Summary of Immunology in the skin

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The video discusses the role of the skin in immunity, and how the immune system can be dysregulated in conditions like psoriasis. It describes how the skin is composed of different layers, and how immune cells are activated after encountering pathogens. It also discusses how psoriasis is characterized by inflammation of the skin, and how this can lead to thickening of the epidermis.

• 00:00:00 The skin is the body's primary barrier against physical insults and microbial pathogens. It is composed of epidermis, dermis, and a subcutaneous fatty region. Living on the skin have beneficial effects in the protection against pathogens and in wound healing. The epidermis is composed of highly specialized epithelial cells known as keratinocytes. These cells are continuously replenished from just one layer of basal keratinocytes which divide frequently. Dead cells called cornea sites form the outermost layer and are largely responsible for the barrier function of the skin. In the dermis, cells known as fibroblasts secrete elastin and collagen fibres that form a dense extracellular matrix. Blood capillaries irrigate the dermis while lymph fluid is drained through lymphatic vessels to lymph nodes. Specialized immune structures in which immune cells are activated after pathogen encounter diverse and functionally specialized immune cells populate the skin. A specialized subset of dendritic cells called Langerhans cells sample antigen. They project dendrites upward towards the qualified epithelial layer and sample bacterial antigens such as toxins. Langerhans cells appear to be both anti-inflammatory and activator ii depending on dendritic cells in the dermis are highly efficient at
• 00:05:00 Psoriasis is a condition that is characterized by inflammation of the skin. Keratinocytes in the skin might release self DNA which in complex with an antimicrobial peptide activates dermal plasma site or dendritic cells to secrete high amounts of the antiviral mediator interferon. Interferon activates dermal dendritic cells to promote T cell differentiation and the earliest recognisable change in the affected skin is the accumulation of T cells and dendritic cells around blood vessels in the dermis. An overt lesion occurs when cd8 t-cells dendritic cells and neutrophils infiltrate the epidermis. Specialized subsets of T cells secrete soluble mediators like interferon gamma and il-17 which stimulate the proliferation of keratinocytes and this produces a marked thickening of the epidermis. Signals from the proliferating keratinocytes act as chemo attractants for infiltrating neutrophils crosstalk between immune cells keratinocytes and dermal cells thus contributes to tissue remodeling and amplification of this dysregulated immune response. Without treatment, acute psoriatic lesions become chronically jhin's. Genetic studies have identified psoriasis associated susceptibility genes some of which linking th17 cells the subset of