to bone

Back 9

tendon

Front 10

Lable the parts of the skeletal muscle fiber

Back 10

Front 11

An action potential traveling down t-tubules cause calcium ions to diffuse from the ______ into the ______

Back 11

sarcoplasmic reticulum; sarcoplasm

Front 12

which of the following best describes the role of calcium in muscle contraction

Back 12

it binds to troponin, moving tropomyosin, so that myosin heads can bind to actin

Front 13

t-tubules are invaginations of the sarcolemma of a muscle cell (T/F)

Back 13

true

Front 14

the component of a muscle fiber that allows an action potential to travel quickly from the sarcolemma throughout the entire muscle fiber is called the

Back 14

transverse tubule (T-tubule)

Front 15

during contraction of a muscle, calcium ions bind to the

Back 15

troponin molecule

Front 16

what is important about the tropomyosin molecule

Back 16

tropomyosin blocks the binding sites on actin, unless calcium is bond to troponin

Front 17

the bond beween the actin and myosin head is broken when

Back 17

an ATP molecule binds to the myosin head

Front 18

energy is released when

Back 18

ATP is broken down into ADP and phosphate

Front 19

the sequence of crossbridge formation and myofilament movement will be repeated as long as calcium ions are present (T/F)

Back 19

true

Front 20

what are the different bands

Back 20

Front 21

Thin filament connect to and extend from either side of a _______. These thin filaments are composed largely of the myofilament______.

Back 21

z-disc; actin

Front 22

myosin heads directly use ______ to transition to their _______ conformation, which enables them ready to bind to actin.

Back 22

ATP; energized

Front 23

The presence of calcium in the sarcoplasm is directly responsible for ______.

Back 23

exposing the binding sites on actin

Front 24

rigor mortis occurs after death because________________.

Back 24

detachment of crossbridges does not occur due to the lack of ATP

Front 25

In which region of the muscle fiber do actin and myosin myofilaments overlap

Back 25

A band

Front 26

during contraction, the actin myofilaments slide toward the

Back 26

H zone

Front 27

the distance from on Z disk to the next Z disk is called a

Back 27

sarcomere

Front 28

in a relaxed muscle, the ends of the actin filaments overlap (T/F)

Back 28

false

Front 29

troponin and tropomyosin are found on thick or thin filaments

Back 29

thin

Front 30

myosin is found on ____ filaments

Back 30

thick

Front 31

label the bands and sarcomere parts

Back 31

Front 32

During crossbridge cycling, tension is created by

Back 32

a change in the shape of the myosin head

Front 33

according tot he sliding filament theory for skeletal muscle contraction, a shortening of the sarcomere is produced by

Back 33

an increase in the amount of overlap between the thick and thin filaments

Front 34

maximum tension is produced in skeletal muscle fiber when it is

Back 34

at resting length, because this is where there is optimum overlap of thick and thin filaments

Front 35

What occurs when ther is optimum overlap of thick and thin filaments

Back 35

this is when the highest number of cross-bridges can form between myosin and actin

Front 36

when the muscle is stretched what happens to the length of the muscle fibers

Back 36

the muscle fibers get longer

Front 37

a single contraction produced maximum tension when the muscle was held at

Back 37

about 28 mm

Front 38

if maximum tension indicates that the thick and thin filaments are set at optimal overlap to produce a maximum number of crossbridges, in this experiment, further stretching of the muscle beyond 28 mm will

Back 38

decrease the amount of thick and thin filament overlap and therefore, the number of crossbridges

Front 39

Since the tension produced by a contracting muscle fiber depends upon the number of crossbridges between the thick and thin filaments, stretching the muscle beyond 28 mm:

Back 39

decreases the amount of overlap and decreases the amount of tension produced by a single contraction

Front 40

One factor that influences the amount of tension a muscle can generate when stimulated is the amount of overlap of thick and thin filaments when the muscle begins its contraction is called

Back 40

length-tension relationship

Front 41

In the gluteus maximus, each motor unit controls a ______ amount of muscle fibers than a motor unit controlling muscles of the eye

Back 41

greater