BIOL 129 Lecture Notes - Lecture 1: Stratum Granulosum, Stratum Spinosum, Stratum Basale
Document Summary
The study of the structure of living things. Greek: ana - up ; tomy - to cut . Includes: (1) cutaneous membrane: skin (2) accessory organs: hair, nails, glands embedded in skin. Largest, most accessible organ of the body. Constantly abraded, attached by microorganisms, irradiated by sunlight, exposed to environmental chemicals. Protection: from pathogens via acidic mantle, resistance to trauma and infections, uv protection via melanin; protection from dehydration/water evaporation, abrasion, harsh chemicals. Vitamin d synthesis: dehydrocholesterol in the blood and is converted to cholecalciferol in the skin. Vitamin d is essential for calcium absorption. Sensory transmission/perception: higher concentration of nerve endings in sensitive areas (face, palms, fingertips, etc. ) Nonverbal communication: skin displays our emotions (embarrasses red face; scared white face) Thermoregulation: help maintain body temperature by altering blood flow to skin. Does so via thermoreceptors which transmit signals to brain; back to dermal vessels. Less blood flow to skin, less heat escapes the body.
