Summary
The immune system is the body’s defense against infectious organisms and other invaders. The first line of defense consists of five parts: skin, mucous membranes, tears, saliva, and stomach acid.
Skin
The skin is the body’s largest organ, and serves as the first line of defense against invading organisms. It does so by providing a physical barrier to the outside world, and its natural oils and sweat help to keep out potential invaders. It also contains antimicrobial peptides which help to fight off bacteria and other organisms.
Mucous Membranes
Mucous membranes are found in the body’s openings, such as the nose, mouth, and eyes. They work to trap and destroy any foreign particles that enter the body. The mucous also contains antibodies which help to fight off invading organisms.
Tears
Tears contain an enzyme called lysozyme which helps to break down the cell walls of bacteria, thus killing them. Tears also contain antibodies which help to fight off invading organisms.
Saliva
Saliva contains an enzyme called salivary amylase which helps to break down carbohydrates and potentially dangerous molecules before they enter the body. Saliva also contains antibacterial compounds that help to fight off invading organisms.
Stomach Acid
The acidic environment of the stomach helps to kill off any invading organisms that enter the body. It does this by breaking down the cell walls of bacteria and other organisms, thus killing them.
Related Questions
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