Week 4 Lecture 1 Flashcards
Give an example of physical/mechanical barrier.
- Linings of the gastrointestinal tract, genitourinary and respiratory tracts.
- Skin.
What are the 3 lines of defense?
Innate - First
Inflammation - Second
Adaptive immunity - Third
Give an example of biochemical barriers.
Synthesized and secreted, saliva, tears, earwax, sweat ad sebum.
What causes the second line of defense to activate?
Infection, mechanical damage, ischemia, nutrient deprivation, temperature extremes and radiation.
Give an example of a characteristic of acute inflammation.
- Redness
- Heating
- Swelling
- Pain
- Loss of function
What is the goal of inflammation?
- Remove agents/prevent spread of
- Remove debris and damage
- Prevent infection
- Facilitate adaptive immunity
- Bring about repair
What is the first major event in a local inflammatory response?
Activated macrophages and mast cells at the injury site release chemical signals that act on nearby capillaries.
What is the second major event in a local inflammatory response?
The capillaries widen and become more permeable, allowing fluid containing antimicrobial peptides to enter the tissue. Signals released by immune cells attract additional phagocytic cells.
What is the third major event in a local inflammatory response?
Phagocytic cells digest pathogens and cell debris at the site, and the tissue heals.
What are the 4 systems involved with plasma and cell derived mediators?
- Protein system
- Complement system
- Coagulation system
- Kinin system
What are the cell derived mediators?
- Mast cells (histamine)
- Platelets (serotonin)
- Neutrophils and macrophages
What is the main role of the complement system?
Activated with every component of inflammatory response.
What is opsonization?
Enhancing phagocytosis of antigens?
What is chemotaxis?
Rupturing membrane of foreign cells.
What is agglutination?
Clustering and binding of pathogens together.
What are the 3 pathways?
- Classical
- Lectin
- Alternative
What is the coagulation system and what does it do? Address 3/6 points.
- Insoluble protein called fibrin.
- Forms a fibrinous network mesh work at an injured or inflamed site.
- Prevents spread of infection.
- Keeps microorganisms and foreign bodies at the site of greatest inflammatory cell activity.
- Forms a clot that stops bleeding.
- Provides framework for repair and healing.
What is the main role of the Kinin system?
Activate and assist inflammatory cells.
What are the components of the cellular mediators?
- Granulocytes
- Platelets
- Monocytes
- Lymphocytes
- Mast cells
- Neutrophils
What are mast cells and how do they work?
- Cellular bags of granules located in loose connective tissue close to blood vessels.
- Activated by physical injury, chemical agents etc
- Released via degranulation and synthesis of lipid-deprived chemical mediators.
What is histamine and what does it do?
Vasoactive anime that causes temporary, rapid construction of the large blood vessels and the dilation of the postcapillary venules.
What are leukotrienes and what do they do?
- Product of arachidonic acid from mast cell membranes.
- Similar effects to histamine in later stages.
What is the effect of prostaglandins?
Similar effect to leukotrienes, induce pain.
What are neutrophils and what do they do?
- Major class of white blood cell in human peripheral blood.
- Predominate in early inflammatory response.
- Short lived, become component of purulent exudate.
- Kill extra cellular pathogens.
What are the 5 steps of phagocytosis?
- Opsonization, recognition and adherence.
- Engulfment
- Phagosome formation
- Fusion with lysosomal granules
- Destruction of target
How are macrophages formed?
Monocytes produced in bone marrow, enter circulation and migrate to the inflammatory site, where they develop into macrophages.
What changes occur once a macrophage activates?
Increase in plasma membrane area, glucose metabolism, number of lysosomes and secretory products.
What is the role of natural killer cells?
Recognize and eliminate cells infected with viruses and in some cases, cancer cells.
What happens when a platelet activates?
Degranulation and interaction with components of the coagulation system.
What is the main role of interferons?
Protect against viral infection.
What is the role of INF a/b?
Induce production of antiviral proteins.
What is the role of INF y?
Increase microbialcidal activity of macrophages?
What is serous exudate?
Watery exudate; indicates early inflammation.
What is fibrinous exudate?
Thick, clotted exudate; indicates more advanced inflammation.
What is purulent exudate?
Pus; indicates bacterial infection.
What is hemorrhagic exudate?
Exudate containing blood; indicates bleeding
What are 3 disadvantages of acute inflammation?
- Excess swelling
- Pain
- Impaired function
- Cell damage and death
- Shock, if severe
What are the 3 outcomes of acute inflammation?
- Growth and repair
- Suppuration/abscess
- Progression to chronic inflammation
What is Suppuration and abscess?
- Inflammation persists
- Dead white cells and damaged tissue increased.
- Area walled off by inflammatory cells.
- Abscess (cavity containing pus)
- Normal tissue replaced by scar tissue.
What are epitheloid cells?
Elongated cells with larger cytoplasm and vacuoles.
What are langhans giant cells?
Up to 50 macrophages with nuclei in horseshoe pattern.
What is resolution and repair?
Resolution - returning injured tissue to the original structure and function.
Repair - replacement of destroyed tissue with scar tissue.
What is the reconstructive phase?
Healing phase of tissue.
What is the maturation phase?
Scar tissue remodelled.
