Describe how the mammalian body protects itself against infections

Pathogenic microbes are found on the skin, respiratory tract, mouth, vagina and the intestinal tract;

In the Skin

The skin has a keratinised and waterproof cornified outer layer; that provides a mechanical barrier to microbes/prevents entry of microbes

Sebaceous Gland

sebaceous gland produces sebum which has antiseptic properties

In the Respiratory Tract

the respiratory tract produce mucus secretions that trap dust cilia sweep/waft/propel the microbes to the pharynx for swallowing or to be coughed out reflex actions of coughing/sneezing/vomiting help remove foreign materials from the respiratory tract/digestive tract.

Lysozymes

Lysozymes/enzymes in saliva/nasal secretions/tears digest walls of bacteria destroying them

Gastric secretions such as hydrochloric acid lowers the pH in the stomach killing micro-organisms

Blood clothing

clotting of blood; prevents entry of microbes after damage of blood vessels.

phagocytosis

phagocytosis by phagocytes engulf and destroy microbes and other foreign bodies.

lymphocytes

lymphocytes are stimulated to produce antibodies by proteins present in microbes protecting the body

antibodies destroy/kill micro-organisms through various ways:

Agglutinins

Agglutinins bind to pathogens making them clump together thereby killing them.

Lysins

Lysins bind to pathogens and make them burst or disintegrate.

Opsonins

Opsonins bind to pathogens making them easily recognized hence be engulfed/destroyed by other lymphocytes.

Anti-toxins

Anti-toxins bind and neutralize toxins produced by micro-organisms.

In the Vagina

vagina is acidic hence making it not conducive for growth and reproduction of micro-organisms.