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
How is dermis connected to epidermis
Highly corrugated (ridges and grooves) dermo-epidermal junction
Two layers of dermis
Papillary layer (superficial) and reticular layer (deep)
The reticular layer of the dermis is…
Considerably thicker (than papillary layer) and features thick bundles of collagen fibres
Cell types and structures found in the dermis
Fibroblasts, mast cells, blood vessels, cutaneous sensory nerves and skin appendages
Mast cells function
Histamine containing cells of innate immune system
Hair follicles and sebaceous glands combine to form a
Pilosebaceous unit
Sebaceous glands release…
Glandular secretions into the hair follicle shaft via a holocrine mechanism
Hair follicles are associated with…
An arrector pili muscle to make the hair stand upright
Two types of sweat glands
Eccrine glands and apocrine glands
