Pulmonary artery Aorta Pulmonary Vein s. vena cava Left Atrium i.vena cava Left Atrio-ventricular valve Right Atrium Right Atrio-ventricular valve Left ventricle Right ventricle Semi-lunar valves Coronary artery
6.3: DEFENCE AGAINST INFECTIOUS DISEASE Pathogen: an organism or virus that causes a disease.
6.3.1: Antibiotics Antibiotics block specific metabolic pathways found in bacteria. Viruses reproduce using the host cell’s metabolic pathways, which are not affected by antibiotics.
6.3.1: Skin and Mucus membranes Mucous membranes line cavities that are exposed to the external. They are at several places continuous with skin: at the nostrils, the mouth, the lips, the eyelids, the ears, the genital area, and the anus. The sticky, thick fluid secreted by the mucous membranes and glands is termed mucus
SkinThe outer layer of skin is dead and difficult for pathogens to grow on or penetrate. The best way to prevent disease is to prevent pathogens from entering the body. Skin forms a physical barrier that prevents most pathogens from entering the body. Glands in the skin secrete lactic acid and fatty acid, which make the skin surface acidic, preventing bacterial growth. The outer layer of skin flakes off, which removes bacteria. Cuts allow pathogens to gain entry to the body.