Muscular System

True or False. The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium.

True

Which neurotransmitter is released by motor neurons at the neuromuscular junction? a. sodium b. acetylcholine c. potassium d. acetylcholinestearse

b. acetylholine

What causes the myosin head to disconnect from actin? a. binding of troponin b. binding of ATP c. binding of calcium d. hydrolysis of ATP

b. binding of ATP

What terms refers to a smooth, sustained contraction? a. muscle twitch b. complete tetanus c. isometric contraction d. isotonic contraction

b. complete tetanus

What is the type of chemical reaction used to rebuild ADP into ATP? a. rehydration synthesis b. dehydration synthesis c. hydrolysis

b. dehydration synthesis

Which of the following processes produces molecules of ATP and has two pyruvic acid molecules as end products? a. Krebs cycle and oxidative phosphorylation b. glycolysis c. hydrolysis of creatine phosphate

b. glycolysis

The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell? a. sarcolemma b. terminal cisterns of the sarcoplasmic reticulum c. cytosol d. T tubule

b. terminal cisterns of the sarcoplasmic reticulum

Which one of the following is composed mostly of the protein myosin? a. all myofilaments b. thick filaments c. light bands d. thin filaments e. Z discs

b. thick filaments

Which of the following processes produces 36 ATP? a glycolysis b. hydrolysis of creatine phosphate c. Krebs cycle and oxidative phosyphorlation

c. Krebs cycle and oxidative phosyphoriation

What mineral is released within muscle cells to trigger contraction? a. sodium b. ATP c. calcium d. potassium

c. calcium

ALS (amyotrophic lateral sclerosis) is a disease that results in progressive paralysis. While the ultimate cause is unknown, ____________ is the direct cause of the paralysis. a. malfunctioning mitochondria b. inflammation c. degeneration of motor neurons d. UV light

c. degeneration of motor neurons

What is the function of creatine phosphate? a. catalyzes aerobic respiration b. makes oxygen available for aerobic respiration c. directly regenerates ATP from ADP within a muscle cell d. triggers anaerobic respiration

c. directly regenerates ATP from ADP within a muscle cell

What means of membrane transport is used to release the neurotransmitter into the synaptic cleft? a. a channel b. a protein carrier c. exocytosis

c. exocytosis

What term describes the ability of a muscle to vary its degree of shortening to generate the strength needed to lift a 5 lb weight, a 7 lb weight, and finally a 10 lb weight? a. isotonic contractions b. isometric contractions c. graded responses d. twitch

c. graded responses

Which chemical is produced during vigorous exercise when the supply of oxygen is limited or inadequate? a. carbon dioxide b. creatine c. lactic acid d. glycogen

c. lactic acid

The rest and recovery period, where the muscle restores depleted reserves, includes all of the following processes EXCEPT_______. a. oxygen rebinds to myoglobin b. ATP is used to rephosphorylate creatine into creatine phosphate c. Pyruvic acid is converted back to lactic acid d. Glycogen is synthesized from glucose molecules

c. pyruvic acid is converted back to lactic acid

What type of exercise causes increase in muscle size? a. aerobic exercise b. anaerobic exercise c. resistance exercise d. infrequent exercise

c. resistance exercise

Which of these is NOT a problem associated with destruction of a motor nerve? a. atrophy b. loss of muscle tone c. flaccid paralysis d. spastic paralysis

d. spastic paralysis

When an action potential arrives at the axon terminal of a motor neuron, which ion channels open? a. chemically gated calcium channels b. voltage-gated-sodium channels c. voltage-gated potassium channels d. voltage-gated calcium channels

d. voltage-gated calcium channels

What changes occur in the sacromere during muscle contraction? a. Z discs move closer together b. A band decreases in length c. I band increases in length d. the thin filament shortens

a. Z discs move closer together

In the neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter? a. acetylcholine (ACH) b. serotoran c. norepinephrine d. dopamine

a. acetylcholine (ACh)

What intiates an action potential on a muscle cell? a. acetylcholine binding to receptors on the sarcolemma within the neuromuscular junction b. acetylcholinesterase c. myosin cross bridges bind to actin d. ATP

a. acetylcholine binding to receptors on the sarcolemma within the neuromuscular junction

How is acetycholine (Ach) removed from the synaptic cleft?

a. acetylcholinesterase (AChE: an enzyme) and endocytosis into the muscle fiber b. simple diffusion away from the synaptic cleft and acetylcholinesterase c. simple diffusion away from the synaptic cleft and endocytosis into the muscle fiber d. acetylcholinesterase (AChE; an enzyme) only

A myosin head binds to which molecule to form a cross bridge? a. actin b. tropomyosin c. troponin

a. actin

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell? a. arrival of an action potential b. ATP c. troponin d. calcium ion pump

a. arrival of an action potential

What metabolic waste accumulates in muscle with excessive exertion? a. lactic acid b. carbon dioxide c. creatine d. ADP

a. lactic acid

What happens to a muscle when the nerve supplying that muscle is cut? a. muscle paralysis and atrophy occur b. the muscle hypertrophies c. muscular dystrophy develops d. myasthenia gravis develops

a. muscle paralysis and atrophy occur

What causes the power stroke? a. release of ADP and P1 b. binding of ATP c. hydrolysis of ATP d. calcium

a. release of ADP and P1

What organelle wraps and surrounds the myofibril and stores calcium? a. sacroplasmic reticulum b. cross bridge c. sarcolemma d. sarcomere

a. sacroplasmic reticulum

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

a. the contractile unit between two Z discs

The binding of calcium to which molecule causes the myosin binding sites to be exposed? a. troponin b. myosin c. tropomyosin d. actin

a. troponin

Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP? a. white fast twitch fibers b. red slow twitch fibers

a. white fast twitch fibers

The plasma membrane of a skeletal muscle cell is called the ________. a. sarcoplasm b. sarcoplasmic reticulum c. sarcomere d. myofilament e. sarcolemma

e. sarcolemma

What creates the alternating light and dark bands that provides the situation pattern on skeletal muscle tissue? a. H zones and M lines b. thick filaments and myosin heads c. A bands and I bands d. Z discs and H zones e. sarcoplasm and sarcolemma

e. sarcoplasm and sarcolemma