Detailed handwritten medical student notes on "SKIN AND ITS APPENDAGES" in the style of BD Chaurasia anatomy notes, written on ruled notebook paper with blue and black ink, some red ink for headings and important points. The notes should cover: TITLE (large underlined): SKIN & ITS APPENDAGES SECTION 1 - SKIN (THE INTEGUMENT): - Largest organ of body (~1.8 m²), 15-20% total body mass - Two main layers: EPIDERMIS (from ectoderm) and DERMIS (from mesoderm) - Hypodermis = subcutaneous fascia (adipose tissue lobules) SECTION 2 - LAYERS OF EPIDERMIS (mnemonic in box: "Grandma Lucy Gets Some Breakfast" or "Come Lets Get Sun Burned"): 1. Stratum Corneum - dead keratinized cells, outermost 2. Stratum Lucidum - only in thick skin (palms, soles) 3. Stratum Granulosum - keratohyalin granules 4. Stratum Spinosum - prickle cell layer, desmosomes 5. Stratum Basale - germinative layer, melanocytes SECTION 3 - DERMIS: - Papillary dermis (loose CT, dermal papillae) - Reticular dermis (dense irregular CT, collagen bundles) - Contains: blood vessels, lymphatics, nerve endings SECTION 4 - SKIN APPENDAGES (underlined red): ★ HAIR FOLLICLE & HAIR: - Invagination of epidermis - Parts: infundibulum, isthmus, bulb (matrix cells + dermal papilla) - Arrector pili muscle → goosebumps - Absent: palms, soles, lips, urogenital orifices ★ NAILS: - Nail plate (hard keratin) - Nail bed, nail matrix (lunula), nail fold - Eponychium (cuticle), hyponychium ★ SEBACEOUS GLANDS: - Holocrine secretion → SEBUM - Open into hair follicle (pilosebaceous unit) - Absent: palms, soles - Androgen-dependent ★ ECCRINE SWEAT GLANDS: - Merocrine secretion → watery sweat (99% H₂O) - Present all over body (esp. palms, soles, forehead) - Thermoregulation + excretion ★ APOCRINE SWEAT GLANDS: - Modified sweat glands → viscous secretion - Pheromones; carbohydrates, lipids, proteins - Found: axilla, groin, areola, external ear (ceruminous) - Become active at puberty SECTION 5 - FUNCTIONS OF SKIN (numbered list): 1. Protection (mechanical, UV, microbial barrier) 2. Thermoregulation 3. Sensation (Meissner's, Pacinian, Merkel's disc) 4. Vitamin D synthesis 5. Excretion (sweat) 6. Immunological (Langerhans cells) Small simple diagrams: cross-section of skin showing layers + hair follicle + sweat gland; nail anatomy diagram. Arrows and annotations. Neat student handwriting, some words underlined or circled for emphasis. Yellow highlighter on key terms.