EXERCISE 7 QUIZ

Which region of a sarcomere contain thin filaments? (a) Both I band and A band (b) H zone (c) A band (d) I band

(a) Both I band and A band

Which protein is used to reinforce the sarcolemma and help transmit the tension generated by the sarcomeres to the tendons? (a) Dystrophin (b) Myosin (c) Troponin (d) Tropomyosin (e) Actin

(a) Dystrophin

This type of muscle works by stabilizing the origin of the agonist so that it can act more efficiently. (a) Fixator (b) Agonist (c) Antagonist (d) Synergist (e) Secondary mover

(a) Fixator

Skeletal muscle contraction is triggered to begin when calcium is released from ________. (a) Terminal cisterns of sarcoplasmic reticulum (b) Mitochondria (c) T-tubules (d) Myofibrils

(a) Terminal cisterns of sarcoplasmic reticulum

Weight training increases muscle fiber size by increasing the number of myofibrils. Why? (a) The amount of force developed by a muscle is determined by the number of myosin heads attached to actin molecules. Increasing the size of the muscle increases the number of actin and myosin molecules. Therefore, more myosin heads can attach to actin molecules and more force is generated. (b) The amount of force developed by a muscle is determined by the number of connective tissue coverings. Increasing the size of the muscle increases the number of connective tissue coverings. Therefore, more connective tissue coverings means more force is generated. (c) The amount of force developed by a muscle is determined by the amount of ATP available. Increasing the size of the muscle increases the amount of ATP. Therefore, a larger amount of ATP molecules means more force is generated. (d) The amount of force developed by a muscle is determined by the number of actin heads attached to myosin molecules. Increasing the size of the muscle increases the number of actin and myosin molecules. Therefore, more actin heads can attach to myosin molecules and more force is generated.

(a) The amount of force developed by a muscle is determined by the number of myosin heads attached to actin molecules. Increasing the size of the muscle increases the number of actin and myosin molecules. Therefore, more myosin heads can attach to actin molecules and more force is generated.

Using the biceps brachii to lower a glass to the table represents an example of a(n): (a) eccentric isotonic contraction. (b) concentric isotonic contraction. (c) isometric contraction. (d) Both concentric isotonic and eccentric isotonic contraction are correct

(a) eccentric isotonic contraction.

Which of the following skeletal muscle structures would be the largest in size? (a) fascicle (b) myofibril (c) muscle fiber (d) filaments

(a) fascicle

Which of the following skeletal muscle structures would be the smallest in size? (a) filaments (b) myofibril (c) muscle fiber (d) fascicle

(a) filaments

Curare poisoning is a muscle paralysis that occurs when the toxin blocks acetylcholine receptors on skeletal muscle fibers. What part of the neuromuscular junction is affected? (a) motor end plate (b) synaptic vesicles (c) axon terminal of the motor neuron (d) synaptic cleft

(a) motor end plate

Which sequence is in the correct order from largest to smallest? (a) muscle, fascicle, muscle fiber, myofibril (b) muscle, muscle fiber, myofibril, fascicle (c) muscle fiber, myofibril, fascicle, filaments (d) myofibril, fascicle, filaments, muscle fiber

(a) muscle, fascicle, muscle fiber, myofibril

For the muscle to contract and relax, what must be present (choose all that apply)? (a) Calcium ions (b) ATP (c) ACh (d) Sodium ions

(b) ATP

The opening of ligand gates on the sarcolemma is directly caused by ________. (a) Sodium influx into the muscle fiber (b) Acetylcholine attachment (c) Calcium influx into the motor neuron (d) All choices are correct (e) Acetylcholinesterase activity

(b) Acetylcholine attachment

Which correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? (a) Sarcolemma, axon of neuron, T tubules (b) Axon of neuron, sarcolemma, T tubules (c) T tubules, sarcolemma, myofilament (d) Muscle fiber, axon of neuron, myofibrils (e) Myofibrils, myofilaments, mitochondria

(b) Axon of neuron, sarcolemma, T tubules

Which property of muscle gives it the ability to stretch without damage? (a) Electrical excitability (b) Extensibility (c) Contractility (d) Elasticity

(b) Extensibility

In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to __________. (a) Rapid destruction of ACh in the synaptic cleft by monoamine oxidase (b) Rapid destruction of ACh in the synaptic cleft by acetylcholinesterase (c) Diffusion of the ACh out of the synaptic cleft (d) Endocytosis of the ACh receptor into the myofiber (e) Rapid uptake of the ACh into the myofiber

(b) Rapid destruction of ACh in the synaptic cleft by acetylcholinesterase

What is the result of acetylcholine attaching to the ligand gates of the motor end plate? (a) Calcium voltage gates on the neurolemma are inactive (b) The sarcolemma increases permeability to sodium (c) Calcium ions will be actively transported into the SR (d) The positive charge of the sarcolemma decreases

(b) The sarcolemma increases permeability to sodium

Rod-like structures within skeletal muscle fiber that contain thin and thick filaments organized into sarcomeres are called: (a) muscle cells (b) myofibrils (c) fascicles (d) T-tubules

(b) myofibrils

This area of the sarcomere is the length of the thick filaments. (a) M line (b) H zone (c) A band (d) Z disc

(c) A band

At the neuromuscular junction, _______must enter the synaptic end bulb to stimulate the release of ____________, which binds to ligand gates so ________can enter the muscle fiber. (a) Sodium ions, calcium ions, ACh (b) ACh, calcium ions, sodium ions (c) Calcium ions; ACh, sodium ions (d) Calcium ions, sodium ions, ACh (e) Sodium ions, ACh, calcium ions

(c) Calcium ions; ACh, sodium ions

Contraction of myofibrils within a muscle fiber begins when _________. (a) Acetylcholine binds to ligand gates (b) Sodium enters the muscle fiber (c) Calcium is released from the sarcoplasmic reticulum (d) An action potential travels t-tubules (e) Calcium is moved into the sarcoplasmic reticulum

(c) Calcium is released from the sarcoplasmic reticulum

Myofibrils contain what type of proteins? (a) Tensile proteins (b) Tegulatory proteins (c) Contractile proteins (d) Structural proteins

(c) Contractile proteins

Which of the following structures experiences a decrease in length when the sarcomere shortens? (a) A band, H zone (b) Z disc, A band (c) I band, H zone (d) M line, I band

(c) I band, H zone

Identify the correct primary tissue type shown in this image. (a) Connective (b) Epithelial (c) Muscle (d) Nervous

(c) Muscle

Using the biceps brachii to lift a glass off the table represents an example of a(n): (a) eccentric isotonic contraction. (b) isometric contraction. (c) concentric isotonic contraction. (d) Both concentric isotonic contraction and eccentric isotonic contraction are correct.

(c) concentric isotonic contraction.

In the figure shown, which light micrograph shows a muscle tissue that is under involuntary control? (a) C only (b) B only (c) A only (d) A and C (e) A and B

(d) A and C A - Smooth muscle C - Cardiac muscle

The length of this sarcomere structure does not change when the sarcomere shortens. (a) H zone (b) Z disc (c) I band (d) A band

(d) A band

Your friend nods "yes" to you, going through flexion, extension and hyperextension. This movement at the fulcrum represents a _________. (a) Third-class lever system (b) Third-class lever system (c) Second- class lever system (d) First- class lever system

(d) First- class lever system

This tissue has elongated cells that shorten and cause movement. (a) Connective (b) Nervous (c) Epithelial (d) Muscle

(d) Muscle

Using the biceps brachii to hold a glass in the same position represents an example of a(n): (a) eccentric isotonic contraction. (b) Both eccentric isotonic and isometric contraction are correct. (c) concentric isotonic contraction. (d) isometric contraction.

(d) isometric contraction.

Myasthenia gravis is an autoimmune disease that attacks the skeletal muscle fiber's acetylcholine receptors. What part of the neuromuscular junction is affected? (a) synaptic cleft (b) synaptic vesicles (c) axon terminal of the motor neuron (d) motor end plate

(d) motor end plate

What energizes the myosin head? (a) Acetylcholine (b) ADP synthesis (c) Phosphate release (d) Calcium ions (e) ATP hydrolysis reaction

(e) ATP hydrolysis reaction

When the knee is being flexed, what is the fulcrum? (a) Tibia (b) Femur (c) Contraction of quadriceps femoris (d) Weight of lower leg and foot (e) Knee joint

(e) Knee joint

Cross bridges are formed during muscle contraction when _____ binds to _____. (a) Myosin; troponin (b) Actin; tropomyosin (c) Actin; myosin (d) Actin; troponin (e) Myosin; actin

(e) Myosin; actin

In the figure shown, which light micrograph contains autorhythmic cells? B C A

B - Cardiac muscle

T/F: Smooth muscle helps move food through the digestive tract and blood through the heart.

False

T/F: The origin of a muscle is the moving point of attachment when a muscle contracts and the insertion is the nonmoving point of attachment.

False

T/F: Skeletal muscle is shown in this image.

True

T/F: Smooth muscle controls blood flow through arteries and veins and controls blood pressure.

True

T/F: Smooth muscle is shown in this image.

True

The attachment of a muscle's tendon to the stationary bone is called the _____; the attachment of the muscle's other tendon to the movable bone is called the _____. (a) Origin, insertion (b) Origin, action (c) Insertion, action (d) Insertion, origin

a) Origin, insertion