Histology General principles of skin
Role of skin Protection antive and passive Cooling Vit d production Sensort
Layers of skin
Epidermis Primery cell keratinocytes Other cells Langerhans Merkel cells Melanocytes
Stratum corneum
No organelles
Cells are flattened
d
Stratum lucidum (sometiems)
Stratum granulosum
Gransules interact with tonofibrils in keratinisation to connect and dehydrate
Hydrophobic glycophospholipid in keratinocyte hyaline grandules to make water barrier
Cells are flattening
Stratum spinosum
Tonofibres are formed by desmosomes??
Connected by desmosomes
Cytoplasm has melanosomes
Langerhans are present
Stratom basale
Stems cells and epidermal cellular proliferation
Basal keratinocytes are in contact with the basal lamina lamina lucida and lamina densa
Cytoplasm has melanosomes
Desmosomes connect keratinocytes to each other
Hemidesmosomes connect keratinocytes to basal lamina
Other cells of the skin Melanocytes Present on the basal lamina Produce melanin pigment No desmosome connection But has hemidesmosome connection
Langerhans Immune function Found in basal and spiny layers
Merkels cells (tactile) Has desmosome connections Sensory nerve ending On basal lamina
Dermis Made of irregular but dense CT Collagen and elastin Ground substance Glycosaminoglycans Glycoproteins and water GLANDS
Papillary Collagen type 3 fine and loose Rete ridges which interdigiate with rete pegs Meissners corpuscles
Reticular Tightly packed collagen Collagen type 2 thick and irregular Pacinian corpuscles
Hypodermis Ct deeper than dermis Mainly adipose Vasculature of BNL Also gland i think
Accessory structures Hairsensory and thermoreg Errector pili erect hair and squeeze sebacous gland
Sebacous glands close to hair glands often Acini fiulled with sebocytes
Sweat glands (apocrine and eccrine)
Apocrine Hormonal oily secretion
Eccrine Just watery sweat Columnar cells are more active than pyramidal
Snesory receptors Touch Meissners corpuscles in the dermal papillae Merkel cells
Pressure Pacinian corpuscles Hypodermis Sometimes dermis Capsule which contains nerve endings
Temperature
Pain