Topic 20 - Immune System 1 Flashcards
Learning Objectives
- Define what is meant by immunity and describe where the immune system is found and its major functions
- Describe the general anatomy of the immune system
- Distinguish the difference between primary and secondary immune deficiencies.
- Describe the general characteristics (hallmarks) of the innate and adaptive immune system
- Explain briefly how the immune system is able to discriminate self vs non-self
- Describe the major components of the innate immune system and their function including Epithelial barriers, Phagocytes, Exocytes, Cytokines and Blood proteins
- Explain what is meant by cytokines acting in an autocrine, paracrine and endocrine manner
- Explain the role of inflammation in immune function and why the resolution of inflammation is important
The Immune system
Collection of cells, tissues and molecules that mediate reactions to pathogens and some non-infectious substances
- coordinated and tightly controlled response to cells and molecules is the immune response
Immunity
- The resistance to an infectious disease
- Non-infectious substances, damaged cells, tumours eleicit on immune response
- Immunity is not just about killing microbes
Function of immune system
- Prevention
- Eradicate established infections
- Control tissue regeneration (wounds)
- Detect and eliminate tumours
- Tolerate self
Immune deficiency
Congenital (primary):
- Not common
Acquired (secondary):
- Much more common
Location of immune system
Everywhere and integrated with other systems
- Immune cells are throughout the body travelling by blood and lymphatic system
- Other cells sit in one place for a long period
Immune system molecules
Autocrine
- have effects on cells that release molecules
Paracrine
- Cells that release the molecules can influence cells in the nearby surrounding environment
Endocrine
- Travel in blood, usually indication there is an infection
- Ideally do not want to see them active
Anatomy of immune system
Physical and chemical barriers
- Immune cells originate from bone marrow stem cells (primary lymhoid organs)
primary lymhoid organs
Bone marrow
Thymus
Secondary Lymphoid Organs
Spleen
Lymph nodes
Mucosal tissues
Peripheral lymphoid organs
All other tissues and systems
Innate immune system
- Early and Rapid
- Short lived duration
- Repetitive response
- Interactive with other cells of the immune system
- Non-reactive to the host
Components of the innate immune system
Epithelial Barriers:
Cells in circulation and tissues:
- Neurophils and macrophages (Phagocytes)
- Exocytes (Release granules that kills microbes)
Molecules:
- Cytokines (TNF)
- Blood proteins
Innate immune system recognising patterns
- Epithelial/ endothelial resident immune cells have receptors that sense danger
- ## Different microbes present different patterns
Mast Cells
- Innate immune cells on peripheral tissues are exposed to the environment
- Have receptors that detect pathogens and danger
- Immediate first response
- Contain powerful pro inflammatory granules (TNF and histamine)
