Kerala SSLC Biology Chapter 5 Notes Soldiers of Defense English Medium
Though we live in the midst of germs, we are not susceptible to diseases. We have several mechanisms to prevent the entry of germs. Our body is equipped with a variety of de¬fense mechanisms like body covering, body secretions and body fluids. The body can be protected from diseases only if it can re¬spond properly against even mild attack of germs. Treatment is the ultimate defense strategy. Several modes of treatment have been developed according to the situations in different countries. This unit familiarizes the various soldiers of defense.
→ Defense : The ability of the body to prevent the entry of pathogens and to destroy those that have already entered the body.
→ Body coverings like skin and mucous mem-brane are the defense mechanisms of the body.
→ Body secretions like mucous, saliva, tear, hydrochloric acid, etc. destroy germs.
→ Skin : The protective covering of the body.
→ Body fluids like blood and lymph play an important role in defense mechanism.
→ White blood cells like neutrophil, basophil, eosinophil, monocyte and lymphocyte play a significant role in defense.
→ Inflammatory response: The defense mechanism in which when a wound occurs, that part swells up.
→ Phagocytosis : The process of engulfing and destroying germs. Monocytes and neutrophils are phagocytes.
→ Blood clotting is also a defense mechanism.
→ Non-specific defense mechanism : Is a mechanism that protects us from all pathogens without considering their characteristic features.
→ Antigens : Any foreign body that stimulates the defense mechanism.
→ Specific defense : The defense mechanism that identifies the structure of each antigen and destroys it specifically.
→ Antibodies : Certain proteins that act against
→ Lymph : The body fluid formed from the blood and reabsorbed into blood.
→ Immunization: Is the artificial method to make the defense cells alert against the attack of pathogens.
→ Vaccines : Are the substances used for artificial immunization.
→ Medicines : Substances either extracted from plants, animals or microorganisms or chemical substances synthesized in laboratories.
→ Antibiotics : Medicines that are extracted from microorganisms like bacteria, fungi, etc. and used to destroy bacteria.
→ On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipient’s blood will react with each other and form a blood clot.
→ Vaccines : Substances used for synthesizing antibodies.