Anatomy And Physiology Of The Skin Flashcards
What are the functions of the skin?
Barrier
Immunologic
Temperature regulation
Protection from radiation
What are the layers of the skin?
Epidermis
Dermis
Subcutis
What are the layers of the epidermis from superficial to deep?
Stratum corneum- anucleated cells
Stratum lucidum- clear layer of dead cells
Stratum granulosum- granular layer, cells become flat
Stratum spinosum- cells look like spines connected with desmosome
Stratum basale- source of stem cells, connected to basement membrane by hemidesmosomes
What are the cells of the epidermis?
Keratinocytes- most abundant
Melanocytes- secrete melanin
Langerhans cells- antigen presenting cells, found in the stratum spinosum
What are some diseases related to to the epidermal layers?
Atopic dermatitis- mutations in filaggrin , protein found in the stratum granulosum
Bullous pemphigoid- autoimmune disease due to antigens affecting hemidesmosomes
Pemphigus vulgaris- disease due to defect desmosomes
Psoriasis- thickening of epidermis due to increase turnover rate
What are the characteristics of the dermis?
Provides flexible but tough support structure
Contains the blood and lymphatic vessels and nerves
Contains sweat glands,hair follicles,fibroblasts and mast cells
What is the function of the fibroblasts?
Responsible for the synthesis and degradation of connective tissue proteins
Instrumental in wound healing
What is the function of the mast cells?
Responsible for immediate Type hypersensitivity reaction
Major effector in urticaria
What constitue the pilosebaceous unit?
Hair follicle
Sebaceous (oil) glands
Apocrine sweat glands
Arrector pili muscle
What are the steps of hair cycle?
Anagen
Catagen
Telegen
What is the disorder associated with the pilosebaceous unit?
Acne vulgaris caused by 4 factors: Plugging of the hair follicle P.acnes (bacteria) breaks down free fatty acids Presence of hormones (androgens) Increase sebaceous activity
What are the Characteristics of eccrine glands?
Do not involve the hair follicle Open directly onto the skin surface Present throughout the body Help regulate temperature Absence causes hyperthermia
What are the types of collagen in the skin?
Type 1- reticular dermis
Type 3- papillary dermis
Type 4 & 7- basement membrane structures
Type 8- endothelial cells
