Question

immunology

1. List and explain a minimum of four different defense mechanisms at the cellular levels? components of the human immune system and how what role did pathogens played in their evolution. 3. Explain the following statement "Immune system co-evolves with pathogens". 4. Provide an argument in favor and against the use of primates as a model system to study the immune system. Justify your answer with the use of appropriate example 5. Provide two examples pertaining to the evolution of Immune genes in modern humans and explain in sufficient detail. The use of figures and diagrams is highly encouraged.

Answer 1

· Immune system is the ability of the body to protect itself from invasion of foreign molecules such as pathogens. Immunity is the protective state of the body against infection.

· The two major components of immunity or immune response are, innate immunity and acquired immunity.

Innate immunity, is in born immunity and act as first line of defense. Innate immunity is non-specific, and acts as defense mechanism in cellular level.

They include:

1) Anatomical barriers or physical barrier include a) .skin- epidermis layer of skin has protective waterproofing keratin protein and dermis layer bear sebaceous glands which produce sebum, that inhibit growth of many microorganisms. B) mucous membrane- are washed and protected by mucous, tears or saliva. Also has ciliated epithelial cells that entraps microbes.

2) Physiological barriers include body temperature, pH (potential of hydrogen), soluble molecules like lysozymes, interferons.

3) Inflammatory response- complex sequence of events, resulting after pathogen invasion through a wound or damage. Results in four typical cardinal signs, rubor (redness), tumor (swelling), calor (heat) and dolor (pain).

4) Phagocytic response- phagocytosis is mediated by endocytosis process of phagocytic cells like macrophages and neutrophils.