A&P Muscular System Lecture EXAM #3

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Which one of the following separates neighboring vertebrae and also functions as shock absorbers? A) ribs B) palatine bones C) intervertebral disks D) intravertebral disks E) osteons

C

Cartilage-forming cells are referred to as chondroblasts. Indicate whether the statement is true or false

True

Muscles produce and resist movement. Indicate whether the statement is true or false

True

True or false. Muscle fibers are among the largest cells in the body and are actually fusions of hundreds of individual cells.

True...Each muscle cell, called a fiber, is packed with myofibrils, which are small cylinders of contractile proteins.

According to the sliding filament mechanism, during a muscle contraction, myosin pulls actin filaments toward the center of a sarcomere, causing the entire sarcomere to shorten. a) True b) False

a) True

Bones continue to lengthen throughout childhood and adolescence because a) a growth plate is present in each epiphysis until the late teens b) ossification cannot occur until after puberty c) the activity of osteoblasts cannot be reduced until adulthood d) the production of cartilage for a lengthening bone occurs primarily on the inside of the growth plate e) primary ossification occurs until death

a) a growth plate is present in each epiphysis until the late teens

Each of the following bones is part of the axial skeleton EXCEPT which one? a) clavicle b) vertebrae c) maxilla d) ribs e) sternum

a) clavicle

Which one of the following separates neighboring vertebrae and also functions as shock absorbers a) intervertebral disks b) vertebral plates c) tendons d) osteons e) ribs

a) intervertebral disks

When bones undergo repair, the process begins with the formation of a blood clot known as a(n) ________. a) bone spur b) hematoma c) fracture d) scab e) callus

b) hematoma

Which type(s) of muscle cells can contract spontaneously? a. smooth muscle cells b. cardiac muscle cells c. skeletal muscle cells d. both (a) and (b)

both (a) and (b)

In which one of the following locations would one expect to find cartilage? a) between the skin and the underlying muscle b) in a tendon c) in adipose tissue d) between the vertebrae e) in the wall of a blood vessel

d) between the vertebrae

The abdominal cavity is separated from the thoracic cavity by the a) lungs b) heart c) liver d) diaphragm e) stomach

d) diaphragm

The wrist is located ________ to the elbow. a) inferior b) proximal c) superior d) distal e) anterior

d) distal

Which bone is frequently broken when someone dies of deliberate strangulation? a) floating ribs b) cervical vertebrae c) maxilla d) hyoid bone e) mandible

d) hyoid bone

All of the following are functions of cartilage EXCEPT which one? a) reduction of friction at joints b) pre-bone models in the fetus that develop into bones c) protection and cushioning of joints d) mineral (calcium, phosphorus) storage e) maintaining shape of body parts, such as nose and ears

d) mineral (calcium, phosphorus) storage

Which of the following is/are characteristic of slow-twitch fibers? a. large amounts of glycogen storage b. myoglobin content enables oxygen storage c. numerous mitochondria d. both (b) and (c)

both (b) and (c)

Which of the following is/are characteristic of slow-twitch fibers?

both myoglobin content that enables oxygen storage and numerous mitochondria

Which type(s) of muscle cells can contract spontaneously?

both smooth muscle cells and cardiac muscle cells

Skeletal muscle attaches to ________, which connect the muscle to bone a) cartilage b) no answers are correct c) tendons d) ligaments e) cuboidal cells

c) tendons (ligaments = bone connected to bone)

The biceps brachii, the brachialis, and the brachioradialis all contribute to some of the same movements. These muscles would be __________.

synergistic

Which of the following structures is not contained within a muscle fiber? Sarcoplasmic reticulum T tubules Tendon Myofibrils

tendons

When a sarcomere contracts

the actin and myosin filaments do not change in length.

When a sarcomere contracts

the actin and myosin filaments do not change in length...The actin and myosin filaments slide past each other, causing the sarcomere to shorten. However, the actin and myosin filaments do not change in length.

Which of the following is the same in both slow-twitch and fast-twitch muscle fibers?

the arrangement of actin and myosin in a sarcomere

During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.

the myosin head

When ATP attaches to a myosin head,

the myosin head detaches from actin.

When ATP attaches to a myosin head,

the myosin head detaches from actin....The binding of ATP to a myosin head causes the head to detach from actin.

During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.

the myosin head....The hydrolysis of ATP causes the myosin head to change position, storing energy that will be used to contract the muscle.

When a muscle relaxes, ATP is required. The reason for this is that __________.

the myosin heads can detach from the actin only when a molecule of ATP binds to the head

A single muscle cell is referred to as a _____.

muscle fiber

MATCH: bends forearm at elbow A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

G) biceps brachii

MATCH: aerobically break down fatty acids and glucose A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

G) slow-twitch fibers

MATCH: increases muscle force by activating more motor units A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

H) recruitment

MATCH: lifts and braces shoulders; draws head back A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

H) trapezius

MATCH: Actin filaments slide over myosin filaments, and the sarcomere shortens. A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

I) contraction

Place the following events of muscle contraction in the proper sequence. Calcium is released from the sarcoplasmic reticulum. Cross-bridges form. Actin slides across myosin. Calcium binds to troponin, causing the troponin-tropomyosin complex to shift its position.

I, IV, II, III

Which of the following processes produces 36 ATP?

Krebs cycle and oxidative phosphorylation.....36 ATPs are produced for each glucose molecule. This process, which takes place in the mitochondria, is considered aerobic respiration because oxygen is required.

Which of the following processes produces 36 ATP?

Krebs cycle and oxidative phosphorylation...Yes, 36 ATPs are produced for each glucose molecule. This process, which takes place in the mitochondria, is considered aerobic respiration because oxygen is required.

The "rest and recovery" period, where the muscle restores depleted reserves, includes all of the following processes EXCEPT __________.

Pyruvic acid is converted back to lactic acid....this is NOT a part of the "rest and recovery" period. When oxygen is available, lactic acid is converted back to pyruvic acid (not vice versa) that then enters the Krebs cycle. Lactic acid is the end product of the anaerobic pathway.

The "rest and recovery" period, where the muscle restores depleted reserves, includes all of the following processes EXCEPT __________.

Pyruvic acid is converted back to lactic acid...Yes, this is NOT a part of the "rest and recovery" period. When oxygen is available, lactic acid is converted back to pyruvic acid (not vice versa) that then enters the Krebs cycle. Lactic acid is the end product of the anaerobic pathway.

Which term describes the subunits of a myofibril?

Sarcomere

Which term describes the subunits of a myofibril?

Sarcomere....Sarcomeres are the subunits of myofibrils and are composed of thin filaments and thick filaments.

Which term describes the subunits of a myofibril?

Sarcomere...Sarcomeres are the subunits of myofibrils and are composed of thin filaments and thick filaments.

Which of the following happens during muscle contraction?

Sarcomeres shorten.

The electrical impulse generated by a muscle cell membrane is transmitted to the sarcoplasmic reticulum by ________.

T (transverse) tubules

TRUE/FALSE: According to the sliding filament mechanism, during a muscle contraction, myosin pulls actin filaments toward the center of a sarcomere, causing the entire sarcomere to shorten.

TRUE

TRUE/FALSE: Following running for a long distance, the muscle soreness that occurs the next day is due to chemicals released to repair damaged muscles.

TRUE

TRUE/FALSE: In the absence of ATP, a contracted muscle can't relax.

TRUE

TRUE/FALSE: Isometric contractions usually result in no movement of the skeleton or objects.

TRUE

TRUE/FALSE: Muscle contraction accounts for over 75% of the heat generated by the body.

TRUE

TRUE/FALSE: Muscle soreness several days after exercise is an indication that some sarcomeres were permanently damaged.

TRUE

TRUE/FALSE: Muscles of the hand contain a high percentage of fast-twitch fibers, which allows for actions that are strong and quick.

TRUE

TRUE/FALSE: Muscles produce and resist movement.

TRUE

TRUE/FALSE: Slow-twitch fibers contain many mitochondria and are well supplied with blood vessels, and can make ATP as they need it.

TRUE

Which of the following structures is not contained within a muscle fiber?

Tendon

Which of the following structures is not contained within a muscle fiber?

Tendon...Tendons connect skeletal muscles to the skeleton and are not contained within muscle fibers.

Which statement describes the sliding-filament theory?

The actin and myosin interact and the actin is pulled over the myosin, shortening the sarcomere.

Which statement describes the sliding-filament theory?

The actin and myosin interact and the actin is pulled over the myosin, shortening the sarcomere....The myosin head binds to the actin during the "power stroke" and the actin is pulled past the myosin, thereby shortening the sarcomere.

Which statement describes the sliding-filament theory?

The actin and myosin interact and the actin is pulled over the myosin, shortening the sarcomere...Correct. The myosin head binds to the actin during the "power stroke" and the actin is pulled past the myosin, thereby shortening the sarcomere.

Which of the following events is the direct result of an action potential in the membrane of a muscle cell?

The muscle cell's endoplasmic reticulum (ER) releases calcium ions.

Which of the following events is the direct result of an action potential in the membrane of a muscle cell?

The muscle cell's endoplasmic reticulum (ER) releases calcium ions....An action potential causes the endoplasmic reticulum (ER) to release calcium ions. The release of calcium ions is necessary for muscle contraction.

Which sequence lists the structures from largest, most inclusive, to smallest?

muscle-fascicle-muscle fiber-myofibril-thick filament

A myosin head binds to which molecule to form a cross bridge?

actin.... the myosin head binds to actin, the major component of thin filaments.

A myosin head binds to which molecule to form a cross bridge?

actin...Yes, the myosin head binds to actin, the major component of thin filaments.

In the sliding-filament mechanism of muscle contraction, __________ slides over __________.

actin; myosin

The contractile proteins that are located in myofibrils are called ________ and ________.

actin; myosin

In the sliding-filament mechanism of muscle contraction, __________ slides over __________.

actin; myosin.....Actin slides over myosin during contraction.

In the sliding-filament mechanism of muscle contraction, __________ slides over __________.

actin; myosin...Actin slides over myosin during contraction.

What is the role of ATP in muscle function? a. ATP provides energy which enables myosin to form crossbridges with actin. b. ATP enables myosin to detach from actin. c. ATP provides energy to transport calcium back into storage. d. all of the above

all of the above

According to the ________ principle, a muscle cell contracts completely when adequately stimulated by a motor neuron.

all-or-none

As you clasp your hands in front of you and push them toward each other, this is an example of:

an isometric contraction

Muscles that oppose each other and produce opposite movements are described as __________.

antagonistic

Muscles which oppose each other and produce opposite movements are described as:

antagonistic

Since contraction of the hamstrings causes the knee to bend and contraction of the quadriceps causes the knee to extend, these muscles are said to be ________.

antagonistic

The biceps brachii and triceps brachii contribute to arm movement. These muscles are considered __________.

antagonistic...Antagonistic muscles oppose each other.

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?

arrival of an action potential... an action potential in the T tubule causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum.

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?

arrival of an action potential...Yes, an action potential in the T tubule causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum.

Which one of the following statements correctly describes activities of muscles? a) All muscles are under conscious control. b) All muscles shorten when they contract. c) All muscles are attached to bones. d) All muscles lengthen when they contract.

b) All muscles shorten when they contract.

Which of the following would have motor units with the smallest number of muscle cells?

muscles in fingers

Which of the following disorders of the muscular system is INCORRECTLY described?

muscular dystrophy—a viral disease that causes muscle wasting....Muscular dystrophy is not a viral disease.

Which of the following disorders of the muscular system is INCORRECTLY described?

muscular dystrophy—a viral disease that causes muscle wasting...Muscular dystrophy is a hereditary not a viral disease.

Arrange the following components of a muscle in order of increasing size.

myofibril, fiber, fascicle, muscle

A muscle cell contains bundles of long

myofibrils

A muscle cell contains bundles of long

myofibrils.

In a muscle cell, __________ contain __________.

myofibrils; actin and myosin filaments

A protein that stores oxygen in slow-twitch muscle fibers is ________.

myoglobin

The thick filaments of sarcomeres are composed of _____.

myosin

Which of the following proteins makes up the thick filament of the sarcomeres?

myosin

Which of the following proteins makes up the thick filament of the sarcomeres?

myosin...Correct. Myosin makes up the thick filaments of the sarcomere.

The region where a skeletal muscle cell and a motor neuron come into close proximity to one another is the ________.

neuromuscular junction

Activities associated with aerobic training result in an increase in the amount of ________ in the body.

oxygen

A student, who was late for class, bounded up four flights of steps, ran down the hall, and then arrived in his classroom, huffing and puffing. This student was breathing hard in order to reverse his body's ________.

oxygen debt

Cells in cardiac muscle that determine the rate of contraction are ________ cells.

pacemaker

T tubules are an invagination of the ________.

plasma membrane

T tubules are an invagination of the ________.

plasma membrane...Correct. The T tubule is an invagination of the plasma membrane.

The process of increasing tone by activating more motor units is called ________.

recruitment

During the stage called ________ in a myogram, calcium is transported into the sarcoplasmic reticulum.

relaxation

Contraction of a skeletal muscle cell is initiated by the

release of acetylcholine by a neuron terminating at the neuromuscular junction

The portion of a myofibril from one Z-line to the next is a(n) ________.

sarcomere

When a muscle contracts, shortening of the muscle occurs because __________.

sarcomeres shorten

Which of the following happens during muscle contraction? a. actin filaments shorten b. myosin filaments shorten c. sarcomeres shorten d. both (a) and (b)

sarcomeres shorten

Which of the following is the site of calcium ion storage within muscles?

sarcoplasmic reticulum

Which type(s) of muscle cells can contract the fastest?

skeletal muscle cells

As the rate of stimulation of motor units of a muscle increases, muscle force increases. This process is known as ________.

summation

Skeletal muscle groups that work together to create the same movement are referred to as

synergistic

Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP?

white fast twitch fibers....white fast twitch fibers have high glycogen content for a readily available source of glucose for glycolysis. They appear white because of the reduced amount of myoglobin and fewer capillaries surrounding them. Because these fibers have reduced myoglobin and very few capillaries surrounding them, they have very little oxygen available for the Krebs cycle and oxidative phosphorylation. They also have fewer mitochondria (where the Krebs cycle and oxidative phosphorylation would take place).

Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP?

white fast twitch fibers...Yes, white fast twitch fibers have high glycogen content for a readily available source of glucose for glycolysis. They appear white because of the reduced amount of myoglobin and fewer capillaries surrounding them. Because these fibers have reduced myoglobin and very few capillaries surrounding them, they have very little oxygen available for the Krebs cycle and oxidative phosphorylation. They also have fewer mitochondria (where the Krebs cycle and oxidative phosphorylation would take place).

Drag the labels onto the flowchart to identify the sequence of steps that occurs during muscle contraction. The step numbers correspond to the numbers in the diagram above.

1. action potential in the motor neurons triggers an action potential in the muscle cell 2. action potential spreads down tubules in the muscle cell 3. Endoplasmic reticulum (ER) releases calcium ions 4. Calcium ions bind to protein complex on thin (actin) filament, exposing myosin-binding sites 5. myosin heads bind to actin & shorten the sarcomere 6. when action potentials stop, calcium ions are pumped back into the ER 7. myosin-binding sites are blocked & muscle relaxes

The following events are associated with muscle contraction. Which one of the following best describes the order in which these events occur, following the initiation of a contraction by a nerve impulse? 1. T tubules transmit electrical impulses throughout the muscle cell. 2. Myosin contacts actin and pulls it toward the center of the sarcomere. 3. Acetylcholine binds to receptors on the muscle. 4. Troponin-tropomyosin complex shifts to expose myosin binding sites. 5. Calcium is released from the sarcoplasmic reticulum.

3, 1, 5, 4, 2

Which of the following choices arranges the structures (1) muscle fiber, (2) fascicle, (3) myofibril, and (4) muscle from the largest (most inclusive) to smallest?

4-2-1-3

Which of the following choices arranges the structures (1) muscle fiber, (2) fascicle, (3) myofibril, and (4) muscle from largest (most inclusive) to smallest?

4-2-1-3

A young man is brought to an emergency room; his diagnosis is a broken cheek bone. Which one of the following bones has been affected? A) zygomatic B) mandible C) frontal D) sphenoid E) temporal

A

At the end of the contractile period, energy from the breakdown of ATP is used to A) transport calcium back into the sarcoplasmic reticulum. B) repair any muscle damaged during contraction. C) digest energy sources to generate new ATP for the next round of contractions. D) produce lactic acid. E) unlink the troponin-tropomyosin complexes.

A

Bones are connected to other bones across a joint by A) ligaments. B) tendons. C) osteocytes. D) cartilage. E) trabeculae.

A

Bones continue to lengthen throughout childhood and adolescence because A) a growth plate is present in each epiphysis until the late teens. B) the production of cartilage for a lengthening bone occurs primarily on the inside of the growth plate. C) ossification cannot occur until after puberty. D) primary ossification occurs until death. E) the activity of osteoblasts cannot be reduced until adulthood.

A

Cardiac muscle differs from skeletal muscle in that A) all cardiac muscle is under involuntary control. B) cardiac muscle is capable of relaxation. C) cardiac muscle contracts in response to an electrical or chemical signal. D) cardiac muscle is excitable and can shorten. E) cardiac muscle gets longer rather than shorter when excited.

A

Contraction of a skeletal muscle cell is initiated by the A) release of acetylcholine by a neuron terminating at the neuromuscular junction. B) release of calcium ions by the neuron into the neuromuscular junction. C) electrical current traveling from the neuron directly into the muscle cell. D) hormones delivered by the blood supply to the nearby tissue. E) release of sodium ions by the neuron into the neuromuscular junction.

A

In characterizing cartilage, which one of the following is CORRECT? A) Cartilage is found where support under pressure is required. B) All types of cartilage are produced by osteocytes. C) Cartilage functions to link muscles to bone. D) Cartilage fibers make up ligaments. E) Cartilage is flexible due to a spongy network of trabeculae.

A

Osteoporosis is a common condition that essentially results when homeostasis cannot be maintained in ________ and ________. A) osteoclasts; osteoblasts B) osteoblasts; osteons C) chondroblasts; osteoclasts D) canaculi; chondroblasts E) canaculi; osteoclasts

A

The following events are associated with muscle contraction. Which one of the following best describes the order in which these events occur, following the initiation of a contraction by a nerve impulse? 1. T tubules transmit electrical impulses throughout the muscle cell. 2. Myosin contacts actin and pulls it toward the center of the sarcomere. 3. Acetylcholine binds to receptors on the muscle. 4. Troponin-tropomyosin complex shifts to expose myosin binding sites. 5. Calcium is released from the sarcoplasmic reticulum. A) 3, 1, 5, 4, 2 B) 1, 3, 5, 2, 4 C) 3, 5, 1, 2, 4 D) 4, 2, 1, 3, 5 E) 3, 5, 1, 4, 2

A

Which one of the following statements correctly describes the origin and insertion of a muscle? A) The insertion is pulled toward the origin during contraction. B) The origin is pulled toward the insertion during contraction. C) The origin of a muscle is generally distal (farther from the body's midline) relative to the insertion. D) The origin and insertion refers to the growth pattern of a muscle during development. E) There is always a ligament at the origin of a muscle and a tendon at the insertion.

A

The following events are associated with muscle contraction. Which one of the following best describes the order in which these events occur, following the initiation of a contraction by a nerve impulse? 1. T tubules transmit electrical impulses throughout the muscle cell. 2. Myosin contacts actin and pulls it toward the center of the sarcomere. 3. Acetylcholine binds to receptors on the muscle. 4. Troponin-tropomyosin complex shifts to expose myosin binding sites. 5. Calcium is released from the sarcoplasmic reticulum. A) 3, 1, 5, 4, 2 B) 1, 3, 5, 2, 4 C) 3, 5, 1, 2, 4 D) 4, 2, 1, 3, 5 E) 3, 5, 1, 4, 2

A) 3, 1, 5, 4, 2

Which one of the following is the most efficient long-term source of ATP for muscle cells? A) creatine phosphate B) ready-made ATP in the cell C) aerobic respiration of glucose D) fermentation of glucose E) aerobic respiration of proteins

C

All of the following occur during the latent period of muscle contraction EXCEPT which one? A) Myofibrils shorten. B) Calcium is released from the sarcoplasmic reticulum. C) Muscle cell membrane initiates an electrical impulse, which travels into the muscle cell. D) Myosin heads bind to actin filaments. E) Troponin-tropomyosin complex shifts, exposing myosin heads.

A) Myofibrils shorten.

Which one of the following statements correctly describes the origin and insertion of a muscle? A) The insertion is pulled toward the origin during contraction. B) The origin is pulled toward the insertion during contraction. C) The origin of a muscle is generally distal (farther from the body's midline) relative to the insertion. D) The origin and insertion refers to the growth pattern of a muscle during development. E) There is always a ligament at the origin of a muscle and a tendon at the insertion.

A) The insertion is pulled toward the origin during contraction.

Cardiac muscle differs from skeletal muscle in that A) all cardiac muscle is under involuntary control. B) cardiac muscle is capable of relaxation. C) cardiac muscle contracts in response to an electrical or chemical signal. D) cardiac muscle is excitable and can shorten. E) cardiac muscle gets longer rather than shorter when excited.

A) all cardiac muscle is under involuntary control.

MATCH: bends lower leg at knee and foot away from ankle A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

A) gastrocnemius

During a marathon, runners use up ATP and glucose early in the race. Which energy source is generally used next for producing more ATP? A) glycogen B) starch C) cellulose D) steroids E) phospholipids

A) glycogen

MATCH: uncontrolled contraction of muscle, usually after heavy exercise A) muscle cramps B) muscular dystrophy C) tetanus D) fasciitis

A) muscle cramps

MATCH: Sarcomere lengthens as calcium is returned to sarcoplasmic reticulum, and the troponin- tropomyosin complex attaches to myosin binding sites on actin. A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

A) relaxation

Contraction of a skeletal muscle cell is initiated by the A) release of acetylcholine by a neuron terminating at the neuromuscular junction. B) release of calcium ions by the neuron into the neuromuscular junction. C) electrical current traveling from the neuron directly into the muscle cell. D) hormones delivered by the blood supply to the nearby tissue. E) release of sodium ions by the neuron into the neuromuscular junction.

A) release of acetylcholine by a neuron terminating at the neuromuscular junction.

When an electrical impulse traveling along a motor neuron arrives at a neuromuscular junction A) there is an increase in the secretion of acetylcholine at the neuromuscular junction. B) calcium is transported back to the sarcoplasmic reticulum. C) sliding of actin and myosin filaments is inhibited. D) myosin-actin cross-bridges are destroyed. E) a new electrical impulse is generated that returns the message to the original nerve.

A) there is an increase in the secretion of acetylcholine at the neuromuscular junction.

At the end of the contractile period, energy from the breakdown of ATP is used to A) transport calcium back into the sarcoplasmic reticulum. B) repair any muscle damaged during contraction. C) digest energy sources to generate new ATP for the next round of contractions. D) produce lactic acid. E) unlink the troponin-tropomyosin complexes.

A) transport calcium back into the sarcoplasmic reticulum.

Botulism toxin inhibits the release of acetylcholine at the neuromuscular junctions. What effect does this have on the muscle activity?

Muscles will not contract because they will not receive nerve stimulation.

In order for fast-twitch muscle fibers to produce ATP, a phosphate from the high-energy molecule creatine phosphate is transferred to ________.

ADP

Complete this sentence. As the sarcomere contracts, ________.

ADP is released and is replaced by ATP, which is required to release the myosin from the actin

Complete this sentence. As the sarcomere contracts, ________.

ADP is released and is replaced by ATP, which is required to release the myosin from the actin...Correct. As the sarcomere contracts, ADP is released and is replaced by ATP, which is required to release the myosin from the actin.

The most common reason for muscle fatigue is the lack of enough ________ to meet the metabolic demands placed on the muscle.

ATP

What is the first and most direct energy source for muscle contraction?

ATP

What is the role of ATP in muscle function?

ATP provides energy that enables myosin to form cross-bridges with actin. ATP enables myosin to detach from actin. ATP provides energy to transport calcium back into storage. -All of the listed choices are correct.

What is the role of ATP in muscle function?

ATP provides energy that enables myosin to form cross-bridges with actin. ATP provides energy to transport calcium back into storage. ATP enables myosin to detach from actin.

Bones of trained athletes may be visibly thicker and heavier than those of nonathletes because A) athletes have lower blood calcium levels than nonathletes. B) weight-bearing exercise increases bone mass and strength. C) nonathletes have a low parathyroid hormone rate. D) athletes produce more growth plates. E) nonathletes produce fewer osteoids.

B

In which of the following bones are the teeth anchored? A) mandible and zygomatic bones B) mandible and maxilla C) maxilla and zygomatic bones D) mandible and sphenoid bone E) sphenoid bone and maxilla

B

In which one of the following would one expect to find motor units made up of only a few muscle cells?A) arm muscles B) eye muscles C) chest muscles D) thigh muscles E) lower-leg muscles

B

Muscle cells produce lactic acid when they have an inadequate supply of A) protein. B) O2. C) calcium. D) actin and myosin. E) glycogen.

B

Which one of the following disorders of the skeletal system results from the "wearing out" of the cartilage that covers the ends of bones? A) bursitis B) osteoarthritis C) tennis elbow D) rheumatoid arthritis E) sinusitis

B

Which one of the following is TRUE regarding bone repair? A) Fibrocartilage degenerates where the two broken ends of the bone were once together. B) Osteoblasts convert cartilage to bone in the injured area. C) Immediately after breaking a bone, a hematoma breaks free from the injured area. D) Bones heal more quickly as individuals age. E) The repaired area of a bone is much thinner than the original bone.

B

Which one of the following is characteristic of an isotonic muscle contraction but not an isometric muscle contraction? A) generates a force B) moves an object or part of the skeleton C) helps an individual maintain an upright position D) requires energy E) helps an individual maintain posture

B

Which one of the following statements CORRECTLY describes the location of compact bone and spongy bone? A) Spongy bone is located at the ends, and compact bone is located in the core of the shaft of the bone. B) Compact bone covers the ends of the bone and forms the shaft, and spongy bone is inside the ends, under the compact bone. C) Spongy bone is found on the outside of the shaft, and compact bone forms the hard core of the shaft. D) Spongy bone is found throughout the shaft and ends, covered by a thin layer of compact bone. E) The ends of long bones are solid compact bone, and the shaft is predominantly spongy bone.

B

Which one of the following statements correctly describes activities of muscles? A) All muscles produce movement. B) All muscles shorten when they contract. C) All muscles are under conscious control. D) All muscles are attached to bones. E) All muscles are synergistic.

B

Which one of the following statements is TRUE regarding the structure of a muscle? A) The outer surface of a muscle is enclosed by many layers of epidermis. B) All muscle cells in a muscle have the same origin and insertion. C) Fascicles of a muscle are surrounded by a thin sheath of hyaline cartilage. D) Connective tissues associated with the muscle converge to form a ligament at each end of the muscle. E) Each fascicle consists of two muscle cells.

B) All muscle cells in a muscle have the same origin and insertion.

Which one of the following statements correctly describes activities of muscles? A) All muscles produce movement. B) All muscles shorten when they contract. C) All muscles are under conscious control. D) All muscles are attached to bones. E) All muscles are synergistic.

B) All muscles shorten when they contract.

Muscle cells produce lactic acid when they have an inadequate supply of A) protein. B) O2. C) calcium. D) actin and myosin. E) glycogen.

B) O2.

Following electrical stimulation of a muscle cell, calcium functions to A) stimulate the enzymes that produce ATP. B) bind to the protein troponin. C) leak out of the muscle cell to re-establish the membrane potential. D) break down acetylcholine. E) maintain the relaxed state of the muscle.

B) bind to the protein troponin.

Intercalated discs A) are characteristic of smooth muscle cells. B) contain gap junctions that allow the signal to spread quickly through cardiac muscle cells. C) support fast-twitch fibers of skeletal muscle. D) stimulate pacemaker cells in cardiac muscle. E) stimulate the contraction of skeletal muscle.

B) contain gap junctions that allow the signal to spread quickly through cardiac muscle cells.

MATCH: raises arm A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

B) deltoid

In which one of the following would one expect to find motor units made up of only a few muscle cells? A) arm muscles B) eye muscles C) chest muscles D) thigh muscles E) lower-leg muscles

B) eye muscles

MATCH: anaerobically break down creatine phosphate A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

B) fast-twitch fibers

Which one of the following is characteristic of an isotonic muscle contraction but not an isometric muscle contraction? A) generates a force B) moves an object or part of the skeleton C) helps an individual maintain an upright position D) requires energy E) helps an individual maintain posture

B) moves an object or part of the skeleton

Which sequence lists the structures from largest, most inclusive, to smallest? A) muscle-thick filament-fascicle-muscle fiber-myofibril B) muscle-fascicle-muscle fiber-myofibril-thick filament C) fascicle-muscle-myofibril-muscle fiber-thick filament D) muscle fiber-myofibril-muscle-fascicle-thick filament E) thick filament-fascicle-myofibril-muscle-muscle fiber

B) muscle-fascicle-muscle fiber-myofibril-thick filament

MATCH: a group of muscular diseases that are hereditary; resulting in muscle wasting; no cure A) muscle cramps B) muscular dystrophy C) tetanus D) fasciitis

B) muscular dystrophy

Which one of the following is an example of an isometric contraction? A) person lifting books from the floor B) tightening of abdominal muscles while sitting C) kicking a soccer ball D) swinging a golf club E) doing abdominal "crunches" (sit-ups)

B) tightening of abdominal muscles while sitting

A myogram is a recording of A) the electrical activity of muscle cells. B) the electrical activity of nerves at neuromuscular junctions. C) the activity of muscle cells. D) blood pressure changes resulting from muscle contraction. E) the movement of myosin filaments.

C

An individual with the condition of myasthenia gravis is faced with an autoimmune disorder in which the body defenses attack acetylcholine receptors on muscle cells. What would be the expected effect on calcium levels near contractile proteins, following the arrival of an electrical impulse at those neuromuscular junctions? A) a rapid decrease in concentration due to uptake by sarcoplasmic reticulum B) a rapid increase in concentration due to release by sarcoplasmic reticulum C) small or no increases in concentration due to weak responses by acetylcholine receptors D) a large decrease in concentration that occurs slowly E) a large increase in concentration that occurs slowly

C

Even before organs begin to form, rudimentary versions of the shapes of bones begin to form in a fetus due to the A) activity of growth hormone. B) formation of secondary ossification sites. C) activity of chondroblasts. D) formation of an osteoclast. E) breakdown of hyaline cartilage.

C

In which one of the following locations would one find a cartilaginous joint? A) between the frontal and parietal bones B) in a hinge joint C) between the lower ribs and sternum D) between the scapula and humerus E) in a ball-and-socket joint

C

Skeletal muscle groups that work together to create the same movement are referred to as A) involuntary. B) antagonistic. C) synergistic. D) sarcomeres. E) myofibrils.

C

Which one of the following activities would fast-twitch fibers be most useful for? A) distance running B) swimming C) lifting weights D) biking E) cross-country skiing

C

Which one of the following is characteristic of cardiac and smooth muscle, but not skeletal muscle? A) voluntary contraction B) striated appearance C) presence of gap junctions D) presence of actin and myosin in muscle cells E) contraction is initiated by motor neurons

C

Which one of the following is found within a sarcomere? A) the muscle cell nuclei B) muscle fibers C) the actin and myosin filaments D) fascicles E) fascia

C

Which one of the following is the correct classification of vertebrae, from the skull to the pelvis? A) sacral, coccygeal, lumbar, thoracic, cervical B) cervical, thoracic, lumbar, coccygeal, sacral C) cervical, thoracic, lumbar, sacral, coccygeal D) coccygeal, thoracic, lumbar, sacral, cervical E) coccygeal, thoracic, lumbar, cervical, sacral

C

Muscle cells produce lactic acid when they have an inadequate supply of

O2

In comparing smooth and cardiac muscle, which one of the following best describes the differences between the two muscle types? A) Smooth muscle is voluntary, whereas cardiac is involuntary. B) Both lack muscle filaments, but cardiac muscle has sarcomeres. C) Cardiac muscle requires periods of relaxation, whereas smooth muscle is always in a state of partial contraction. D) Cardiac muscle filaments are arranged in bundles, whereas smooth muscles lack filament bundles. E) Cardiac muscle contracts slowly compared to smooth muscle.

C) Cardiac muscle requires periods of relaxation, whereas smooth muscle is always in a state of partial contraction.

Which one of the following is the most efficient long-term source of ATP for muscle cells? A) creatine phosphate B) ready-made ATP in the cell C) aerobic respiration of glucose D) fermentation of glucose E) aerobic respiration of proteins

C) aerobic respiration of glucose

MATCH: causes lateral rotation of the trunk and abdominal compression A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

C) external oblique

The primary energy source used by muscle cells to generate ATP is A) steroids. B) glycogen. C) glucose. D) starch. E) fatty acids.

C) glucose.

As part of your fitness training, you do biceps curls lifting two 10-lb weights. The muscle contractions enabling these movements are A) isometric contractions. B) tetanic contractions. C) isotonic contractions. D) tendon-mediated contractions. E) ligament-mediated contractions.

C) isotonic contractions.

Which one of the following activities would fast-twitch fibers be most useful for? A) distance running B) swimming C) lifting weights D) biking E) cross-country skiing

C) lifting weights

Which one of the following is characteristic of cardiac and smooth muscle, but not skeletal muscle? A) voluntary contraction B) striated appearance C) presence of gap junctions D) presence of actin and myosin in muscle cells E) contraction is initiated by motor neurons

C) presence of gap junctions

T, or transverse, tubes in skeletal muscle function to A) transport calcium ions throughout muscle cells. B) allow actin and myosin filaments to slide over each other. C) promote the rapid penetration of the electrical impulse deep into the cell. D) help decrease the amount of ATP produced. E) convert glucose to lactic acid, which helps muscles relax.

C) promote the rapid penetration of the electrical impulse deep into the cell.

An individual with the condition of myasthenia gravis is faced with an autoimmune disorder in which the body defenses attack acetylcholine receptors on muscle cells. What would be the expected effect on calcium levels near contractile proteins, following the arrival of an electrical impulse at those neuromuscular junctions? A) a rapid decrease in concentration due to uptake by sarcoplasmic reticulum B) a rapid increase in concentration due to release by sarcoplasmic reticulum C) small or no increases in concentration due to weak responses by acetylcholine receptors D) a large decrease in concentration that occurs slowly E) a large increase in concentration that occurs slowly

C) small or no increases in concentration due to weak responses by acetylcholine receptors

Skeletal muscle groups that work together to create the same movement are referred to as A) involuntary. B) antagonistic. C) synergistic. D) sarcomeres. E) myofibrils.

C) synergistic.

MATCH: disease caused by a bacterial infection; bacterial toxin affects primarily the muscles of the jaw and neck; also known as "lockjaw" A) muscle cramps B) muscular dystrophy C) tetanus D) fasciitis

C) tetanus

Which one of the following is found within a sarcomere? A) the muscle cell nuclei B) muscle fibers C) the actin and myosin filaments D) fascicles E) fascia

C) the actin and myosin filaments

A myogram is a recording of A) the electrical activity of muscle cells. B) the electrical activity of nerves at neuromuscular junctions. C) the activity of muscle cells. D) blood pressure changes resulting from muscle contraction. E) the movement of myosin filaments.

C) the activity of muscle cells.

Plantar fasciitis is an inflammation of the fascia within the sole of the foot, resulting in foot and heel pain. What is a fascia? A) a bundle of muscle cells that are enclosed in a connective tissue sheath B) a bundle of protein filaments (thick and thin) located within muscle cells C) the fibrous connective tissue sheath that surrounds the fascicles of the muscle D) a connective tissue structure that attaches one muscle to another muscle E) the area where the actin and myosin filaments overlap within a muscle cell

C) the fibrous connective tissue sheath that surrounds the fascicles of the muscle

MATCH: complete cycle of contraction and relaxation A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

C) twitch

What is the function of calcium ions in the contraction of a muscle (sarcomere)?

Calcium binds to the troponin-tropomyosin complex so that the actin and myosin can interact and the sarcomere can contract.

What is the function of calcium ions in the contraction of a muscle (sarcomere)?

Calcium binds to the troponin-tropomyosin complex so that the actin and myosin can interact and the sarcomere can contract...Correct. Calcium binds to the troponin-tropomyosin complex, freeing the binding sites so that the actin and myosin can interact and the sarcomere can contract.

A clear fluid lubricates A) ligaments. B) suture. C) fibrous joints. D) synovial joints. E) hyaline cartilage.

D

TRUE/FALSE: Unlike skeletal muscle, cardiac and smooth muscle do not respond at all to the nervous system, but contract on their own. Differences in the rate of contraction of smooth and cardiac muscle are due to the action of pacemakers in cardiac muscles.

FALSE

Following intense exercise, the human body attempts to overcome oxygen debt by A) sweating. B) elevating heart rate. C) producing ATP. D) taking deep breaths. E) inhibiting contractions of smooth muscle.

D

In the lower leg, the gastrocnemius muscle bends the foot away from the knee, as in pointing one's toes. The tibialis anterior muscle flexes the foot toward the knee. These two muscles are A) synergistic. B) homeostatic. C) mutualistic. D) antagonistic. E) cooperative.

D

Once a muscle cell has depleted its small supply of ready-made ATP, what will it use next for energy? A) fats B) phospholipids C) proteins D) creatine phosphate E) glycogen

D

The type of cell responsible for the production of red and white blood cells in bone marrow is the A) osteon. B) osteocyte. C) osteoclast. D) stem cell. E) canaliculi.

D

Which one of the following statements is TRUE regarding parathyroid hormone (PTH)? A) It stimulates the release of growth hormone. B) It is released when blood calcium levels are high. C) It has the same function as calcitonin. D) It causes the breakdown of bone. E) It causes decreased activity of osteoclasts.

D

In comparing all three major muscle types, which one of the following statements best describes the differences between them? A) Cardiac muscle can be stimulated only by nerves, whereas smooth and skeletal muscle contract spontaneously. B) Smooth and skeletal muscles appear striated, due to the arrangement of muscle filaments, whereas cardiac muscles lack these filaments. C) Only cardiac muscle is under voluntary control. D) Smooth and cardiac muscle do not fatigue, whereas skeletal does fatigue. E) Gap junctions are present in skeletal muscles, but not in other types of muscle.

D) Smooth and cardiac muscle do not fatigue, whereas skeletal does fatigue.

In the lower leg, the gastrocnemius muscle bends the foot away from the knee, as in pointing one's toes. The tibialis anterior muscle flexes the foot toward the knee. These two muscles are A) synergistic. B) homeostatic. C) mutualistic. D) antagonistic. E) cooperative.

D) antagonistic.

Once a muscle cell has depleted its small supply of ready-made ATP, what will it use next for energy? A) fats B) phospholipids C) proteins D) creatine phosphate E) glycogen

D) creatine phosphate

MATCH: inflammation of the connective tissue layers surrounding a muscle; common in the sole of the foot A) muscle cramps B) muscular dystrophy C) tetanus D) fasciitis

D) fasciitis

MATCH: decline in muscle activity as ATP levels decrease A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

D) fatigue

Following intense exercise, the human body attempts to overcome oxygen debt by A) sweating. B) elevating heart rate. C) producing ATP. D) taking deep breaths. E) inhibiting contractions of Answer: D

D) taking deep breaths.

MATCH: extends forearm at elbow A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

D) triceps brachii

A typical long bone has an epiphysis at each end, which can be thought of as A) yellow bone marrow. B) a cylindrical hollow shaft. C) a tough layer of connective tissue. D) a site of water storage. E) an enlarged knob.

E

Each of the following bones is part of the axial skeleton EXCEPT which one? A) ribs B) vertebrae C) sternum D) maxilla E) clavicle

E

All of the following are necessary for contraction to occur EXCEPT which one? A) Calcium levels must increase in close proximity to the contractile proteins. B) ATP must be present. C) Troponin-tropomyosin complex must shift out of the way. D) Cross-bridges must form between actin and myosin. E) The troponin and tropomysin must slide relative to each other, shortening the sarcomere.

E) The troponin and tropomysin must slide relative to each other, shortening the sarcomere.

In order for a muscle contraction to occur, cross-bridges must form between which one of the following structures within a muscle cell? A) the plasma membrane and the sarcoplasmic reticulum B) troponin and tropomyosin C) calcium and tropomyosin D) acetylcholine and muscle cell receptors E) actin and myosin

E) actin and myosin

MATCH: contain gap junctions that permit rapid electrical stimulation of muscle cells A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

E) intercalated discs

MATCH: flexes thigh at the hip; extends leg at knee A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

E) quadriceps

Which of the following best describes the action of sarcomeres within a muscle cell during a contraction?

Each sarcomere shortens a little.

Which of the following best describes the action of sarcomeres within a muscle cell during a contraction?

Each sarcomere shortens a little...Each sarcomere will contribute to the contraction.

MATCH: time between the stimulation of a muscle and the beginning of a muscle contraction A) relaxation B) fast-twitch fibers C) twitch D) fatigue E) intercalated discs F) latent period G) slow-twitch fibers H) recruitment I) contraction

F) latent period

MATCH: flexes foot toward knee A) gastrocnemius B) deltoid C) external oblique D) triceps brachii E) quadriceps F) tibialis anterior G) biceps brachii H) trapezius

F) tibialis anterior

TRUE/FALSE: Fast-twitch fibers contain large amounts of myoglobin and predominate in "red" muscle.

FALSE

TRUE/FALSE: In skeletal muscle, potassium ions are stored in the sarcoplasmic reticulum.

FALSE

TRUE/FALSE: Muscles constitute 60-70% of our body mass.

FALSE

TRUE/FALSE: Tetanus results from a state of maximum muscle relaxation, which is necessary to allow the muscle to rest before the next contraction.

FALSE

TRUE/FALSE: The "all-or-none principle" states that in a given muscle, all of the cells are contracting simultaneously or none of them is contracting.

FALSE

TRUE/FALSE: The heads of myosin molecules contact the actin filaments when a muscle is relaxed.

FALSE

Plantar fasciitis is an inflammation of the fascia within the sole of the foot, resulting in foot and heel pain. What is a fascia? a) the fibrous connective tissue sheath that surrounds the fascicles of the muscle b) a bundle of muscle cells that are enclosed in a smooth muscle c) a connective tissue structure that attaches one muscle to another muscle d) the area where the actin and myosin filaments overlap within a muscle cell e) a bundle of protein filaments (thick and thin) located within muscle cells

a) the fibrous connective tissue sheath that surrounds the fascicles of the muscle

A student in a biology class was asked to describe the structure of a stratified squamous epithelium. Which one of the following is the best description? a) tissue composed of several layers of flat cells resting on a basement membrane b) tissue composed of one layer of flat cells located on a basement membrane c) tissue composed of protein fibers in a ground substance and a few cells d) tissue composed of contracting protein fibers enclosed by plasma membranes e) tissue composed of several layers of tall cells resting on a basement membrane

a) tissue composed of several layers of flat cells resting on a basement membrane

All of the following are functions of the muscular system, EXCEPT __________. a. maintenance of body calcium stores b. resisting movement c. movement d. maintenance of body temperature

a. maintenance of body calcium stores

Which of the following disorders of the muscular system is INCORRECTLY described? a. muscular dystrophy—a viral disease that causes muscle wasting b. fasciitis—inflammation of the connective tissue sheath around a muscle c. tetanus—a bacterial disease that causes forceful muscle contractions d. pulled muscle—muscle fibers tear apart due to excessive stretching of the muscle

a. muscular dystrophy—a viral disease that causes muscle wasting

Which of the following would interfere most with a muscle's ability to contract?

absence of acetylcholine binding sites on the muscle membrane..... Without acetylcholine binding sites, a muscle will be unable to respond to a message.

Which of the following would interfere most with a muscle's ability to contract?

absence of acetylcholine binding sites on the muscle membrane...Without acetylcholine binding sites, a muscle will be unable to respond to a message.

The neurotransmitter, ________, has an excitatory effect on skeletal muscle, causing it to contract.

acetylcholine

The thin filaments of sarcomeres are composed of _____.

actin

The sliding filament mechanism describes the process during which __________.

actin and myosin slide relative to each other

The sliding filament mechanism describes the process during which:

actin and myosin slide relative to each other

Which one of the following is TRUE regarding bone repair? a) Cartilage degenerates where the two broken ends of the bone were once together. b) Bones heal more slowly in older individuals. c) The repaired area of a bone is much thinner than the original bone. d) Osteoclasts convert cartilage to bone in the injured area. e) Immediately after breaking a bone, a hematoma breaks free from the injured area.

b) Bones heal more slowly in older individuals.

Muscle cells produce lactic acid when they have an inadequate supply of a) actin and myosin b) O2 c) calcium d) protein e) H2O

b) O2

The muscle that bends the forearm at the elbow is a) gastrocnemius b) biceps brachii c) quadriceps d) external oblique e) triceps brachii

b) biceps brachii

Which one of the following is the correct classification of vertebrae, from the skull to the pelvis? a) sacral, coccygeal, lumbar, thoracic, cervical b) cervical, thoracic, lumbar, sacral, coccygeal c) coccygeal, thoracic, lumbar, cervical, sacral d) cervical, thoracic, lumbar, coccygeal, sacral e) coccygeal, thoracic, lumbar, sacral, cervical

b) cervical, thoracic, lumbar, sacral, coccygeal

The muscles that allow the rotation of the trunk is a) triceps brachii b) external oblique c) quadriceps d) gastrocnemius e) biceps brachii

b) external oblique

Connective tissue differs from epithelial tissue in that connective tissue a) can produce and secrete products into the bloodstream b) is composed primarily of a nonliving extracellular material, which is located between the cells c) is composed of cells supported by a basement membrane d) is composed of cells that can be described as squamous or cuboidal e) is composed of cells interconnected by gap junctions or adhesion junctions

b) is composed primarily of a nonliving extracellular material, which is located between the cells

Which hierarchical sequence lists the structures from largest to smallest? a) muscle fiber-myofibril-whole muscle-fascicle thick filament b) whole muscle-fascicle-muscle fiber-myofibril-thick filament c) thick filament-fascicle-myofibril-whole muscle-muscle fiber d) fascicle-whole muscle-myofibril-muscle fiber-thick filament e) whole muscle-thick filament-fascicle-muscle fiber-myofibril

b) whole muscle-fascicle-muscle fiber-myofibril-thick filament

All of the following may happen in response to exercise training, EXCEPT __________. a. increase in the storage of glycogen and creatine phosphate b.increase in the number of muscle fibers c.increase in the number of mitochondria d.increase in the number of myofibrils

b.increase in the number of muscle fibers

Calcium ions

bind to the protein that blocks the myosin-binding sites on actin.

Calcium ions

bind to the protein that blocks the myosin-binding sites on actin....Calcium ions bind to the protein that blocks the myosin-binding sites on actin. The binding of calcium ions causes the myosin-binding sites to be exposed. This allows the myosin heads to bind to actin.

Following electrical stimulation of a muscle cell, calcium functions to

bind to the protein troponin

What causes the myosin head to disconnect from actin?

binding of ATP

What causes the myosin head to disconnect from actin?

binding of ATP...Yes, the binding of ATP causes the myosin head to disconnect from actin.

The binding of calcium to which molecule causes the myosin binding sites to be exposed?

binding of calcium to the protein complex....when calcium binds to the protein complex, the myosin binding sites are exposed.

The binding of calcium to which molecule causes the myosin binding sites to be exposed?

binding of calcium to the protein complex...Yes, when calcium binds to the protein complex, the myosin binding sites are exposed.

The following events are associated with muscle contraction. Which one of the following best describes the order in which these events occur, following the initiation of a contraction by a nerve impulse? 1. T tubules transmit electrical impulses throughout the muscle cell. 2. Myosin contacts actin and pulls it toward the center of the sarcomere. 3. Acetylcholine binds to receptors on the muscle. 4. Troponin-tropomyosin complex shifts to expose myosin binding sites. 5. Calcium is released from the sarcoplasmic reticulum. a) 3, 4, 5, 1, 2 b) 3, 5, 1, 4, 2 c) 3, 1, 5, 4, 2 d) 4, 2, 1, 3, 5 e) 3, 5, 1, 2, 4

c) 3, 1, 5, 4, 2

Intercalated discs: a) stimulate the contraction of skeletal muscle b) are characteristic of smooth muscle cells c) contain gap junctions that allow the signal to spread quickly through cardiac muscle cells d) support fast-twitch fibers of skeletal muscle e) stimulate nerve cells in cardiac muscle

c) contain gap junctions that allow the signal to spread quickly through cardiac muscle cells

In which one of the following would one expect to find the smallest muscles (made up of only a few muscle cells)? a) arm muscles b) thigh muscles c) eye muscles d) chest muscles e) lower-leg muscles

c) eye muscles

In which of the following bones are the teeth anchored? a) sphenoid bone and maxilla b) vomer and zygomatic bones c) mandible and maxilla d) maxilla and zygomatic bones e) mandible and sphenoid bone

c) mandible and maxilla

Skin functions to a) synthesize components for bone tissue b) produce vitamin C c) provide protection from dehydration d) absorb sunlight to facilitate the synthesis of vitamin A e) initiate muscle contractions

c) provide protection from dehydration

A group of cells that are similar in structure and work together to perform a common function are referred to as a(n) a) organism b) community c) tissue d) organ system e) organ

c) tissue

The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.

calcium ca+

The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.

calcium...Calcium ions interact with proteins on the thin filament, resulting in the exposure of the myosin-binding sites on the actin.

Approximately how many skeletal muscles are in the human? a) 450 b) 17 c) 25 d) 600 e) 200

d) 600

Which one of the following statements correctly describes the origin and insertion of a muscle? a) The origin and insertion refers to the growth pattern of a muscle during development. b) The origin of a muscle is generally distal (farther from the body's midline) relative to the insertion. c) The origin is pulled toward the insertion during contraction. d) The insertion is pulled toward the origin during contraction. e) There is always a ligament at the origin of a muscle and a tendon at the insertion.

d) The insertion is pulled toward the origin during contraction.

Which one of the following statements is TRUE regarding glial cells? a) They stimulate the contraction of cardiac muscle b) They produce blood plasma. c) They transmit nerve impulses from the brain to the internal organs. d) They support and protect neurons. e) They are located in the matrix of cartilage.

d) They support and protect neurons.

A young man is brought to an emergency room; his diagnosis is a broken shin (lower leg) bone. Which one of the following bones has been affected? a) patella b) humerus c) femur d) tibia e) zygomatic

d) tibia

The anterior muscle of the lower leg is a) biceps brachii b) triceps brachii c) trapezius d) tibialis anterior e) gastrocnemius

d) tibialis anterior

Bones of trained athletes may be visibly thicker and heavier than those of nonathletes because a) athletes have lower blood calcium levels than nonathletes b) athletes produce more growth plates c) non-athletes produce fewer osteoids d) weight-bearing exercise increases bone mass and strength e) non-athletes have a low parathyroid hormone rate

d) weight-bearing exercise increases bone mass and strength

What is the type of chemical reaction used to rebuild ADP into ATP?

dehydration synthesis....a water molecule is removed, thus it is called dehydration synthesis. Building ATP from ADP requires a synthetic enzyme plus a source of energy to rebuild the high energy bond.

What is the type of chemical reaction used to rebuild ADP into ATP?

dehydration synthesis...Yes, a water molecule is removed, thus it is called dehydration synthesis. Building ATP from ADP requires a synthetic enzyme plus a source of energy to rebuild the high energy bond.

Which of the following is necessary for contraction to occur? a) Cross-bridges must form between actin and myosin. b) Troponin-tropomyosin complex must shift out of the way. c) Calcium levels must increase close to the contractile proteins d) ATP must be present. e) all of the above.

e) all of the above.

A typical long bone has an epiphysis at each end, which can be thought of as a) yellow bone marrow b) a tough layer of connective tissue c) a site of water storage d) a cylindrical hollow shaft e) an enlarged knob

e) an enlarged knob

Bones are connected to other bones across a joint by a) trabeculae b) osteocytes c) cartilage d) tendons e) ligaments

e) ligaments (tendons = skeletal muscle connected to bone)

Which one of the following tissues can respond to the environment by generating electrical signals? a) muscle b) epithelial c) dermis d) connective e) nervous

e) nervous

At the end of the contractile period, energy from ATP is used to a) produce lactic acid b) unlink the troponin-tropomyosin complexes c) repair any muscle damaged during contraction d) digest energy sources to generate new ATP for the next round of contractions e) release myosin heads from actin filaments

e) release myosin heads from actin filaments

In regions of the human body that must precisely control what enters or exits tissues, which one of the following is(are) present so neighboring cells are packed close together? a) basement membrane b) adhesion junctions c) gap junctions d) collagen e) tight junctions

e) tight junctions

In which one of the following would one expect to find motor units made up of only a few muscle cells?

eye muscles

Unlike skeletal muscle, cardiac and smooth muscle do not respond at all to the nervous system, but contract on their own. Differences in the rate of contraction of smooth and cardiac muscle are due to the action of pacemakers in cardiac muscles.

false

A muscle is arranged in bundles of muscle fibers, called ________.

fascicles

The swinging of a tennis racket is a brief, high-intensity activity that requires the contraction of ________ fibers.

fast-twitch

Tetanic contractions result from __________.

frequent stimulation preventing a muscle from relaxing

Tetanic contractions result from __________.

frequent stimulation, preventing a muscle from relaxing...Tetany occurs when a muscle is unable to relax.

Which of the following processes produces molecules of ATP and has two pyruvic acid molecules as end products?

glycolysis....glucose is broken down in the process called glycolysis. This process takes place in the cytoplasm and does not require oxygen - hence it is called anaerobic respiration. If oxygen is available, the pyruvic acid moves into the mitochondria and glycolysis contributes to aerobic respiration.

Which of the following processes produces molecules of ATP and has two pyruvic acid molecules as end products?

glycolysis...Yes, glucose is broken down in the process called glycolysis. This process takes place in the cytoplasm and does not require oxygen - hence it is called anaerobic respiration. If oxygen is available, the pyruvic acid moves into the mitochondria and glycolysis contributes to aerobic respiration.

Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____.

he pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum...

What energizes the power stroke?

hydrolysis of ATP....Energy is transferred from ATP to the myosin head.

What energizes the power stroke?

hydrolysis of ATP...Yes, the hydrolysis of ATP provides the energy for the power stroke. Energy is transferred from ATP to the myosin head.

All of the following may happen in response to exercise training except:

increase in the number of muscle fibers

All of the following may happen in response to exercise training, EXCEPT __________.

increase in the number of muscle fibers

When a skeletal muscle contracts, the __________ is pulled toward the __________.

insertion; origin

We are unable to exert any conscious control over the contraction of smooth or cardiac muscle. These muscles are referred to as ________ muscle.

involuntary

Steroid use in men may lead to __________.

irreversible changes in the body

Steroid use in men may lead to __________.

irreversible changes in the body....Changes that occur with steroid use may be irreversible.

Steroid use in men may lead to __________.

irreversible changes in the body...Changes that occur with steroid use may be irreversible

The ability to maintain an upright position is due to ________ muscle contractions.

isometric

During a workout session, you may begin to experience a burning sensation in a muscle group that you are targeting with your choice of exercises. This is most likely due to anaerobic metabolism in that muscle, generating ________.

lactic acid

All of the following are functions of the muscular system except:

maintenance of body calcium stores

All of the following are functions of the muscular system, EXCEPT __________.

maintenance of body calcium stores

To minimize muscle stiffness and soreness, undertake a new exercise activity in ________ for the first few days.

moderation

Contraction of skeletal muscle is caused by the release of neurotransmitters from ________ neurons.

motor

Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____. the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum the release of myosin heads from the thin filament thin filaments slide back to their relaxed positions proteins on the thin filaments block actin's myosin-binding sites all of these events occur simultaneously

the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum

When an electrical impulse traveling along a motor neuron arrives at a neuromuscular junction

there is an increase in the secretion of acetylcholine at the neuromuscular junction

Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.

thin filaments

Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.

thin filaments....Myosin heads bind to thin filaments, release their bound ADP and phosphate, and bend, sliding the thin filaments toward the center of the sarcomere.

At the end of the contractile period, energy from the breakdown of ATP is used to

transport calcium back into the sarcoplasmic reticulum

In the absence of calcium, myosin cannot contact actin because of the presence of the ________ covering the myosin binding sites on actin.

troponin-tropomyosin complex

Muscle contraction accounts for over 75% of the heat generated by the body.

true

True or false. Muscle fibers are among the largest cells in the body and are actually fusions of hundreds of individual cells.

true because Each muscle cell, called a fiber, is packed with myofibrils, which are small cylinders of contractile proteins.

True or false. Muscle fibers are among the largest cells in the body and are actually fusions of hundreds of individual cells.

true....Each muscle cell, called a fiber, is packed with myofibrils, which are small cylinders of contractile proteins.

A complete cycle of contraction and relaxation of muscle cells due to stimulation by a motor neuron is called a muscle ________.

twitch

The all-or-none principle states that __________.

when a muscle cell is stimulated, it responds with a complete cycle of contraction and relaxation

The all-or-none principle states that __________.

when a muscle cell is stimulated, it responds with a complete cycle of contraction and relaxation...The all-or-none principle states that if a motor unit responds, it will respond completely.


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