Pathology Flashcards
What are the potential causes for a disease?
VINDICATE Vascular Infection/Inflammation Neoplasm Drugs/toxins Iatrogenic Congenital Autoimmune Trauma Endocrine/metabolic
What mediators cause vasodilation?
Histamine and NO
What is margination?
As the rate of blood flow slows in vasodilation WBCs move to the edges of vessels
What do pro-inflammatory mediators cause?
Increased expression of ICAM and Selectin on endothelial cells which bind glycoproteins and integrins respectively on WBC surface
What is rolling?
When bonds between endothelial vessel wall cells and WBCs are initially weak and WBCs can move along the walls of the vessels
What is the function of chemokines?
They are released from site of injury and bind endothelial cells, then increase the affinity of their binding
What is pavementing?
WBCs flatten against the vessel wall
What is migration/diapedisis?
WBCs extend pseudopods through gaps in endothelial wall and move out of the vessel
What is chemotaxis?
Once outside vessels, WBCs follow concentration gradient towards to site of injury established by chemokines
What are examples of chemokines?
C5a
Interleukins
Leukotrines
What is the main WBC?
Neutrophil
What are the features of neutrophils?
Multilobed (polymorph)
Granulocytes int he cytoplasm
What is the function of neutrophils?
Phagocytosis
What are the possible outcomes of inflammation?
Resolution
Suppuration
Organisation
Chronic inflammation
When will restoration occur?
The site can renew well
Good blood supply
Source of injury removed easily and quickly
What is suppuration?
Formation of pus - collection of dead cells
When will organisation happen?
Poor blood supply
Extensive cell death and necrosis
Lots of fibrin produced
Tissue type has limited regenerative capacity
What can organisation result in?
Granulation tissue
Fibrosis and scarring
What is granulation tissue?
Tissue formed to facilitate healing if damage goes beyond basement membrane
Capillaries formed and myofibroblasts lay down collagen and smooth muscle
How is fibrosis and scarring formed, and what is the problem with it?
Neutrophils, then macrophages, then fibroblasts lat down collagen
Loss of function
What is the predominant cell of chronic inflammation?
Lymphocyte
When is chronic inflammation likely?
Suppuration produced walled areas of pus (called abscess or empyema)
Infection is caused by virus or is persistent
Autoimmune cause
What can chronic inflammation produce?
Granulomas
Caseous necrosis
What are granulomas, why are they formed, and what is a condition that classically causes them?
Aggregate of epithelioid histiocytes or organised collection of macrophages
Formed when immune system cannot eliminate percieved foreign material
Sarcoidosis
What are the two causes of cell death?
Necrosis
Apoptosis
What are the types of necrosis?
Coagulative - preserved cell outline filled with fibrosis
Liquefactive no structure remains
Caseous - area of necrosis surrounded by granulomatous inflammation
What is apoptosis?
Programmed cell death
When is apoptosis physiological?
Normal growth
Loss of self-reactive lymphocytes
Hormonally resulted processes
How does apoptosis occur?
Via caspases that cleave DNA
What is the extrinsic pathway of apoptosis?
Loss of growth signals - replacement of anti-apoptotic molecules with Bak and Bax increase permeability of the mitochondria, release proteins that stimulate caspases
What is the intrinsic pathway of apoptosis?
Cell membrane receptors bind and activate caspases
What is hyperplasia?
Increase in cell number in response to stimulus
What is hypertrophy?
Increase in cell size
What is atrophy?
Reduction in cell size
What is neoplasia?
Any new growth
What is a malignant growth?
Growth that has spread path basement membrane the can metastasise - cancer
What is a precursor lesion?
A stage where a cell is at high risk of becoming malignant
What is metaplasia?
Reversible change from one mature cell type to another
What is dysplasia?
Disordered cell growth but no invasion past basement membrane
What is carcinoma in situ?
Dysplasia affecting the whole basement membrane - the last stage before malignancy
What are features of a benign tumour?
Symmetrical
Encapsulated
Homogenous
Well differentiated
What are features of a malignant tumour?
Poorly defined and irregular edges Hetrogenous Pleomorphism (all cells look different) High nucleus to cytoplasm ratio Purple when stained Poorly differentiated
What are the names of benign and malignant squamous epithelium tumours?
Benign - papilloma
Malignant - carcinoma
What are the names of benign and malignant glandular epithelium tumours?
Benign - adenoma
Malignant - adenocarcinoma
What are the names of benign and malignant mesenchymal tumours?
Benign - _oma
Malignant - _sarcoma
What is the grading of a tumour?
How well differentiated
What is the staging of a tumour?
How far has it spread - TNM
What are the hallmarks of cancer?
Sustains proliferative signalling Evading growth suppressors Avoid immune destruction Enabling replicative immortality Tumour promoting inflammation Activating invasion and metastasis Inducing angiogenesis Genome instability and mutation Resisting cell death Deregulating cellular energetics
What are oncogenes?
Genes that when activated will cause cancer
What are porto-oncogenes?
Normal genes involved in cell growth and division which if mutated can cause cancer
What are tumour suppressors?
Genes that try to prevent cancer formation
What is an example of a tumour suppressor?
p53
What is thrombosis?
Intravascular activation of coagulation
When is thrombosis more likely?
If Virchow’s triad present
What is embolism?
Part of thrombosis has dislodges from site of formation and travels until lodges
What is ischaemia?
Insufficient blood flow to tissue
What is infarction?
Death of tissue due to lack of blood supply and hypoxic cell injury
