Life Sciences - Term 4 - Week 2

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

The immune system includes various types of cells such as white blood cells (leukocytes), which are crucial for immune responses. Key players include lymphocytes (B cells and T cells), macrophages, and dendritic cells. B cells are responsible for producing antibodies, while T cells help in killing infected host cells and regulating immune responses. Additionally, the lymphatic system plays a vital role in transporting immune cells throughout the body.

When a pathogen enters the body, B cells recognize specific antigens on the pathogen's surface. Upon activation, B cells proliferate and differentiate into plasma cells, which produce antibodies. These antibodies bind to the antigens, marking the pathogen for destruction by other immune cells. This process illustrates how the adaptive immune response is tailored to effectively eliminate specific threats.

In pairs, students will be given images of different immune cells (B cells, T cells, macrophages). They will discuss the functions of each cell type and how they contribute to the immune response. After the discussion, each pair will present their findings to the class, highlighting the unique roles of each cell type in fighting infections.

Students will choose a vaccine (e.g., measles, flu, COVID-19) and conduct research on how it works to enhance immunity. They will prepare a short presentation that includes the vaccine's mechanism of action, its effectiveness, and any side effects. This will help students understand the importance of vaccination in public health.

• Producing antibodies
• Killing infected cells
• Regulating immune responses
• Phagocytosing pathogens

Answer: Producing antibodies

B cells are primarily responsible for producing antibodies that target specific antigens on pathogens.

• Adaptive immune system
• Innate immune system
• Lymphatic system
• Antibodies

Answer: Innate immune system

The innate immune system provides immediate but non-specific defense against pathogens.

Answer: T cells help in killing infected host cells and regulating the immune response.

T cells are crucial for identifying and destroying infected cells and coordinating the overall immune response.

• Producing antibodies
• Phagocytosing pathogens
• Activating B cells
• Transporting immune cells

Answer: Phagocytosing pathogens

Macrophages engulf and digest pathogens, playing a key role in the innate immune response.

• By directly killing pathogens
• By introducing a harmless form of the pathogen
• By increasing the number of white blood cells
• By blocking pathogen entry

Answer: By introducing a harmless form of the pathogen

Vaccines stimulate the immune system by introducing a harmless form of the pathogen, prompting an immune response.

Answer: An antigen is a substance that triggers an immune response, typically found on the surface of pathogens.

Antigens are molecules that the immune system recognizes as foreign, leading to the activation of immune cells.