Test Muscular System

Question 1

What are the three types of muscles?
a) Skeletal muscle, Smooth muscle, Cardiac muscle
b) Voluntary muscle, Involuntary muscle, Striated muscle
c) Somatic muscle, Autonomic muscle, Reflex muscle
d) Flexor muscle, Extensor muscle, Stabilizing muscle

Answer 1

a

Question 2

Which nervous system innervates skeletal muscle?
a) Autonomic nervous system
b) Somatic nervous system
c) Sympathetic nervous system
d) Parasympathetic nervous system

Answer 2

b

Question 3

What gives skeletal muscle its striated appearance?
a) The presence of mitochondria
b) Sarcomeres (arrangement of actin and myosin into repeating units)
c) Dense connective tissue
d) The fusion of muscle fibers

Answer 3

b

Question 4

Why is skeletal muscle multinucleated?
a) Each fiber develops multiple nuclei during contractions
b) It undergoes mitosis frequently
c) It is formed as individual muscles fuse into long rods during development
d) It absorbs nuclei from surrounding cells

Answer 4

c

Question 5

What characterizes red fibers (slow-twitch fibers)?
a) High myoglobin content, derive energy aerobically, contain many mitochondria
b) Low oxygen demand, primarily use glycolysis
c) Quick contraction but fatigue rapidly
d) Low mitochondrial density and high ATP reserves

Answer 5

a

Question 6

What characterizes white fibers (fast-twitch fibers)?
a) High myoglobin, slow to fatigue
b) Less myoglobin, less iron, lighter color, can contract rapidly but fatigue quickly
c) High oxygen consumption, used for endurance
d) Contain more mitochondria than red fibers

Answer 6

b

Question 7

What is the function of tendons?
a) Anchor muscle to bones
b) Connect muscle to muscle
c) Provide electrical stimulation to muscles
d) Store calcium for muscle contractions

Answer 7

a

Question 8

What is a sarcomere?
a) The storage unit for calcium in muscle cells
b) The fluid-filled cavity in muscle fibers
c) The basic contractile unit of skeletal muscle
d) A type of nerve that signals muscle contraction

Answer 8

c

Question 9

What are the thick filaments in a sarcomere made of?
a) Bundles of myosin
b) Strands of actin
c) Overlapping layers of troponin
d) Collagen fibers

Answer 9

a

Question 10

What are the thin filaments in a sarcomere made of?
a) Myosin
b) Actin, troponin, tropomyosin
c) Elastin and keratin
d) Sarcoplasmic reticulum proteins

Answer 10

b

Question 11

What role does titin play in muscle structure?
a) Acts as a spring, anchors actin & myosin filaments together
b) Provides ATP for contractions
c) Signals muscle fatigue
d) Forms the contractile filaments

Answer 11

a

Question 12

What is the Z-line in a sarcomere?
a) The boundary of each sarcomere
b) The point where actin and myosin overlap
c) The storage area for calcium ions
d) The thickest part of the muscle fiber

Answer 12

a

Question 13

What is the A-band in a sarcomere?
a) The central part where only thin filaments exist
b) The full thick filaments with any overlap with thin filaments
c) The segment that disappears during contraction
d) The region where calcium is stored

Answer 13

b

Question 14

What happens to the A-band during muscle contraction?
a) It remains constant in size
b) It disappears
c) It shortens significantly
d) It expands to twice its original size

Answer 14

a

Question 15

What is myogenic activity?
a) Muscle contraction triggered only by nerve impulses
b) Contraction of smooth muscle without nervous system input
c) The ability of muscles to generate ATP without oxygen
d) The involuntary contraction of skeletal muscles

Answer 15

b

Question 16

Where is smooth muscle found?
a) Heart, diaphragm, kidneys
b) Respiratory tree, digestive tract, bladder, uterus, blood vessel walls
c) Skeletal muscles, tendons, ligaments
d) Brain, spinal cord, nervous tissue

Answer 16

b

Question 17

What is the role of intercalated discs in cardiac muscle?
a) Store calcium for muscle contractions
b) Anchor the muscle fibers to the bone
c) Generate electrical impulses for heart contractions
d) Contain gap junctions allowing rapid & coordinated depolarization

Answer 17

d

Question 18

What is the primary function of cardiac muscle?
a) Involuntary contraction
b) Rapid voluntary contraction
c) Providing structural support for the heart
d) Storing oxygen for the body

Answer 18

a

Question 19

What initiates depolarization in cardiac muscle?
a) The vagus nerve
b) SA node
c) The spinal cord
d) The bundle of His

Answer 19

b

Question 20

Which neurotransmitter slows the heart rate?
a) Dopamine
b) Acetylcholine from the vagus nerve
c) Norepinephrine
d) Serotonin

Answer 20

b

Question 21

What effect does norepinephrine have on the heart?
a) Increases heart rate and greater contractility
b) Decreases heart rate and weakens contractions
c) Causes the heart to stop beating
d) Reduces blood pressure by relaxing the heart

Answer 21

a

Question 22

Fill in the blank: Calcium release from the _______ triggers muscle contraction.
a) Mitochondria
b) Sarcoplasmic reticulum
c) Golgi apparatus
d) Nucleus

Answer 22

B

Question 23

What happens when acetylcholine binds to the sarcolemma?
a) Closes Na channels, stopping an action potential
b) Opens Na channels, starting an action potential
c) Releases calcium from the nucleus
d) Triggers immediate muscle relaxation

Answer 23

b

Question 24

What is the sarcoplasmic reticulum?
a) Modified ER covering that surrounds the myofibrils
b) A layer of connective tissue around muscles
c) The energy powerhouse of muscle cells
d) A neurotransmitter involved in muscle contractions

Answer 24

a

Question 25

What is the role of T-tubules? a) Store calcium for later use b) Propagate action potentials and distribute them to all sarcomeres c) Prevent muscle contractions d) Transport oxygen to the muscle fibers

Answer 25

b

Question 26

What occurs after calcium ions bind to troponin? a) Tropomyosin is moved out of the way, allowing myosin to bind to actin b) ATP is immediately hydrolyzed c) The muscle enters a resting state d) Actin becomes deactivated

Answer 26

a

Question 27

What is tonus in smooth muscle? a) A constant state of low-level contractions b) A single muscle twitch c) Rapid, repeated contractions d) The inability to contract

Answer 27

a

Question 28

What is tetanus in muscle contraction? a) A single brief muscle contraction b) Muscle is unable to relax due to too frequent contractions c) The relaxation phase of muscle activity d) The response of a muscle to an external shock

Answer 28

b

Question 29

What is the latent period in muscle contraction? a) The phase when the muscle is fully relaxed b) The time between reaching the threshold and the onset of contraction c) The moment when calcium is fully depleted d) When the sarcomere is at maximum contraction

Answer 29

b

Question 30

What is a simple twitch? a) A prolonged and strong contraction b) Response of a single muscle fiber to a brief stimulus at the threshold or above it c) The fusion of multiple contractions d) A failure to respond to a stimulus

Answer 30

b

Question 31

What is frequency summation? a) A single, isolated muscle contraction b) The breakdown of ATP for energy c) Frequent and prolonged contractions combined and become stronger and more prolonged d) A muscle fiber returning to rest

Answer 31

c

Question 32

What happens to the sarcolemma during relaxation? a) It depolarizes b) It repolarizes c) It stores calcium for contraction d) It contracts the muscle fiber

Answer 32

b

Question 33

What happens to acetylcholine during relaxation? a) It binds to myosin b) It remains active in the synapse c) It gets degraded by acetylcholinesterase d) It moves calcium back into the sarcoplasmic reticulum

Answer 33

c

Question 34

What happens on the sarcolemma when acetylcholine is released? a) Na channels open and Na enters the muscle cell b) Ca channels close c) The muscle immediately relaxes d) ATP is stored in myosin

Answer 34

a

Question 35

Till where do these Na channels open? a) The mitochondria b) Till the T-tubule c) The Golgi apparatus d) The synaptic cleft

Answer 35

b

Question 36

What happens when calcium is released from the sarcoplasmic reticulum? a) It binds to actin, enabling myosin to bind b) It attaches to troponin, which moves tropomyosin and exposes the actin for myosin to bind c) It binds to tropomyosin, allowing actin to bind with myosin d) It attaches to myosin, triggering the power stroke of contraction

Answer 36

b

Question 37

What happens when ATP attaches to myosin? a) Myosin binds tightly to actin b) Myosin detaches from the actin c) The sarcomere contracts immediately d) Calcium is released into the nucleus

Answer 37

b

Question 38

What happens to myosin when it hydrolyzes ATP? a) It enters a high-energy state b) It detaches from actin permanently c) It becomes inactive d) The actin filament disappears

Answer 38

a

Question 39

How does myosin bring back and push on actin? a) It does this when the phosphate group is released b) By directly using calcium c) By storing ATP in the nucleus d) By attaching to troponin

Answer 39

a

Question 40

What happens to actin when calcium is present? a) It immediately contracts without myosin b) Calcium binds to troponin, which loosens tropomyosin and opens actin for myosin to bind c) The muscle enters a state of relaxation d) Actin molecules break down ATP

Answer 40

b