Muscle Contraction
This phase of a muscle twitch occurs between stimulation and the start of contraction.
A) Contraction period
B) Relaxation period
C) Latent period
D) Action potential phase
This high-energy molecule provides the initial ATP for muscle contractions.
A) Glycogen
B) Creatine phosphate
C) Lactic acid
D) Myoglobin
This fiber type is best suited for endurance activities.
A) Fast glycolytic (FG) fibers
B) Slow oxidative (SO) fibers
C) Fast oxidative (FO) fibers
D) Mixed muscle fibers
The type of contraction where tension increases but the muscle does not shorten.
A) Isometric contraction
B) Concentric contraction
C) Eccentric contraction
D) Tonic contraction
Smooth muscle is found in these structures.
A) Skin, tendons, ligaments
B) Organs, blood vessels, digestive tract
C) Bone marrow, joints, fascia
D) Cardiac tissue, veins, lymph nodes
The neurotransmitter that triggers an action potential in muscle cells.
A) Dopamine
B) Acetylcholine
C) Serotonin
D) Epinephrine
This anaerobic process produces 2 ATP per glucose molecule.
A) Glycolysis
B) Krebs cycle
C) Electron transport chain
D) Beta oxidation
This fiber type is powerful but fatigues quickly.
A) Slow oxidative (SO) fibers
B) Fast oxidative (FO) fibers
C) Fast glycolytic (FG) fibers
D) Myosin-heavy fibers
What is motor unit recruitment?
A) Increasing the number of muscle fibers per motor neuron
B) The process of activating more motor units to increase muscle strength
C) The process of decreasing muscle response
D) Blocking synaptic transmission
How does smooth muscle contraction differ from skeletal muscle contraction?
A) It is slower, involuntary, and can sustain tension longer
B) It is voluntary and fast
C) It does not require calcium
D) It fatigues quickly
The process where calcium release leads to actin-myosin binding.
A) Cross-bridge cycling
B) Depolarization
C) Tetany
D) Excitation-contraction uncoupling
This energy pathway produces the most ATP but requires oxygen.
A) Glycolysis
B) Phosphagen system
C) Aerobic respiration
D) Fermentation
Which fiber type is intermediate in function?
A) Slow oxidative (SO) fibers
B) Fast oxidative (FO) fibers
C) Type I fibers
D) Type IIx fibers
The two types of isotonic contraction.
A) Concentric and eccentric
B) Isometric and isokinetic
C) Twitch and tetanus
D) Fast and slow
What are the effects of endurance training on muscle fibers?
A) Increases mitochondria, improves oxygen use, enhances endurance
B) Causes muscle hypertrophy
C) Decreases ATP production
D) Reduces overall muscle function
Why can’t cardiac muscle experience tetany?
A) It has a short contraction phase
B) It lacks a sarcoplasmic reticulum
C) Because of a long refractory period
D) It does not rely on calcium for contraction
How long does creatine phosphate provide energy?
A) 30 seconds
B) 10-15 seconds
C) 5 minutes
D) 1 hour
What determines a person’s muscle fiber composition?
A) Age
B) Training
C) Genetics and training
D) Diet
What causes muscle fatigue?
A) Increased ATP production
B) Lack of ATP, ion imbalances, and metabolic waste buildup
C) Overproduction of creatine phosphate
D) Decrease in calcium levels only
How does resistance training affect muscle fibers?
A) Increases muscle size and strength by promoting hypertrophy
B) Converts slow fibers to fast fibers
C) Increases ATP use
D) Weakens tendons
What is the difference between incomplete and complete tetanus?
A) Complete tetanus results in a sustained contraction with no relaxation
B) Incomplete tetanus leads to paralysis
C) Incomplete tetanus only occurs in smooth muscle
D) Complete tetanus only occurs in cardiac muscle
What happens when a muscle runs out of ATP?
A) It stops contracting and enters rigor mortis
B) It switches to anaerobic respiration
C) It becomes hyperactive
D) It absorbs more calcium
Which type of respiration do slow oxidative fibers primarily use?
A) Anaerobic glycolysis
B) Aerobic respiration
C) Lactic acid fermentation
D) Phosphagen system
Which muscle fibers fatigue the fastest?
A) Slow oxidative (SO) fibers
B) Fast oxidative (FO) fibers
C) Fast glycolytic (FG) fibers
D) Mixed fibers
Name one benefit of regular exercise for muscle function.
A) Increases strength, endurance, or metabolic efficiency
B) Reduces ATP production
C) Decreases blood flow
D) Weakens muscle fibers