first immune defense

The first line of defense system in human body

As well as the immune system the body has several other ways to defend itself against pathogens, such as bacteria, parasites, toxins, fungi and viruses. Your body has two lines of defense against pathogens. The first line of defence includes physical and chemical barriers that are always ready and prepared to defend the body from infections. These include your tears, skin, mucus, stomach acid, urinary tract, defecation, vomiting and white blood cells called neutrophils.

pathogenic, a disease causing microorganisms must make it past this first line of defence. If this first line of defence is broken, the second line of defence, the nonspecific resistance within your body is activated that destroys invaders in a generalized way without targeting specific individuals.

First line of defence system in human body are:

  • Skin: The skin is the largest organ of your body. It acts as a barrier between invaders(pathogens) and your body. It is a waterproof barrier that secretes oil with bacteria killing properties.
  • Lungs: The mucous in the lungs known as phlegm, is a type of mucous traps foreign particles, and very fine hair known as cilia is lining your windpipe which waves the mucous and trapped particles upward so it can be coughed out.
  • Digestive Tract or Stomach Acid: The mucus lining contains antibodies and acid in the stomach kills bacteria and parasites that have  been swallowed.
  • Urinary Tract: The urinary tract also has several effective barriers. The bladder is protected by the urethra, the tube that drains urine from the body. But in the case of males the urethra is long enough that bacteria are seldom able to pass through it to reach the bladder, unless the bacteria are unintentionally placed there by surgical instruments like catheters. In females, the urethra is shorter, occasionally allowing external bacteria to pass into the bladder. In both sexes, when the bladder empties, it flushes out any bacteria that reach it. In the case of vagina which is normally acidic and that acidity of vagina prevents harmful bacteria from growing and helps maintain the number of protective bacteria.
  • Hair: Hair within the nose filters microbes, dust and pollutants from the air to prevent them from invading the body.
  • Beneficial bacteria, Defecation and Vomiting: There is beneficial bacteria growing on your skin, in your bowel and other places in the body such as the mouth and the  guts that stops other harmful bacteria from taking over by expelling micro-organisms via bowel movements and vomit.
  • Tears, Saliva and Mucus:  Your eyes, nose and mouth are obvious entry points for pathogens(micro-organisms). However tears, mucus and saliva contain an enzyme that breaks down the cell wall of many bacteria. Those that are not killed immediately are trapped in mucus and swallowed. Special lines of cells protect the nose and throat and other passages within your body. The inner lining of your gut and lungs also produces mucus to trap invading pathogens.  
  • Neutrophils: Neutrophils are types of white blood cells that help heal damaged tissues and resolve infections. Neutrophils blood levels increase naturally in response to infections, injuries and other types of stress.

Role of fever in immune response

A rise in body temperature or fever can happen to anyone with some infections. This is actually an immune system response, where rise in temperature can kill some microbes. Fever also triggers the body’s repair process.

Types of immune system

  1. Innate immunity: Innate immunity also known as natural immunity is a type of general protection available in humans from their birth. For example, Skin and enzymes in saliva.
  1. Adaptive immunity: Adaptive immunity also known as active immunity develops throughout your lives. You develop adaptive immunity when you are exposed to diseases or immunized against them with vaccines.
  1. Passive Immunity: This immunity is borrowed from another source rather than producing them through his or her own immune system. For example, antibodies in mother’s breast milk known as colostrum give a baby temporary immunity to diseases the mother has been exposed to.
Embryonic stem cells

Embryonic stem cells are undifferentiated, allowing them to be used in all parts of the body, giving them the potential to cure hundreds of diseases with the use of all of the different cells that can be created from them.

[Related Content: How to keep your body Immune system Healthy? ]

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