Life Sciences - Term 3 - Week 7

The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful pathogens such as bacteria, viruses, and parasites. It is divided into two main types: innate immunity, which provides immediate, non-specific defense, and adaptive immunity, which develops a targeted response to specific pathogens over time.

Key components of the immune system include white blood cells (leukocytes), antibodies, the lymphatic system, and various organs such as the spleen and thymus. Leukocytes are further categorized into phagocytes, which engulf pathogens, and lymphocytes, which are crucial for the adaptive immune response. Antibodies are proteins produced by B cells that specifically target antigens on pathogens.

Consider a scenario where a person is exposed to a common cold virus. The innate immune response kicks in immediately, utilizing barriers like skin and mucous membranes, as well as phagocytes that attack the virus. If the virus persists, the adaptive immune system is activated, producing specific antibodies against the virus, which can provide long-term immunity.

In pairs, students will analyze case studies of different infections. Each pair will identify whether the immune response described is innate or adaptive, and explain the role of specific immune cells involved. This will help reinforce the differences between the two types of immunity.

Students will choose a vaccine (e.g., measles, flu, COVID-19) and research how it works to stimulate the immune system. They will prepare a short presentation that includes the type of immunity it promotes, the components of the vaccine, and its impact on public health.

• To digest food
• To protect the body from pathogens
• To circulate blood
• To regulate temperature

Answer: To protect the body from pathogens

The immune system's main role is to defend against harmful microorganisms and maintain health.

• Adaptive immunity
• Innate immunity
• Acquired immunity
• Passive immunity

Answer: Innate immunity

Innate immunity is the body's first line of defense and is present from birth.

Answer: Antibodies bind to specific antigens on pathogens, marking them for destruction by other immune cells.

Antibodies are crucial for identifying and neutralizing pathogens.

• Phagocytes
• B cells and T cells
• Red blood cells
• Natural killer cells

Answer: B cells and T cells

B cells produce antibodies, while T cells help regulate the immune response and kill infected cells.

Answer: Vaccines introduce a harmless component of a pathogen, stimulating the immune system to produce a response and memory cells without causing disease.

This prepares the immune system to respond more effectively if exposed to the actual pathogen in the future.

• To produce antibodies
• To engulf and digest pathogens
• To transport oxygen
• To regulate blood pressure

Answer: To engulf and digest pathogens

Phagocytes are immune cells that ingest and break down harmful microorganisms.