MUSCLE CONTRACTIONS

Question 1

generates mechanical forces necessary for locomotion, manipulation of objects, and physiological actions necessary to maintain homeostasis

Answer 1

MUSCULAR SYSTEM

Question 2

these two contractile proteins are the source of motion in muscle fibers

Answer 2

ACTIN and MYOSIN

Question 3

these muscles pull on tendons, which pull on bones on each side of a joint – muscle contraction pulls one bone toward or away from the bone with which it articulates

Answer 3

SKELETAL MUSCLES

Question 4

muscles act ANTAGONISTICALLY to one another – the muscle that produces a particular action is the _________; the muscle that produces the opposite movement is the __________

Answer 4

AGONIST;

ANTAGONIST

Question 5

this muscular movement refers to a movement that decreases the angle between two body parts

Answer 5

FLEXION

Question 6

this muscular movement refers to a movement that increases the angle between two body parts

Answer 6

EXTENSION

Question 7

these consist of long, striated cells with many nuclei (muscle fibers) organized in bundles wrapped by connective tissue

Answer 7

SKELETAL MUSCLES

Question 8

the term for the plasma membrane in muscle cells that has multiple inward extensions that form TRANSVERSE TUBULES

Answer 8

SARCOLEMMA

Question 9

the SARCOLEMMA has multiple inward extensions that form what

Answer 9

TRANSVERSE TUBULES

Question 10

the SARCOPLASM and ENDOPLASMIC RETICULUM in muscle fibers is called the what

Answer 10

SARCOPLASMIC RETICULUM

Question 11

these are made up of two types of MYOFILAMENTS or FILAMENTS

Answer 11

MYOFIBRILS

Question 12

MYOFIBRILS are made up of these two types of MYOFILAMENTS or FILAMENTS

Answer 12

THICK MYOSIN FILAMENTS

THIN ACTIN FILAMENTS

Question 13

this composition of MYOFIBRILS consist mainly of the protein MYOSIN

Answer 13

THICK MYOSIN FILAMENTS

Question 14

this composition of MYOFIBRILS consist mainly of the protein actin; they also contain the proteins TROPOMYOSIN and TROPONIN, which regulate interaction with myosin filaments

Answer 14

THIN ACTIN FILAMENTS

Question 15

THIN ACTIN FILAMENTS consist of the three proteins:

Answer 15

ACTIN;
TROPOMYOSIN;
TROPONIN

Question 16

MYOSIN and ACTIN FILAMENTS are organized into repeating units called __________, the basic units of muscle contraction

Answer 16

SARCOMERES

Question 17

SARCOMERES are joined at their ends by the ______

Answer 17

Z line

Question 18

MYOSIN and ACTIN FILAMENTS overlap lengthwise in muscle fibers, producing three pattern of striations, namely:

Answer 18

I band
A band
H zone

Question 19

this occurs when sarcomeres shorten

Answer 19

MUSCLE CONTRACTION

Question 20

according to the this model, sarcomeres shorten as actin and myosin filaments slide past one another, increasing their overlap

Answer 20

SLIDING FILAMENT MODEL

Question 21

these two pattern of striations decrease in length, but ____ and _______ themselves do not shorten

Answer 21

I band and H zone;

actin and myosin filaments

Question 22

these transmit signals from the brain or spinal cord to muscle fibers

Answer 22

MOTOR NEURONS

Question 23

a MOTOR NEURON releases the neurotransmitter _____________ into the SYNAPTIC CLEFT

Answer 23

ACETYLCHOLINE

Question 24

ACETYLCHOLINE binds with receptors on each muscle fiber, causing ___________ across its sarcolemma

Answer 24

DEPOLARIZATION

Question 25

this phenomenon causes an electrical signal (action potential) to be generated in the muscle fiber

Answer 25

DEPOLARIZATION

Question 26

this travels along the sarcolemma and into T-tubule membranes, triggering release of Ca2+ from the sarcoplasmic reticulum into myofibrils

Answer 26

ACTION POTENTIAL

Question 27

an ACTION POTENTIAL travels along the sarcolemma and into T-tubule membranes, triggering what?

Answer 27

the release of Ca2+ from the sarcoplasmic reticulum into myofibrils

Question 28

how do action potentials contract the myofibrils?

Answer 28

> action potential triggers the release of Ca2+ from the sarcoplasmic reticulum into myofibrils > Ca2+ binds to TROPONIN which pushes TROPOMYOSIN away from active sites on actin filaments > ATP attached to myosin is split into ADP and Pi – the myosin head binds to the active site on the actin filament, forming a CROSS BRIDGE > the release of Pi from the myosin head triggers a conformational change which bends the myosin head about 45 DEGREES in a flexing motion (POWER STROKE) > during the power stroke, myosin heads pull actin filaments toward the center of the sarcomere, shortening the muscle; ADP is released > myosin heads bind to new ATP and detach from actin

Question 29

these molecules power cocking, attachment of myosin heads to actin filaments, flexion, and release of the myosin heads

Answer 29

ATP molecules

Question 30

energy stored in __________________ is transferred to ATP as needed, but it is quickly depleted

Answer 30

CREATINE PHOSPHATE

Question 31

serves as an important reservoir of high-energy phosphates in striated muscle

Answer 31

CREATINE PHOSPHATE

Question 32

muscle fibers store energy in __________, which is degraded into ________, which is degraded in _______________

Answer 32

GLYCOGEN; GLUCOSE; cellular respiration

Question 33

oxygen debt during exercise causes muscles to obtain energy anaerobically through what

Answer 33

LACTIC ACID FERMENTATION

Question 34

ATP _________ results in weaker contractions and muscle fatigue

Answer 34

depletion

Question 35

accumulation of _________ contributes to muscle fatigue

Answer 35

LACTIC ACID

Question 36

the period of rapid breathing that generally follows strenuous exercise pays back the oxygen debt by consuming what

Answer 36

LACTIC ACID

Question 37

enumerate the THREE TYPES OF SKELETAL MUSCLE FIBERS

Answer 37

SLOW-OXIDATIVE FIBERS (RED FIBERS) FAST-GLYCOLYTIC FIBERS (WHITE FIBERS) FAST-OXIDATIVE FIBERS (INTERMEDIATE FIBERS)

Question 38

type of skeletal muscle fiber that is adapted for endurance activities and maintaining posture such as swimming and long-distance running

Answer 38

SLOW-OXIDATIVE FIBERS (RED FIBERS)

Question 39

type of skeletal muscle fiber that contracts slowly and fatigues slowly

Answer 39

SLOW-OXIDATIVE FIBERS (RED FIBERS)

Question 40

types of skeletal muscle fiber that require a steady supply of oxygen; derive most of their energy from aerobic respiration

Answer 40

SLOW-OXIDATIVE FIBERS (RED FIBERS) | FAST-OXIDATIVE FIBERS (INTERMEDIATE FIBERS)

Question 41

types of skeletal muscle fiber that are rich in MITOCHONDRIA, CAPILLARIES and MYOGLOBIN

Answer 41

SLOW-OXIDATIVE FIBERS (RED FIBERS) | FAST-OXIDATIVE FIBERS (INTERMEDIATE FIBERS)

Question 42

type of skeletal muscle fiber that generates a great deal of power and carries out rapid movements, but only for a short time (sprinting, weight lifting)

Answer 42

FAST-GLYCOLYTIC FIBERS (WHITE FIBERS)

Question 43

type of skeletal muscle fiber that has few MITOCHONDRIA; obtain most of their energy from GLYCOLYSIS

Answer 43

FAST-GLYCOLYTIC FIBERS (WHITE FIBERS)

Question 44

type of skeletal muscle that fatigues rapidly when their glycogen supply is depleted

Answer 44

FAST-GLYCOLYTIC FIBERS (WHITE FIBERS)

Question 45

type of skeletal muscle that has a low MYOGLOBIN content and are white

Answer 45

FAST-GLYCOLYTIC FIBERS (WHITE FIBERS)

Question 46

o contract rapidly and type of skeletal muscle that have an intermediate rate of fatigue

Answer 46

FAST-OXIDATIVE FIBERS (INTERMEDIATE FIBERS)

Question 47

in humans, most muscles have a _________ of different types of fibers

Answer 47

MIXTURE

Question 48

aerobic training increases the __________ DENSITY, number of ____________, and ________ content of muscle fibers

Answer 48

CAPILLARY; MITOCHONDRIA; MYOGLOBIN

Question 49

the ___________ of a muscle depends on these: o types of muscle fibers making up the muscle o number of muscle fibers contracting o tension developed by each fiber o frequency of stimulation o condition of the muscle

Answer 49

CONTRACTION

Question 50

strength training increases the number of _________ in muscle fibers, which increases the size of the muscle

Answer 50

FILAMENTS

Question 51

the more muscle fibers that contract, the greater the ________ in the muscle

Answer 51

TENSION

Question 52

each junction of a motor neuron with a muscle fiber is called a what

Answer 52

NEUROMUSCULAR JUNCTION

Question 53

the more motor units recruited, the stronger the what

Answer 53

CONTRACTIONS

Question 54

when a series of separate stimuli arrive very closely together, the twitches add together (called _________), resulting in a smooth, sustained contraction (called ________)

Answer 54

SUMMATION; | TETANUS

Question 55

when you are not moving, your muscles are in a state of partial contraction (called __________), keeping muscles prepared for action

Answer 55

muscle tone

Question 56

type of muscle that is not under voluntary control; not striated

Answer 56

SMOOTH MUSCLE

Question 57

type of muscle found in tubular organs that often contract in response to simple stretching; contraction tends to be sustained

Answer 57

SMOOTH MUSCLE

Question 58

type of muscle that contracts slowly and squeezes strongly

Answer 58

SMOOTH MUSCLE

Question 59

type of muscle that shortens more than striated muscle – cross bridges in these muscles remain in the attached state longer

Answer 59

SMOOTH MUSCLE

Question 60

type of muscle that is not under voluntary control; striated

Answer 60

CARDIAC MUSCLE

Question 61

• contracts and relaxes type of muscle that contracts and relaxes in alternating rhythm, propelling blood with each contraction; regulates heart beat

Answer 61

CARDIAC MUSCLE

Question 62

in CARDIAC MUSCLE, fibers are electrically coupled by what

Answer 62

GAP JUNCTIONS or INTERCALATED DISCS

Question 63

each heartbeat is initiated by a what

Answer 63

PACEMAKER

Question 64

this system transmits the signal through cardiac muscle – heart beats independently of nerve supply

Answer 64

CONDUCTION SYSTEM