HESI A2 Anatomy & Physiology 2025/2026 –
Verified V1–V3 Questions with Expert Body
System Explanations
100% Verified V1–V3 Questions with Expert Body System Explanations 100 Questions –
Answers in red – Full Rationales
(Updated November 16, 2025 – Verified for HESI A2 2025/2026 Cycles)
INTEGUMENTARY SYSTEM (1–5)
1. What is the deepest layer of the epidermis? Stratum basale
Rationale: The stratum basale (basal cell layer) is the deepest epidermal layer, where mitosis
occurs. New keratinocytes are generated here and migrate upward through the stratum spinosum,
granulosum, lucidum (in thick skin), and corneum.
2. Which protein is primarily responsible for the strength of the dermis? Collagen
Rationale: Collagen fibers (type I) provide tensile strength and resistance to stretching. Elastin
provides elasticity. Dermal fibroblasts synthesize both.
3. The arrector pili muscles are stimulated by: Sympathetic nervous system
Rationale: Cold or fear triggers norepinephrine release → contraction of arrector pili → hair
erection (“goosebumps”) for heat conservation or emotional response.
4. The primary role of melanin in the skin is: UV radiation absorption
Rationale: Melanosomes in keratinocytes absorb UV rays, preventing DNA damage and skin
cancer. Melanocytes produce melanin via tyrosinase.
5. A second-degree burn involves damage to the: Epidermis and part of the dermis
, Rationale: Partial-thickness burn → blisters, pain, edema. Heals in 2–3 weeks via re-
epithelialization from hair follicles and sweat glands.
SKELETAL SYSTEM (6–10)
6. The bone that forms the base of the skull and contains the foramen magnum is the:
Occipital bone
Rationale: The occipital bone supports the cerebellum and allows passage of the spinal cord
through the foramen magnum.
7. The patella is classified as a: Sesamoid bone
Rationale: Sesamoid bones form within tendons to reduce friction and modify pressure. The
patella is the largest sesamoid in the quadriceps tendon.
8. The primary mineral component of bone matrix is: Hydroxyapatite (calcium phosphate)
Rationale: Ca₁₀(PO₄)₆(OH)₂ crystals provide compressive strength. 99% of body calcium is
stored in bone.
9. Longitudinal bone growth occurs at the: Epiphyseal plate
Rationale: Hyaline cartilage growth plate → chondrocyte proliferation → ossification. Closes at
puberty under estrogen influence.
10. The axial skeleton consists of: Skull, vertebral column, ribs, and sternum
Rationale: 80 bones; protects brain, spinal cord, and thoracic organs. Appendicular = limbs +
girdles (126 bones).
MUSCULAR SYSTEM (11–15)
Verified V1–V3 Questions with Expert Body
System Explanations
100% Verified V1–V3 Questions with Expert Body System Explanations 100 Questions –
Answers in red – Full Rationales
(Updated November 16, 2025 – Verified for HESI A2 2025/2026 Cycles)
INTEGUMENTARY SYSTEM (1–5)
1. What is the deepest layer of the epidermis? Stratum basale
Rationale: The stratum basale (basal cell layer) is the deepest epidermal layer, where mitosis
occurs. New keratinocytes are generated here and migrate upward through the stratum spinosum,
granulosum, lucidum (in thick skin), and corneum.
2. Which protein is primarily responsible for the strength of the dermis? Collagen
Rationale: Collagen fibers (type I) provide tensile strength and resistance to stretching. Elastin
provides elasticity. Dermal fibroblasts synthesize both.
3. The arrector pili muscles are stimulated by: Sympathetic nervous system
Rationale: Cold or fear triggers norepinephrine release → contraction of arrector pili → hair
erection (“goosebumps”) for heat conservation or emotional response.
4. The primary role of melanin in the skin is: UV radiation absorption
Rationale: Melanosomes in keratinocytes absorb UV rays, preventing DNA damage and skin
cancer. Melanocytes produce melanin via tyrosinase.
5. A second-degree burn involves damage to the: Epidermis and part of the dermis
, Rationale: Partial-thickness burn → blisters, pain, edema. Heals in 2–3 weeks via re-
epithelialization from hair follicles and sweat glands.
SKELETAL SYSTEM (6–10)
6. The bone that forms the base of the skull and contains the foramen magnum is the:
Occipital bone
Rationale: The occipital bone supports the cerebellum and allows passage of the spinal cord
through the foramen magnum.
7. The patella is classified as a: Sesamoid bone
Rationale: Sesamoid bones form within tendons to reduce friction and modify pressure. The
patella is the largest sesamoid in the quadriceps tendon.
8. The primary mineral component of bone matrix is: Hydroxyapatite (calcium phosphate)
Rationale: Ca₁₀(PO₄)₆(OH)₂ crystals provide compressive strength. 99% of body calcium is
stored in bone.
9. Longitudinal bone growth occurs at the: Epiphyseal plate
Rationale: Hyaline cartilage growth plate → chondrocyte proliferation → ossification. Closes at
puberty under estrogen influence.
10. The axial skeleton consists of: Skull, vertebral column, ribs, and sternum
Rationale: 80 bones; protects brain, spinal cord, and thoracic organs. Appendicular = limbs +
girdles (126 bones).
MUSCULAR SYSTEM (11–15)
