Flashcards in Injuries to cells Deck (50)
What can stress of the cell lead to?
-cell adaptation and if cell cant adapt cell injury
Cell injury is reversible, what happens if it is irreversible?
cell death, by either :
Cell adaptation has four main types what are these?
What happens with hyperplasia?
increase in number of cell
normally results in large organ
Give a pathological and physiological example of hyperplasia.
- Pathological = endometrial hyperplasia if hormone stimulus continues (gets to much cells than normal, can progress on to cancer)
- Physiological = menstrual cycle
What is hypertrophy?
increase in cell size
What is a physiological example of hypertrophy?
- body builders when their muscles get bigger
What is a pathological example of hypertrophy?
- heart in hypertension (when high blood pressure causes heart to work harder, thickening of left ventricular wall)
What is atrophy?
shrinkage of the cell due to loss of cell substance
Why may cause atrophy ?
- decreased workload
- general ageing process
- reduced blood supply
- inadequate nutrition
- loss of hormonal stimulation
What happens in metaplasia?
- when one adult cell type is replaced by another adult cell type
What is an example of metaplasia ?
chronic gastro-oesophageal reflux or Barretts oesophagus
In barrett's oesophagus what happens?
squamous epithelium changes to columnar epithelium due to acid reflux leaking in to lower end of the oesophagus ad causing damage
Is metaplasia reversible?
What are the 3 most common causes of cell injury?
- Hypoxia ( low oxygen supply)
- Ischaemia (loss of blood supply leading to low oxygen and nutrients)
- Chemical exposure ( eg. smoking, alcohol, paracetamol)
What are the other causes of cell injury?
- immunologic reactions
What are the findings of reversible cell injury (when looking under a microscope)?
- cellular swelling
- fatty change
Cell death occurs via two main pathways, what are these?
necrosis and apoptosis
Which cell death pathway causes local inflammation?
How does apoptosis and necrosis cause cell death?
necrosis - damage to cell membrane allows enzymes to digest the cell
Apoptosis - programmed cell death. irreparable damage to cells DNA or deprived of growth factors
Is necrosis pathological or physiological?
it is always pathological
Is apoptosis pathological or physiological?
In apoptosis how are dead cells rapidly removed?
When is physiological apoptosis needed?
- to get rid of cells which have served their purpose
- to get rid of potentially harmful self-reactive lymphocytes
Give an example of physiological apoptosis when it is supposed to occur.
- Involution of hormone dependent tissues upon hormone deprivation ( uterus in postmenopausal women )
When might pathological apoptosis occur?
- DNA damage ( radiation)
- certain infections ( hepatitis )
- cell death induced by cytotoxic T cells
What does apoptosis result from ?
enzymes called caspases
What are the types of necrosis?
These describe what the necrosis looks like after it has died
What is an example of where coagulative necrosis may occur?