Biology Form 4 KSSM Chapter 11 IMMUNITY (11.1) BODY DEFENCE, FIRST AND SECOND LINE OF DEFENCE скачать в хорошем качестве

Biology Form 4 KSSM Chapter 11 IMMUNITY (11.1) BODY DEFENCE, FIRST AND SECOND LINE OF DEFENCE

BIOBRAIN GYM ANSWERS (11.1) 1) Inflammatory Response a) The damaged tissue releases histamine which stimulates an immediate inflammatory response. b) Histamine causes blood capillaries to expand and more blood flows to infected area. c) Histamine increases permeability of blood capillaries to phagocytes so more phagocytes move out of capillaries into body tissues. d) Phagocytes carry out phagocytosis to ingest pathogens at site of infection. e) The blood clotting mechanism is triggered. f) The phagocytes and clotting factors will accumulate in the infected area. (any 4) 2) a) The skin acts as a PHYSICAL BARRIER because it has a dead keratinised layer of cells which is difficult for microorganisms to penetrate. (1) The continuous shedding of dead cells on the skin surface makes it difficult for microorganisms to grow. (1) b) The skin acts as a CHEMICAL BARRIER through the secretion of sebum from the sebaceous glands. Oil and acid in the sebum prevent growth of microorganisms. (1) Sweat secreted by sweat glands contains lysozyme that breaks down the cell walls bacteria. (1) 3) GOOD EFFECT OF FEVER -- it increases phagocytic activity so that more pathogens are destroyed through phagocytosis. (1) -- it inhibits the growth and reproduction of pathogens in the body. (1) BAD EFFECT OF FEVER -- it can cause dehydration (1) -- it can cause seizures and organ damage if the fever is too high. (1) 4) He can drink more water to stay hydrated and replace fluids lost through sweating. He can stay in bed and rest to allow the body to recover from the infection. He can sponge his exposed skin with lukewarm water to bring the temperature down. 5) A pH balanced skincare product has the same pH as the skin, about pH 5.5 (1) This acidic condition keeps the skin healthy by inhibiting bacterial growth.(1) If the skincare products are not pH balanced, it can cause the skin to become too alkaline or acidic.(1) The skin will be attacked by pathogens which cause skin problems. (1)