Chapter 7 (2)

What is the function of the transverse tubule? to transmit electrical impulses to the cell's interior the storage of calcium ions to allow cross-bridge attachment to store sodium ions to produce myofibrils

to transmit electrical impulses to the cell's interior

Tropomyosin strands are held in position by which of the following? actin molecules ATP molecules myosin molecules troponin molecules calcium ions

troponin molecules

A single stimulus-contraction-relaxation sequence in a muscle fiber is known as a(n) summation. complete tetanus. latent period. twitch. incomplete tetanus.

twitch

Each myofibril consists of approximately ________ sarcomeres. 100,000 10 500 10,000 2-3 million

10,000

Place these steps of muscle contraction in the correct order. 1. Action potential is generated along the sarcolemma 2. Nerve impulse arrives at synapse 3. Calcium is released into muscle cell cytoplasm 4. Acetylcholine is produced 5. Actin and myosin molecules continuously cross-link, with actin molecules being pulled inward 2, 3, 4, 1, 5 1, 2, 4, 3, 5 4, 2, 1, 5, 3 2, 4, 1, 3, 5 1, 2, 4, 5, 3

2, 4, 1, 3, 5

A layer of collagen fibers that surrounds an entire muscle is called epimysium. perimysium. endomysium. sarcomere. sarcolemma.

epimysium

The term used to describe muscular growth in response to usage is muscular dystrophy. multiple sclerosis. hypertrophy. myopathy. atrophy.

hypertrophy

Which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur? latency complete tetanus incomplete tetanus tension plateau resting period

incomplete tetanus

The skeletal muscles store calcium ions in the terminal cisternae of the sarcosome. sarcomere. sarcoplasmic reticulum. sarcoplasm. sarcolemma.

sarcoplasmic reticulum

Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to the nucleus. thick filaments. the sarcolemma. the sarcoplasmic reticulum. the endomysium.

the sarcoplasmic reticulum

The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of DNA. ATP. cAMP. RNA. tRNA.

ATP

Which of the following is one of the steps that ends a contraction? Acetylcholine binds to receptors on the sarcolemma. Calcium ions bind to troponin. Acetylcholine is broken down by acetylcholinesterase. An action potential spreads across the entire surface of the muscle fiber. Sarcoplasmic reticulum absorbs sodium ions.

Acetylcholine is broken down by acetylcholinesterase

The area of the sarcomere that is the light region between two successive A-bands is the M line. myofibril. H band. Z line. I band.

I band

Which of the following is characteristic of cardiac muscle? Cardiac muscle fibers are faster than skeletal muscles. Cardiac muscle cells are striated. Cardiac muscle cells achieve tetany with every contraction. Cardiac muscle fibers are multinucleated. Neurons that innervate cardiac muscle tissue are under voluntary control.

Cardiac muscle cells are striated.

Rigor mortis occurs at death due to a lack of A) cAMP B) DNA C) RNA D) ATP

D) ATP

The area between Z lines is the myofibril. myofilament. sarcolemma. sarcoplasmic reticulum. sarcomere.

sarcomere

During moderate activity, which of the following is true regarding muscle metabolism? The ATP produced is used to build energy reserves of ATP and glycogen. Mitochondria are not involved. Mitochondrial activity provides about one-third of the ATP consumed. Most ATP is produced through glycolysis, with lactate and hydrogen ions as byproducts. Glucose and fatty acids are catabolized.

Glucose and fatty acids are catabolized

Which of the following occurs when glycolysis produces pyruvate faster than it can be used by the mitochondria? Oxygen is produced. Lactic acid is produced. Lactic acid dissociates into a water molecule and hydrogen. Pyruvate levels drop in the cytoplasm. Pyruvate is converted to sucrose.

Lactic acid is produced.

Which statement regarding "heat loss" is true? Heat loss is reduced when blood flow to the skin increases. Muscle activity does not generate heat. Shivering in a cold environment results in higher levels of heat loss. Muscle contractions play an important role in the maintenance of normal body temperature. When skeletal muscles are contracting at peak levels, body temperature drops.

Muscle contractions play an important role in the maintenance of normal body temperature

Which of the following statements describes how muscles help maintain homeostasis? Skeletal muscle contractions help maintain body temperature. Skeletal muscles are responsible for the pumping action of the heart. Skeletal muscles are responsible for guarding the openings of the digestive and urinary tracts. Skeletal muscles support the weight of some internal organs. The contractions of skeletal muscles pull on tendons and move elements of the skeleton.

Skeletal muscle contractions help maintain body temperature

Which of the following is an effect of aging on the muscular system? Scar tissue formation does not occur. Skeletal muscle fibers become smaller in diameter. Tolerance for exercise increases. Muscle fibers contain more myoglobin. Skeletal muscles become more elastic.

Skeletal muscle fibers become smaller in diameter

Which statement regarding skeletal muscle is true? Skeletal muscles are directly, but not indirectly, attached to bones. Skeletal muscles do not contain connective tissue. Skeletal muscles do not contain nervous tissue. Skeletal muscles do not maintain body temperature. Skeletal muscles contain blood vessels.

Skeletal muscles contain blood vessels

In response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases sodium ions. calcium ions. acetylcholine. potassium ions. acetylcholinesterase.

calcium ions

Which statement regarding isometric contractions is true? Examples are walking and running. Tension rises during a contraction. The tension produced never exceeds the load. Tension remains at a constant level until relaxation occurs. The skeletal muscle's length changes.

The tension produced never exceeds the load

Myofibrils are made primarily of epimysium. tropomyosin. ATP and ADP. troponin. actin and myosin.

actin and myosin

Myofibrils are made primarily of troponin. tropomyosin. epimysium. ATP and ADP. actin and myosin

actin and myosin

The striated appearance of skeletal muscle results from actin and myosin arrangement. the sarcoplasmic reticulum. cisternae placement. the transverse tubule pattern. the perimysium arrangement.

actin and myosin arrangement

A resting muscle generates most of its ATP by conversion of creatine phosphate. aerobic respiration. anaerobic respiration. heat loss. glycolysis.

aerobic respiration

Smooth muscle cells have to be innervated by motor neurons. are larger than cardiac muscle cells. contain intercalated discs. are multinucleate. are spindle-shaped.

are spindle-shaped

Muscle cells actively lengthen. possess a mechanism that regulates the tension amount by changing the number of contracting sarcomeres. generate compression. vary tension production based on the amount of sodium ions bound to actin. can only contract.

can only contract

Active muscles generate heat and oxygen. blood and sodium. carbon dioxide and heat. sodium and oxygen. oxygen and carbon dioxide.

carbon dioxide and heat

"Anaerobic endurance" is determined by the availability of carbohydrates, lipids, or amino acids for breakdown. does not promote muscle hypertrophy. is exemplified by contractions of fast muscle fibers. is used during long, slow athletic activities. is the length of time a muscle can continue to contract while supported by mitochondrial activities.

is exemplified by contractions of fast muscle fibers

Calcium ions are released from the sarcoplasmic reticulum during the ________ phase of contraction. contraction twitch relaxation recovery latent

latent

Regarding lactic acid regulation, which cells in the body consume extra oxygen and produce ATP for the conversion of excess lactate absorbed from the blood back to glucose? skeletal muscle fibers neurons erythrocytes liver cells cardiac muscle cells

liver cells

During activities requiring aerobic endurance, fatigue occurs in a few minutes. glycogen and glycolysis are the primary sources of reserve energy. amino acids are not broken down. muscle hypertrophy often occurs. most of the muscle's energy is produced in mitochondria.

most of the muscle's energy is produced in mitochondria.

The specialized sarcolemma that contains acetylcholine receptors is the motor unit. I band. motor end plate. synaptic cleft. synaptic knob.

motor end plate

Neurotransmitters that cause skeletal muscle contraction are normally stored in actin. motor neuron axon terminals. motor units. motor end plates. myofibrils.

motor neuron axon terminals

Exhaustion of energy reserves or decline in pH due to production and dissociation of lactic acid causes muscle relaxation. the conduction of neural information to the muscle fiber. muscle contraction. muscle fatigue. the striated appearance of skeletal muscle.

muscle fatigue

The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called the aerobic oxygen conversion. anaerobic oxygen threshold. refractory oxygen amount. oxygen debt. aerobic oxygen threshold.

oxygen debt

A sheath of connective tissue surrounding a bundle of striated muscle fibers is called sarcoplasmic reticulum. perimysium. epimysium. endomysium. sarcolemma.

perimysium

A person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more ________ in his or her leg muscles. red fibers intermediate fibers dark fibers fast fibers slow fibers

slow fibers

Nonstriated, involuntary muscle is white skeletal. intermediate skeletal. cardiac. red skeletal. smooth.

smooth

Creatine phosphate serves to supply energy to synthesize ATP. decompose ADP. cause the decomposition of ATP. synthesize glucose. synthesize ADP.

supply energy to synthesize ATP

Acetylcholinesterase is found within the nucleus. myofibril. sarcomere. synaptic cleft. sarcolemma.

synaptic cleft