System Structure: Integumentary - Massage and Bodywork Licensing Examination Mblex
- Which epidermal cell functions in immune defense by presenting antigens in the skin?
- Langerhans cell (epidermal dendritic cell). Derived from bone marrow, these cells activate immune responses by processing and presenting antigens to T-cells in the skin.
- Which epidermal layer is composed of dead, flattened, fully keratinized cells?
- Stratum corneum. These anucleate cells form a protective barrier that prevents water loss and shields against environmental damage through constant shedding.
- Which glands produce watery sweat for thermoregulation and are widely distributed on the body?
- Eccrine (merocrine) sweat glands. These glands secrete a hypotonic solution via exocytosis to cool the body through evaporation, abundant on most skin surfaces.
- Which skin type lacks hair follicles and sebaceous glands: thick skin or thin skin?
- Thick skin. Found on palms and soles, it prioritizes thickness for protection over hair and oil production present in thin skin.
- Which two main layers make up the dermis, from superficial to deep?
- Papillary layer, reticular layer. The dermis is divided into these layers to provide superficial vascular support and deeper structural integrity.
- Which cutaneous receptor detects light touch and low-frequency vibration in glabrous skin?
- Meissner (tactile) corpuscle. Located in dermal papillae, these encapsulated neurons respond to transient, light stimuli for discriminative touch sensation.
- Which cutaneous receptor detects deep pressure and high-frequency vibration?
- Pacinian (lamellated) corpuscle. Deep in the dermis or hypodermis, their layered structure adapts to rapid pressure changes, transmitting vibrations to sensory nerves.
- What do sebaceous glands secrete, and what is the primary function of that secretion?
- Sebum; lubricates and waterproofs hair and skin. This oily mixture softens and protects against dryness, bacteria, and environmental factors on skin and hair surfaces.
- Which epidermal layer is characterized by desmosomes and a "spiny" appearance of cells?
- Stratum spinosum. Desmosomes connect cells here, providing tensile strength and resistance to shearing forces in the epidermis.
- What is the primary protein that contributes to the epidermis being tough and water resistant?
- Keratin. As a fibrous protein, it fills epidermal cells, creating a durable, impermeable layer that resists abrasion and dehydration.
- Which epidermal layer is present only in thick skin such as palms and soles?
- Stratum lucidum. It appears as a clear band in areas of high friction, aiding in additional protection and thickness where mechanical stress is greatest.
- What type of epithelium forms the epidermis?
- Keratinized stratified squamous epithelium. This tissue type provides a tough, protective barrier against mechanical damage, pathogens, and water loss due to its multiple layers of flattened, keratin-filled cells.
- Which epidermal cell produces melanin pigment that helps protect against ultraviolet radiation?
- Melanocyte. These cells synthesize melanin, which absorbs UV rays to prevent DNA damage in underlying tissues.
- What is the correct superficial-to-deep order of the five epidermal strata in thick skin?
- Corneum, lucidum, granulosum, spinosum, basale. This sequence reflects the maturation process of keratinocytes from basal division to surface desquamation in regions like palms and soles.
- What is the primary function of dermal papillae at the epidermal-dermal junction?
- Increase surface area for adhesion and nutrient diffusion. These projections enhance mechanical interlocking and facilitate exchange of nutrients and waste between dermis and avascular epidermis.
- What is the key structural difference between thick skin and thin skin?
- Thick skin has stratum lucidum and a thicker stratum corneum. Thick skin's additional lucidum layer and expanded corneum enhance durability in high-wear areas like palms and soles.
- Which epidermal cell type is a tactile receptor associated with sensory nerve endings?
- Merkel cell (tactile epithelial cell). Located at the epidermal-dermal junction, they function as mechanoreceptors for detecting fine touch and texture.
- Which sweat glands are associated with hair follicles in axilla and groin and become active at puberty?
- Apocrine sweat glands. Activated during puberty, they release a viscous secretion into hair follicles, influenced by hormones and contributing to body odor.
- What are the three primary layers of the integumentary system from superficial to deep?
- Epidermis, dermis, hypodermis (subcutaneous layer). These layers form the skin's structure, with the epidermis as the protective outer barrier, dermis providing strength and elasticity, and hypodermis offering insulation and anchorage.
- What is the hypodermis primarily composed of, and what is its main role?
- Adipose + areolar CT; insulation, cushioning, energy storage. Composed mainly of fat and loose fibers, it anchors skin to underlying structures while providing thermal regulation and shock absorption.
- What type of connective tissue predominates in the reticular layer of the dermis?
- Dense irregular connective tissue. Its irregular collagen bundles provide strength and resilience against multi-directional stresses in the deeper dermis.
- Which epidermal layer is the deepest and produces new keratinocytes by mitosis?
- Stratum basale (stratum germinativum). As the basal layer, it contains stem cells that divide to replenish the epidermis, ensuring continuous renewal of skin cells as they migrate upward.
- Which epidermal layer contains keratohyalin granules that support keratin formation?
- Stratum granulosum. Keratohyalin granules in this layer cross-link keratin fibers, contributing to the waterproofing and strengthening of the epidermal barrier.
- What type of connective tissue predominates in the papillary layer of the dermis?
- Areolar (loose) connective tissue. This loose arrangement allows for flexibility, nutrient diffusion, and houses capillaries that nourish the epidermis.