ZOOL Chapter 10 Muscle Tissue

Which of the following events most directly occurs due to an action potential generated by the motor neuron? a) ACh is released at the synapse. b) An action potential is generated on the muscle fiber. c) Na rushes into the sarcolemma. d) AChE breaks down ACh in the synaptic cleft. e) ACh binds to ACh receptors.

a) ACh is released at the synapse.

The characteristic muscle stiffness associated with rigor mortis is due to the inability of myosin filaments to detach from the active site on actin filaments. What molecule is essential for this detachment? a) ATP b) acetylcholinesterase c) calcium d) acetylcholine

a) ATP

The cross bridge cycle starts when _________. a) Ca2+ from the sarcoplasmic reticulum binds to troponin b) acetylcholine diffuses away from the synaptic cleft c) Ca2+ is actively transported into the sarcoplasmic reticulum d) Ca2+ from the sarcoplasmic reticulum binds to tropomyosin e) ATP binds to troponin and is hydrolyzed to ADP and Pi

a) Ca2+ from the sarcoplasmic reticulum binds to troponin

Which of the following statements is true? a) The neurotransmitter is stored in the presynaptic motor neuron. b) The sarcolemma is the presynaptic membrane. c) Acetylcholinesterase (AChE) is stored in vesicles within the presynaptic motor neuron. d) The acetylcholine (ACh) receptors are located on the myofibril membrane.

a) The neurotransmitter is stored in the presynaptic motor neuron.

Titin is a(n) __________. a) elastic protein b) tropomyosin-binding protein c) calcium-binding protein d) thin filament protein

a) elastic protein

What area of the thick filament binds to actin once its active binding sites are exposed? a) myosin cross-bridge (head) b) troponin c) hinge d) tropomyosin

a) myosin cross-bridge (head)

Which of the following is/are mechanism(s) to end neural transmission at the neuromuscular junction? a) ACh binds to ACh receptors. b) ACh diffuses away from the synaptic cleft. c) ACh is broken down into acetic acid and choline by the enzyme acetylcholinesterase (AChE). d) ACh is taken up by the axon terminal via endocytosis.

b) ACh diffuses away from the synaptic cleft. c) ACh is broken down into acetic acid and choline by the enzyme acetylcholinesterase (AChE).

Sarcomere is best defined as __________. a) a storage organelle for calcium b) a repeating functional unit of striated muscle c) actomyosin proteins d) thick and thin filaments

b) a repeating functional unit of striated muscle

The capillaries that wrap around each muscle fiber are located within the __________. a) epimysium b) endomysium c) perimysium d) sarcolemma

b) endomysium

What is the function of the structure indicated by the arrow? (T tubules) a) houses the genetic material (DNA) of the cell b) part of coupling the action potential (electrical event) to contraction (mechanical event) c) storage of calcium d) making of energy (ATP), "power house" of the cell

b) part of coupling the action potential (electrical event) to contraction (mechanical event)

The action potential in skeletal muscle fibers is first generated on the __________. a) sarcoplasmic reticulum b) sarcolemma c) sarcophagus d) sarcoplasm

b) sarcolemma

What component of the thin filament binds to calcium once calcium is released from the terminal cisternae of the sarcoplasmic reticulum? a) tropomyosin b) troponin c) actin d) myosin

b) troponin

Triads in skeletal muscle fibers function in __________. a) neuromuscular transmission b) sarcomere shortening c) calcium ion release d) calcium ion uptake

c) calcium ion release

Muscle fibers are directly surrounded by which thin layer of connective tissue? a) perimysium b) tendon c) endomysium d) epimysium

c) endomysium

The muscle action potential penetrates deep into a fiber along the __________. a) neuromuscular junction b) sarcoplasmic reticulum c) transverse tubules d) Z discs

c) transverse tubules

The post-synaptic reaction on the sarcolemma is short in duration. Which of the following explanations describes why the reaction of the sarcolemma is short in duration? a) Muscle tissue has a smaller membrane potential than nervous tissue. b) ACh diffuses across the synaptic cleft toward the sarcolemma. c) The ACh receptors respond only for a short period of time. d) ACh diffuses out of the synaptic cleft. e) AChE acts to breakdown the ACh in the synaptic cleft.

d) ACh diffuses out of the synaptic cleft. e) AChE acts to breakdown the ACh in the synaptic cleft.

Which of these statements about skeletal muscles is FALSE? a) They support soft tissues. b) They pull on tendons. c) They store nutrient reserves. d) Their fibers branch.

d) Their fibers branch.

During neuromuscular transmission, the axon terminals release __________. a) sodium ions b) acetylcholinesterase c) calcium ions d) acetylcholine

d) acetylcholine

Skeletal muscle does each of these EXCEPT __________. a) produce movement b) maintain posture c) store nutrients d) pump blood

d) pump blood

In response to an action potential along the transverse tubules, the __________ release(s) calcium ions into the sarcoplasm. a) motor-end plate b) troponin molecules c) sarcomere d) sarcoplasmic reticulum

d) sarcoplasmic reticulum

Which region of the sarcomere gives rise to the structure (band or line) indicated by the arrow? (Z line) a) the region of the resting sarcomere that only contains thick filaments b) the point of connection for adjacent thick filaments c) the region of the sarcomere that contains only thin filaments d) the boundary between adjacent sarcomeres

d) the boundary between adjacent sarcomeres

Which region of the sarcomere gives rise to the structure (band or line) indicated by the arrow? (H band) a) the boundary between adjacent sarcomeres b) the point of connection for adjacent thick filaments c) the region of the sarcomere that contains only thin filaments d) the region of the resting sarcomere that only contains thick filaments

d) the region of the resting sarcomere that only contains thick filaments

Which region of the sarcomere gives rise to the structure (band or line) indicated by the arrow? (I band) a) the region of the resting sarcomere that only contains thick filaments b) the boundary between adjacent sarcomeres c) the point of connection for adjacent thick filaments d) the region of the sarcomere that contains only thin filaments

d) the region of the sarcomere that contains only thin filaments