Skin Ultratissue Flashcards
Skin primary function
Provides a mechanical, chemical, osmotic, thermal and UV barrier. Also provides barriers against microbial infections
Skin secondary functions
Vitamin D synthesis, body temp regulation, psychosexual communication, touch stimuli
Glabrous skin - structure and location
Thick skin found on soles of feet, palms and flexor (inside) portions of fingers
Glabrous skin - structure and location
Hairless hard skin found on soles of feet, palms and inside portion of fingers
Three layers of skin (deep to superficial)
Hypodermis, dermis, epidermis
Epidermis structure
Mostly keratinocytes which undergo constant maturation due to increased keratin production. This is in a process called cornification
Non-keratinocyte cells in the epidermis
Melanocytes - produce melanin. Langerhan cells - antigen presenting dendritic cells. Merkel cells - sensory mechanoreceptors (think MLM)
Layers of epidermis (deep to superficial)
Stratum basale, spinosum, granulosum, lucidum, corneum
What happens in s.basale
Mitosis of keratinocytes
What happens in S spinosum
Keratinocytes are joined by intercellular junctions called desmosomes
What happens in S granulosum
Cells secrete lipids and other hydrophobic molecules
What happens in S lucidium
Cells lose nuclei and increase keratin production
What happens in S corneum
Cells lose all organelles and continue to produce keratin (cells are effectively dead)
What happens in S corneum
Cells lose all organelles and produce more keratin (become dead)
Lifespan of keratinocyte (how long it takes to go from S basale to S corneum)
30-40 days
