ATI RN
Muscular System Questions Questions
Question 1 of 5
Identify a muscle that flexes the vertebral column.
Correct Answer: A
Rationale: Rectus abdominis, along the abdomen, flexes the vertebral column, bending the spine forward, as in sit-ups. Serratus anterior protracts scapula. Sternocleidomastoid flexes the neck, not full column. Trapezius extends the head or adducts scapula. Rectus abdominis' anterior pull distinguishes it, key for trunk flexion, unlike scapular or neck-specific actions.
Question 2 of 5
What is the significance of the A band during muscle contraction?
Correct Answer: B
Rationale: The A band in a sarcomere represents the region containing thick myosin filaments, overlapping with thin actin filaments in striated muscle. During contraction, the sliding filament theory explains that actin slides over myosin, shortening the sarcomere as Z lines draw closer. However, the A band's length defined by the fixed length of myosin filaments remains constant. The I band (actin-only) and H zone (myosin-only) shrink as overlap increases, but the myosin span doesn't change, keeping the A band stable. Z lines anchor actin, not define the A band, and actin-only regions are the I band, not A. This unchanged A band length is a key feature in muscle mechanics, reflecting the structural integrity of myosin and the dynamic overlap driving contraction, a fundamental concept in understanding sarcomere function.
Question 3 of 5
Which of the following statement about cervical vertebrae [when comparing with thoracic vertebrae] is FALSE?
Correct Answer: B
Rationale: Cervical vertebrae (C1-C7) differ from thoracic (T1-T12). They have smaller bodies, supporting the lighter head versus the thorax's trunk. Their spinous processes are shorter (except C7), aiding neck mobility, unlike thoracic's longer, downward-slanting ones for muscle attachment. Transverse processes are shorter but feature foramina transversaria for arteries, unlike thoracic's longer ones. However, cervical vertebrae have larger vertebral foramina to accommodate the spinal cord's cervical enlargement, not smaller this supports greater nerve output for upper limbs. The false statement is smaller foramina, as cervical design prioritizes cord space, distinguishing it from thoracic structure.
Question 4 of 5
What nutritional strategies will not improve performance during prolonged endurance type exercise?
Correct Answer: B
Rationale: Tapering, reducing training volume pre-event, preserves energy and aids recovery but doesn't directly enhance fuel availability or use during prolonged endurance exercise, unlike nutritional strategies. Carbohydrate loading and the classic regime (depletion then high-carb intake) boost muscle glycogen stores, extending endurance. Exogenous carbohydrate ingestion during exercise (e.g., gels) maintains blood glucose, delaying fatigue. Tapering's rest focus, while beneficial for freshness, lacks the direct substrate impact of carb-based methods, distinguishing it as less performance-enhancing in fuel terms, key for endurance optimization.
Question 5 of 5
The location of a muscle s insertion and origin can determine
Correct Answer: A
Rationale: A muscle's origin (fixed) and insertion (mobile) determine its action e.g., biceps originates on scapula, inserts on radius, flexing the elbow. Force depends on fiber type and size, not just attachments. Muscle names (e.g., flexor carpi) may reflect action or location, but origin-insertion directly dictates motion, not naming convention. Load capacity ties to training and physiology, not solely attachment points. Action derives from how bones move relative to these points, distinguishing it as the primary outcome, key for movement mechanics.