guarantied 20 questions Ch. 6 test
According to the sliding filament theory, how does muscle contraction occur? A) Myosin heads form cross bridges and pull thin filaments, causing them to slide. B) Both thick and thin filaments shorten as the muscle contracts. C) A bands bunch up and shorten as myosin heads attach to thin filaments. D) Myosin heads attach and detach from thin filaments, causing thin filaments to shorten.
A
Contractions in which muscles shorten and produce movement are known as ________. A) isotonic contractions B) twitches C) isometric contractions D) resistance exercises
A
The plasma membrane of a skeletal muscle cell is called the ________. A) sarcolemma B) sarcomere C) myofilament D) sarcoplasm
A
Which one of the following is composed mostly of the protein myosin? A) thick filaments B) thin filaments C) all myofilaments D) Z discs
A
A sarcomere is ________. A) the nonfunctional unit of skeletal muscle B) the contractile unit between two Z discs
B
During skeletal muscle contraction, to what do myosin heads bind? A) myosin filaments B) actin filaments C) Z discs D) thick filaments E) the H zone
B
One neuron and all the skeletal muscles it stimulates is known as a ________. A) sarcoplasmic reticulum B) motor unit C) synaptic cleft D) neuromuscular junction
B
What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma? A) neuromuscular junction B) action potential C) neurotransmitter D) acetylcholine
B
Anaerobic glycolysis requires ________ to make ATP. A) creatine phosphate only B) oxygen only C) glucose only D) both oxygen and glucose
C
Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________. A) elasticity B) irritability C) contractility D) extensibility
C
The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction. A) neuromuscular junctions B) synapses C) cross bridges D) motor units
C
What creates the alternating light and dark bands that provides the striation pattern on skeletal muscle tissue? A) sarcoplasm and sarcolemma B) thick filaments and myosin heads C) A bands and I bands D) H zones and M lines
C
What is covered by the endomysium? A) fascicles of muscle cells B) an entire muscle C) an individual muscle cell D) myofibrils E) smooth muscle only
C
Why are calcium ions necessary for skeletal muscle contraction? A) Calcium ions increase the speed of the action potential transmitted along the sarcolemma. B) Calcium ions release the inhibition on Z discs. C) Calcium ions trigger the binding of myosin heads to actin filaments. D) Calcium ions cause ATP binding to actin. E) Calcium ions bind to regulatory proteins on the myosin filaments, changing both their shape and their position on the thick filaments.
C
Creatine phosphate (CP) functions within the muscle cells by ________. A) forming a temporary chemical compound with myosin B) forming a chemical compound with actin C) inducing a conformational change in the myofilaments D) storing energy that will be transferred to ADP to resynthesize ATP as needed E) storing energy that will be transferred to ATP to resynthesize ADP as needed
D
Striated involuntary muscle tissue found in the heart is ________. A) smooth muscle B) skeletal muscle C) dense regular D) cardiac muscle
D
What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract? A) potassium ions B) actin C) sodium ions D) acetylcholine E) myosin heads
D
What must rush into a muscle cell to promote its depolarization? A) potassium ions B) calcium ions C) acetylcholine D) sodium ions E) acetylcholinesterase
D
What organelle wraps and surrounds the myofibril and stores calcium? A) cross bridge B) sarcomere C) sarcolemma D) sarcoplasmic reticulum
D
Which of the following is NOT a function of the muscular system? A) production of movement B) maintenance of posture C) stabilization of joints D) blood cell formation
D