MCQ on Muscular System

🟢 Easy Level (1–20)

1. Which type of muscle is voluntary?
   A) Cardiac
   B) Smooth
   C) Skeletal ✅
   D) Involuntary
   Explanation: Skeletal muscles are under conscious control.
2. Which muscle type is found in the heart?
   A) Skeletal
   B) Smooth
   C) Cardiac ✅
   D) Voluntary
   Explanation: Cardiac muscle is specialized and involuntary, found only in the heart.
3. Which muscle type is involuntary and non-striated?
   A) Skeletal
   B) Smooth ✅
   C) Cardiac
   D) Voluntary
   Explanation: Smooth muscle is found in internal organs like intestines and blood vessels.
4. Which protein is responsible for muscle contraction?
   A) Hemoglobin
   B) Insulin
   C) Actin and myosin ✅
   D) Keratin
   Explanation: Actin and myosin filaments slide past each other during contraction.
5. Which of the following muscles is under conscious control?
   A) Heart
   B) Intestine
   C) Biceps ✅
   D) Lungs
   Explanation: Biceps are skeletal muscles controlled voluntarily.
6. Where are smooth muscles found?
   A) Arms
   B) Lungs
   C) Intestines ✅
   D) Heart
   Explanation: Smooth muscles line hollow internal organs.
7. Cardiac muscle is:
   A) Voluntary and striated
   B) Involuntary and non-striated
   C) Involuntary and striated ✅
   D) Voluntary and non-striated
   Explanation: Cardiac muscle is striated like skeletal muscle but functions involuntarily.
8. The basic unit of a muscle fiber is the:
   A) Myosin
   B) Sarcomere ✅
   C) Actin
   D) Fiber
   Explanation: Sarcomeres are the structural units where contraction occurs.
9. Which connective tissue surrounds individual muscle fibers?
   A) Perimysium
   B) Epimysium
   C) Endomysium ✅
   D) Myofibril
   Explanation: Endomysium encases each individual muscle fiber.
10. Which muscle contracts when you smile?
    A) Deltoid
    B) Biceps
    C) Zygomaticus ✅
    D) Masseter
    Explanation: The zygomaticus pulls the mouth’s corners upward.
11. Muscles are attached to bones by:
    A) Ligaments
    B) Cartilage
    C) Tendons ✅
    D) Fascia
    Explanation: Tendons connect muscle to bone.
12. What is the function of the diaphragm?
    A) Heartbeat
    B) Digestion
    C) Breathing ✅
    D) Blinking
    Explanation: The diaphragm helps in the mechanics of inhalation.
13. Which of the following is a facial muscle?
    A) Triceps
    B) Masseter ✅
    C) Deltoid
    D) Quadriceps
    Explanation: The masseter assists in chewing.
14. Which muscle group is found in the front of the thigh?
    A) Hamstrings
    B) Triceps
    C) Quadriceps ✅
    D) Gluteals
    Explanation: Quadriceps extend the knee.
15. Which muscle helps in arm abduction?
    A) Biceps
    B) Trapezius
    C) Deltoid ✅
    D) Pectoralis major
    Explanation: Deltoid lifts the arm away from the body.
16. Muscle contraction requires which energy molecule?
    A) DNA
    B) ATP ✅
    C) RNA
    D) Glucose
    Explanation: ATP provides energy for muscle contraction.
17. Which muscle is known as the calf muscle?
    A) Sartorius
    B) Hamstring
    C) Gastrocnemius ✅
    D) Tibialis
    Explanation: The gastrocnemius forms the bulk of the calf.
18. Which type of muscle tires the fastest?
    A) Cardiac
    B) Smooth
    C) Skeletal ✅
    D) Involuntary
    Explanation: Skeletal muscles fatigue faster than the other types.
19. Muscles that work in pairs are called:
    A) Antagonistic ✅
    B) Cooperative
    C) Agonistic
    D) Flexors
    Explanation: One muscle contracts while the other relaxes.
20. Which is the longest muscle in the human body?
    A) Biceps
    B) Sartorius ✅
    C) Rectus abdominis
    D) Triceps
    Explanation: Sartorius runs from the hip to the knee.

🟡 Moderate Level (21–40)

21. Which part of the sarcomere shortens during contraction?
    A) Z-line
    B) H-zone ✅
    C) A-band
    D) Myofibril
    Explanation: The H-zone narrows as actin and myosin overlap.
22. The neurotransmitter at the neuromuscular junction is:
    A) Dopamine
    B) GABA
    C) Acetylcholine ✅
    D) Serotonin
    Explanation: Acetylcholine initiates muscle contraction.
23. The muscle responsible for blinking is the:
    A) Masseter
    B) Orbicularis oculi ✅
    C) Buccinator
    D) Zygomaticus
    Explanation: Orbicularis oculi closes the eyelids.
24. Which is a flexor muscle of the forearm?
    A) Triceps
    B) Biceps ✅
    C) Deltoid
    D) Latissimus dorsi
    Explanation: Biceps help bend the elbow.
25. The sliding filament theory involves interaction between:
    A) Tendons and bones
    B) Actin and myosin ✅
    C) Ligaments and tendons
    D) Calcium and potassium
    Explanation: Muscle contraction results from actin sliding over myosin.
26. The point where a muscle attaches to a stationary bone is called the:
    A) Insertion
    B) Origin ✅
    C) Joint
    D) Belly
    Explanation: Origin is the fixed attachment point.
27. Tetanus in muscles refers to:
    A) Muscle paralysis
    B) Sustained contraction ✅
    C) Muscle growth
    D) Relaxation
    Explanation: Tetanus is continuous muscle contraction without relaxation.
28. What is the role of calcium in muscle contraction?
    A) Forms ATP
    B) Binds to troponin ✅
    C) Converts actin to myosin
    D) Inhibits contraction
    Explanation: Calcium binds to troponin to expose binding sites on actin.
29. Which enzyme breaks down acetylcholine?
    A) Amylase
    B) Acetylcholinesterase ✅
    C) Lipase
    D) Kinase
    Explanation: It terminates the signal at the neuromuscular junction.
30. Muscle fatigue is primarily caused by:
    A) Lack of oxygen ✅
    B) Muscle growth
    C) Excess protein
    D) Cold temperature
    Explanation: Anaerobic respiration leads to lactic acid buildup.
31. Which muscle stabilizes the shoulder joint?
    A) Deltoid
    B) Trapezius
    C) Rotator cuff muscles ✅
    D) Pectoralis
    Explanation: These muscles hold the humerus in place.
32. Which muscle elevates the mandible during chewing?
    A) Orbicularis oris
    B) Temporalis ✅
    C) Buccinator
    D) Platysma
    Explanation: Temporalis helps in mastication.
33. Which of these is a deep core muscle?
    A) External oblique
    B) Rectus abdominis
    C) Transverse abdominis ✅
    D) Gluteus maximus
    Explanation: Transverse abdominis stabilizes the spine.
34. Which mineral is crucial for muscle contraction?
    A) Iron
    B) Calcium ✅
    C) Magnesium
    D) Zinc
    Explanation: Calcium ions trigger the contraction process.
35. Which muscle helps in rotating the head?
    A) Deltoid
    B) Sternocleidomastoid ✅
    C) Trapezius
    D) Pectoralis
    Explanation: This muscle helps in head flexion and rotation.
36. Muscle tone refers to:
    A) Muscle mass
    B) State of partial contraction ✅
    C) Total contraction
    D) Flaccidity
    Explanation: Even relaxed muscles are slightly contracted.
37. Which is not a function of the muscular system?
    A) Movement
    B) Posture
    C) Heat production
    D) Hormone secretion ✅
    Explanation: Hormones are secreted by glands, not muscles.
38. Myoglobin in muscles stores:
    A) Glucose
    B) Oxygen ✅
    C) Carbon dioxide
    D) Nitrogen
    Explanation: Myoglobin binds oxygen for use during contraction.
39. A muscle that assists the prime mover is called a:
    A) Fixator
    B) Synergist ✅
    C) Antagonist
    D) Origin
    Explanation: Synergists aid in the movement.
40. What is a motor unit?
    A) One muscle
    B) One neuron and all the muscle fibers it controls ✅
    C) One sarcomere
    D) Muscle and bone
    Explanation: It includes a motor neuron and its associated muscle fibers.

🔴 Hard Level (41–50)

41. Which band remains constant during muscle contraction?
    A) A-band ✅
    B) I-band
    C) H-zone
    D) Z-line
    Explanation: A-band contains overlapping actin and myosin and stays the same.
42. Fast-twitch muscle fibers are best suited for:
    A) Endurance
    B) Marathon running
    C) Short bursts of strength and speed ✅
    D) Digestion
    Explanation: These fibers contract quickly and fatigue rapidly.
43. Which condition causes progressive muscle degeneration?
    A) Arthritis
    B) Muscular dystrophy ✅
    C) Rickets
    D) Myasthenia gravis
    Explanation: Muscular dystrophy is a genetic disorder.
44. Which receptor binds acetylcholine in muscles?
    A) Dopamine receptor
    B) Nicotinic receptor ✅
    C) Muscarinic receptor
    D) GABA receptor
    Explanation: Nicotinic receptors mediate skeletal muscle responses.
45. Rigor mortis occurs due to lack of:
    A) Oxygen
    B) Glucose
    C) ATP ✅
    D) Calcium
    Explanation: Without ATP, muscles remain contracted after death.
46. Creatine phosphate is used for:
    A) Muscle fatigue
    B) Prolonged contraction
    C) Short-term ATP regeneration ✅
    D) Muscle atrophy
    Explanation: It quickly donates phosphate to ADP.
47. Which filament is anchored to the Z-line?
    A) Myosin
    B) Actin ✅
    C) Tropomyosin
    D) Troponin
    Explanation: Actin is a thin filament attached at the Z-line.
48. Which disease affects neuromuscular transmission?
    A) Diabetes
    B) Osteoporosis
    C) Myasthenia gravis ✅
    D) Parkinson’s
    Explanation: It’s an autoimmune disorder affecting acetylcholine receptors.
49. Which organelle in muscle cells stores calcium?
    A) Mitochondria
    B) Sarcoplasmic reticulum ✅
    C) Nucleus
    D) Ribosome
    Explanation: It regulates calcium release for contraction.
50. During isotonic contraction:
    A) Muscle changes length ✅
    B) Tension doesn’t change
    C) Muscle doesn’t shorten
    D) No ATP is used
    Explanation: Isotonic contractions involve movement.