Immunity and Cell Recognition

• The immune system is made up of cells, tissues, organs, and proteins that work together to defend the body against pathogens.
• Phagocytosis involves engulfing and destroying foreign particles by phagocytes.
• Antibodies are produced by B lymphocytes (B cells) in response to antigens.
• T lymphocytes (T cells) play a role in cell-mediated immunity.
• Lymph nodes filter blood and contain white blood cells involved in immune responses.
• Thymus gland produces T cells and plays a role in maturation and selection of T cells.
• Mast cells release histamine during allergic reactions.
• Innate immunity includes physical barriers such as skin and mucous membranes, chemical defenses like stomach acid and enzymes, and inflammation caused by white blood cells.
• Active immunity provides long-term protection against specific pathogens through memory T and B cells.
• Innate immunity includes physical barriers such as skin, mucous membranes, and cilia.
• Red blood cells (erythrocytes): Carry oxygen throughout the body
• White blood cells (leukocytes): Cells that defend against infection
• The adaptive immune system has two types of cells - B cells and T cells.
• Antigens are foreign substances that trigger an immune response.
• B cells produce antibodies against foreign substances called antigens.