Immune System and Allergic Reactions

• The skin creating sebum and sweat is one function of the first layer of immune defense: chemical and physical barrier
• Neutrophils, highly phagocytic cells, are a component of the innate immune response.
• Leukocytosis, an increase in neutrophil count, is expected in a complete blood count with differential white cell count of a patient who has an accute bacterial infection.
• Mast cells and basophils release histamine during systemic allergic reactions, which antihistamines counteract when treating allergies.
• Basophils are least likely to be present when joint fluid is aspirated from the knee of an individual with rheumatoid arthritis, these cells are associated with allergic inflammation, instead of chronic autoimmune inflammation.
• Allergic rhinitis results in symptoms of stuffy, runny nose, sneezing, itchy eyes, postnasal drip, and cough.
• Lymph nodes are the most important location in the body for activation of an adapative immune response because those nodes facilitate communication between antigen-presenting cells, T cells, and B cells during immune response development.
• Natural killer (NK) cells kill virus-infected and cancerous cells.
• Macrophages, T cells, and B cells responding to tissue antigens results in chronic inflammation.
• Innate immunity begins with myeloid lineage blood cells and recognizes common pathogen patterns.
• Macrophages primarily produce cytokines and advance wound healing after an acute injury.
• A genetic mutation in filaggrin is implicated in the pathogenesis of atopic dermatitis by resulting in epithelial damage.
• Inflammaging can be defined as a shift to a pro-inflammatory state as homeostatic control and immune response adjustment becomes less stable with age.
• A red blood cell's small size and membrane flexibility for easy flow through small capillaries contributes the most to its optimal lifespan because abnormal cells from hereditary spherocytosis or sickle cell disease are vulnerable to hemolysis and have shorter lifespans.
• Iron ions released when red blood cells (RBCs) are broken down bind to plasma transferrin and are transported to the bones marrow for new RBC production; 95% of the iron used for new RBC synthesis comes from this recycling process.
• Following a gastrectomy, a patient who has lightheadedness, fatigue and exercise intolerance who appears pale and has low hemoglobin is most likely to have a mean cell volume test conducted to differentiate between B12 deficiency and iron-deficiency because a mean cell volume is high in B12 deficiency and low in iron-deficiency.
• Jaundice and hyperbilirubinemia are common findings with hemolytic anemias because accelerated red blood cell (RBC) breakdown results in high rates of heme release, resulting in elevated bilirubin.
• Vitamin K is oxidized during liver clotting factor carboxylation, which is required for factor function, explaining why vitamin K deficiency results in increased prothrombin time and excess bleeding.
• A 62-year-old female with rheumatoid arthritis taking an 8-hour plane trip poses the greatest risk for deep vein thrombosis (DVT).
• Iron circulating from the spleen after the breakdown of aging red blood cells is the source of the most iron required for new red blood cell (RBC) synthesis.
• Loss of erythropoietin production causes anemia in chronic kidney disease (CKD) because normal RBC production depends on erythropoietin levels which the kidneys stimulate production of.
• Healthy endothelial cells synthesize and secrete prostacyclin (PGI2), a vasodilator and inhibitor of platelet adhesion.
• By inhibiting the enzyme cyclooxygenase, aspirin reduces platelet synthesis of thromboxane after tissue injury.
• Dehydration is not a part of "Virchow's triad" of factors that promote clot formation, whereas endothelial injury, hypercoagulability, and venous stasis are.
• The liver stores the greatest amount of iron intracellularly.
• Myocardial infarctions, which occur when dysregulation of homeostasis increases risk of thrombus formation, can stem from hypercoagulability.
• Blood cells that appear microcytic and hypochromic on a periphereal blood smear are characteristic of iron-deficiency anemia.
• Layers of blood flowing smoothly through the vessel can cause shear stress because laminar flow and high velocity cause shear stress in large arteries.
• The abdominal aorta is the most common site of atherosclerosis followed by aneurysm formation; abdominal aortic aneurysm affects 1% to 2% of older men and is uncommon in women.
• Platelet adhesion to plaque and thrombus formation occurs last in the progress of atherosclerosis.

This lesson covers the skin's role as a barrier, neutrophils in the immune response, leukocytosis during bacterial infections, histamine release by mast cells and basophils, and allergic rhinitis symptoms. Additionally, it explains why lymph nodes crucial for adapative immune response.