Life Sciences - Term 4 - Week 10

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 defense against infection, 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 lymphocytes (B cells and T cells), which play vital roles in adaptive immunity.

Consider a scenario where a person is exposed to a common cold virus. The innate immune response is the body's first line of defense, involving barriers like skin and mucous membranes, as well as phagocytic cells that engulf pathogens. If the virus persists, the adaptive immune response kicks in, where B cells produce antibodies specific to the cold virus, and T cells help destroy infected cells.

In pairs, students will examine diagrams of various white blood cells and their functions. Each pair will identify the type of cell, its role in the immune response, and present their findings to the class. For example, they might discuss how neutrophils respond to bacterial infections and the role of T cells in fighting viral infections.

Students will choose a specific pathogen (e.g., HIV, influenza, or tuberculosis) and research how the immune system responds to it. They will prepare a short presentation that includes the pathogen's characteristics, how it evades the immune system, and the immune response it triggers. This will help reinforce their understanding of the adaptive immune response.

• Transport oxygen
• Fight infections
• Regulate body temperature
• Produce hormones

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

• They destroy pathogens directly.
• They signal other immune cells.
• They neutralize toxins.
• They all of the above.

Answer: They all of the above.

Antibodies can neutralize toxins, signal other immune cells, and directly target pathogens.

Answer: B cells and T cells. B cells produce antibodies, while T cells help destroy infected cells.

B cells and T cells are crucial for the adaptive immune response, with distinct but complementary roles.

• Spleen
• Thymus
• Bone marrow
• Liver

Answer: Thymus

The thymus is where T cells mature and learn to recognize pathogens.

Answer: Active immunity develops after exposure to a pathogen, while passive immunity is acquired through antibodies from another source.

Active immunity involves the body's own immune response, whereas passive immunity provides immediate protection without the body having to respond.