Defense is the ability of the body to prevent the entry of pathogens and to destroy those that have already entered the body. Our body is well equipped with a variety of defense mechanisms. A mechanism that protects us from all pathogens without considering their characteristic features like non-specific defense mechanism and specific defense mechanism where the blood cells that specifically identify and destroy pathogens that enter the body are the parts of defense mechanisms.
Study Notes

  1. Non specific defence mechanisms are classified in to 3 categories Body coverings (skin,
    mucous membrane)
    Body secretions (mucus, saliva, tears, urine, sweat, sebum, ear wax, HCI) Body fluids (Blood
    and lymph)
  2. .Skin is the protective covering of the body which prevents the entry of germs Topmost layer
    of the skin is known as Epidermis
    -> Keratin protein present in the epidermis prevents the entry of germs
    -> Sebum produced by the sebaceous gland makes the skin oily
    -> The sweat produced by the sweat gland is having disinfectant property
  3. Phagocytosis is the process of engulfing and destroying of germs
    The cells that are engaged in this process are called phagocytes
    The white blood cells, namely monocytes and neutrophils are phagocytes
  4. Fever is an important defense mechanism of our body at the time of entry of germs
    Fever is a condition when the body temperature rises above the normal level Fever is a
    symptom -> If the rise in body temperature persists for a long time, it may badly affect the internal organs including the brain
    -> It is advisable to treat after diagnosing the exact reason 5. Immunization is the artificial method to make the defense cells alert against the attack of pathogens
    -> Vaccines are the substances used for artificial immunization-> The components of vaccines
    act as antigens that stimulate the defense mechanism of the body 6. Medicines that are used to destroy bacteria are called antibiotics
    Antibiotics are extracted from microorganisms like bacteria, fungi, etc. They can be used externally and internally
    It was Alexander Fleming who first discovered antibiotics 7. The transfer of blood from one person to another is called blood transfusion
    The major blood groups are A, B, AB and o
    Blood grouping is performed on the basis of A, B antigens seen on the surface of RBC – Blood groups are called as positive or negative based on another antigen antigen D (Rh factor) seen on the surface of RBC

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