Inflammation Flashcards
Hyperaemia
Active increase in blood flow to an area. First step in acute inflammation
Oedema
increase fluid (from the vessels) in the interstitial tissue (does not enter cells, however sits in the connective tissue between the cells)
2 classifications of oedema
Exudate and transudate
Describe Exudate
Inflammatory extravascular fluid with high protein concentration
Describe Transudate
Extravascular fluid with low protein concentration
Effusions meaning
fluid leaks into body cavity
Resolution
Healing without scarring, restoration of structure & function.
Possible following acute inflammation
Depends on:
Tissue type
Extent of the injury
Presence of factors that can impair repair (infection, nutrition, etc).
Some tissues will never undergo resolution
Organisation
Healing by scarring/fibrosis.
Possible following acute inflammation
Depends upon:
(Inevitable following chronic inflammation)
Prior to maturation scar tissue is composed of granulation tissue
Granulation tissue:
- Macrophages: signalling and gobbling
-Fibroblasts/Myofibroblasts: make collagen
- Angiogenesis: growth of new capillaries
Mature scar is made of collagen protein
Ulcer
area of necrosis on surface. a lesion or sore on a body surface like the skin or mucous membranes
Abscess
Area of necrosis from acute inflammation. If the microbes are gone, the area becomes a cystic space. If the microbes remain, the body walls off area with granulation tissue and becomes chronic abscesses.
What form of cell death causes an inflammatory response?
Necrosis
What are the 3 features of acute inflammation?
- Hyperaemia
- Oedema (exudate)
- Neutrophils
What are the 3 possible outcomes of acute inflammation?
- Resolution: healing
- Organisation: healing
- Chronic inflammation
What are the 3 main components of granulation tissue & their role/purpose in repair?
- Macrophages remove the debris
- Fibroblasts secrete collagen
- New vessels grow (angiogenesis) & provide oxygen & nutrients
What happens following granulation tissue response?
Once complete, fibroblasts & macrophages leave, the vessels die by apoptosis leaving the acellular collagen scar, which will contract over time
Just filling a gap where tissue has been lost
Function lost
Distortion of surrounding tissue
What are the consequences of healing through organisation?
- Scarring: lost function and healthy tissue
- Distortion of surrounding tissue
- Contraction in larger scars can cause pain and discomfort
What are the 3 main causes of chronic inflammation?
- Unresolved acute
- Repeated acute
- Special cases - no acute response (some infections and diseases)
Define the 3 components of chronic inflammation?
- Continued injury/necrosis
- Repeated attempts to repair: a. Granulation tissue (3 components) b. Proliferating parenchymal (normal, functional) cells
- Lymphocytes
Describe the possible negative consequences of chronic inflammation.
- Loss of function through scarring
- If epithelial cells are proliferating, more chance of cancer
What is meant by sterile & non-sterile sites in the human body? Give examples.
Sterile - sites where microbes should not be present. This includes: Blood Brain & CSF Bone & Marrow Lower Respiratory Upper urogenital Stomach - unsure
Non-sterile - where microbes can be present. such as- Skin
GIT
Upper Respiratory
Lower urogenital
Main differences between the innate & adaptive systems
Innate: fast response, not specific, Gremline encoded, cellular (neutrophils, macrophages, NK cells), Humoral: complement components
Acquired/adaptive: Slow response, able to differentiate between targets, learns and remembers memory, cellular (T and B cells), Humoral: antibodies
Autoimmune response
Healthy cells are attacked by the immune system, causing harm to functional systems
Hypersensitivity response
Overactive immune system leading to allergies, asthma, anemia, lupus etc.
Immune-compromised meaning
Individuals’ immune system are underactive.
Genetic
Drugs/treatment - RT can kill haemopoetic cells. Diabetes can make you immunocompromised
Comorbid conditions
What are the general features of chronic inflammation
Later onset (days)
Longer duration (weeks- years)
Involves lymphocytes & macrophages
Involves further injury & repeated attempts to repair
Always results in organisation (scarring)
Types of microorganisms
• Parasites - largest, multiple celled • Yeast & fungi • Bacteria - intra or extra cellular • Viruses - intracellular parasites, survive within host unlike other microorganisms Prions - smaller than virus
What are the two types of defences?
Innate and acquired
Where in the body is the innate defence more dominant?
Epithelium, mucous, cilia on epithelium, hair, keratin, bacteria and the conditions they induce (e.g. the low pH of the female ectocervix), reflex coughing
Where is the acquired system more dominant?
immune system = lymphocytes
Prolonged “treatment” and “battle” against antigens
Microbiology
Study of infectious diseases
What factors do infections depend on?
- The host & principally the host response to infection
- Site of infection
- Characteristics of the organism principally the intrinsic virulence (power to cause disease) of the organism
How do microbes cause disease?
- Overcome defenses
- Damage host cells
- Alter host cells &/or cytokine production
- Adhesive/invasive factors, capsules, slime, fimbriae, pili, enzymes
- Toxins (exotoxins, endotoxins, enterotoxins etc)
- Cause damage & impair host defense
Overall, establish infection causing disease
Monocyte
immature macrophage (phagocyte)
Congestion
passive build up of blood within vessels
Pus
like exudate, purulent inflammatory exudate high in neutrophils, cell debris & sometimes pyogenic organisms
Inflammation
The body’s general response to injury (necrosis) and infection.
Acute inflammation is the start of repair although it can lead to further injury.
Chronic inflammation is not part of repair.
5 signs of Acute Inflammation
Heat - hyperaemia
Redness - hyperaemia
Swelling (exudate)– oedema due to hyperaemia & increased permeability
Pain – Stretch receptors & chemical mediators
Loss of function – swelling & pain
Chemical mediators of inflammation
Cause pain and conducts the process
Vast majority of plasma proteins are made in liver (important for inflammatory response)
Some mediators released from cells (special cells)
Chemotaxis
Locomotion according to a chemical gradient
Chemokine
Agent that induces chemotaxis (type of cytokine)
Cytokine
Hormone of the Immune system
Process of Extravasation in acute inflammation
- Margination
- Rolling
- Adhesion
- Diapedesis
- Migration
Process of phagocytosis in acute inflammation
- Recognition and attachment
- Engulfment
- Killing and degradation
Steps following necrosis and infection
- Release of chemical mediators creating a vascular and cellular response
- Vascular response: hyperaemia (vasodialition and increase in permeability), oedema (exudate)
- Leukocyte activation and recruitment leads to attack by neutrophils
Fibrinous exudate
Increases chance of organisation
Occurs following acute inflammation within linings of the body (meninges, pleural, pericardial and peritoneal)
May be removed by fibrolysis & phagocytosis
Otherwise may lead to the ingrowth of granulation tissue & scarring
Role of lymphocytes in the acquired immune system
• T cells
• B cells à Plasma cells à Antibodies
• Feature in chronic inflammation where the immune system is causing problems
• Autoimmune disorders
• Hypersensitivity disorders
• Involves lymphocytes macrophages & fibroblasts
• Involves continued injury, inflammation & repeated attempts to repair
Healing inevitably by organization
Roles of Immune System
Defense against infections
Defense against tumors
Recognition of foreign proteins & tissues
Recognition of other foreign substances (lipids, carbohydrates)
4 parts of the immune response
- Non-specific INNATE
- Specific response (slower) ADAPTIVE
- Non-specific reinforcement INNATE
- Memory ADAPTIVE