BIOL 2020U Lecture Notes - Pseudopodia, Phagosome, Antigen
Document Summary
Skin is composed of dead cells containing the indigestible protein keratin. Sebum produced by the skin lowers the ph to inhibit growth of pathogens. Lysozymes in salvia, sweat and tears are anti-bacterial enzymes. Many ingested bacteria in the stomach are destroyed by acid (hcl) A sticky substance, mucus, traps pathogens in the respiratory tract. Cilia moves away mucus towards the throat to protect gas exchange surfaces. The immune system targets foreign materials and pathogens. Histamine is released into the wound by white cells. This increases vasodilation and increases vascular permeability. Vasodilation increases the local blood flow area becomes red, warm. Tissue fluid contains plasma proteins (antibodies) and may cause swelling. Increased permeability allows escape of tissue fluid into the tissues. White cells (phagocytes) contain digestive enzymes within lysosomes: neutrophils primarily engulf bacteria, macrophages engulf larger particles; including old and infected red blood cells. Found in blood, lymph systems and tissues.
