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Animal Course Physiology Exam > 8. Muscles > Flashcards

8. Muscles Flashcards

1
Q
  1. Which muscle naming criteria are used to name the quadriceps femoris?
    A. Muscle action and location
    B. The origin and insertion
    C. Location and direction of muscle fibres
    D. Location and number of origins
A

Answer is D: Femoris refers to location on the femur; quadriceps refers to four origins.

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2
Q
  1. By what name is the plasma membrane of a muscle cell known?
    A. Sarcoplasm
    B. Sarcomere
    C. Sarcoplasmic reticulum
    D. Sarcolemma
A

Answer is D: “Sarco-” refers to flesh (muscle); “lemma-” refers to sheath (membrane) around the cell.

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3
Q
  1. Of the events that lead to myofilaments sliding over each other, which of the following happens first?
    A. The myosin head engages with the binding site on actin.
    B. Troponin changes shape and pulls on tropomyosin.
    C. Calcium ions enter the cell cytoplasm.
    D. ATP is hydrolysed to ADP and inorganic phosphate.
A

Answer is C: Ca must first enter the cytoplasm in order to bind with troponin. Once the binding site is exposed, the myosin head may engage the site. Prior to engagement, ATP must be hydrolysed to ADP.

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4
Q
  1. Smooth muscle is different from skeletal muscle because smooth muscle:
    A. Is found in the walls of arteries
    B. Can be voluntarily contracted
    C. Has many nuclei in a cell
    D. Has intercalated discs between cells
A

Answer is A: Smooth muscle occurs in the walls of tubes, whereas skeletal muscle does not.

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5
Q
  1. Which of the following muscles is named according to its origin and insertion?
    A. Transversus abdominis
    B. Semimembranosus
    C. Sternocleidomastoid D. Deltoid
A

Answer is C: The origin is on the sternum and clavicle (sternocleido-), while the insertion (on the “moving bone”) is to the mastoid process of the temporal bone.

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6
Q
  1. All of the following structures are part of a muscle cell except one. Which one?
    A. Sarcoma
    B. Sarcolemma
    C. Sarcoplasm
    D. Sarcoplasmic reticulum
A

Answer is A: Sarcoma refers to a malignant tumour (a cancer) of connective or other non-epithelial tissue (bones, muscles, tendons, cartilage, nerves, fat and blood vessels).

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7
Q
  1. During muscle cell contraction, what happens because of Ca++ binding to troponin?
    A. The binding site on actin is uncovered.
    B. Acetylcholine (ACh) is released.
    C. The cross-bridge disengages from the thin filament.
    D. ATP hydrolyses to ADP.
A

Answer is A: Troponin causes tropomyosin (which covers the binding site of actin) to be shifted away.

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8
Q
  1. Which of the following muscle cell structures is the longest?
    A. A myofilament
    B. A myofibril
    C. A sarcomere
    D. A troponin molecule
A

Answer is B: A muscle cell is a bundle of myofibrils. Myofibrils contain many sarcomeres joined end to end. Within sarcomeres are found (the shorter) thick and thin myofilaments.

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9
Q
  1. Which of the muscles listed below is named according to its action?
    A. Adductor longus
    B. Temporalis
    C. Sternocleidomastoid D. Peroneus longus
A

Answer is A: Adduction is the action of bringing an abducted bone back towards the body’s midline.

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10
Q
  1. Which of the following is the smallest structure within a muscle fibre?
    A. Myosin
    B. Myofilament
    C. Myofibril
    D. Sarcomere
A

Answer is A: Myosin is a molecule that makes up a thick myofilament. Many thick and thin myofilaments make up a sarcomere. Many sarcomeres joined end to end form a myofibril.

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11
Q
  1. Which of the events below is the FIRST to occur prior to a muscle cell contracting?
    A. ATP binds to myosin.
    B. ADP detaches from myosin.
    C. The active site on actin is exposed.
    D. Ca++ is released from the sarcoplasmic reticulum.
A

Answer is D: The release of Ca from where it is stored (in the SR) is necessary before the active binding site of actin can be exposed.

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12
Q
  1. What is a “sarcomere”?
    A. A cancer of connective tissue
    B. The cytoplasm of a muscle cell
    C. A section of a myofilament
    D. The plasma membrane of a muscle cell
A

Answer is C: A myofilament is a long line of sarcomeres joined end to end. So one section of a myofilament is a sarcomere.

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13
Q
  1. Smooth muscle cells may be described by which of the following?
    A. Striated, voluntary, multinucleate
    B. Not striated, voluntary, multinucleate C. Striated, involuntary, uninucleate
    D. Not striated, involuntary, uninucleate
A

Answer is D: Smooth muscle is not striated, and it is involuntary and has one nucleus.

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14
Q
  1. By which term is a muscle that opposes or reverses a particular movement called?
    A. Agonist
    B. Synergist
    C. Antagonist
    D. Fixator
A

Answer is C: An agonist muscle performs the action, while the antagonist must relax (be stretched) while the action is being performed (and can reverse the action of the agonist).

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15
Q
  1. Which term is given to the unit of a myofibril that contracts?
    A. Sarcoplasm
    B. Sarcomere
    C. Sarcolemma
    D. Sarcoplasmic reticulum
A

Answer is B: The contraction of a myofibril is due to the shortening of its component sarcomeres.

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16
Q
  1. Which is the largest of the structures in a muscle fibre?
    A. Myofibril
    B. Myofilament
    C. Myosin
    D. Myopic
A

Answer is A: A myofibril extends the length of a muscle cell. A myofilament is shorter than a sarcomere, while myosin is a molecule in a thick myofilament.

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17
Q
  1. Where are the semimembranosus and semitendinosus muscles located? In the:
    A. Seminal vesicle
    B. Thigh
    C. Forearm
    D. Back
A

Answer is B: They are two of the three “hamstring” muscles on the dorsal thigh, the other being the biceps femoris.

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18
Q
  1. By what name is something that attaches a bone to another bone known?
    A. Aponeurosis
    B. Sarcomere
    C. Ligament
    D. Tendon
A

Answer is C: Ligament is the “ligature” that joins articulating bones. A tendon (or an aponeurosis) attaches a muscle to a bone.

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19
Q
  1. Which protein(s) are found in thin myofilaments?
    A. Actin
    B. Actin and tropomyosin
    C. Actin, tropomyosin and troponin
    D. Actin, myosin, tropomyosin and troponin
A

Answer is C: Actin is the major component of a thin filament. Tropomyosin covers the biding site, while troponin provides the mechanism for removing tropomyosin from the binding site.

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20
Q
  1. Which statement below best describes the role of Ca++ in muscle contraction?
    A. Ca++ binds to troponin, thereby changing its shape to expose the binding site.
    B. Ca++ causes ADP and inorganic phosphate to detach from the myosin cross-bridge.
    C. Ca++ attaches to the myosin head, causing it to disengage from its binding site.
    D. Ca++ crosses the sarcolemma from the axon terminal which allows the action potential to propagate along the sarcolemma
A

Answer is A: Ca attaches to troponin causing a shape change which shifts the
attached tropomyosin away from binding sites of actin.

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21
Q
  1. What characteristic of a smooth muscle cell distinguishes it from cardiac and from skeletal muscle?
    A. Being branched
    B. Being under involuntary control
    C. Lack of striations
    D. Being uninucleate
A

Answer is C: Both cardiac and skeletal muscle show striations when viewed under the microscope, but smooth muscle does not.

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22
Q
  1. What information is contained in the muscle name “biceps brachii”?
    A. The muscle location and the number of origins
    B. The number of origins and the muscle action
    C. The muscle size and location in the body
    D. The muscle’s shape and its action
A

Answer is A: “Brachii” indicates location on the brachium (arm), while “biceps” refers to the two origins (attachments) of the muscle.

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23
Q
  1. Which of the following muscles is a common intramuscular injection site?
    A. Deltoid
    B. Gluteus maximus
    C. Vastus medialis
    D. Latissimus dorsi
A

Answer is A: The upper arm at the shoulder is the location of the deltoid. It is the gluteus medius (rather than the gluteus maximus) that is used for IM injections to avoid the sciatic nerve.

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24
Q
  1. What causes the myosin binding site of an actin molecule to be exposed?
    A. ATP attaching to the myosin cross-bridge
    B. A nerve impulse reaching the motor end plate of a motor nerve
    C. Calcium ions attaching to troponin
    D. Acetylcholine crossing the neuromuscular junction
A

Answer is C: Ca causes a change of shape to the troponin molecule when they attach. This causes troponin to wrench tropomyosin away from its resting position covering the binding site.

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25
Q
  1. What is the source of the majority of the energy needed by muscles for physical activity that continues for longer than 30 or 40 min?
    A. ATP stored in muscle fibres
    B. Glycolysis of glucose in the cell cytoplasm
    C. ATP produced from creatine phosphate stored in muscle fibres D. Aerobic respiration of pyruvic acid in mitochondria
A

Answer is D: Choice A lasts for a few seconds only. Choice B can provide energy for a couple of minutes. Choice C can provide energy for vigorous activity lasting about 15 s.

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26
Q
  1. Which one of the following is NOT a characteristic of skeletal muscle?
    A. Excitability
    B. Autonomic innervation
    C. Contractility
    D. Extensibility
A

Answer is B: Skeletal muscle is voluntary and so is innervated by the somatic nervous system, not the autonomic system.

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27
Q
  1. What is the gluteus maximus named for? Its:
    A. Size
    B. Shape
    C. Action
    D. Origin and insertion
A

Answer is A: The gluteus maximus is larger than either the gluteus medius or gluteus minimus.

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28
Q
  1. Which of the following muscles is NOT named after its location in the body?
    A. Deltoid
    B. Extensor carpi ulnaris C. Rectus abdominis
    D. Biceps femoris
A

Answer is A: The deltoid is named after its shape, which is likened to the capital Greek letter delta (a triangle).

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29
Q
  1. Skeletal muscle cells have all of the following characteristics EXCEPT one. Which one?
    A. A neuromuscular junction crossed by ACh (acetyl choline)
    B. Invaginations of sarcolemma called “T tubules”
    C. They are branched
    D. They are striated
A

Answer is C: Skeletal muscle cells are not branched (but cardiac muscle cells are).

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30
Q
  1. What is the role of Ca++ in muscle contraction?
    A. Ca causes an action potential to travel along the sarcolemma.
    B. Ca binds to troponin changing its shape.
    C. Ca attaches to the binding site of myosin, energising it.
    D. Ca engages with the binding site of actin causing the power stroke.
A

Answer is B: The myosin head cannot attach to actin until its binding site is exposed. Ca causes this to happen.

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31
Q

Which of the following muscle structures is the largest?
A. Sarcomere B. Fascicle
C. Myofibril
D. Muscle fibre

A

Answer is B: A muscle fascicle is a bundle of muscle fibres (cells). Choice A and B are smaller than a cell.

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32
Q
  1. Which of the following muscles is NOT named after its location in the body?
    A. Biceps brachii
    B. Sternocleidomastoid C. Rectus abdominis
    D. Flexor carpi radialis
A

Answer is B: The sternocleidomastoid is named after its origins (on the sternum and clavicle) and insertion (the mastoid process).

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33
Q
  1. Which feature is shared by cardiac muscle cells and skeletal muscle cells?
    A. Striations
    B. Intercalated discs
    C. Branching
    D. Involuntary nature
A

Answer is A: Both types of muscle cells are striated. Choices B, C and D are characteristics of cardiac muscle cells only.

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34
Q
  1. What structures attach a muscle to a bone?
    A. A tendon
    B. A fasciculus
    C. A sarcomere
    D. An internal intercostal
A

Answer is A: Tendons (thin ropelike structures) attach muscle to bone.

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35
Q
  1. What is the substance that binds to troponin in order to cause muscle contraction?
    A. PO4 2−
    B. H3O+
    C. Ca++
    D. Fe++
A

Answer is C: Calcium ions do the job.

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36
Q
  1. Which of the following muscles is NOT named after its location in the body?
    A. Latissimus dorsi
    B. Adductor longus
    C. Rectus femoris
    D. Biceps brachii
A

Answer is B: “Adductor” refers to the action of adduction, while longus refers to its size. Latissimus dorsi refers to the dorsal surface of the body.

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37
Q
  1. Which of the following muscle structures is the smallest?
    A. Sarcomere
    B. Fasciculus
    C. Myofibril
    D. Muscle fibre
A

Answer is A: A sarcomere is a section of a myofibril. A muscle fibre (cell) is a bundle of myofibrils, while a fasciculus is a bundle of muscle fibres.

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38
Q
  1. A feature of skeletal muscle that is NOT shared with cardiac or smooth muscle is:
    A. Striations
    B. Branched cells
    C. Intercalated discs
    D. Many nuclei
A

Answer is D: A skeletal muscle cell is a “syncytium” being derived from many cells and so retains their many nuclei.

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39
Q
  1. Which muscles extend the leg?
    A. Quadriceps
    B. Hamstrings
    C. Gluteus muscles
    D. Soleus, gastrocnemius and tibialis anterior
A

Answer is A: Anatomically “leg” refers to the limb between the knee and ankle. Extension of the leg is achieved by contacting the quadriceps (on the front of the thigh).

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40
Q
  1. What is the role of acetylcholine in muscle cell contraction?
    A. It is a neurotransmitter.
    B. It binds to troponin causing it to change shape.
    C. It supplies the energy for contraction.
    D. It engages with the binding site on actin.
A

Answer is A: ACh crosses the synaptic cleft to transmit a neural impulse to the muscle sarcolemma.

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41
Q
  1. What is a sarcomere?
    A. It is the plasma membrane of a muscle cell.
    B. It is the cytoplasm of a muscle cell.
    C. It is a section of myofibril.
    D. It is a bundle of thick and thin myofilaments.
A

Answer is C: While there are thick and thin myofibrils within a sarcomere, choice C is the better answer.

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42
Q
  1. Which of the following muscles IS named after its location in the body?
    A. Sartorius
    B. Triceps brachii
    C. Soleus
    D. Trapezius
A

Answer is B: “Brachii” refers to the location on the arm (brachium).

43
Q
  1. Which of the following is the smallest unit in a muscle?
    A. Muscle fibre
    B. Myosin
    C. Fasciculus
    D. Myofibril
A

Answer is B: Myosin is a molecule, many of which combine to make a thick myofibril.

44
Q
  1. Skeletal muscle cells can be characterised as:
    A. Unstriated, involuntary, multinucleate
    B. Unstriated, voluntary, multinucleate
    C. Striated, voluntary, uninucleate
    D. Striated, voluntary, multinucleate
A

Answer is D: Being multinucleate (and voluntary) distinguishes skeletal muscle cells from smooth; being voluntary distinguishes skeletal muscle from cardiac muscle cells.

45
Q
  1. The muscles involved in mastication include which of the following?
    A. Sternocleidomastoid, scalene
    B. Sartorius, gracilis, soleus
    C. Temporalis, masseter, buccinator
    D. Orbicularis oculi, mentalis
A

Answer is C: The muscles in choice A move the neck and head; those in choice B are in the thigh and leg, while the orbicularis oculi is a facial muscle that encircles the eye.

46
Q
  1. What action does the flexor carpi ulnaris perform?
    A. It flexes the lower arm.
    B. The same as the extensor carpi ulnaris. C. It flexes the fingers.
    D. The same as the flexor carpi radialis.
A

Answer is D: The flexor carpi ulnaris and the flexor carpi radialis perform the same action – flexing the wrist; the former lies superficial to the ulna bone, while the latter is adjacent and superficial to the radius bone.

47
Q
  1. Which one of the following is not made of skeletal muscle?
    A. The diaphragm
    B. Pyloric sphincter
    C. Vastus lateralis
    D. The tongue
A

Answer is B: We are able to exercise conscious control over the other three muscles so they are skeletal muscle.

48
Q
  1. Which of the following muscles is named using the criterion of its size?
    A. Sternocleidomastoid
    B. Gluteus medius
    C. Flexor digitorum profundus
    D. Trapezius
A

Answer is B: “Medius” implies intermediate, in this case between the gluteus maxi- mus and the gluteus minimus.

49
Q
  1. What is the cytoplasm of a skeletal muscle cell called?
    A. Sarcolemma
    B. Sarcomere
    C. Sarcoplasm
    D. Fasciculus
A

Answer is C: The prefix “sarco” is commonly used to describe microscopic muscle cell structures.

50
Q
  1. What does the term “origin” refer to in the musculoskeletal system?
    A. The point of attachment of a muscle to the “moveable” bone B. The line that separates the shaft from the end of a long bone
    C. The point of attachment of a muscle to the “stationary” bone D. The end of a long bone
A

Answer is C: Muscles are said to “originate” on the bone that does not move when that muscle contracts and to insert on the bone that does flex or extend when the muscle contracts.

51
Q
  1. Which of the following muscles causes the wrist to bend?
    A. Extensor digitorum
    B. Extensor carpi ulnaris
    C. Flexor digitorum profundus
    D. Abductor pollicis longus
A

Answer is B: The term “carpi” refers to the carpal bone (the eight bones of the wrist), so this muscle extends the wrist.

52
Q
  1. Which of the following muscles increases the angle between the bones of the fingers and hand?
    A. Extensor digitorum
    B. Extensor carpi ulnaris
    C. Flexor digitorum profundus
    D. Abductor pollicis longus
A

Answer is A: “Extensor” refers to the action of extension (increasing the angle between the hand and fingers), while “digitorum” refers to the digits (fingers).

53
Q
  1. What is the protein of thick myofilaments in a skeletal muscle cell?
    A. Tropomyosin
    B. Myosin
    C. Actin
    D. Acetylcholine
A

Answer is B: Choices A and C are both proteins of thin myofilaments. ACh is a neurotransmitter.

54
Q
  1. What are the muscles known as triceps brachii, biceps femoris and quadriceps femoris named according to? Their:
    A. Relative size and location of muscle’s origin
    B. Number of origins and location in the body
    C. Shape of muscle and direction of muscle fibres
    D. Number of insertions and location in the body
A

Answer is B: Bi-, tri- and quad- refer to the number of origins, while the second word refers to location (arm or femur).

55
Q
  1. A skeletal muscle fibre (cell) consists of many sections (units) which contract. What is the name given to one of the units that contract?
    A. Sarcomere
    B. Sarcolemma
    C. Sarcoplasm
    D. Fasciculus
A

Answer is A: A muscle fibre consists of many sections (sarcomeres) connected end to end that shorten (contract) as the thick and thin filaments slide past each other.

56
Q
  1. The neurotransmitter that causes an action potential to occur in a muscle cell membrane is called:
    A. Inorganic phosphate (HPO42−)
    B. Adenosine diphosphate (ADP)
    C. Calcium (Ca++)
    D. Acetylcholine (ACh)
A

Answer is D: Acetylcholine is the neurotransmitter. All somatic motor neurons release ACh at their synapses with skeletal muscle fibres.

57
Q
  1. Which of these events is necessary for the contraction of a muscle cell?
    A. The shortening of myofilaments
    B. The conversion of ADP and HPO4 2− to ATP in the cross-bridge
    C. Ca2+ binding to troponin causing it to change shape
    D. The movement of ACh from the sarcolemma to the axon terminal
A

Answer is C: The binding of calcium is essential. (Choice A is wrong as myofilaments don’t shorten – they slide past each other. Choices B and D are the reverse of what actually happens.)

58
Q
  1. Which statement about thick or thin myofilaments is CORRECT?
    A. Thick myofilaments contain the three proteins myosin, tropomyosin and troponin.
    B. Thin myofilaments contain the three proteins actin, tropomyosin and troponin.
    C. Thick myofilaments contain about 300 myosin molecules, each of which has a binding site for a cross-bridge.
    D. Thin myofilaments contain about 300 myosin molecules, each of which has a cross-bridge.
A

Answer is B: Thin myofilaments contain these three proteins. Choices C and D are wrong as myosin has a cross-bridge rather than a binding site.

59
Q
  1. What is the role of calcium ions in muscle contraction? To:
    A. Bind to troponin, thus changing its shape and pulling it away from the actin molecule
    B. Cause the myosin cross-bridge to detach from its binding site
    C. Cause the action potential to propagate along the sarcolemma
    D. Bind with ADP during aerobic respiration to produce ATP to provide energy
A

Answer is A: Calcium binds to troponin. All other choices are wrong statements.

60
Q
  1. The space between the ribs is filled with:
    A. Intercostal muscle
    B. Costal cartilage
    C. Intercostal space
    D. Pleura
A

Answer is A: “Costa” means rib. Intercostal means between the ribs.

61
Q
  1. Which of the following describes skeletal muscle?
    A. Striated, voluntary, multinucleate, individually named.
    B. Striated, branched, uninucleate, involuntary.
    C. Not striated, uninucleate, voluntary, individually named.
    D. Not striated, multinucleate, involuntary, with intercalated discs.
A

Answer is A: Skeletal muscle is striated and is not branched (cardiac muscle cells are branched).

62
Q
  1. Which list is in the correct order of DECREASING size?
    A. Muscle fibre, sarcomere, myofilament, myofibril
    B. Muscle, fasciculus, muscle fibre, myofibril
    C. Sarcomere, fasciculus, myofibril, myofilament
    D. Muscle, muscle fibre, myosin, myofibril
A

Answer is B: A myofibril consists of sarcomeres joined end to end; a myofibril con- tains many myofilaments; a myofibril is larger than a molecule of myosin.

63
Q
  1. What are the muscles known as gluteus maximus, gluteus medius and gluteus minimus named according to? Their:
    A. Size
    B. Shape
    C. Whimsy
    D. Direction of their muscle fibres
A

Answer is A: Maximus > medius > minimus

64
Q
  1. Which of these events is necessary for the contraction of a muscle cell?
    A. The shortening of myosin molecules
    B. The hydrolysis of ATP to ADP and HPO4 2− in the myosin cross-bridge
    C. Ca2+ binding to tropomyosin causing it to change shape
    D. The movement of Ca2+ from the sarcoplasm into the sarcoplasmic
    reticulum
A

Answer is B: The hydrolysis of ATP energises the cross-bridge (myosin molecules do not get shorter; calcium binds to troponin, not tropomyosin; calcium returns to the SR after contraction).

65
Q
  1. Select the one INCORRECT statement about skeletal muscles
    A. An “agonist” opposes or reverses a particular movement.
    B. A muscle’s attachment point to a stationary bone is called its “origin”. C. A skeletal muscle cell is a “syncytium”.
    D. Muscles that immobilise a bone are called “fixators”.
A

Answer is A: An antagonist opposes a movement. All other statements are correct.

66
Q
  1. Which of the following groupings of muscle type and their characteristics is
    INCORRECT?
    A. Skeletal, striated, voluntary
    B. Smooth, visceral, involuntary
    C. Cardiac, striated, voluntary
    D. Skeletal, striated, syncytium
A

Answer is C: Cardiac muscle is not voluntary.

67
Q
  1. Microscopically, muscle fibres contain parallel myofibrils. What are the units joined end to end within a myofibril called? A:
    A. Myofilament
    B. Motor unit
    C. Myosin
    D. Sarcomere
A

Answer is D: Sarcomeres joined end to end, like train carriages, form a myofibril.

68
Q
  1. The part of a skeletal muscle cell that is able to contract is called
    A. Sarcoplasm
    B. Sarcolemma
    C. Sarcomere
    D. Sarcoplasmic reticulum
A

Answer is C: Sarcomeres contain myofilaments that slide past each other as the sarcomere contracts.

69
Q
  1. What is the role of Ca++ in the contraction of a muscle cell?
    A. Ca++ binds to troponin to change its shape which reveals actin’s binding site.
    B. Ca++ attaches to the binding site of actin.
    C. Ca++ detaches from ATP as it forms ADP.
    D. Ca++ causes the myosin head to detach from the binding site of actin.
A

Answer is A: Actin’s binding site is covered until calcium causes it to be exposed.

70
Q
  1. The energy for muscle contraction is derived from the mechanisms below
    EXCEPT for one. Which one is NOT a method of producing ATP?
    A. Anaerobic glycolysis
    B. Aerobic respiration
    C. Direct phosphorylation of ADP by creatinine phosphate D. Anaerobic digestion of lactic acid
A

Answer is D: ATP is not produced from lactic acid – lactic acid is produced from pyruvic acid after glucose is anaerobically lysed into ATP and pyruvic acid.

71
Q
  1. With respect to the flexion of the forearm, which of the following statements is correct?
    A. The origin of the biceps brachii is on the radius and its insertion is on the scapula.
    B. The origin of the biceps brachii is on the ulna and its insertion is on the scapula.
    C. The agonist muscle is the biceps brachii and the antagonist is the triceps brachii.
    D. The agonist muscle is the biceps brachii and the antagonist is the brachialis.
A

Answer is C: Antagonist for flexion is the triceps brachii (the origin, not the insertion of the biceps brachii, is on the scapula).

72
Q
  1. Patients confined to bed and those with plaster casts immobilising a bone fracture suffer muscle wasting. What is the term used for this condition?
    A. Disuse atrophy
    B. Denervation atrophy C. Muscle dystrophy
    D. Muscle hypertrophy
A

Answer is A: Immobilising a bone will mean the attached muscles are not used. Their nerve supply is intact, albeit nervous stimulation is reduced.

73
Q
  1. What is the source of the ATP used by muscles for vigorous activity that may last for 10–15 s?
    A. Glycolysis of glucose in the cell cytoplasm forms ATP.
    B. The ATP that is stored in muscle cells as ATP.
    C. Aerobic respiration in the mitochondria produces the ATP.
    D. Creatinine phosphate in muscle and ADP reacts to form the required ATP.
A

Answer is D: Creatinine phosphate is used to “recharge” the ADP that forms from ATP when the cross-bridge is energised.

74
Q
  1. Which muscle and bone listed below do NOT work together in combination?
    A. Humerus and biceps femoris
    B. Quadriceps and tibia
    C. Femur and gluteal muscles
    D. Radius and biceps brachii
A

Answer is A: The biceps femoris lies adjacent to the femur, not the humerus.

75
Q
  1. Which of the following muscles is named after its origin and insertion points?
    A. Tibialis anterior
    B. Extensor digitorum longus
    C. Rectus femoris
    D. Sternocleidomastoid
A

Answer is D: The sternocleidomastoid has its origin on the sternum and clavicle, while it’s insertion is on the mastoid process of the temporal bone.

76
Q
  1. Which of the following is NOT a common intramuscular injection site?
    A. Gluteus medius
    B. Deltoid
    C. Gluteus maximus
    D. Vastus lateralis
A

Answer is C: The gluteus maximus is avoided so that the sciatic nerve is not pierced by the needle.

77
Q
  1. What structure attaches a muscle to a bone?
    A. A meniscus
    B. A ligament
    C. A cartilage
    D. A tendon
A

Answer is D: A tendon is part of a muscle. Ligaments attach bones to each other, while cartilage covers the articulating surfaces of bone.

78
Q
  1. What binds to troponin causing it to expose the binding site on actin to enable muscle cell contraction?
    A. Ca++ (calcium)
    B. ACh (acetylcholine)
    C. PO42− (phosphate)
    D. ADP (adenosine diphosphate)
A

Answer is A: Troponin has a binding site for calcium.

79
Q
  1. The muscle known as the “transversus abdominis” is named according to:
    A. Its size and number of origins
    B. The direction of its muscle fibres and its action
    C. Its action and its location in the body
    D. Location in the body and direction of muscle fibres
A

Answer is D: Its location = abdominis; its muscle fibre direction = transversus.

80
Q
  1. When a muscle contracts, exactly what structure gets shorter?
    A. The fascicles of a muscle
    B. The myosin molecules of a myofilament
    C. The actin molecules of a myofilament
    D. The sarcomeres of a myofibril
A

Answer is D: The length of the sarcomeres decreases.

81
Q
  1. What is the neurotransmitter that crosses the neuromuscular junction?
    A. Acetylcholine (ACh)
    B. Adrenalin (epinephrine)
    C. Noradrenalin (norepinephrine)
    D. Ca++
A

Answer is A: All somatic motor neurons release ACh at their synapses with skeletal muscle fibres, that is, at the neuromuscular junction.

82
Q
  1. What does aerobic respiration refer to?
    A. Glycolysis in the cytoplasm in the absence of oxygen
    B. Oxidative phosphorylation in the mitochondria in the presence of oxygen
    C. Glycolysis in the liver in the presence of oxygen
    D. Gluconeogenesis in the liver in the absence of oxygen
A

Answer is B: Respiration occurs in the mitochondria of a cell. The term aerobic refers to the presence of oxygen.

83
Q
  1. Which muscle is one of the “hamstrings” group?
    A. Biceps brachii
    B. Biceps femoris
    C. Triceps brachii
    D. Quadriceps femoris
A

Answer is B: The hamstrings are in the thigh. “Femoris” refers to the femur bone. Biceps femoris is one of the three hamstring muscles. Choices A and C are on the arm (from “brachii”).

84
Q
  1. What is the name given to the membrane that surrounds a muscle fascicle?
    A. Pericardium
    B. Peritoneum
    C. Periosteum
    D. Perimysium
A

Answer is D: The syllable “mys-” refers to muscle. The other choices refer to the heart, abdomen and bone, respectively.

85
Q
  1. One of the following muscle names refers to a superficial muscle that lies between the ribs. Which one is it?
    A. Serratus anterior
    B. Rectus femoris
    C. Extensor carpi radialis brevis
    D. External intercostals
A

Answer is D: “Costa” refers to rib. There are internal intercostal muscles, so the external intercostals are more superficial. The muscles in choices B and C lie on the femur and radius bones, respectively.

86
Q
  1. Which of the following muscles is NOT a flexor of the knee?
    A. Semimembranosus
    B. Semitendinosus
    C. Rectus femoris
    D. Biceps femoris
A

Answer is C: The rectus femoris is on the anterior of the thigh and extends to the knee. The other three together constitute the “hamstrings” and flex the knee.

87
Q
  1. Which molecule in a muscle cell has a cross-bridge that attaches to a binding site to effect the shortening of the cell?
    A. Tropomyosin
    B. Myosin
    C. Actin
    D. Troponin
A

Answer is B: Myosin (the thick filament) has a cross-bridge that attaches to a bind- ing site on actin (the thin filament) when it is exposed.

88
Q
  1. Which event causes the thick filament to slide over the thin filament (i.e. the “power stroke”) during muscle contraction?
    A. The attachment of Ca ions to troponin
    B. The hydrolysis of ATP to ADP, inorganic phosphate and energy
    C. The engagement of the head of the myosin cross-bridge with its binding site
    on actin
    D. The attachment of a molecule of ATP to the head of myosin’s cross-bridge
A

Answer is C: The attachment of the already energised cross-bridge to its binding site stimulates the head to swivel and so cause the filaments to slide over each other. Choice A causes the binding site to be exposed. Choice B energises the cross-bridge. Choice D causes detachment of the cross-bridge.

89
Q
  1. Which muscle is located on the posterior part of the forearm?
    A. Flexor digitorum superficialis
    B. Flexor digitorum profundus
    C. Extensor digitorum
    D. Triceps brachii
A

Answer is C: This question is testing the knowledge that muscles on the posterior part of the forearm are extensors (extend the fingers), while muscles on the anterior part are flexors. It also relies on knowing that these muscles are named according to their action. Hence the answer is C.

90
Q
  1. Which of the listed muscles is named according to its action?
    A. Rectus abdominis
    B. Peroneus longus
    C. Pronator teres
    D. Latissimus dorsi
A

Answer is C: The pronator teres pronates the forearm (turns the radius so that it crosses over the ulna).

91
Q
  1. Which muscle is located on the front of the anatomical leg?
    A. Tibialis anterior
    B. Rectus femoris
    C. Sartorius
    D. Flexor carpi radialis
A

Answer is A: The “leg” is between the knee and ankle – it contains the tibia and fibula. Anterior refers to the “front”, hence tibialis anterior. The other muscles are not on the leg. Rectus femoris is on the front of the “thigh”.

92
Q
  1. To what does the term “endomysium” refer?
    A. The protein of thick myofilaments
    B. The tissue that surrounds a muscle fibre
    C. The gap between the axon terminal of a motor nerve cell and a motor end-
    plate of a muscle cell
    D. The vessel from which Ca2+ ions are released prior to a muscle cell
    contraction
A

Answer is B: Endomysium is the connective tissue that surrounds a muscle cell (a fibre). Perimysium surrounds a muscle fascicle, while epimysium surrounds the whole muscle. The other choices are wrong.

93
Q
  1. On which molecule is the energised cross-bridge which produces muscle cell contraction located?
    A. Fibrin
    B. Troponin
    C. Actin
    D. Myosin
A

Answer is D: The myosin molecule has a “cross-bridge”. The actin molecule has the binding site for the cross-bridge which is covered by tropomyosin. Ca binds to troponin in order to move tropomyosin away from the binding site.

94
Q
  1. Why does anaerobic respiration occur during vigorous exercise?
    A. There may be insufficient oxygen supplied to the muscle cells.
    B. Carbon dioxide builds up in the respiring muscle cells.
    C. Anaerobic respiration releases more energy from glucose than aerobic
    respiration.
    D. During anaerobic respiration enzymes make more ATP than during aerobic
    exercise.
A

Answer is A: Vigorous exercise may require more oxygen than can be supplied by the circulation. In this case ATP must be produced anaerobically which is less efficient than when sufficient oxygen is present. Hence choices C and D are wrong.

95
Q
  1. Which is the correct equation for anaerobic respiration in humans?
    A. Glucose + lactic acid → carbon dioxide + water B. Glucose → lactic acid + carbon dioxide
    C. Glucose → lactic acid +(little energy)
    D. Glucose→ lactic acid
A

Answer is C: Anaerobic respiration produces lactic acid and (of course) energy.

96
Q
  1. Which is the correct equation for aerobic respiration in humans?
    A. Glucose + oxygen → carbon dioxide + water
    B. Glucose + oxygen → carbon dioxide
    C. Glucose → carbon dioxide + water + energy
    D. Glucose + oxygen → carbon dioxide + water +energy
A

Answer is D: Aerobic means that oxygen must be an input. Respiration must result in energy being produced, hence D.

97
Q
  1. What is true about the energy released from glucose respiration?
    A. Anaerobic respiration releases more than aerobic respiration.
    B. Aerobic respiration releases more than anaerobic respiration.
    C. Aerobic and anaerobic respiration release about the same amount. D. Anaerobic respiration releases no energy.
A

Answer is B: Aerobic respiration produces 36 ATP molecules, while anaerobic respiration produces just 2 molecules of ATP.

98
Q
  1. Which muscle named below includes its origin and insertion?
    A. Pubococcygeus
    B. Sartorius
    C. External abdominal obliques
    D. Serratus anterior
A

Answer is A: This muscle (part of the pelvic floor) has two parts to its name: origin is on the pubis (pubic bone); insertion is to the coccyx. Choice B is named “whimsically”, choice C is named according to location and direction of muscle fibres and choice D is named according to location and appearance.

99
Q
  1. Which pair of terms below refers to a contraction and relaxation?
    A. Flexor and extensor
    B. Origin and insertion
    C. Brachialis and radialis D. Agonist and antagonist
A

Answer is D: An agonist muscle causes a movement to occur (by contracting), while an antagonist muscle cooperates in the movement by relaxing (allowing itself to lengthen).

100
Q
  1. One muscle below is NOT named after its shape. Which one?
    A. Deltoid
    B. Rhomboid
    C. Masseter D. Trapezius
A

Answer is C: The masseter is named after its action which allows mastication (chewing) of food.

101
Q
  1. On what part of the body is the serratus anterior muscle located?
    A. On the front of the torso
    B. On the lower back
    C. At the front of the thigh
    D. In the serratus region
A

Answer is A: “Anterior” refers to front, so choice B is wrong. There is no “serratus” region.

102
Q
  1. Which list below has the superficial muscles of the superior medial thigh in the correct order from medial to lateral?
    A. Gracilis, adductor longus, pectineus
    B. Gracilis, pectineus, adductor longus
    C. Adductor longus, gracilis, pectineus
    D. Pectineus, adductor longus, gracilis
A

Answer is A: Gracilis is most medial while pectineus is most lateral.

103
Q
  1. Which list has the muscles of the hamstrings in order from most lateral to medial?
    A. Semitendinosus, biceps femoris, semimembranosus, gracilis
    B. Rectus femoris, semitendinosus, semimembranosus
    C. Vastus lateralis, semitendinosus, semimembranosus
    D. Biceps femoris, semitendinosus, semimembranosus
A

Answer is D: There are three (not four) muscles in the hamstrings. The rectus femoris and vastus lateralis are in the quadriceps, not the hamstrings.

104
Q
  1. Which two muscles are on the dorsal side of the body?
    A. Rectus abdominis, pectoralis major
    B. Latissimus dorsi, trapezius
    C. External obliques, erector spinae
    D. Infraspinatus, vastus medialis
A

Answer is B: While the erector spinae and infraspinatus are on the dorsal side, their partners are not. Choice A muscles are on the ventral surface.

Animal Course Physiology Exam (15 decks)

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