PHAR 303 Lecture Notes - Lecture 18: Leukotriene, Phototoxicity, Furanocoumarin

• School: McGill University
• Department: Pharmacology and Therapeutics
• Course: PHAR 303
• Professor: Bernard Robaire

Document Summary

Epidermis: deep invaginations into dermis - rete ridges. Supplies hair follicles, bulbs, and sweat glands: nutrients reach epidermis by diffusion from capillaries in rete ridges. Terminal differentiation from base to surface ~4 weeks lifespan: basal (germinative) layer, keratinocytes: proliferative, melanocytes: melanin, strum spinosum: Langerhans cells: dendritic cells: merkel cells: mechanoreceptors, stratum granulosum, keratinocytes secrete lipids in intercellular spaces: moisture conservation, stratum corneum: corneocytes/squames. Flattened dead cells, always shedding (80% keratin content) First surface that meets compounds, agents, or potential toxicants. Acid mantle: thin layer of acidic oils (ph 4-6) on skin surface: protects from alkaline compounds, bacteria, fungi. Compromised sc --> enhanced uptake: abrasion or wound, high water content, moist, occluded areas. Thickness of sc affects penetration: thick sc: palm and sole (biggest risk of exposure to toxicants, thin skin: behind ears, eyelids. Amount of toxicant and length of exposure. Thermoregulation: heat dissipation or retention: capillaries: vasodilatation or vasoconstriction. Metabolism (type i and ii metabolic enzymes)