FOM Flashcards
What is an autopsy?
- used to determine cause of death and learn about the disease a person had when they died
Reasons for an autopsy
- investigate death that is/may be unnatural
- educational purposes
What is coroner?
- determines who died, how, when and where they met their death
What are the different types of autopsies?
- coronial
- consented
What is a coronial autopsy?
- investigate cause of death
- under jurisdiction of coroner
What is a consented autopsy?
- cause of death is known. education, research
- family-consented
What is inflammation?
coordinated response by vascularised tissue to injury or presence of micro-organisms
What two events occur in inflammation?
- vascular events
-cellular events
What are the cardinal signs of inflammation?
- redness
- swelling
- pain
- heat
- loss of function
What comprises the vascular events of inflammation?
- increased blood flow
- increased permeability of endothelium
- protein-rich plasma fluid enters tissue
- consequences of exudate
How does blood flow increase to capillaries in inflammation?
- pre-capillary sphincter muscle relaxes increasing blood supply
How is exudate formed in inflammation?
- blood plasma passes out of bloodstream into extravascular space through gaps of cells
What is consequence of exudate forming in inflammation?
- increased lymphatic flow and collection of oedema fluid (swelling)
- can lead to capacity of local lymphatic vessels being exceeded and plasma collecting in tissues
What are the two main parts of cellular events in inflammation?
- adhesion
- emigration
How do neutrophils adhere to endothelial cells?
- endothelial cells stimulated to increase number of cells adhesion molecules (transmembrane proteins)
- neutrophils have specific receptors so now are able to adhere to endothelial cell
What characterises acute inflammation?
- rapid, short duration
- dilation of small vessels
- increase permeability of microvascular
- emigration of leucocytes from microcirculation
What are two most important phagocyte in acute inflammation?
- macrophages: cell-cell interaction, secretion of cytokines, antigen presentation
- neutrophils
What is opsonisation?
- immune system coats bacteria with proteins which increase phagocyte affinity towards
What two pathways are involved in acute inflammation mechanisms?
- oxygen-dependent
- oxygen-independent
Describe the oxygen-independent pathway of acute inflammation
- rely on pre-formed toxic substances e.g. lysosomes
- fuse with phagocytic vacuole and release enzymes into it. phagolysosome
Describe the oxygen-dependent pathway of acute inflammation
- variety of highly reactive oxygen species
- uses large amounts of ATP and describe as ‘respiratory burst’. Enzymes involved located in membrane of phagolysosome
What characterises chronic inflammation?
- prolonged reaction to stimuli
- inflammation, tissue injury and scarring
- bind to receptors of target cells
What are cytokines?
- inflammatory mediators produced or activated at site when required.
- bind to receptors of target cells
Describe fibrosis produced by granulation tissue
- endothelial cells, fibroblasts, myofibroblasts and inflammatory cells
- looks red, granular surface
- maturation: new blood supply, increase of collagen, dense fibrous tissue
- function: produce a scar which restores physical integrity of body
What is necrosis?
- tissue that has died within an otherwise living organism
- used for macroscopic appearance of tissue that’s died
What is gangrene?
- particular type of necrosis generally meaning discoloured, infected dead tissue
Describe gangrene
- infection can spread to other parts of body, gangrenous tissue becomes weak
- weakness can cause walls of organs to break down, producing hole or rupture
What is dry gangrene?
- tissue dies and extremity takes on mummified appearance
- can affect limbs when blood supply is poor
What are the different types of necrosis?
- coagulative
- liquefactive
- caseous
- fat
- fibrinoid
- hemorrhagic
What necrosis typically occurs in the brain?
- liquefactive
- due to hydrolytic enzyme release
What is apoptosis?
- programmed cell death
- damage of lesser severity
- occurs as part of normal physiology and growth
Describe key features of apoptosis
- requires ATP
- cell shrinks, nucleus becomes more dense, breaks up and organelles fragment
- caspases: initiate by activating executioner caspases in cascade system
What do apoptotic bodies express on their outer membrane?
- phosphatidylserine
- many cells have receptors for this can so can bind to bodies and phagocytose them
What are the mechanisms of apoptosis?
- lack of GF/hormones
- ligand-receptor interaction
- 3 stages : initiation, execution and disposal
What is the difference between ischaemia and hypoxia?
- ischaemia is lack of sufficient blood supply
- hypoxia is lack of oxygen in blood
What is a granuloma?
- several epitheliod cells aggregated together in a mass
- ball of epitheliod macrophages with scattered lymphocytes
What is the inflammation where granulomas are found?
- granulomatous inflammation
- tends to usually occur when cause of inflammation is difficult for macrophages to digest
What is a giant cell?
- macrophages which fuse together. multi-nucleated
- appears when more than more macrophage tries to ingest same object resulting in mass of cytoplasm with many nuclei in it
What is hypertrophy?
- enlargement of tissue or organ by enlargement of size of cells
- functional capacity also increased
What is hyperplasia?
- enlargement of tissue/organ by an increase of number of cells
- not seen in skeletal/cardiac muscle or nerve cells
What is atrophy?
- reduction in mass of tissue/organ by reduction in cell size, number or both
- by apoptosis
- can be both normal or abnormal
What is metaplasia?
- change of one mature tissue into another
- benign and reversible process
What is the -oma suffix meaning?
- benign tumour
What is the carcinoma suffix meaning?
- malignant epithelial tumour
What is the -sarcoma suffix meaning?
- malignant non-epithelial tumour
- applies to connective tissue and bone
What is a neoplasm?
- abnormal mass of tissue, growth of which exceeds and is uncoordinated with that of normal tissue
- purposeless proliferation
Explain tumour grade
- extent to which tumour resembles tissue of origin
- 1-3: well-poorly differentiated
What is the neoplasia structure comprised of?
- neoplastic cells (parenchyma) and connective tissue which vascular supply is essential for growth
What does the tumour microenvironment (TME) include?
- stromal cells, cancer stem cells, immune cells and vasculature
