If one is stabbed on the lateral side of the abdomen, what abdominal muscles, in order from superficial to deep, will the knife go through?

Correct Answer: B

Rationale: On the lateral abdomen, the muscle layers from superficial to deep are external oblique, internal oblique, and transversus abdominis. The external oblique runs diagonally downward and medially, the internal oblique courses upward and medially, and the transversus abdominis runs horizontally, deepest of the three, compressing the abdomen. Rectus abdominis is midline, not lateral, so it's excluded. Other options misorder the layers or include incorrect muscles. External oblique, internal oblique, transversus abdominis is the correct sequence, as it follows the anatomical layering of the lateral abdominal wall, critical for surgical or assessments.

Correct Answer: B

Rationale: Smooth muscle operates without conscious control, managing essential involuntary functions. It lines the digestive tract, facilitating peristalsis to move food, and surrounds blood vessels, aiding in blood flow regulation not pumping, which is the heart's role, but still vital for circulation. Voluntary movements, like running, rely on skeletal muscle, not smooth muscle, which lacks the striations for such tasks. Claiming it controls all involuntary movements overstates its scope, as cardiac muscle handles heartbeats independently. 'None of the above' dismisses its clear role. Smooth muscle's involuntary nature and presence in visceral organs and vascular walls make it key for digestion and circulation support, distinguishing it from skeletal muscle's voluntary domain and cardiac muscle's specialized pumping, aligning with its physiological purpose across multiple systems.

Correct Answer: D

Rationale: Exercise strengthens muscles by stressing fibers, prompting growth and repair. Resistance training or cardio increases muscle mass, endurance, and power through repeated contraction and recovery. Diet and food provide nutrients protein, carbs but without exercise, they don't build strength directly, only support it. Sleeping aids recovery, allowing muscle repair, but doesn't actively strengthen. Exercise's mechanical stress triggers hypertrophy, enhancing fiber size and efficiency, unlike diet's passive fuel role or sleep's restorative one. Regular activity, like lifting or running, directly fortifies muscles, making it the primary driver, supported but not replaced by nutrition and rest, critical for physical capability.

Correct Answer: D

Rationale: Joints that are fibrous and immovable are classified as synarthroses, such as skull sutures, where dense connective tissue binds bones tightly, ensuring stability with no motion. Tendons connect muscles to bones, and tibia is a bone neither are joint types. Ligaments link bones, and femur is a bone, but this pairing doesn't define a joint category. Diarthrosis refers to freely movable synovial joints, like the knee, opposite to the question's intent. Synarthroses accurately describe fibrous, fixed joints, critical for structures requiring rigidity, like the cranium, distinguishing them from movable or cartilaginous joints in anatomical classification.

Correct Answer: C

Rationale: Myosin, the thick filament in sarcomeres, features cross-bridges protruding heads that bind actin during contraction. These bridges, powered by ATP, pull actin inward, driving the power stroke. Troponin, on thin filaments, binds calcium to regulate contraction, lacking bridges. Actin forms thin filaments, receiving cross-bridges, not bearing them. Tropomyosin shields actin's sites, also without bridges. Myosin's cross-bridges are unique, enabling force generation, distinguishing it from actin's structural role or troponin and tropomyosin's regulatory functions, essential for the sliding filament mechanism and muscle movement.