Immune + Lymphatic Flashcards
How does the skin contribute to immunity?
Physical barrier
Produces anti microbial peptides and IgA to destroy/inhibit pathogens
Epidermal Langerhan’s Cells capture and activate immune response
Skin has own microbiota to compete
How do mucous membranes contribute to immunity?
Physical barrier covered in mucous to trap microbes
Substances within mucous inhibits microbes
Immune cells in membrane capture and activate immune response if mucous breached
Some have cilia to expel trapped microbes - mucociliary clearance
How do tonsils and adenoids contribute to immunity?
Lymphoid tissue has B + T cells to capture invaders
Helps produce IgA
Helps develop immune tolerance by exposing to harmless antigens regularly in early life
How does the appendix contribute to immunity?
Lymphoid tissue with lymphocytes and IgA
May assist with gut microbiota
May help with immune tolerance
How does the spleen contribute to immunity?
Filters blood using macrophages to engulf invaders
Surveils the blood with lymphocytes and antigen-presenting cells to identify and activate response
Produces antibodies from B cells
Houses memory B and T cells for immune memory
Hematopoiesis (makes blood cells) can occur here if failing in usual areas of body
What is a lymphocyte?
Main WBC
Includes natural killer cells, T and B cells
Recognise and destroy antigens
What is a macrophage?
WBC that surrounds and destroys pathogens or dead cells
Can stimulate other immune cells to respond
What is a dendritic cell?
WBC that identifies and captures an invader and shows to other immune cells to activate them
What is innate immunity?
Natural
Non-specific
Immediate defence
What are the 3 components of innate immunity?
Physical (skin, mucous membranes)
Chemical (enzymes, pH, peptides etc)
Inflammatory response
Describe the inflammatory response
Recognition of injury/infection
Vasodilation and permeability occurs (improve flow to area)
Cytokinins release which recruit immune cells
Immune cells are activated (including phagocytosis)
Inflammatory mediators are released (histamine, prostaglandin)
Tissue repair and resolution begins
What are phagocytes?
WBC engulf and destroy via phagocytosis
E.g. neutrophils, macrophages
What are natural killer cells?
Type of lymphocyte
Destroys infected cells without needing activation or prior exposure
What is the complement system?
Group of proteins that enhance the immune response
Can kill pathogens, recruit immune cells and increase inflammation
What is adaptive immunity?
Acquired
Specific to antigens
Mediated by lymphocytes (B & T cells)
What is clonal selection?
When T and B cells recognise an antigen, duplicate themselves and an army of antibodies is formed
What is humoral immunity?
Adaptive immunity with B cells producing antibodies
B cell identifies antigen, differentiates into plasma cell which produces antibodies. These bind to antigen to kill or mark for other immune cells
What is cell mediated immunity?
Adaptive immunity with T cells
Helped T cells release cytokinins to activate other cells and help B cells produce antibodies
Cytotoxic T cells recognise and destroy infected or cancerous cells
What does the lymphatic system do?
Balance fluid by regulating interstitial fluid
Absorb dietary fat
Transport immune cells
Describe lymphatic vessels
Thin vessels run parallel to blood vessels
Collect leaked interstitial fluid to return to blood
What is lymph?
Fluid of the lymphatic system comprising of interstitial fluid, immune cells, waste products and fat
What do lymph nodes do?
Filter foreign particles and waste from lymph
Site of immune cell activation
What are the lymphoid organs and why are they significant?
Spleen, thymus, tonsils and peyers patches
Produce and mature T cells
What is lymphoedema?
Build up of interstitial fluid causing oedema due to damaged lymphatic system
Primary: genetic abnormality
Secondary: from injury
