muscular system

The prime mover of arm abduction is the ________ muscle. trapezius latissimus dorsi deltoid quadratus lumborum

deltoid

A smooth, sustained contraction is called ________. unfused, or incomplete, tetanus a twitch summing of contractions fused, or complete, tetanus

fused, or complete, tetanus

Paralysis of which of the following would make an individual unable to flex the hip ________. gastrocnemius biceps femoris soleus tibialis anterior iliopsoas

iliopsoas

Smooth muscle cells are ________. involuntary cylindrical striated branched multinucleate

involuntary

A motor neuron and all of the skeletal muscle fibers it stimulates are termed a ________. synaptic cleft neurotransmitter neuromuscular junction myofilament motor unit

motor unit

One neuron and all the skeletal muscles it stimulates is known as a ________. neuromuscular junction synaptic cleft motor unit sarcoplasmic reticulum

motor unit

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract? acetylcholine (ACh) causes temporary permeability to sodium sodium ions rush into the cell operation of the sodium-potassium pump acetylcholinesterase (AchE) breaks down acetylcholine (ACh) diffusion of potassium ions out of the cell

acetylcholine (ACh) causes temporary permeability to sodium

The A band within a skeletal muscle fiber is indicated by ________. Label D Label B Label A Label C

Label A

The I band within a skeletal muscle fiber is indicated by ________. Label C Label B Label D Label A

Label B

The H zone, located within the A band, lacks thin filaments and is represented by ________. Label D Label A Label B Label C

Label D

Neurotransmitters are released upon stimulation from a nerve impulse by the ________. thick filaments sarcoplasmic reticulum myofibrils axon terminals of the motor neuron sarcolemma of the muscle cell

axon terminals of the motor neuron

Which of the following muscles are antagonists? masseter and temporalis vastus medialis and vastus lateralis gastrocnemius and soleus bicpes femoris and biceps brachii biceps brachii and triceps brachii

biceps brachii and triceps brachii

Which of the following muscles closes the jaw? buccinator sternocleidomastoid both masseter and temporalis zygomaticus frontalis

both masseter and temporalis

A nursing infant develops a powerful sucking muscle that adults also use for whistling or blowing a trumpet called the ________. temporalis platysma buccinator masseter zygomaticus

buccinator

Which of the following is NOT a function of the muscular system? maintenance of posture production of movement generation of heat hematopoiesis stabilization of joints

hematopoiesis

A muscle located on the ventral (anterior) side of the body is the ________. pectoralis major occipitalis gluteus medius gastrocnemius latissimus dorsi

pectoralis major

The ________ is an organelle that wraps and surrounds the myofibril and stores calcium. sarcolemma cross bridge sarcoplasmic reticulum sarcomere

sarcoplasmic reticulum

The type of muscle tissue pictured in Figure 6.3 is ________. smooth muscle found only in the heart voluntary skeletal muscle striated

smooth muscle

A muscle group that works with and assists the action of a prime mover is a(n) ________. synergist only antagonist only antagonist and fixator antagonist and synergist fixator only

synergist only

Which of these muscles is a synergist to masseter? temporalis sternocleidomastoid orbicularis oris buccinator trapezius

temporalis

A sarcomere is ________. the contractile unit between two Z discs the nonfunctional unit of skeletal muscle the wavy lines on the cell, as seen in a microscope the area between two intercalated discs a compartment in a myofilament

the contractile unit between two Z discs

Striated involuntary muscle tissue found in the heart is ________. dense regular smooth muscle skeletal muscle cardiac muscle dense irregular

cardiac muscle

Sandra is playing the piano for her recital. Which muscle is NOT involved in the movement of her hands and/or fingers ________. flexor carpi ulnaris extensor digitorum flexor carpi radialis extensor digitorum longus extensor carpi radialis

extensor digitorum longus

A skeletal muscle twitch differs from a tetanic contraction in that ________. the muscle twitch occurs only in small muscles while a tetanic contraction occurs in large muscle groups the muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continuous the tetanic contraction is caused by a single stimulus, while the twitch is caused by very rapid multiple stimuli the muscle twitch is prolonged and continuous while a tetanic contraction is brief and "jerky" the tetanic contraction is considered abnormal, while the twitch is a normal muscle response

the muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continuous

Which one of the following is composed of myosin protein? thick filaments thin filaments light bands Z discs all myofilaments

thick filaments