8) Integumentary System Flashcards
What are the three layers of the skin?
- Epidermis: The outermost, continuously proliferating stratified squamous keratinized epithelium.
- Dermis: Fibrous and fibro-adipose connective tissue supporting the epidermis.
- Subcutaneous layer (Hypodermis): Loose connective tissue with adipose, underlying the skin.
What are the functions of the integumentary system?
Protection from mechanical, biological, chemical threats, UV radiation, and water loss.
Thermoregulation.
Moisture control.
Sensory organ.
Vitamin D production.
Excretion.
What are the differences between thick and thin skin?
Thick Skin: Contains all five epidermal layers, including the stratum lucidum. Found on palms and soles.
Thin Skin: Lacks stratum lucidum, contains sebaceous glands, and is present throughout the rest of the body.
Name the five layers of the epidermis (from top to bottom).
Stratum Corneum: Dead, flattened keratinocytes.
Stratum Lucidum: Present only in thick skin.
Stratum Granulosum: Keratinocytes produce keratin here.
Stratum Spinosum: Contains desmosomes giving a spiny appearance.
Stratum Basale: Single row of cuboidal/columnar cells; site of cell division.
What cells are found in the epidermis?
Keratinocytes: Most abundant, produce keratin.
Melanocytes: Produce melanin, located in the basal layer.
Langerhans’ Cells: Macrophages involved in immune response.
Merkel Cells: Sensory mechanoreceptors found at the epidermal-dermal junction.
What are the two layers of the dermis and their features?
Papillary Layer: Areolar connective tissue, highly vascularized, contains sensory nerves, capillaries, and dermal papillae.
Reticular Layer: Dense irregular connective tissue with collagen and elastic fibers; contains sweat glands, sebaceous glands, and nerves.
What is the role of the subcutaneous layer (hypodermis)?
Composed of areolar and adipose tissue.
Acts as a shock absorber and thermal insulator.
Stabilizes skin position.
Loosely attached to the dermis and underlying muscles.
What are the two types of sweat glands, and how do they differ?
Eccrine Glands: Found throughout the body; secrete watery sweat directly to the surface. Important for thermoregulation.
Apocrine Glands: Found in axillary and genital areas; secrete a milky product into hair follicles. Includes modified glands like ceruminous (earwax) and mammary (milk).
What is the role of melanocytes?
Found in the stratum basale.
Produce melanin, which protects against UV radiation.
Have a stable population with low turnover.
What are the key structures of the hair follicle?
Hair Shaft: Extends above the skin.
Hair Root: Embedded within the skin.
Hair Bulb: Base of the follicle, contains hair papilla with blood vessels.
Hair Matrix: Actively dividing cells for hair growth.
Describe the structure and function of sebaceous glands.
Located in the dermis, associated with hair follicles.
Secretes sebum to lubricate and waterproof the skin and hair.
Sebum also inhibits microbial growth.
What structures are associated with the hair follicle?
Sebaceous Glands: Produce sebum to lubricate hair.
Arrector Pili Muscle: Causes goosebumps when contracted.
What is the function of sebaceous glands?
Secrete sebum to lubricate skin and hair, prevent drying, and provide antimicrobial protection.
What type of gland are sebaceous glands?
Holocrine glands, releasing sebum by rupturing cells.
Where are sebaceous glands not found?
Palms and soles (thick skin areas).
