ATI RN
Multiple Choice Questions Muscular System Questions
Question 1 of 5
What information is contained in the muscle name biceps brachii ?
Correct Answer: A
Rationale: Biceps brachii encodes two origins ( bi- ) two tendon heads on the scapula and location ( brachii ) on the arm's humerus. Action (flexion) isn't specified, nor is size (e.g., maximus) or shape (e.g., deltoid). This origin-location naming, common in muscles like triceps, aids anatomical mapping, distinguishing it from action- or shape-based names, reflecting skeletal muscle's attachment-based classification.
Question 2 of 5
Which of the following is the smallest unit in a muscle?
Correct Answer: B
Rationale: Myosin, a protein molecule (160 nm), forms thick myofilaments within sarcomeres, inside myofibrils, within muscle fibres (cells), grouped into fasciculi. As a molecular component, myosin is the smallest unit, distinguishing it from larger structural assemblies, foundational to contraction mechanics.
Question 3 of 5
What is the protein of thick myofilaments in a skeletal muscle cell?
Correct Answer: B
Rationale: Thick myofilaments in sarcomeres are composed of myosin, a motor protein with heads forming cross-bridges to actin during contraction. Actin forms thin myofilaments with tropomyosin and troponin, while acetylcholine is a neurotransmitter, not a filament component. Myosin's bundled structure, comprising about 300 molecules per filament, drives the sliding filament mechanism, distinguishing it as the thick filament's core protein, critical for muscle force generation and movement.
Question 4 of 5
What are the muscles known as gluteus maximus, gluteus medius and gluteus minimus named according to? Their:
Correct Answer: A
Rationale: Gluteus maximus, medius, and minimus are named for size largest, middle, smallest among buttock muscles. Shape (e.g., trapezius), whimsy (e.g., sartorius), or fibre direction (e.g., rectus) aren't indicated. Size-based naming distinguishes them, reflecting relative mass critical for hip function and anatomical clarity.
Question 5 of 5
What is the source of the ATP used by muscles for vigorous activity that may last for 10 to 15 seconds?
Correct Answer: D
Rationale: For 10-15 seconds of vigorous activity, creatine phosphate rapidly phosphorylates ADP to ATP, sustaining high-intensity effort beyond stored ATP (seconds). Glycolysis (minutes) and aerobic respiration (long-term) are slower. This quick energy buffer distinguishes creatine phosphate's role, vital for short bursts like sprinting.