BIOS 252 EXAM 1 TEST BANK | ANATOMY & PHYSIOLOGY II QUESTIONS & ANSWERS | MUSCLE TISSUE, CONTRACTION MECHA… EXAM
P R O F E S S I O N A L P R A C T I C E M AT E R I A L S
BIOS 252 Exam 1 Test Bank | Anatomy &
Physiology II Questions & Answers | Muscle
Tissue, Contraction Mechanisms &
Sarcomere Breakdown | 2026/2027
Chamberlain
Verified Answers Exam Ready With Rationales
100 QUESTIONS
DOCUMENT OVERVIEW
This document provides 100 verified questions with provided correct answers and detailed explanations,
focusing on muscle physiology and function. It serves as a comprehensive study resource for students to
review core concepts, prepare for exams, and reinforce their understanding of anatomy and physiology II.
CONTENTS
01 Muscle Contraction & Excitation-Coupling Q1–Q14
02 Muscle Fiber Structure & Sarcomere Anatomy Q15–Q29
03 Muscle Tissue Organization & Connective Tissue Q30–Q41
04 Muscle Metabolism & Injury Markers Q42–Q45
05 Skeletal Muscle Actions & Biomechanics Q46–Q68
06 Cranial Nerves & Special Senses Q69–Q78
07 Axial Musculature & Respiration Q79–Q84
08 Nervous System Anatomy & Physiology Q85–Q89
09 Neuromuscular Junction & Nerve Conduction Q90–Q93
10 Central Nervous System Protection Q94–Q100
E XA M Q U EST I O N S
Q1 QUESTION 1 OF 100
During a biomechanical analysis of a patient requiring gait assistance, the neuromuscular diagnostician observes that the tibialis anterior muscle shows a peak electrical
potential of only 45 mV during dorsiflexion, significantly below the expected baseline of 100 mV. This finding suggests compromised neural activation or a deficit in the
muscle's contractile machinery responsible for generating force against gravity. The diagnostician must prioritize further investigation.
Page 1
,A) Assess the sarcomeric structure for Z-line streaming.
B) Evaluate the neuromuscular junction for acetylcholine receptor density.
C) Measure the resting membrane potential of the muscle fibers.
D) Examine the actin and myosin filament overlap within the sarcomeres.
CORRECT ANSWER
B) Evaluate the neuromuscular junction for acetylcholine receptor density.
RATIONALE
A reduced peak electrical potential during contraction indicates impaired excitation-contraction coupling, most likely stemming from a compromised signal transmission at the
neuromuscular junction, thus necessitating assessment of acetylcholine receptor function. This directly relates to the neuron's ability to signal the muscle cell to contract.
Q2 QUESTION 2 OF 100
During a diagnostic electromyography (EMG) procedure on a patient exhibiting unexplained muscle weakness, the on-call neurologist observes that motor neurons
innervating the quadriceps femoris muscle are failing to elicit a contractile response when stimulated at 50 millivolts. This failure to respond to a typical stimulus voltage
indicates a deficit in which fundamental property of these muscle cells?
A) Contractility
B) Elasticity
C) Excitability
D) Conductivity
CORRECT ANSWER
C) Excitability
RATIONALE
Excitability is the muscle cell's ability to respond to stimuli, and the inability of motor neurons to elicit a contraction at a normal voltage indicates a failure in this property, not
necessarily in the ability to shorten (contractility), transmit signals (conductivity), or return to resting length (elasticity).
Q3 QUESTION 3 OF 100
During a neuromuscular junction examination of a patient presenting with muscle weakness, the electrophysiologist observes that a 10-millivolt stimulus applied to the
motor neuron axon results in a graded potential in the muscle cell that only propagates 0.5 millimeters before dissipating. This finding most strongly indicates a deficit
in which of the following properties of the excitable tissue?
A) Excitability
B) Contractility
C) Conductivity
D) Elasticity
CORRECT ANSWER
C) Conductivity
RATIONALE
Conductivity refers to the ability of excitable tissue to transmit an electrical impulse along its membrane; a diminished propagation distance signifies a failure in this transmission
capacity. This contrasts with excitability (ability to respond to a stimulus) or contractility (ability to shorten).
Q4 QUESTION 4 OF 100
During a cadaveric dissection of the quadriceps femoris, the lead anatomist observes that the rectus femoris muscle fibers are unusually resistant to elongation when
passively stretched by 15 cm beyond their resting length. This finding primarily indicates a deficit in which fundamental property of muscle tissue?
A) Contractility
B) Excitability
Page 2
,C) Elasticity
D) Extensibility
CORRECT ANSWER
D) Extensibility
RATIONALE
Extensibility is the inherent ability of muscle tissue to be stretched beyond its normal resting length. Resistance to elongation, even when passively stretched, directly points to a
compromised extensibility of the muscle fibers.
Q5 QUESTION 5 OF 100
During a biomechanical assessment of a sprinter's quadriceps, the physiotherapist observes that after a forceful eccentric contraction, the muscle fibers do not fully
return to their original length when passive stretch is applied, instead maintaining a partial elongation of 5 mm beyond baseline. This finding primarily indicates a deficit
in which intrinsic property of the muscle tissue?
A) Contractility
B) Excitability
C) Elasticity
D) Conductivity
CORRECT ANSWER
C) Elasticity
RATIONALE
Elasticity is the intrinsic ability of muscle fibers to recoil and return to their resting length after being stretched, and a persistent elongation suggests this property is compromised.
Contractility, excitability, and conductivity are distinct properties of muscle tissue not directly measured by a failure to rebound to baseline length.
Q6 QUESTION 6 OF 100
A physiologist observes that a stimulated skeletal muscle fiber fails to shorten, despite exhibiting normal electrical excitation. Upon microscopic examination, the
sarcolemma and T-tubules show intact depolarization, and ATP levels are sufficient, but the cross-bridges between thick and thin filaments do not cycle. This
observation PRIMARILY indicates a defect in which characteristic of muscle tissue?
A) Excitability
B) Elasticity
C) Conductivity
D) Contractility
CORRECT ANSWER
D) Contractility
RATIONALE
Contractility is the intrinsic ability of muscle cells to shorten forcibly when stimulated, a process requiring the interaction of actin and myosin filaments to generate tension and
movement. The inability of cross-bridges to cycle, despite intact excitation and ATP, directly points to a failure in this fundamental property.
Q7 QUESTION 7 OF 100
During a microscopic examination of a muscle biopsy sample from a patient experiencing significant fatigue, the technician observes that the sarcolemma appears
unusually thickened and less permeable to ion influx. This finding most directly impairs which critical function for skeletal muscle contraction?
A) Binding of calcium ions to troponin
B) Release of acetylcholine into the synaptic cleft
Page 3
, C) Propagation of the action potential along the muscle fiber
D) Extension of the T-tubules into the sarcoplasm
CORRECT ANSWER
C) Propagation of the action potential along the muscle fiber
RATIONALE
The sarcolemma's role as the receptive membrane for electrical signals is compromised by its thickened, less permeable state, directly hindering the travel of the action potential,
which is necessary to trigger calcium release. Impaired permeability disrupts the generation and conduction of the electrical impulse required for contraction.
Q8 QUESTION 8 OF 100
A biopsy reveals a muscle fiber with significantly reduced intracellular calcium stores and impaired ability to release this calcium upon stimulation. According to the
sliding filament theory, what is the most direct consequence for muscle contraction?
A) Lack of ATP binding to myosin heads
B) Failure of myosin heads to bind to actin filaments
C) Inability of voltage-gated calcium channels on the sarcolemma to open
D) Insufficient troponin-tropomyosin complex displacement from actin binding sites
CORRECT ANSWER
D) Insufficient troponin-tropomyosin complex displacement from actin binding sites
RATIONALE
Adequate calcium release from the sarcoplasmic reticulum is required to bind troponin, causing a conformational change that shifts tropomyosin away from actin-myosin binding
sites, thereby enabling cross-bridge formation and contraction. Impaired calcium release directly inhibits this critical regulatory step.
Q9 QUESTION 9 OF 100
During a simulation of muscle excitation-contraction coupling, the chronometer indicates 3 milliseconds (ms) post-stimulus when the sarcolemma action potential fully
propagates into the T-tubules. However, observable cross-bridge cycling does not commence until 7 ms. This 4 ms delay suggests a problem primarily within which step
of the sequence?
A) Release of acetylcholine from the neuron terminal.
B) Calcium ion (Ca2+) release from the sarcoplasmic reticulum.
C) Formation of myosin cross-bridges with actin filaments.
D) Propagation of the action potential along the sarcolemma.
CORRECT ANSWER
B) Calcium ion (Ca2+) release from the sarcoplasmic reticulum.
RATIONALE
The delay between sarcolemma action potential arrival at the T-tubules and subsequent cross-bridge cycling indicates a malfunction in the calcium release mechanism from the
sarcoplasmic reticulum, which is the intermediary step required for myosin-actin interaction. This step must be completed before myosin can bind to actin.
Q10 QUESTION 10 OF 100
During a high-intensity interval training session, a kinesiologist observes that the Z-lines within the sarcomeres of a subject's vastus lateralis muscle are not moving
closer together, despite maximal voluntary effort. The subject's motor neuron firing rate is confirmed to be high. This lack of sarcomere shortening indicates a potential
failure in which specific step of the sliding filament theory?
A) ATP hydrolysis initiating cross-bridge detachment from actin.
B) Calcium release from the sarcoplasmic reticulum binding to troponin.
Page 4
P R O F E S S I O N A L P R A C T I C E M AT E R I A L S
BIOS 252 Exam 1 Test Bank | Anatomy &
Physiology II Questions & Answers | Muscle
Tissue, Contraction Mechanisms &
Sarcomere Breakdown | 2026/2027
Chamberlain
Verified Answers Exam Ready With Rationales
100 QUESTIONS
DOCUMENT OVERVIEW
This document provides 100 verified questions with provided correct answers and detailed explanations,
focusing on muscle physiology and function. It serves as a comprehensive study resource for students to
review core concepts, prepare for exams, and reinforce their understanding of anatomy and physiology II.
CONTENTS
01 Muscle Contraction & Excitation-Coupling Q1–Q14
02 Muscle Fiber Structure & Sarcomere Anatomy Q15–Q29
03 Muscle Tissue Organization & Connective Tissue Q30–Q41
04 Muscle Metabolism & Injury Markers Q42–Q45
05 Skeletal Muscle Actions & Biomechanics Q46–Q68
06 Cranial Nerves & Special Senses Q69–Q78
07 Axial Musculature & Respiration Q79–Q84
08 Nervous System Anatomy & Physiology Q85–Q89
09 Neuromuscular Junction & Nerve Conduction Q90–Q93
10 Central Nervous System Protection Q94–Q100
E XA M Q U EST I O N S
Q1 QUESTION 1 OF 100
During a biomechanical analysis of a patient requiring gait assistance, the neuromuscular diagnostician observes that the tibialis anterior muscle shows a peak electrical
potential of only 45 mV during dorsiflexion, significantly below the expected baseline of 100 mV. This finding suggests compromised neural activation or a deficit in the
muscle's contractile machinery responsible for generating force against gravity. The diagnostician must prioritize further investigation.
Page 1
,A) Assess the sarcomeric structure for Z-line streaming.
B) Evaluate the neuromuscular junction for acetylcholine receptor density.
C) Measure the resting membrane potential of the muscle fibers.
D) Examine the actin and myosin filament overlap within the sarcomeres.
CORRECT ANSWER
B) Evaluate the neuromuscular junction for acetylcholine receptor density.
RATIONALE
A reduced peak electrical potential during contraction indicates impaired excitation-contraction coupling, most likely stemming from a compromised signal transmission at the
neuromuscular junction, thus necessitating assessment of acetylcholine receptor function. This directly relates to the neuron's ability to signal the muscle cell to contract.
Q2 QUESTION 2 OF 100
During a diagnostic electromyography (EMG) procedure on a patient exhibiting unexplained muscle weakness, the on-call neurologist observes that motor neurons
innervating the quadriceps femoris muscle are failing to elicit a contractile response when stimulated at 50 millivolts. This failure to respond to a typical stimulus voltage
indicates a deficit in which fundamental property of these muscle cells?
A) Contractility
B) Elasticity
C) Excitability
D) Conductivity
CORRECT ANSWER
C) Excitability
RATIONALE
Excitability is the muscle cell's ability to respond to stimuli, and the inability of motor neurons to elicit a contraction at a normal voltage indicates a failure in this property, not
necessarily in the ability to shorten (contractility), transmit signals (conductivity), or return to resting length (elasticity).
Q3 QUESTION 3 OF 100
During a neuromuscular junction examination of a patient presenting with muscle weakness, the electrophysiologist observes that a 10-millivolt stimulus applied to the
motor neuron axon results in a graded potential in the muscle cell that only propagates 0.5 millimeters before dissipating. This finding most strongly indicates a deficit
in which of the following properties of the excitable tissue?
A) Excitability
B) Contractility
C) Conductivity
D) Elasticity
CORRECT ANSWER
C) Conductivity
RATIONALE
Conductivity refers to the ability of excitable tissue to transmit an electrical impulse along its membrane; a diminished propagation distance signifies a failure in this transmission
capacity. This contrasts with excitability (ability to respond to a stimulus) or contractility (ability to shorten).
Q4 QUESTION 4 OF 100
During a cadaveric dissection of the quadriceps femoris, the lead anatomist observes that the rectus femoris muscle fibers are unusually resistant to elongation when
passively stretched by 15 cm beyond their resting length. This finding primarily indicates a deficit in which fundamental property of muscle tissue?
A) Contractility
B) Excitability
Page 2
,C) Elasticity
D) Extensibility
CORRECT ANSWER
D) Extensibility
RATIONALE
Extensibility is the inherent ability of muscle tissue to be stretched beyond its normal resting length. Resistance to elongation, even when passively stretched, directly points to a
compromised extensibility of the muscle fibers.
Q5 QUESTION 5 OF 100
During a biomechanical assessment of a sprinter's quadriceps, the physiotherapist observes that after a forceful eccentric contraction, the muscle fibers do not fully
return to their original length when passive stretch is applied, instead maintaining a partial elongation of 5 mm beyond baseline. This finding primarily indicates a deficit
in which intrinsic property of the muscle tissue?
A) Contractility
B) Excitability
C) Elasticity
D) Conductivity
CORRECT ANSWER
C) Elasticity
RATIONALE
Elasticity is the intrinsic ability of muscle fibers to recoil and return to their resting length after being stretched, and a persistent elongation suggests this property is compromised.
Contractility, excitability, and conductivity are distinct properties of muscle tissue not directly measured by a failure to rebound to baseline length.
Q6 QUESTION 6 OF 100
A physiologist observes that a stimulated skeletal muscle fiber fails to shorten, despite exhibiting normal electrical excitation. Upon microscopic examination, the
sarcolemma and T-tubules show intact depolarization, and ATP levels are sufficient, but the cross-bridges between thick and thin filaments do not cycle. This
observation PRIMARILY indicates a defect in which characteristic of muscle tissue?
A) Excitability
B) Elasticity
C) Conductivity
D) Contractility
CORRECT ANSWER
D) Contractility
RATIONALE
Contractility is the intrinsic ability of muscle cells to shorten forcibly when stimulated, a process requiring the interaction of actin and myosin filaments to generate tension and
movement. The inability of cross-bridges to cycle, despite intact excitation and ATP, directly points to a failure in this fundamental property.
Q7 QUESTION 7 OF 100
During a microscopic examination of a muscle biopsy sample from a patient experiencing significant fatigue, the technician observes that the sarcolemma appears
unusually thickened and less permeable to ion influx. This finding most directly impairs which critical function for skeletal muscle contraction?
A) Binding of calcium ions to troponin
B) Release of acetylcholine into the synaptic cleft
Page 3
, C) Propagation of the action potential along the muscle fiber
D) Extension of the T-tubules into the sarcoplasm
CORRECT ANSWER
C) Propagation of the action potential along the muscle fiber
RATIONALE
The sarcolemma's role as the receptive membrane for electrical signals is compromised by its thickened, less permeable state, directly hindering the travel of the action potential,
which is necessary to trigger calcium release. Impaired permeability disrupts the generation and conduction of the electrical impulse required for contraction.
Q8 QUESTION 8 OF 100
A biopsy reveals a muscle fiber with significantly reduced intracellular calcium stores and impaired ability to release this calcium upon stimulation. According to the
sliding filament theory, what is the most direct consequence for muscle contraction?
A) Lack of ATP binding to myosin heads
B) Failure of myosin heads to bind to actin filaments
C) Inability of voltage-gated calcium channels on the sarcolemma to open
D) Insufficient troponin-tropomyosin complex displacement from actin binding sites
CORRECT ANSWER
D) Insufficient troponin-tropomyosin complex displacement from actin binding sites
RATIONALE
Adequate calcium release from the sarcoplasmic reticulum is required to bind troponin, causing a conformational change that shifts tropomyosin away from actin-myosin binding
sites, thereby enabling cross-bridge formation and contraction. Impaired calcium release directly inhibits this critical regulatory step.
Q9 QUESTION 9 OF 100
During a simulation of muscle excitation-contraction coupling, the chronometer indicates 3 milliseconds (ms) post-stimulus when the sarcolemma action potential fully
propagates into the T-tubules. However, observable cross-bridge cycling does not commence until 7 ms. This 4 ms delay suggests a problem primarily within which step
of the sequence?
A) Release of acetylcholine from the neuron terminal.
B) Calcium ion (Ca2+) release from the sarcoplasmic reticulum.
C) Formation of myosin cross-bridges with actin filaments.
D) Propagation of the action potential along the sarcolemma.
CORRECT ANSWER
B) Calcium ion (Ca2+) release from the sarcoplasmic reticulum.
RATIONALE
The delay between sarcolemma action potential arrival at the T-tubules and subsequent cross-bridge cycling indicates a malfunction in the calcium release mechanism from the
sarcoplasmic reticulum, which is the intermediary step required for myosin-actin interaction. This step must be completed before myosin can bind to actin.
Q10 QUESTION 10 OF 100
During a high-intensity interval training session, a kinesiologist observes that the Z-lines within the sarcomeres of a subject's vastus lateralis muscle are not moving
closer together, despite maximal voluntary effort. The subject's motor neuron firing rate is confirmed to be high. This lack of sarcomere shortening indicates a potential
failure in which specific step of the sliding filament theory?
A) ATP hydrolysis initiating cross-bridge detachment from actin.
B) Calcium release from the sarcoplasmic reticulum binding to troponin.
Page 4
