What is osteoporosis?

Correct Answer: A

Rationale: Osteoporosis is a condition where bones weaken and become brittle from reduced density, increasing fracture risk, often age-related or hormonal. It's not a fracture , infection (c, osteomyelitis), or joint disorder (d, arthritis). Its systemic bone loss, per pathology, makes 'a' correct.

Correct Answer: C

Rationale: The occipital bone forms the skull's base, with the foramen magnum for spinal cord exit, supporting the brain posteriorly. Temporal is lateral, frontal is anterior, maxilla is facial. Occipital's foundational role, per skull anatomy, makes 'c' correct.

Correct Answer: D

Rationale: The skeletal system provides structural support via bones and enables movement by anchoring muscles at joints (e.g., femur in walking). The cardiovascular system circulates blood, not support/movement. The endocrine system regulates via hormones. The muscular system moves but relies on skeletal framework. Skeletal system's foundational role, per body systems, makes 'd' correct.

Correct Answer: D

Rationale: Normal anatomical position is standing, facing forward, arms at sides, palms forward, feet together standard for describing anatomy (missing from options, assumed 'd'). Prone is face-down, arms aside. Option b is arms out, wide stance incorrect. Supine is face-up. 'd' aligns with convention, per anatomical terms, making it correct.

Correct Answer: B

Rationale: Muscle tissue is organized hierarchically, with fascicles bundles of muscle fibers encased by perimysium, a connective tissue sheath. This layer provides structural support, houses blood vessels and nerves, and separates fascicles within the muscle, facilitating coordinated contraction. Endomysium surrounds individual muscle fibers, a finer layer penetrating within fascicles. Epimysium envelops the entire muscle, integrating with tendons dense connective tissue linking muscle to bone. Deep fascia, a broader sheet, encases muscle groups externally, not specific fascicles. The perimysium's role is critical: its collagen and elastin composition balances flexibility and strength, protecting fascicles during stretching or contraction. Histological analysis reveals its thicker, more organized structure compared to endomysium's reticular fibers, distinguishing it from tendons' load-bearing function or epimysium's holistic coverage. Misidentifying these layers could obscure muscle organization, but perimysium's fascicle-specific wrapping is evident in dissections and biomechanical studies, underscoring its intermediate position in muscle anatomy.