Skin Secretions The and secreted by the sebaceous and the sweat glands contain some fatty acids and oil sweat lactic acid which make the surface of the skin acidic with a pH of 3-5. This prevents micro organisms from growing on the skin. The skin harbours some friendly bacteria also which release acids and other metabolic wastes that check the growth of microbes. Lysozyme, an enzyme present in sweat, kills many bacteria by destroying their cell wall. Saliva Saliva also contains lysozyme which kills micro organisms that are not the normal inhabitants of the buccal cavity. Bacteria which escape the action of saliva, when they reach the stomach, are killed by the hydrochloric acid and the proteolytic enzymes of the gastric juice. Tear Tears, a slightly saline fluid secreted by the lachrymal gland over the eyes, also contain lysozyme which prevents eye infections. Frequent washing of eyes reduces the disinfecting power of the lachrymal secretions. Tears also wash off the chemical irritants of polluted air, from the eyes. Skin and mucous membranes may fail to keep out the invaders. Some parasites through the skin e.g., hook worm, or through wounds and swellings of sweat glands and hair follicles. It is therefore very essential to have a second line of defence for controlling the parasites that have entered the body by breaking through the first line of defence. Second line of defence or body's internal defence is carried out by leucocytes, macrophages, inflammatory reactions, fever, interferons and natural killer cells. These operate together to check the damage to the body by the pathogens. Second line of defence or body's internal defence is carried out by leucocytes, macrophages, inflammatory reactions, fever, interferons and natural killer cells. These operate together to check the damage to the body by the pathogens. Leucocytes The number of leucocytes increases due to an infection. They creep out of the capillaries by amoeboid movement into the intercellular spaces if there is an infection. This process is called
Skin Secretions The oil and sweat secreted by the sebaceous and the sweat glands contain some fatty acids and lactic acid which make the surface of the skin acidic with a pH of 3-5. This prevents micro organisms from growing on the skin. The skin harbours some friendly bacteria also which release acids and other metabolic wastes that check the growth of microbes. Lysozyme, an enzyme present in sweat, kills many bacteria by destroying their cell wall. Saliva Saliva also contains lysozyme which kills micro organisms that are not the normal inhabitants of the buccal cavity. Bacteria which escape the action of saliva, when they reach the stomach, are killed by the hydrochloric acid and the proteolytic enzymes of the gastric juice. Tear Tears, a slightly saline fluid secreted by the lachrymal gland over the eyes, also contain lysozyme which prevents eye infections. Frequent washing of eyes reduces the disinfecting power of the lachrymal secretions. Tears also wash off the chemical irritants of polluted air, from the eyes. Skin and mucous membranes may fail to keep out the invaders. Some parasites through the skin e.g., hook worm, or through wounds and swellings of sweat glands and hair follicles. It is therefore very essential to have a second line of defence for controlling the parasites that have entered the body by breaking through the first line of defence. Second line of defence or body's internal defence is carried out by leucocytes, macrophages, inflammatory reactions, fever, interferons and natural killer cells. These operate together to check the damage to the body by the pathogens. Second line of defence or body's internal defence is carried out by leucocytes, macrophages, inflammatory reactions, fever, interferons and natural killer cells. These operate together to check the damage to the body by the pathogens. Leucocytes The number of leucocytes increases due to an infection. They creep out of the capillaries by amoeboid movement into the intercellular spaces if there is an infection. This process is called