Immune system Flashcards
Describe the key differences between the ‘innate immunity’ and the ‘specific / adaptive immunity’
Innate Immunity: Physical barrier (skin &mucous membranes), fever, inflammation, immune cells & proteins. Specific/adaptive: activate immune cells to target specific pathogen
List FOUR ways in which pathogens can enter the body
- Breaks in the skin.
- The respiratory system.
- The digestive system.
- Male / female reproductive systems.
- Eyes.
Define the following terms:
a. Antigens
b. Antibodies
a. Antigen: is a substance that can be recognised by leukocytes
b. Antibodies: proteins produced in response of specific antigen
Explain what is meant by a ‘self-antigen’
Own cells that bring their passport so are not attacked by white blood cell which recognize as their own cells
Describe how the following contribute to the first line of immune defense:
a. Sweat
b. Sebum
c. Saliva
d. Tears
- Sweat removes microbes from skin and contains IgA.
- Sebum contains fatty acids which inhibit microbial growth.
- Saliva & Tears: wash away microbes and have antimicrobial substances. contain IgA and lysozymes. Lysozymes are enzymes that break down bacterial cell walls.
Explain how the micro ciliary escalator contributes to immune defense
In the respiratory tract, cilia propel the foreign substances towards the pharynx where they are swallowed = mucociliary escalator.
Second Line of Defence: Name 3 examples
- Complement system.
- Transferrins.
- Phagocytes.
- Natural killer cells.
- Inflammation.
- Cytokines (e.g. interferons).
- Fever.
Name TWO main phagocytes
Neutrophils & Macrophages
Describe in detail the FIVE stages of phagocytosis
- Chemotaxis: Release of chemicals by microbes, leukocytes, damaged tissue and by activated complement that attract phagocytes.
- Adherence: Attachment of phagocyte to target (aided by complement).
- Ingestion: The cell membrane extends projections that engulf the microbe.
- Digestion: The ingested structure merges with lysosomes to form a phagolysosome. Lysozymes and digestive enzymes ‘digest’.
- Excretion: Indigestible material is excreted.
1.Who Natural Killer cells attack?
2. Describe specifically how natural killer cells cause cytolysis
- anything they don’t recognize
2.NK cells bind to a target cell and release granules containing the protein ‘perforin’. Perforin cause foreign cells to rupture and burst (go into the cell membrane and creates a channel for tissue fluid to flow into the cell) -> cytolysis.
List TWO functions of non-specific fever
- Makes interferons more effective.
- Inhibits growth of some microbes.
- Speeds up the reactions that aid repair.
Describe the specific role of:
- MHC-I
- MHC-II
- MHC-I in all cells less erythrocytes has the role to present what the cell produce and if mutation it displays on the cell membrane faulty proteins. (indicating a ‘non-self’ cell) — t So MHC-I allows our leukocytes to determine healthy body cells from abnormal / infected cells.
- MHC-II are located only on Macrop& B-Lympho: they present the foreign antigen to the T-helper cell
Explain the role of TCR (T-cell receptors)
T-lymphocytes (or T-cells) play a central role in cell-mediated immunity. Each T-lymphocytes has a unique T-cell receptor (TCR) that only recognises a specific antigen.
Describe the difference between ‘self-recognition’ and ‘self-tolerance’
T-cells when ‘tested’ against thymus epithelial cells should recognize self-antigens. if they don’t recognize but lack of reactivity it’s called self-tolerance.
Explain the role of interleukin-2.
It’s a cytokine that causes clonal selection
Draw and label an ‘antibody’
