Integument Flashcards
What are the three main layers of the skin, and what are the primary functions of each layer?
• Epidermis: Stratified squamous epithelium; provides a protective barrier.
• Dermis: Connective tissue; provides tensile strength, sensory receptors, and vascular supply.
• Hypodermis: Loose connective tissue with adipocytes; anchors skin to underlying tissues and insulates.
Describe the structure and function of the stratum basale and its role in skin regeneration.
• Single cuboidal cell layer adjacent to the dermis.
• Contains dividing keratinocytes, melanocytes, and free nerve endings.
• Primary role: Continuous cell division to regenerate the epidermis.
Explain the characteristics and significance of the stratum corneum in thick skin compared to thin skin.
• Thick skin: Many layers of dead, keratinized cells; found on palms and soles.
• Thin skin: Fewer layers of keratinized cells; lacks the stratum lucidum.
• Significance: Enhanced protection against friction in thick skin areas.
What are the primary differences between the papillary and reticular layers of the dermis?
• Papillary Layer: Loose CT with fine collagen fibers; contains dermal papillae, capillaries, and sensory receptors.
• Reticular Layer: Dense, irregular CT with thicker collagen bundles; provides structural integrity and supports accessory structures.
Describe the structure and sensory function of Meissner’s corpuscle and its location within the skin layers.
• Oval, encapsulated nerve ending in the papillary dermis.
• Myelinated nerve fibers lose myelin and become ensheathed by collagenous fibrils.
• Detects light touch and texture.
What is the structural composition of a Pacinian corpuscle, and what type of stimuli does it detect?
• Onion-like lamellar structure with concentric rings of endoneurium and fluid.
• Located in the deep dermis and hypodermis.
• Detects deep pressure and vibration.
How do Ruffini corpuscles differ in structure and function compared to Meissner’s and Pacinian corpuscles?
• Smaller, encapsulated structures with a single axon that branches into multiple bulbs.
• Sensitive to skin stretch and sustained pressure.
• Located in the dermis.
Outline the anatomy and functional components of sweat glands, including the duct and secretory portion.
• Coiled tubular glands with a duct and secretory portion.
• Duct: Stratified cuboidal epithelium that transports sweat to the skin surface.
• Secretory portion: Pale pink columnar cells with contractile myoepithelial cells that push sweat toward the duct.
What is the role of myoepithelial cells in sweat glands, and how do they contribute to sweat secretion?
• Located around the secretory portion of the sweat gland.
• Contract to expel sweat through the duct to the skin surface.
Compare and contrast the structural differences between thick skin and thin skin in terms of epidermal layers and appendages.
• Thick Skin: Contains stratum lucidum, more layers of stratum corneum, lacks hair follicles and sebaceous glands.
• Thin Skin: Lacks stratum lucidum, thinner stratum corneum, contains hair follicles, sebaceous glands, and sweat glands.
Explain the process of hair growth, starting from the hair bulb to the emergence of the hair shaft.
• Hair bulb contains the dermal papilla and matrix cells.
• Matrix cells divide and keratinize to form the hair shaft.
• Hair shaft emerges from the follicle, composed of keratinized cells.
What are sebaceous glands, and how do they secrete sebum through holocrine secretion?
• Sac-like glands located in the dermis, associated with hair follicles.
• Cells accumulate lipids, disintegrate, and release sebum as they die.
How do arrector pili muscles function, and what physiological response do they produce in the skin?
• Smooth muscle bands that connect the dermal papilla to the hair follicle.
• Contract to raise hair and cause “goosebumps,” squeezing sebum from sebaceous glands.
Describe the anatomical structure of the nail, including the nail plate, matrix, and associated layers.
• Nail plate: Keratinized structure extending from the matrix to the free edge.
• Matrix: Source of new nail cells.
• Eponychium: Skin at the proximal nail fold.
• Hyponychium: Skin under the distal nail edge.
What is the clinical significance of the hypodermis, and how does it contribute to thermoregulation and structural support?
• Composed of loose CT and adipocytes.
• Anchors skin to underlying tissues, insulates body, and stores fat for energy.
