Life Sciences - Term 1 - Week 10

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 but non-specific defense, and adaptive immunity, which develops a targeted response to specific pathogens over time.

Innate immunity includes physical barriers like the skin and mucous membranes, as well as immune cells such as macrophages, neutrophils, and natural killer cells. These components act quickly to identify and eliminate pathogens. For instance, macrophages engulf and digest pathogens through a process called phagocytosis.

Adaptive immunity involves lymphocytes, specifically B cells and T cells. B cells produce antibodies that bind to specific antigens on pathogens, marking them for destruction. T cells, on the other hand, can directly kill infected cells or help coordinate the immune response. This system has a memory component, allowing for a faster response upon re-exposure to the same pathogen.

Consider a scenario where a person gets a cut on their skin. The innate immune system responds immediately by sending white blood cells to the site of injury. These cells release chemicals that promote inflammation, which helps to isolate the area and prevent the spread of infection. This response is non-specific and occurs regardless of the type of pathogen.

When a person is vaccinated against a disease, their adaptive immune system is exposed to a harmless part of the pathogen, such as a protein. This exposure stimulates B cells to produce antibodies and creates memory cells. If the person encounters the actual pathogen in the future, their immune system can respond more rapidly and effectively due to this prior exposure.

In groups, students will be given images and descriptions of various immune cells, such as macrophages, T cells, and B cells. They will work together to match each cell type with its function and role in the immune response. This activity will help reinforce their understanding of the different components of the immune system.

Students will choose a specific pathogen (e.g., influenza virus, HIV, or bacteria) and research how the immune system responds to it. They will prepare a short presentation that includes information on the pathogen, the immune response involved, and any vaccines or treatments available. This assignment will encourage independent learning and application of the concepts covered in class.

• To digest food
• To protect the body from pathogens
• To regulate body temperature
• To produce hormones

Answer: To protect the body from pathogens

The immune system's main role is to defend against harmful microorganisms that can cause disease.

• Adaptive immunity
• Innate immunity
• Acquired immunity
• Cell-mediated immunity

Answer: Innate immunity

Innate immunity is the body's first line of defense and is present from birth, providing immediate but non-specific protection.

Answer: B cells and T cells

B cells produce antibodies, while T cells help coordinate the immune response or directly kill infected cells.

• To produce antibodies
• To engulf and digest pathogens
• To regulate inflammation
• To create memory cells

Answer: To engulf and digest pathogens

Macrophages are key players in the innate immune response, acting as phagocytes that consume and destroy pathogens.

• Liver
• Spleen
• Thymus
• Kidney

Answer: Kidney

While the liver, spleen, and thymus are all involved in immune functions, the kidney primarily functions in filtering blood and producing urine.

Answer: To bind to specific antigens on pathogens and neutralize them.

Antibodies are proteins produced by B cells that specifically target and neutralize pathogens.

• Phagocytosis