Deck 40: Action and Support: the Muscles and Skeleton

Question 1

Muscles used for fine motor control have:

A)motor units consisting of many muscle cells.
B)motor units consisting of only a few muscle cells.
C)many neuromuscular junctions.
D)large amounts of ATP.

Answer 1

B

Question 2

Cnidarians have a(n)________ skeleton.

A)exo-
B)endo-
C)hydrostatic
D)absent

Answer 2

C

Question 3

Protein discs that connect sarcomeres are called:

A)T tubules.
B)Z lines.
C)actin.
D)myofilaments.

Answer 3

B

Question 4

Earthworms and sea anemones move by the actions of circular and longitudinal muscles in the body wall, a system called a:

A)endoskeleton.
B)hydrostatic skeleton.
C)circular skeleton.
D)longitudinal skeleton.

Question 5

The function of the accessory proteins of the thin filaments is to:

A)facilitate muscle contraction.
B)prevent bonding between actin and myosin, unless calcium ions are present.
C)prevent overcontraction of muscle fibers.
D)prevent calcium from entering the fibers.
E)remove calcium from the sarcomere.

Question 6

What is the purpose of the sarcoplasmic reticulum?

A)storage of calcium
B)storage of ATP
C)bundling of nerve cells
D)contraction

Question 7

An action potential travels into the muscle fiber interior by passing down the:

A)sarcomere.
B)T tubules.
C)myofilaments.
D)actin and myosin.

Question 8

The thick filaments of a myofibril are composed of:

A)tendons.
B)T tubules.
C)actin.
D)myosin.
E)reticulum.

Question 9

The connective tissues that connect muscles to bones are called:

A)tendons.
B)ligaments.
C)thick filaments.
D)thin filaments.

Question 10

Which of these animals is correctly matched with its type of skeleton?

A)earthworm  endoskeleton
B)human  exoskeleton
C)lobster  exoskeleton
D)mayfly  hydroskeleton
E)snail  endoskeleton

Question 11

Which of these muscle components is the smallest?

A)myofibril
B)myosin filament
C)sarcomere
D)muscle fiber

Question 12

The body can control the strength of leg muscle contractions when lifting a heavy object by increasing or decreasing the:

A)frequency of action potentials sent to the leg muscles.
B)number of thick and thin filaments involved in each sarcomere during contraction.
C)number of calcium ions released by the sarcoplasmic reticulum.
D)amount of ATP used by each active sarcomere during muscle contraction.

Question 13

The site of communication between a neuron and a muscle fiber is called a:

A)Z line.
B)neuromuscular junction.
C)sarcomere.
D)axon.

Question 14

Which molecule contains a binding site for the attachment of myosin heads?

A)actin
B)sarcoplasmic reticulum
C)ATP
D)calcium

Question 15

T tubules are made of:

A)blood proteins.
B)plasma membrane.
C)brain cells.
D)osteocytes.
E)actin.

Question 16

Skeletal muscle appears striped because of:

A)T tubules.
B)accessory proteins in thin filaments.
C)the arrangement of thick and thin filaments.
D)wrapping of sarcoplasmic reticulum around the myofibril.
E)the arrangement of ions on each side of the sarcoplasmic reticulum.

Question 17

The hard exoskeleton of a crustacean:

A)encases, individually, each of the animal's vital organs.
B)provides a substitute for muscles.
C)necessitates periodic molting to permit growth.
D)is entirely different from the exoskeleton of an insect.

Question 18

The myofibrils of skeletal muscle are organized into units called:

A)the sarcoplasmic reticulum.
B)sarcomeres.
C)Z lines.
D)exoskeletons.
E)T tubules.

Question 19

Skeletal muscle:

A)makes up the heart.
B)squeezes food through the digestive tract.
C)contracts the large blood vessels.
D)moves the body.
E)expands the large blood vessels.

Question 20

An exoskeleton is found in ________; an endoskeleton is found in ________.

A)humans; insects
B)humans; spiders only
C)insects; humans
D)fetal humans; adult humans

Question 21

The fluid in the sarcoplasmic reticulum contains a high concentration of ________ ions, which are released when an action potential stimulates it.

A)calcium
B)potassium
C)sodium
D)iron
E)phosphorus

Question 22

Which of the following is TRUE of cardiac muscle?

A)Its cells are tapered at each end.
B)Its cells are branched.
C)It is not striated, like skeletal muscle.
D)It is under voluntary control.

Question 23

Smooth muscle in the human body includes the:

A)quadriceps (leg muscle).
B)ventricles of the heart.
C)muscles of the uterus.
D)eye muscles.

Question 24

What would happen to a person who was poisoned with a chemical that blocks the production of neurotransmitters at neuromuscular junctions?

A)The person's muscles would contract uncontrollably.
B)The sarcoplasmic reticulum would release its stores of calcium ions.
C)The muscles would be unable to contract.
D)The muscles would enlarge.

Question 25

________ is part of the thick filaments; ________ is part of the thin filaments.

A)Actin; myosin
B)Myosin; actin
C)Z lines; T tubules
D)T tubules; Z lines

Question 26

A muscle fiber generates maximum contractile force when:

A)it has been stretched excessively.
B)some of the myofibrils contract and then relax at the same time.
C)it receives repeated action potentials from a nerve.
D)it has been exposed to creatine phosphate.

Question 27

Smooth muscle:

A)contracts when stretched.
B)produces fast contractions.
C)does not contain actin or myosin.
D)is under voluntary control.

Question 28

When a muscle fiber receives an action potential from a neuron, how many sarcomeres in the fiber contract?

A)a number directly proportional to the strength of the stimulus
B)a number inversely proportional to the strength of the stimulus
C)all of them
D)none of them

Question 29

________ is/are found in both smooth and cardiac muscles.

A)Gap junctions
B)Sarcoplasmic reticulum
C)A regular arrangement of sarcomeres
D)Desmosomes

Question 30

Which of the following human muscles have the largest motor units?

A)facial muscles
B)leg muscles
C)abdominal muscles
D)muscles in the hand

Question 31

________ muscle constricts veins when blood pressure drops suddenly.

A)Smooth
B)Cardiac
C)Striated

Question 32

From a skeletal muscle perspective, what happens if a person has a calcium deficiency?

A)The myosin heads do not release from actin.
B)Muscles do not contract as strongly as they should.
C)Motor neurons do not function properly.
D)ATP does not fuel muscle contraction.

Question 33

In a muscle that is resistant to fatigue, such as a marathon runner's leg muscle, you would expect:

A)very few mitochondria.
B)a limited (or decreased)blood supply.
C)elevated levels of ATP.
D)a nonstriated appearance.

Question 34

Which of the following is TRUE according to the sliding filament mechanism of muscle contraction?

A)When a muscle fiber is not contracting, the thin fibers are not connected to the thick fibers.
B)When actin pushes the Z lines farther apart, the muscle expands.
C)The energy for contraction comes from the breakdown of actin into myosin.
D)The muscle relaxes when calcium ions are released into the fluid surrounding the thick and thin filaments.

Question 35

Fast-twitch muscle fibers ________ than slow-twitch fibers.

A)contain fewer mitochondria
B)produce more ATP
C)have a greater blood supply
D)have a smaller diameter

Question 36

The term "motor unit" refers to:

A)an entire skeletal muscle.
B)all the motor neurons going to a skeletal muscle.
C)all the skeletal muscles in one body part.
D)all the muscle fibers with which one motor neuron synapses.
E)a group of sarcomeres in a muscle fiber.

Question 37

Skeletal muscle produces force as the ________ "walk" along the ________.

A)actin heads; myosin
B)myosin heads; actin
C)ATP molecules; microtubules
D)creatine phosphate molecules; ATP molecules

Question 38

The binding site where calcium binds to a protein and activates skeletal muscle contraction is:

A)myosin.
B)actin.
C)troponin.
D)tropomyosin.

Question 39

In skeletal and cardiac muscles, relaxation occurs as ________ ions are pumped back into the sarcoplasmic reticulum.

A)sodium
B)calcium
C)potassium
D)chloride

Question 40

In cardiac muscle:

A)potassium is released from the sarcoplasmic reticulum.
B)calcium enters the cell from storage chambers called intercalated discs.
C)an action potential spreads throughout the Z bands.
D)desmosomes hold the muscle fibers together.

Question 41

The hard, outer shell of vertebrate bone:

A)is compact bone.
B)does not contain osteons.
C)is spongy bone.
D)is made of glucosamine.

Question 42

Osteoporosis is:

A)the loss of calcium from hard bone.
B)the painful swelling of joints.
C)the detachment of a ligament from a bone.
D)the conversion of cartilage to bone in the developing embryo.

Question 43

What advantage does the activity of osteoblasts and osteoclasts impart to vertebrates, even after growth has finished?

A)It permits additional increases in body size.
B)It allows for body size decreases when needed.
C)It enables bone to lengthen and shorten as needed.
D)It allows bone to get stronger as physical demands are placed on it.

Question 44

Bone marrow is located in the:

A)cartilage.
B)spongy bone.
C)compact bone.
D)chondrocytes.

Question 45

Osteoporosis may occur when the activity of ________ exceeds the activity of ________.

A)osteoclasts; osteoblasts
B)osteoblasts; osteoclasts
C)osteoclasts; osteocytes
D)osteocytes; osteoclasts

Question 46

Bones store:

A)magnesium.
B)amino acids.
C)glycogen.
D)phosphorus.
E)manganese.

Question 47

If you break your leg, the bone heals by forming a thickened area around the outside of the bone. Over a period of time, this thickened area:

A)is eaten away by osteoclasts.
B)becomes a permanent part of the spongy bone.
C)is digested by enzymes secreted by the muscles.
D)forms new tendons, ligaments, and/or muscles.
E)moves to the skin surface and is shed as dead skin.

Question 48

If you removed the calcium portion of a chicken bone by immersing it in vinegar for an extended time:

A)it would become rigid and inflexible.
B)it would become extremely flexible.
C)the bone would disintegrate.
D)nothing would happen.

Question 49

Which of the following people has the greatest bone density?

A)a person who has been chronically ill and in bed
B)a professional bodybuilder
C)an astronaut who has been in space for an extended time
D)a computer programmer

Question 50

If an athlete damages the cartilage in her knee, it tends to heal very slowly because cartilage:

A)is dead tissue.
B)hardens with age.
C)cannot be replaced or repaired by the body.
D)is rejected by the body as it is formed.
E)lacks blood vessels.

Question 51

After a fall, it feels like you broke your ankle. The doctor, however, says you tore a ligament. This means you tore the:

A)connective tissue that attaches muscle to bone.
B)connective tissue that joins two bones.
C)compartments of fluid that smooth the movement of a joint.
D)cartilage that covers the end of a bone.
E)insertion of a muscle.

Question 52

The living cells of cartilage are called:

A)osteocytes.
B)osteoclasts.
C)osteoblasts.
D)chondrocytes.

Question 53

Which of the following increases bone strength?

A)dietary nitrogen supplements
B)weightlifting exercises
C)increasing the action potentials that directly stimulate bones
D)increased osteoclast activity

Question 54

Which of the following attaches one bone to another bone at a joint?

A)tendon
B)ligament
C)chondrocyte
D)cartilage

Question 55

The muscles of your lower leg are arranged in antagonistic pairs so that you:

A)can both flex and extend your leg.
B)can stand upright.
C)have a backup when one muscle is not strong enough.
D)get a stronger contraction than you would with a single muscle.

Question 56

Cartilage contains:

A)actin.
B)myosin.
C)ligaments.
D)glycoproteins.
E)calcium and phosphate.

Question 57

What happens to an astronaut who spends 2 months in space?

A)Bone density increases and muscle mass decreases.
B)Bone density increases and muscle mass increases.
C)Bone density decreases and muscle mass increases.
D)Bone density decreases and muscle mass decreases.

Question 58

If a doctor tells a patient that his axial bones are weak, which of these bones is/are affected?

A)humerus
B)femur
C)tibia
D)radius
E)vertebrae

Question 59

A callus is:

A)formed after a bone breaks.
B)involved in bone formation in the vertebrate embryo.
C)a thickening of the fibrous structure of a muscle.
D)a form of bone cancer.

Question 60

Bone-forming cells are known as:

A)osteocytes.
B)osteoclasts.
C)osteoblasts.
D)chondrocytes.

Question 61

The part of a skeletal muscle that is attached to the movable bone on one side of a joint is known as the origin. True or False?

Question 62

What might be a major disadvantage of having a ball-and-socket joint, rather than a hinge joint, in the human knee?

A)decreased muscle strength
B)decreased joint stability
C)decreased joint flexibility
D)a reduced angle of bend

Question 63

The vertebrate skeleton is made up of ________, ________, and ________.

Question 64

During embryonic development, the initial skeleton is made of ________.

Question 65

A joint that is movable in only two dimensions is called a(n)________ joint.

Question 66

Describe the differences between fast-twitch and slow-twitch muscle fibers.

Question 67

In the human skeleton, the ________ is a ball-and-socket joint.

Question 68

In a hinge joint:

A)a flexor muscle moves the insertion toward the origin.
B)an extensor muscle moves the origin toward the insertion.
C)motion is accomplished when flexor and extensor muscles both contract.
D)movement in three dimensions is possible.
E)the flexor and the extensor must expand at the same time.

Question 69

Some joints are immobile and do not allow the two bones involved to move. True or False?

Question 70

What are tendons?

Question 71

Motor units are all of the sarcomeres that make up a muscle fiber. True or False?

Question 72

The end of a skeletal muscle that is attached to a movable bone is called the:

A)flexor.
B)extensor.
C)origin.
D)insertion.

Question 73

Describe some important functions of muscles and skeletons.

Question 74

The ion ________ is found in high concentrations in the sarcoplasmic reticulum.

Question 75

Arrange these muscle tissue groupings in order, from most inclusive to least inclusive: sarcomere, motor unit, thick and thin filaments, myofibril, muscle fiber.

Question 76

In light of the role of calcium ions in muscle contraction, what happens to a person who is deficient in dietary calcium?

Question 77

Calcium ions are released by the sarcoplasmic reticulum when an action potential stimulates it. True or False?

Question 78

The pectoral girdle is part of the axial skeleton. True or False?

Question 79

Blood vessels penetrate cartilage. True or False?

Question 80

What two types of motion do smooth muscles perform?