Muscle Physiology SAVE ME

From smallest to largest, which of the following is the correct order of arrangement? a. fiber, myofibril, myofilament b. myofibril, myofilament, fiber c. myofilament, myofibril, fiber d. fiber, myofilmanet, myofibril

. myofilmanet, myofibril, fiber

The molecule called [blank] helps the muscle cell regenerate ATP from ADP so energy is always available for muscle contraction a. creatine phosphate b. phosphokinase c. botulinum d. acetylcholinesterase

a. creatine phosphate

White fibers are also called a. fast fibers b. slow fibers c. elongated fibers d. intermediate fibers

a. fast fibers

The ability of muscle cells to respond to nerve stimulus is called a. irritability b. contractility c. extensibility d. elasticity

a. irritability

Most body movements are a. isotonic contractions b. isometric contractions c. a combination of isotonic and isometric contractions

a. isotonic contractions

Bundles of fine fibers that extend lengthwise along muscle fibers are called a. myofibrils b. myofilaments c. striae d. sarcoplasmic reticulum

a. myofibrils

Which of the following proteins found in myofilaments contains the cross-bridges? a. myosin b. actin c. tropomyosin d. troponin

a. myosin

The cross bridges involved in a muscle contraction are located on the a. myosin filaments b. actin filaments c. ATPase d. motor end plate

a. myosin filaments

During which phase of the twitch contraction is there a triggering of the release of calcium ions into the sarcoplasm a. latent period b. contraction phase c. relaxation phase d. none

a. or c. latent or relaxation the games

The plasma membrane of a muscle fiber is called the a. sarcolemma b. myofibril c. sarcoplasm d. sarcomere

a. sarcolemma

Somatic motor neurons innervate a. skeletal muscle b. cardiac muscle c. smooth muscle d. glands

a. skeletal muscle

Skeletal muscles are innervated by a. somatic motor neurons b. autonomic motor neurons c. both somatic and autonomic motor neurons d. internal stimulation

a. somatic motor neurons

A motor unit is made up of a. all the muscle fibers within a given muscle b. a motor neuron and the muscle fibers it controls c. all the neurons going into an individual section of the body d. a muscle and a nerve

b. a motor neuron and the muscle fibers it controls

A decrease in muscle size is termed a. hyperplasia b. atrophy c. hypertrophy d. treppe

b. atrohpy

Painful muscle contractions or involuntary twitches are called a. tetanic contractions b. cramps c. convulsions d. fibrillations

b. cramps

A contraction in which the tension within the muscle remains the same but the length changes is called a a. tonic contraction b. isotonic contraction c. isometric contraction d. tetanic contraction

b. isotonic contraction

The protein molecule that has heads jutting out for cross-briding is a. actin b. myosin c. troponin d. tropomyosin

b. myosin

Which of the following is not one of the major functions of muscles? a. movement b. protection c. heat production d. posture

b. protection

Which of the following is known as a striated muscle? a. smooth muscle b. skeletal muscle c. involuntary muscle d. visceral muscle

b. skeletal muscle

Which of these statements is correct regarding muscle contraction? a. ATP does not supply the energy needed for muscle contraction b. Muscle contraction continues for long periods after nervous stimulation ceases c. The cross-bridges bind to the actin and shorten teh sarcomeres d. Acetylcholinesterase is the neurotransmitter

c. The cross-bridges bind to the actin and shorten the sarcomeres

Sarcolemma is a. a system of transverse tubules that extend at a right angle to the long axis of the cell b. a segment of the myofibril between two successive Z-lines c. a unique name for the plasma membrane of a muscle fiber d. none of the above

c. a unique name for the plasma membrane of a muscle fiber

The neurotransmitter secreted at the motor end plates of skeletal muscles is/are a. dopamine b. norepinephrine c. acetylcholine d. any of the above

c. acetylcholine

Endurance training is also known as a. isometrics b. hypertrophy c. aerobic training d. strength training

c. aerobic training

The characteristic of the muscle cell that directly causes movement is a. excitability b. irritability c. contractility d. extensibility

c. contractility

All of the following are true characteristics of an isometric contraction except: a. the muscle does not shorten b. they can produce work by tightening to resist a force c. movement is produced

c. movement is produced

A motor unit is most correctly described as a a. sarcomere and a motor neuron b. myofibril and a motor neuron c. muscle fiber and a motor neuron d. filament and a motor neuron

c. muscle fiber and a motor neuron

The layer of connective tisuue that separates the muscle tissue into small compartments is called the a. aponeuroses b. epimysium c. perimysium d. endomysium

c. perimysium

The purpose of creatine phosphate in muscle contraction is to a. carry oxygen b. store calcium c. replenish energy supply d. rotate the cross bridges

c. replenish energy supply

The smallest contractile unit of muscle is a a. fiber b. myofibril c. sarcomere d. myofilament

c. sarcomere

The first event to occur in muscle relaxation is a. tropomyosin returns to its original position b. myosin cross-bridges are prevented from binding to actin c. the sarcoplasmic reticulum begins actively pumping calcium back into its sacs d. acetylcholine is released

c. the sarcoplasmic reticulum begins actively pumping calcium back into its sacs

The minimal stregngth that is required to cause a muscle contraction is called a. the latend period b. recruitment c. summation d. a threshold stimulus

d. a threshold stimulus

Physiological muscle fatigue may be caused by a. a relative lack of ATP b. high levels of lactic acid c. high levels of metabolic waste products d. all of the above

d. all of the above

The strength of a muscle contraction is influenced by a. the amount of load b. the initial length of muscle fibers c. the recruitment of motor units d. all of the above

d. all of the above

When does a muscle develop oxygen debt? a. when the supply of oxygen is inadequate to meet the demand of aerobic respiration b. when lactic acid builds up in muscle tissue c. when supplies of ATP are depleted d. all of the above

d. all of the above

The ion necessary for cross-bridgingg is a. iron b. sodium c. potassium d. calcium

d. calcium

Glucose can be stored in the muscle as a. creatine phosphate b. ATP c. myoglobin d. glycogen

d. glycogen

Attempging to pick up an object too heavy to lift would result in which type of muscle contraction? a. isotonic b. flaccid c. treppe d. isometric

d. isometric

Aerobic respiration a. allows the body to avoid the use of oxygen for a short time b. results in the formation of an incompletely catabolized molecule c. results in the formation of lactic acid d. produces the maximum amount of energy avilable from each glucose molecule

d. produces the maximum amount of energy available from each glucose molecule

The graded strength principle states a. that muscle fibers will either contract with b. skeletal muscles contract with the same degree of strength at all times, but the force generated is graded c. muscle size is indirectly proportional to muscle strength d. skeletal

d. skeletal muscles contract with varying degrees of strength at different times

Into what does the neuron relase its neurotransmitter at the neuromuscular junction? a. motor end plate b. cytoplasm of the muscle cell c. cisternae d. synaptic cleft (gap)

d. synaptic cleft (gap)