Life Sciences - Term 3 - Week 5

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 divided into two main types: innate immunity, which provides immediate but non-specific defense, and adaptive immunity, which develops a targeted response to specific pathogens.

Key components of the immune system include white blood cells (leukocytes), antibodies, the lymphatic system, and various organs such as the spleen and thymus. White blood cells are crucial for identifying and eliminating pathogens. There are several types of leukocytes, including neutrophils, lymphocytes, and macrophages, each with specialized functions.

Innate immunity is the body's first line of defense and includes physical barriers like skin and mucous membranes, as well as immune cells that respond quickly to any threat. For example, when a pathogen enters the body, neutrophils are among the first responders, attacking and engulfing the invader. In contrast, adaptive immunity involves a slower, more specific response, where lymphocytes (B cells and T cells) recognize and remember specific pathogens, leading to a stronger response upon subsequent exposures.

In pairs, students will examine diagrams of various white blood cells and match them with their functions. For example, students will identify neutrophils as the primary responders to infection, while B cells are responsible for antibody production. This activity will help reinforce the understanding of how different cells contribute to the immune response.

Students will choose a specific component of the immune system, such as a type of white blood cell or an organ like the spleen, and conduct research to create a short presentation. They should include information about its structure, function, and importance in the immune response. This will encourage independent learning and deepen their understanding of the immune system.

• Transport oxygen
• Fight infections
• Regulate body temperature
• Digest food

Answer: Fight infections

White blood cells are essential for the immune response, as they identify and eliminate pathogens.

• Adaptive immunity
• Innate immunity
• Cell-mediated immunity
• Humoral immunity

Answer: Innate immunity

Innate immunity provides immediate, non-specific defense against pathogens.

Answer: B cells and T cells

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

• They directly kill pathogens
• They signal other immune cells
• They neutralize toxins and pathogens
• They produce energy

Answer: They neutralize toxins and pathogens

Antibodies bind to specific antigens on pathogens, marking them for destruction.

Answer: Macrophages engulf and digest pathogens and dead cells.

Macrophages are important for clearing infections and debris from the body.

• Spleen
• Thymus
• Bone marrow
• Liver

Answer: Thymus

The thymus is where T cells mature and learn to distinguish between self and non-self.

• Produce antibodies
• Engulf pathogens
• Regulate immune response
• Transport nutrients