Introduction to Pathology & The mechanism of Injury to cells Flashcards
What are the 5 different components of Pathology and explain what they each focus on?
1) Histopathology= surgical histology, autopsy, cytopathology
2) Microbiology = Focuses on infections (e.g. viral or bacterial)
3) Immunology = Focuses on Antibodies and allergic diseases
4) Haematology = Focuses on blood cell indices
5) Chemical pathology (aka biochemistry) = biochemical substances
Expand on the 3 components of Histology?
1) Cytopathology = the examination of cells only
2) Surgical histology (aka biopsy) = the examination of tissue samples from living patients
3) Autopsy (aka post-morterm examination) = the examination of tissue samples from dead patients
Describe a cell in homoeostasis?
A cell is normally confine to a:
Structured environment
A narrow range of function
Describe the process how what happens to a cell when it comes into contact with a stress stimulus?
1) Cell (homeostatic state)
2) Stress stimulus
3) Adaptation or (in unable to adapt) cell injury
4) Cell injury is either: 1) Reversible (if the stress stimulus was mild and short-lived) or 2) Irreversible (if the stress stimulus was severe and progressive)
5) Reversible cell injury will return the cell back into it’s homeostatic state
6) Irreversible cell injury will cause cell death
Describe and compare the 2 types of cell death?
1) Necrosis = always abnormal cell death and always pathological
Causes: Damage to cell membrane, enzymes digest the cell and causes the inflammatory process
2) Apotosis = (aka programmed cell death) It is apart of the body’s normal regulatory process and can be either pathological or physiological
Causes: Cell membrane remains in tact, clean phagocytosis process removes the cell and no inflammatory process is caused
The 4 ways in which a cell can adapt?
1) Hyperplasia
2) Hypertrophy
(Hyperplasia & Hypertrophy can run alongside eachother)
3) Metaplasia
4) Atrophy
Define Hyperplasia and give a Physiological & Pathological example:
Hyperplasia = When the number of cells increase leading to a larger organ.
Physiological example: Endometrial cells increase in number during the menstrual cycle
Pathological example: Endometrial cells increase in number if a hormone persists
Define Hypertrophy and give a Physiological & Pathological example:
Hypertrophy = When the size of the cell increases leading to the size of the organ increasing.
Physiological example: Muscle cells increasing in size in body builders
Pathological example: Myocytes in the heart will increase in size in order to work hard during hypotension
Define Metaplasia and why does it happen?
Metaplasia = where 1 cell type changes into another mature cell type.
It happens so that the cell can withstand the stress of a changed environment.
Metaplasia is a REVERSIBLE process.
Give an example of metaplasia:
Barrett’s Metaplasia =
The role of the gasto-oesophageal sphincter is to prevent the acidic contents of the stomach refluxing into the oesophagus.
However, in Barrett’s Metaplasia (aka indigestion) the acidic contents refluxes into the oesophagus. This causes the normal Squamous Epithelium of the oesophagus (that copes with neutral pH) to change into Glandular epithelium (that copes with acidic pH).
Define atrophy:
Atrophy = Shrinking of the cell size due to loss of cell substances
What are the 5 different causes for cell atrophy?
1) Reduced work load
2) Reduced blood supply
3) Inadequate nutrition
4) Loss of hormone stimulation
5) Ageing cell
What are the 8 causes of cell injury (rather than the cell adapting to the stress response)?
C = Chemical exposure (e.g. cigarettes/alcohol) H = Hypoxia (lack of O2) I = Ischemia (loss of blood supply - lack of nutrients & O2) N = Lack of nutrients A = Ageing (cells have a finite life span) I = Immunological reactions (body attacking own cells) I = Infections R = Radiation (alters cell's DNA)
Describe the morphology of reversible cell change?
1) Swelling of the cell
2) Fatty deposits within the cell
Examples of Physiological reasons for Necrosis cell death?
NECROSIS CELL DEATH IS ALWAYS PATHOLOGICAL - NEVER PHYSIOLOGICAL!!!
Examples of Physiological reasons for Apotosis cell death?
1) Embryo-genesis
2) Elimination of hormonal-dependent tissues that are no longer receiving hormone stimulants
3) Elimination of cells that have served their purpose
4) Elimination of self-reactive lymphocytes (lymphocytes that are dangerous because they can detect self-cells)
4 main examples of Pathological reasons for Necrosis cell death?
1) Coagulative necrosis (think red cells) e.g. in lung and heart attacks
2) Caseous necrosis (think cheese) e.g. in TB
3) Liquefactive necrosis (think missing parts) e.g. in the brain following a stroke
4) Fat necrosis (think white blobs) e.g. in the breast tissue
Examples of Pathological reasons for Apoptosis cell death?
1) Hepatitis virus
2) DNA damage
3) Misfolded proteins
4) Duct obstructions (leading to parenchyma organs dying)
5) Cell death by Cytoxic-T cells
What is the danger of Apototic cell death not occuring?
Leading cause of cancer
