PHAR 1002 Lecture Notes - Lecture 15: Melanoma, Subcutaneous Tissue, Itch
Document Summary
Integumentary system: consists of skin and associated organs. Largest organ in the body: accounts for 7-8% of body weight. Most vulnerable part of the body -- continually exposed to chemicals, trauma, and infection. Few infectious organisms can penetrate the skin on their own. Use accidental breaks or rely on animals such as ticks and mosquitos. Blood receives 1-2% of o2 from diffusion. Withstands the toxic pollution of modern life. Sheds is superficial cells and renews them continually throughout life. Outer layer of epidermis: stratum corneum: layer of compact, dead cells packed with keratin. Keratin: tough, scaly protein that makes up hair and nails. Dandruff: clumps of dead cells stuck together with sebum: oil from sebaceous glands. Stratum lucidum: thin layer of translucent layer cells on the thick skin of palms, soles, fingers, and toes - filled with keratinocytes. Stratum granulosum: keratinocytes produce a fatty mixture that covers the surface of cells and waterproofs them.
