Pathology Flashcards
Definition of risk factor?
Social or individual factor which increases the risk of development of a disease
Aetiology definition?
Causative element in disease
Pathogenesis definition?
Sequence of events from healthy state to clinical disease
Sequelae definition?
Range of possible outcomes of disease process
Outcome definition?
Patient health or illness at a defined time
Necrosis requires energy. True or False?
FALSE
Requires no energy
What is necrosis? And what does it elicit?
Death of tissues
Pathological
-Elicits adjacent tissue response
Different patterns of necrosis?
- Coagulative
- Colliquative
- Caseous
- Gangrenous
- Fibrinoid
- Fat necrosis
Coagulative necrosis?
Proteins coagulate
Preservation of cell outline
-Eg MI
Colliquitive necrosis?
Necrotic material becomes softened and liquefied (PUS)
No cell structure remains
-Eg brain
Caseous necrosis?
Cheese-like
-Eg TB
Gangrenous necrosis?
Cell death by necrosis then infection on top of it
Anaerobic bacteria may grow
Fibrinoid necrosis?
Fibre deposition
-Eg damage to blood vessel in malignant hypertension
Fat necrosis example?
Eg- Acute pancreatitis
What process requires energy?
Apoptosis
What is apoptosis?
Programmed cell death
Defence against inherited injury
-Eithe physiological (normal growth) or pathological (injury, infection, chemo)
What is P53 and what can it lead to?
- Protein
- If lost it can lead to development of cancer, which is more likely resistant to treatment
Where does P53 function?
Cell cycle at G1 (like a spell checker)
-If mistakes are found cycle is paused and repair is attempted
What can occur at G1 checkpoint?
Apoptosis
If DNA is damaged
G2 checkpoint?
Mitosis will not occur if DNA is damaged or not replicated
M checkpoint?
Mitosis stops if chromosomes are not properly aligned
What happens if DNA can’t be repaired?
Then P53 stimulates and indices apoptosis
What part of the cell is involved in cell aging?
Telomere
Shortening
How do chromosomes prevent degradation and fusion?
They are capped
What does cancer reactivate?
Telomerase gets reactivated in cancer and can become immoral
What causes loss of membrane integrity?
Failure of ion pumps
Disruption of membrane
Alteration of lipids
Cross-linking of membrane proteins
What are free radicals formed by?
- Drugs
- O2 toxicity
- Reperfusion injury
- Inflammation
- Intracellular killing of bacteria
What is a metabolic disorder?
Biochemical abnormality which may itself be deleterious, but which also causes target organ damage, usually by accumulation of injurious agent
How would you inherit a metabolic disorder?
Autosomal recessive
Inherited metabolic disorder causes…?
Loss of function
What is phenylketonuria?
Due to accumulation of phenylalanine
Caused by deficiency in enzyme (phenylalanine hydroxylase) which converts phenylalanine to tryosine
Guthrie test - foot prick (PKU)
Vascular phase of inflammation?
Dilation and increased permeability of blood vessels
Exudative and cellular phase of inflammation?
Fluid and cells escape from permeable venules
What is a diagnostic feature for inflammation?
Neutrophil accumulation in extracellular space
Beneficial effects of inflammation?
- Toxin dilution
- Entry of ABs
- Fibrin formation
- Drug transport
- Oxygen and nutrient delivery
- Immune response stimulation
Harmful effects of inflammation?
- Digestion of normal tissues
- Swelling
- Inappropriate inflammatory response (Type 1 sensitivity)
What is chronic inflammation?
Subsequent and often prolonged tissue reactions
Characteristics of inflammation?
- Redness
- Heat
- Swelling
- Pain
- Loss of function
Why does redness occur in inflammation?
Due to dilation of small blood vessels
Why does heat occur in inflammation?
Increased blood flow through region
Why does swelling occur in inflammation?
Accumulation of fluid in extravascular space
Why does pain occur in inflammation?
Distortion of tissues
Why does loss of function occur in inflammation?
Inhibited by pain or swelling
What is in fluid exudate?
Proteins including immunoglobins
When does fibrinogen turn to fibrin?
On contact with ECM (Extra-cellular matric fibrin), acutely inflammed organ surfaces commonly covered in fibrin
What is margination?
Loss of intravascular fluid and increased plasma viscosity allows neutrophils into plasma (only occurs in venules)
What do neutrophils stimulate?
Inflammation
Adhesion of neutrophils increased by?
Complement C5a
Leukotriene B2
TNF
Endothelial expression of adhesion molecules increased by?
IL1
Endotoxins
TNF
What is chemotaxis?
Locomotion orientated along a chemical gradient
Examples of chemical mediators?
Histamine Seratonin Chemokines Leukotrienes Prostaglandins
What does histamine do?
-Vascular dilation
What are histamines released by?
Mast cells, eosinophils, basophils, platelets
Release of histamine is stimulated by?
C3a, C5a and lysosomal proteins (released by neutrophils)
What does seratonin cause?
Increased vascular permeability
What is another term for seratonin receptors?
5HT