PHSI3012 Lecture Notes - Lecture 4: Stratum Corneum, Keratinocyte, Dermis

• School: University of Sydney
• Department: Physiology
• Course: PHSI3012
• Professor: any

Document Summary

The keratinocyte differentiation programme (occurring in upper layer) is a slow, coordinated process which allows the formation of a layer of dead cells (corneocytes) to create a physical barrier for the skin. Major cell in epidermis: keratinocytes: differentiate as they move up the layers of epidermis to form outer cornified layer. To outline the electromagnetic spectrum of sunlight and the effect of ozone on. Effect of the atmosphere: ozone absorbs ~everything between 200-290 nm and some in uvb range, decreases in depth of ozone layer lead to increased uvb, at lower atmosphere: Scattering, absorption by atmospheric particles and clouds. Short l (lambda) attenuated > long l. Distance travelled alters spectrum: time of day (uva altered < uvb, altitude -20% > uv than at sea level. Uv penetration: schematic diagram of penetration of various wavelengths of em radiation, wavelengths below 290nm are cut out by ozone layer and do not reach the earth"s surface.