Question 1

Which muscle type(s) use(s) calcium to trigger actin-myosin interactions for movement?

Accepted Answer

A)  Smooth muscle only 
B)  Cardiac muscle only 
C)  Skeletal muscle only 
D)  Both smooth and cardiac muscle, but not skeletal muscle 
E)  Smooth, cardiac, and skeletal muscle 
A)  Smooth muscle only 
B)  Cardiac muscle only 
C)  Skeletal muscle only 
D)  Both smooth and cardiac muscle, but not skeletal muscle 
E)  Smooth, cardiac, and skeletal muscle

Question 2

Which event occurs during skeletal and cardiac muscle contraction?

Accepted Answer

A)  The distance between Z lines increases. 
B)  The sarcomeres lengthen. 
C)  The width of the H zone increases. 
D)  The width of the I band increases. 
E)  The area of actin and myosin overlap increases. 
A)  The distance between Z lines increases. 
B)  The sarcomeres lengthen. 
C)  The width of the H zone increases. 
D)  The width of the I band increases. 
E)  The area of actin and myosin overlap increases.

Question 3

Refer to the figure showing different lever systems.   The position of the fulcrum and the ratios of the lengths of the load arm and force arm indicate that lever(s) _______ is/are _______.

Accepted Answer

A)  A; maximized for speed because the ratio of the load arm to force arm is 1:2 
B)  B; maximized for speed because the ratio of the load arm to force arm is 5:1 
C)  A and B; both maximized for force because the fulcrum is not positioned between the load arm and force arm 
D)  A; a class 1 lever because the fulcrum is located between the load and the point of force application 
E)  B; a class 2 lever because the load is located between the fulcrum and the point of force application 
A)  A; maximized for speed because the ratio of the load arm to force arm is 1:2 
B)  B; maximized for speed because the ratio of the load arm to force arm is 5:1 
C)  A and B; both maximized for force because the fulcrum is not positioned between the load arm and force arm 
D)  A; a class 1 lever because the fulcrum is located between the load and the point of force application 
E)  B; a class 2 lever because the load is located between the fulcrum and the point of force application

Question 4

Which pairing of a sarcomere structure with its corresponding description is correct?

Accepted Answer

A)  H zone: appears light on an electron micrograph; found where actin and myosin filaments overlap when muscle is relaxed 
B)  Z line: where myosin is anchored in the center of the H zone 
C)  M band: dark stripe within the H zone whose proteins hold actin in a regular arrangement 
D)  A band: region containing only myosin filaments when the muscle is contracted 
E)  I band: appears light on an electron micrograph; found where actin and myosin filaments do not overlap 
A)  H zone: appears light on an electron micrograph; found where actin and myosin filaments overlap when muscle is relaxed 
B)  Z line: where myosin is anchored in the center of the H zone 
C)  M band: dark stripe within the H zone whose proteins hold actin in a regular arrangement 
D)  A band: region containing only myosin filaments when the muscle is contracted 
E)  I band: appears light on an electron micrograph; found where actin and myosin filaments do not overlap

Question 5

Refer to the figure showing muscle cells.   In the living tissue, if an action potential stimulates contraction of cell 1, will cell 2 also contract?

Accepted Answer

A)  Yes, because an action potential in cell 1 will spread to cell 2 through gap junctions in structure A. 
B)  Yes, because the motor neuron A that innervates cell 1 also innervates cell 2. 
C)  No, because the action potential will be stopped by structure A, which separates cell 1 and cell 2. 
D)  Yes, because the smooth muscle cell labeled 1 will spread the action potential to cell 2 through the neuromuscular junction at A. 
E)  No, because the skeletal muscle cell labeled 1 is not physically connected to cell 2 through gap junctions. 
A)  Yes, because an action potential in cell 1 will spread to cell 2 through gap junctions in structure A. 
B)  Yes, because the motor neuron A that innervates cell 1 also innervates cell 2. 
C)  No, because the action potential will be stopped by structure A, which separates cell 1 and cell 2. 
D)  Yes, because the smooth muscle cell labeled 1 will spread the action potential to cell 2 through the neuromuscular junction at A. 
E)  No, because the skeletal muscle cell labeled 1 is not physically connected to cell 2 through gap junctions.

Question 6

When you lift a cup of coffee from the table to your mouth, both the muscle fibers in your biceps and the sarcomeres within these muscle fibers become _______.

Accepted Answer

The answer of When you lift a cup of coffee...

Question 7

Bone tissue includes _______ cells enclosed in a matrix containing _______.

Accepted Answer

A)  osteoblast; polysaccharide 
B)  osteocyte; collagen and calcium phosphate 
C)  osteocyte; myosin and actin 
D)  chondrocyte; calcium phosphate 
E)  chondroblast; polysaccharide 
A)  osteoblast; polysaccharide 
B)  osteocyte; collagen and calcium phosphate 
C)  osteocyte; myosin and actin 
D)  chondrocyte; calcium phosphate 
E)  chondroblast; polysaccharide

Question 8

Which statement about the long bones in a human skeleton is true?

Accepted Answer

A)  Ossification starts at the ends of developing long bones and continues until it reaches the center of the bones. 
B)  Elongation occurs at the articular surfaces. 
C)  Secondary sites of ossification occur in the center of developing long bones. 
D)  They are first laid down as cartilage. 
E)  They form on a scaffold of connective tissue membrane. 
A)  Ossification starts at the ends of developing long bones and continues until it reaches the center of the bones. 
B)  Elongation occurs at the articular surfaces. 
C)  Secondary sites of ossification occur in the center of developing long bones. 
D)  They are first laid down as cartilage. 
E)  They form on a scaffold of connective tissue membrane.

Question 9

Which statement about the molecular arrangement of actin and myosin in myofibrils is true?

Accepted Answer

A)  A thin filament consists of myosin and tropomyosin. 
B)  Two chains of myosin monomers are twisted into a helix. 
C)  Two strands of tropomyosin lie in the grooves of the myosin. 
D)  Troponin forms the head of the myosin molecule. 
E)  The myosin heads have ATPase activity and interact with the actin. 
A)  A thin filament consists of myosin and tropomyosin. 
B)  Two chains of myosin monomers are twisted into a helix. 
C)  Two strands of tropomyosin lie in the grooves of the myosin. 
D)  Troponin forms the head of the myosin molecule. 
E)  The myosin heads have ATPase activity and interact with the actin.

Question 10

Skeletal muscle fibers show a range of responses to different levels of stimulation because

Accepted Answer

A)  each muscle fiber contraction is "all or none." 
B)  the availability of Ca2+ sets an upper limit to the strength of the contraction. 
C)  a new contraction can occur only after the resting condition is reached. 
D)  following stimulation, the fibers stay contracted. 
E)  individual twitches in quick succession in the same fiber can undergo summation. 
A)  each muscle fiber contraction is "all or none." 
B)  the availability of Ca2+ sets an upper limit to the strength of the contraction. 
C)  a new contraction can occur only after the resting condition is reached. 
D)  following stimulation, the fibers stay contracted. 
E)  individual twitches in quick succession in the same fiber can undergo summation.

Question 11

Which statement about the skeletal system as a series of joints and levers is true?

Accepted Answer

A)  An extensor muscle moves a bone closer to the body. 
B)  Antagonistic pairs include an extensor muscle and a flexor muscle associated with the same joint. 
C)  Tendons hold together bones that meet at joints. 
D)  Ligaments attach muscles to bones. 
E)  The knee joint is a ball-and-socket joint. 
A)  An extensor muscle moves a bone closer to the body. 
B)  Antagonistic pairs include an extensor muscle and a flexor muscle associated with the same joint. 
C)  Tendons hold together bones that meet at joints. 
D)  Ligaments attach muscles to bones. 
E)  The knee joint is a ball-and-socket joint.

Question 12

Most of the compact bone in mammals is composed of concentric bony cylinders with a central canal called _______ systems.This type of bone _______.

Accepted Answer

A)  calciform; is lightweight 
B)  Haversian; can withstand compression forces 
C)  cavernosa; is dense 
D)  cancellous; can withstand bending forces 
E)  cartilaginous; is replaced by spongy bone 
A)  calciform; is lightweight 
B)  Haversian; can withstand compression forces 
C)  cavernosa; is dense 
D)  cancellous; can withstand bending forces 
E)  cartilaginous; is replaced by spongy bone

Question 13

The most important determinant of the proportions of muscle fiber types a person has is

Accepted Answer

A)  amount of exercise they engage in. 
B)  genetic heritage. 
C)  type of exercise they do. 
D)  body size. 
E)  age. 
A)  amount of exercise they engage in. 
B)  genetic heritage. 
C)  type of exercise they do. 
D)  body size. 
E)  age.

Question 14

The _______ activates _______, which phosphorylates myosin heads, leading to cycles of binding and releasing of actin in smooth muscle cells.

Accepted Answer

A)  enzyme myosin kinase; myosin phosphatase 
B)  Ca2+-calmodulin complex; myosin kinase 
C)  Ca2+ in the sarcoplasm; myosin kinase 
D)  myosin-Ca2+ complex; myosin phosphatase 
E)  Ca2+-calmodulin complex; myosin phosphatase 
A)  enzyme myosin kinase; myosin phosphatase 
B)  Ca2+-calmodulin complex; myosin kinase 
C)  Ca2+ in the sarcoplasm; myosin kinase 
D)  myosin-Ca2+ complex; myosin phosphatase 
E)  Ca2+-calmodulin complex; myosin phosphatase

Question 15

What is the role of Ca2+ in the control of muscle contraction?

Accepted Answer

A)  It causes depolarization of the T tubule system. 
B)  It changes the conformation of troponin, which ultimately results in myosin-binding sites being exposed. 
C)  It changes the conformation of myosin heads, causing actin and myosin filaments to slide past each other. 
D)  It binds to tropomyosin and breaks actin-myosin cross-bridges. 
E)  It blocks the ATP-binding site on myosin heads, enabling muscles to relax. 
A)  It causes depolarization of the T tubule system. 
B)  It changes the conformation of troponin, which ultimately results in myosin-binding sites being exposed. 
C)  It changes the conformation of myosin heads, causing actin and myosin filaments to slide past each other. 
D)  It binds to tropomyosin and breaks actin-myosin cross-bridges. 
E)  It blocks the ATP-binding site on myosin heads, enabling muscles to relax.

Question 16

After the first 15 minutes of a 10-km run, the major energy requirements of the leg muscles are supplied by

Accepted Answer

A)  preformed ATP. 
B)  glycolysis. 
C)  oxidative metabolism. 
D)  pyruvate and lactate. 
E)  the high-protein drink consumed right before the run. 
A)  preformed ATP. 
B)  glycolysis. 
C)  oxidative metabolism. 
D)  pyruvate and lactate. 
E)  the high-protein drink consumed right before the run.

Question 17

Refer to the figure.   Based on the figure, which of the following represents the stages of muscle contraction in the correct order?

Accepted Answer

A)  A F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 D F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 F 
B)  A F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 D F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 B 
C)  D F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 A 
D)  A F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 D 
E)  D F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 A 
A)  A F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 D F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 F 
B)  A F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 D F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 B 
C)  D F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 A 
D)  A F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 D 
E)  D F1F1F1S1F1F1F10 E F1F1F1S1F1F1F10 F F1F1F1S1F1F1F10 B F1F1F1S1F1F1F10 C F1F1F1S1F1F1F10 A

Question 18

Based on observations that the H zone and I band in a sarcomere become narrower as a skeletal muscle contracts, Huxley and Huxley proposed the _______ model of muscle contraction.

Accepted Answer

The answer of Based on observations that the H zone...

Question 19

Refer to the figure showing the growth of a long bone.

Accepted Answer

A-cartilage; B-primary ossific

Question 20

A hiker is bitten by a venomous snake.The venom prevents the release of calcium from the sarcoplasmic reticulum.Which symptom might the patient exhibit?

Accepted Answer

A)  The patient's muscles will not relax. 
B)  The patient's muscles will become overly active. 
C)  The patient's muscles will not contract. 
D)  The patient's body will be unable to form bone. 
E)  The patient's cells will not be able to make ATP. 
A)  The patient's muscles will not relax. 
B)  The patient's muscles will become overly active. 
C)  The patient's muscles will not contract. 
D)  The patient's body will be unable to form bone. 
E)  The patient's cells will not be able to make ATP.

Exam 47: Musculoskeletal Systems

Which muscle type(s) use(s) calcium to trigger actin-myosin interactions for movement?

Which event occurs during skeletal and cardiac muscle contraction?

Refer to the figure showing different lever systems. The position of the fulcrum and the ratios of the lengths of the load arm and force arm indicate that lever(s) _______ is/are _______.

Which pairing of a sarcomere structure with its corresponding description is correct?

Refer to the figure showing muscle cells. In the living tissue, if an action potential stimulates contraction of cell 1, will cell 2 also contract?

When you lift a cup of coffee from the table to your mouth, both the muscle fibers in your biceps and the sarcomeres within these muscle fibers become _______.

Bone tissue includes _______ cells enclosed in a matrix containing _______.

Which statement about the long bones in a human skeleton is true?

Which statement about the molecular arrangement of actin and myosin in myofibrils is true?

Skeletal muscle fibers show a range of responses to different levels of stimulation because

Which statement about the skeletal system as a series of joints and levers is true?

Most of the compact bone in mammals is composed of concentric bony cylinders with a central canal called _______ systems.This type of bone _______.

The most important determinant of the proportions of muscle fiber types a person has is

The _______ activates _______, which phosphorylates myosin heads, leading to cycles of binding and releasing of actin in smooth muscle cells.

What is the role of Ca2+ in the control of muscle contraction?

After the first 15 minutes of a 10-km run, the major energy requirements of the leg muscles are supplied by

Refer to the figure. Based on the figure, which of the following represents the stages of muscle contraction in the correct order?

Based on observations that the H zone and I band in a sarcomere become narrower as a skeletal muscle contracts, Huxley and Huxley proposed the _______ model of muscle contraction.

Refer to the figure showing the growth of a long bone.

A hiker is bitten by a venomous snake.The venom prevents the release of calcium from the sarcoplasmic reticulum.Which symptom might the patient exhibit?

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Refer to the figure showing different lever systems. The position of the fulcrum and the ratios of the lengths of the load arm and force arm indicate that lever(s) _ is/are _.

Bone tissue includes _ cells enclosed in a matrix containing _.

Most of the compact bone in mammals is composed of concentric bony cylinders with a central canal called _ systems.This type of bone _.

The _ activates _, which phosphorylates myosin heads, leading to cycles of binding and releasing of actin in smooth muscle cells.

What is the role of Ca²⁺ in the control of muscle contraction?