physical barrier

epithelial surfaces act as barriers against pathogens >

pathogen breaches host's physical barriers, other innate immune mechanisms act immediately

chemical barriers

mucus, tears, saliva produced by mucous membranes trap pathogens, provide washing action, inhibit colonisation by fungi, bacteria >

stomach mucus acidic pH prevent microorganism growth >

antimicrobial enzymes cleaves peptidoglycan glycosidic bonds -> bacterial cell lysis >

antimicrobial peptides disrupt bacteria, fungi membranes, membrane envelopes of some viruses

phagocytic cells

inflammation; protective response, eliminate infecting pathogens by delivering immune cells to right place, right time >

histamines(mast cells), cytokines(macrophages) released; increases blood flow to infection site & leakage of fluid, proteins from blood into tissue space, produce redness, swelling

Review: H2 Biology 20 - Infectious diseases