The ______ is connected to the hypothalamus by a collection of nerve axons whose cell bodies are in the hypothalamus.

The ______ is connected to the hypothalamus by a collection of nerve axons whose cell bodies are in the hypothalamus. Answer: Posterior lo...

Positive feedback is not common in the endocrine system and is self- ____.

Positive feedback is not common in the endocrine system and is self- ____. Answer: self augmenti...

The ____ and Pituitary gland act in coordination to carry out many functions of the endocrine system.

The ____ and Pituitary gland act in coordination to carry out many functions of the endocrine system. Answer: hypothalamu...

During the recovery period the body's need for oxygen is increased because

During the recovery period the body's need for oxygen is increased because a) the liver requires more oxygen to produce lactic acid. b) additional...

Which of the following is not a type of motor unit?

Which of the following is not a type of motor unit? a) whiteslow twitch b) redfast twitch c) whitefast twitch d) redslow twitch e) All of these...

Each skeletal muscle fiber is controlled by a motor neuron at a single

Each skeletal muscle fiber is controlled by a motor neuron at a single a) synaptic knob. b) synaptic cleft. c) sarcomere. d) transverse tubule. e)...

How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?

How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle? a) It would have little effect on skeletal muscles. b)...

Compared to a "typical" body cell, skeletal muscle cells are

Compared to a "typical" body cell, skeletal muscle cells are a) multinucleate. b) filled with crystalline 3-D arrays of fibrous proteins. c) larger...

The region of the sarcomere that always contains thin filaments is the

The region of the sarcomere that always contains thin filaments is the a) A band. b) M line. c) I band. d) Z line. e) H band. Answer:...

Creatine phosphate

Creatine phosphate a) is only formed during strenuous exercise. b) can replace ATP in binding to myosin molecules during contraction. c) is produced...

The type of contraction in which the muscle fibers do not shorten is called

The type of contraction in which the muscle fibers do not shorten is called a) tetany. b) isometric. c) treppe. d) concentric. e) isotonic. Answer:...

Fast fibers

Fast fibers a) have low resistance to fatigue. b) rely on aerobic metabolism. c) have many mitochondria. d) have twitches with a very brief contraction...

During anaerobic glycolysis

During anaerobic glycolysis a) pyruvic acid is produced. b) oxygen is not consumed. c) ATP is produced. d) all of the above e) B and C only Answer:...

During the recovery period following exercise, all of the following are true, except

During the recovery period following exercise, all of the following are true, except a) oxygen is consumed at above the resting rate. b) lactic...

Calcium ions are binding to troponin during the ________ of a muscle twitch.

Calcium ions are binding to troponin during the ________ of a muscle twitch. a) latent period b) contraction phase c) relaxation phase d) recovery...

Fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to

Fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to a) sustained low levels of muscle activity. b)...

Cross-bridges are portions of

Cross-bridges are portions of a) myosin molecules. b) actin molecules. c) troponin molecules. d) tropomyosin molecules. e) calcium ions. Answer:...

How would a drug that blocks acetylcholine receptors at the motor end plate affect skeletal muscle?

How would a drug that blocks acetylcholine receptors at the motor end plate affect skeletal muscle? a) It would have little effect on skeletal muscles. b)...

Receptors for acetylcholine are located on the

Receptors for acetylcholine are located on the a) transverse tubule. b) synaptic knob. c) sarcomere. d) synaptic cleft. e) motor end plate. Answer:...

When calcium ion binds to troponin,

When calcium ion binds to troponin, a) muscle relaxation occurs. b) tropomyosin moves into the groove between the helical actin strands. c) active...

In a sarcomere, thick filaments are linked laterally by proteins of the

In a sarcomere, thick filaments are linked laterally by proteins of the a) H band. b) Z line. c) I band. d) M line. e) A band. Answer:...

The thin filaments of striated muscle are made of which protein(s)?

The thin filaments of striated muscle are made of which protein(s)? a) troponin b) actin c) tropomyosin d) nebulin e) all of the above Answer:...

Which of the following statements is false?

Which of the following statements is false? a) Skeletal muscle stimulation is neural. b) Cardiac muscle stimulation is neural. c) Skeletal muscle...

During activities requiring aerobic endurance

During activities requiring aerobic endurance a) oxygen debts are common. b) oxygen is not required. c) most of the muscle's energy is produced...

The narrow space between the synaptic terminal and the muscle fiber is the

The narrow space between the synaptic terminal and the muscle fiber is the a) motor unit. b) synaptic cleft. c) M line. d) synaptic knob. e) motor...

Which of the following best describes the term Z line?

Which of the following best describes the term Z line? a) thin filaments are anchored here b) protein that accounts for elasticity of resting muscle c)...

At peak levels of muscle exertion the mitochondria can supply

At peak levels of muscle exertion the mitochondria can supply a) all of the energy required by the muscle. b) more than half of the energy required...

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called a) recruitment. b)...

The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter

The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter a) acetylcholine. b) antidiuretic hormone. c)...

Each thin filament consists of

Each thin filament consists of a) chains of myosin molecules. b) a rod-shaped structure with "heads" projecting from each end. c) a double strand...

Which of the following best describes the term sarcoplasmic reticulum?

Which of the following best describes the term sarcoplasmic reticulum? a) thin filaments are anchored here b) protein that accounts for elasticity...

The following is a list of the events that occur during a muscle contraction.

The following is a list of the events that occur during a muscle contraction. 1. Myosin cross-bridges bind to the actin. 2. The free myosin head splits...

In which of the following would the motor units have the fewest muscle fibers?

In which of the following would the motor units have the fewest muscle fibers? a) muscles that control the eyes b) postural muscles of the back c)...

Which of the following become connected by myosin cross-bridges during muscle contraction?

Which of the following become connected by myosin cross-bridges during muscle contraction? a) thin filaments and t-tubules b) thin filaments and...

Synaptic vesicles containing neurotransmitters are released by ________ when the action potential arrives.

Synaptic vesicles containing neurotransmitters are released by ________ when the action potential arrives. a) apoptosis b) exocytosis c) hydrolysis d)...

Which of the following best describes the term titin?

Which of the following best describes the term titin? a) protein that accounts for elasticity of resting muscle b) repeating unit of striated myofibrils c)...

At rest, the tropomyosin molecule is held in place by

At rest, the tropomyosin molecule is held in place by a) actin molecules. b) troponin molecules. c) myosin molecules. d) calcium ions. e) ATP...

Which statement about the microscopic anatomy of skeletal muscle fibers is true?

Which statement about the microscopic anatomy of skeletal muscle fibers is true? a) Muscle fibers are continuous from tendon to tendon. b) Tubular...

The muscle weakness of myasthenia gravis results from

The muscle weakness of myasthenia gravis results from a) insufficient acetylcholine release from presynaptic vesicles. b) the motor neuron action...

A resting muscle generates most of its ATP by

A resting muscle generates most of its ATP by a) aerobic metabolism of fatty acids. b) the tricarboxylic acid cycle. c) glycogenolysis. d) anaerobic...

The area in the center of the A band that contains no thin filaments is the

The area in the center of the A band that contains no thin filaments is the a) H band. b) zone of overlap. c) M line. d) Z line. e) I band. Answer:...

The skeletal muscle complex known as the triad consists of

The skeletal muscle complex known as the triad consists of a) filaments, myofibrils, and sarcomeres. b) actin, myosin, and sarcomeres. c) a transverse...

A muscle producing tension that peaks and falls at intermediate stimulus rates is said to be in

A muscle producing tension that peaks and falls at intermediate stimulus rates is said to be in a) complete tetanus. b) recruitment. c) treppe. d)...

Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of

Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of a) fatty muscles. b) slow fibers. c)...

A single motor neuron together with all the muscle fibers it innervates is called

A single motor neuron together with all the muscle fibers it innervates is called a) a motor unit. b) an end foot. c) a myotome. d) a dermatome. e)...

Skeletal muscle fibers are formed from embryonic cells called

Skeletal muscle fibers are formed from embryonic cells called a) myofibrils. b) myoblasts. c) fascicles. d) myomeres. e) sarcomeres. Answer:...

Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for

Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for a) contraction. b) conduction. c)...

The most important factor in decreasing the intracellular concentration of calcium ion after contraction is

The most important factor in decreasing the intracellular concentration of calcium ion after contraction is a) diffusion of calcium out of the cell. b)...

Active sites on the actin become available for binding after

Active sites on the actin become available for binding after a) myosin binds to troponin. b) troponin binds to tropomyosin. c) calcium binds to...

Which of the following acts as an ATPase during the contraction cycle of muscle?

Which of the following acts as an ATPase during the contraction cycle of muscle? a) tropomyosin molecules b) troponin molecules c) actin molecules d)...

Which of the following is not characteristic of smooth muscle?

Which of the following is not characteristic of smooth muscle? a) The thin filaments of smooth muscle fibers are attached to dense bodies. b) Neurons...

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called a) incomplete tetanus. b)...

The plasma membrane of skeletal muscle is called the

The plasma membrane of skeletal muscle is called the a) sarcolemma. b) sarcoplasm. c) sarcoplasmic reticulum. d) sarcomere. e) sarcosome. Answer:...

Which of the following statements is (are) true regarding human muscles?

Which of the following statements is (are) true regarding human muscles? a) Slow fibers are abundant in the calf muscles. b) Eye muscles are composed...

The advantage of having many nuclei in a skeletal muscle fiber is

The advantage of having many nuclei in a skeletal muscle fiber is a) the ability to produce more ATP with little oxygen. b) the ability to contract. c)...

In an isotonic contraction,

In an isotonic contraction, a) tension rises and falls but the muscle length is constant. b) the peak tension is less than the load. c) flexion...

The increase in muscle tension that is produced by increasing the number of active motor units is called

The increase in muscle tension that is produced by increasing the number of active motor units is called a) incomplete tetanus. b) recruitment. c)...

The type of muscle fiber that is most resistant to fatigue is the ________ fiber.

The type of muscle fiber that is most resistant to fatigue is the ________ fiber. a) high-density b) anaerobic c) slow d) fast e) intermediate Answer:...

Muscle fibers differ from "typical cells" in that muscle fibers

Muscle fibers differ from "typical cells" in that muscle fibers a) have many nuclei. b) are very small. c) lack a plasma membrane. d) lack mitochondria. e)...

At rest, active sites on the actin are blocked by

At rest, active sites on the actin are blocked by a) troponin molecules. b) myosin molecules. c) ATP molecules. d) calcium ions. e) tropomyosin...

In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases

In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases a) hydrogen ions. b) acetylcholine. c)...

The rapid rise and fall in force produced by a muscle fiber after a single action potential is

The rapid rise and fall in force produced by a muscle fiber after a single action potential is a) a tetanus. b) an end plate potential. c) an unfused...

Which of the following best describes the term sarcomere?

Which of the following best describes the term sarcomere? a) largely made of myosin molecules b) repeating unit of striated myofibrils c) thin filaments...

After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs.

After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs. a) treppe b) paralysis c) atrophy d) tetanus e) an oxygen...

Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass?

Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass? a) calcitonin b) testosterone c)...

When comparing slow motor units to fast motor units, slow units

When comparing slow motor units to fast motor units, slow units a) take about three times as long to reach peak tension. b) have much smaller fiber...

When a skeletal muscle fiber contracts,

When a skeletal muscle fiber contracts, a) the zones of overlap get larger. b) the Z lines get closer together. c) the width of the A band remains...

The action potential is conducted into a skeletal muscle fiber by

The action potential is conducted into a skeletal muscle fiber by a) neuromuscular junctions. b) motor end plates. c) transverse tubules. d) triads. e)...

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes a) less permeable to potassium ions. b) more permeable...

Muscular force can be adjusted to match different loads by

Muscular force can be adjusted to match different loads by a) recruiting larger motor units b) varying the frequency of action potentials in motor...