A scientist wants to study how the body uses foods and fluids during a marathon run. This scientist is most likely a(n)

Correct Answer: A

Rationale: An exercise physiologist studies how the body functions during physical activity, like a marathon, focusing on metabolism, hydration, and energy use perfect for analyzing food/fluid utilization. A microscopic anatomist examines cellular structures, not whole-body processes. Regional physiologist isn't a standard term; physiology isn't typically region-specific here. Systemic anatomist studies structural systems, not dynamic function. Exercise physiology's emphasis on performance and metabolism, per scientific roles, makes 'a' correct.

Correct Answer: B

Rationale: MRI disadvantages include high cost (expensive machines) and need for shielding from strong magnetic fields, protecting nearby devices/patients. It doesn't release radiation (a, d), images are high-quality (not a), views all tissues (not c), and confinement is a minor issue. Cost and shielding, per imaging tech, make 'b' correct.

Correct Answer: A

Rationale: Muscle structure follows a hierarchy from largest to smallest: the whole muscle (e.g., biceps), encased by epimysium, contains fascicles bundles of fibers wrapped in perimysium. Each fascicle holds muscle fibers, single elongated cells in endomysium, visible under light microscopy. Within fibers, myofibrils, rod-like organelles, house sarcomeres, the contractile units. This sequence muscle (centimeters), fascicle (millimeters), fiber (micrometers), myofibril (nanometers) reflects anatomical nesting. Reversing fascicle and fiber misaligns bundles with cells, while placing myofibrils before fibers ignores their intracellular role. A whole muscle, spanning bone to bone, dwarfs fascicles (10-100 fibers), which outsize fibers (10-100 micrometers wide), containing hundreds of myofibrils. Dissection and electron microscopy confirm this descending scale, critical for understanding force transmission from sarcomeres to gross movement, distinguishing organizational levels in muscle physiology.

Correct Answer: C

Rationale: Muscles require regular movement to maintain their length and elasticity. Without stretching and contraction, they adapt to a shortened position due to immobility, losing their ability to elongate fully over time. This results in reduced elasticity, making them prone to stiffness and contractures. Longer and flexed muscles would imply active stretching, which doesn't occur without intervention. Fibrosis and spasticity suggest scarring or neurological overactivity, more common in specific conditions like cerebral palsy, not general immobility. Shorter and painful could occur, but pain isn't a universal outcome of disuse shortening and loss of elasticity are the primary physiological changes. This explanation underscores the need for exercise to preserve muscle function, aligning with the natural response of tissues to prolonged inactivity.

Correct Answer: C

Rationale: A CPM machine gently flexes and extends a joint post-surgery, like a knee replacement, to prevent stiffness and promote healing. The statement about resetting it to go faster and flex more suggests misunderstanding, as the machine's settings are calibrated by professionals to optimize recovery without overstraining the joint. Too much speed or flexion could damage tissues or delay healing. The other statements reflect humor, acceptance of rest periods, or comfort with the device, aligning with its use. Further teaching is needed to clarify that adjusting the CPM independently risks harm, emphasizing the importance of following prescribed parameters for safe, effective rehabilitation.