Diseases and Immunity

Diseases and Immunity

I. Understanding Diseases

  • Diseases are health conditions that impair normal body functions. They can be caused by various pathogens like bacteria, viruses, fungi, and protozoa.
  • Some diseases can be spread directly from one individual to another while others are spread via vectors such as mosquitoes.

II. Different Types of Diseases

  • Infectious diseases: These are diseases caused by pathogens that can be passed from person to person.
  • Non-infectious diseases: These diseases are not caused by pathogens and cannot be passed from one person to another. They may be caused by other factors such as genetics, lifestyle or environmental factors.

III. An Overview of the Immune System

  • The immune system constitutes the body’s defence mechanism against pathogens.
  • It involves several types of cells like white blood cells, also known as leukocytes, which fight against foreign objects in our bodies.
  • The system utilises specific and non-specific responses. Non-specific responses like skin provide broad and immediate protection while specific responses target specific pathogens and provide long-lasting immunity.

IV. Vaccination and Immunity

  • Vaccination is a method of providing immunity to specific diseases by introducing a controlled dose of the disease-causing organism (or part of it) into the body.
  • Upon vaccination, the immune system creates memory cells that remember the pathogen, providing immunity if the same disease is encountered again.

V. Understanding Gas Exchange

  • Gas exchange is the process by which oxygen and carbon dioxide are exchanged between the cells, the blood and the environment.
  • In humans, it mainly takes place in the lungs where blood accepts oxygen and releases carbon dioxide. The oxygen-rich blood then gets transported to the body’s cells.

VI. Diseases of the Gas Exchange System

  • Certain diseases, like asthma and emphysema, affect the gas exchange system.
  • These diseases can reduce the amount of surface area available for gas exchange, resulting in reduced oxygen supply to the body’s cells.

VII. Preventing Diseases

  • Use of vaccines, good hygiene practices, safe sex, and avoiding exposure to harmful substances are some of the ways to prevent diseases.
  • The spread of diseases can also be curbed by controlling vector populations and keeping our surroundings clean.