Session 1 Cell Injury Flashcards
(34 cards)
How would villi differ in cilliac disease?
Short, fat and blunted.
What do macrophages do to dead fat cells?
Digest them
What forms in lymph cancer?
Glands form in lymph cancer on the outer edges. (White things)
How can you identify basal cell carcinomas on a histological section of skin?
The darker patches are where the carcinoma is.
What is used to fix and stain tissue?
Formalin used to fix
Then embedded in paraffin wax.
- remove water from tissue using alcohol and a vacuum
Stain with Haematoxycilin (stain nucleus purple) and eosin stains cytoplasm and CT pink
Name 3 things that can cause call injury.
Hypoxia
Toxins
Physical agents (trauma/extreme temperature/pressure)
What are the causes of hypoxia?
Hypoxaemic hypoxia
- arterial content of oxygen is low
- e.g higher altitudes and reduced absorption secondary to lung disease
Anaemic hypoxia
- decreased ability to carry oxygen
- anaemia or carbon monoxide poisoning
Ischaemic hypoxia
- interruption of blood supply
- blockage of a vessel or heart failure
Histiocytic hypoxia
- inability to utilise oxygen in cells due to disabled oxidative phosphorylation enzymes.
- cyanide poisoning
How does the immune system damage Body cells?
- hypersensitivity reactions = host tissue is injured secondary to an overly vigorous immune reaction
- autoimmune reactions = immune system fails to distinguish self from non self e.g Graves’ disease of thyroid.
Which cell components are most susceptible to injury?
- cell membranes
- nucleus
- proteins
- mitochondria
What is happening at the molecular level in hypoxia?
In the case if ischaemic hypoxia
- blockage
- less oxidative phosphorylation in mitochondria of cell
- less atp for protein synthesis as a result
- increased glycolysis
- less action of Na pump = efflux of K and cellular swelling due to influx of h2o and Na and Ca
What happens if hypoxia is irreversible?
Changes are irreversible
- mitochondria and ER release calcium into the cytosole = decrease ATP and phospholipids, disrupt cytoskeleton proteins and cause nuclear chromatin damage
What enzymes in the body control free radicals?
Superoxide dismutase
Catalase
Glutathione peroxidase
What is a heat shock protein? Give an example.
Ubiquitin
Aims to mend misfolded proteins and maintain cell viability in cell injury.
How does a dead cell change in appearance?
- pyknosis = normal cell with dark nucleus
- karyorrhexis = coagulation of proteins so cell looks dotty. Some proteins leak out of cell. Because of coagulation, take up stain making cytoplasm appear darker.
- karyolysis = nucleus dissolves away = irreversible cell death.
How would a cell look if injury was reversible??
- blebs of cytoplasm
- clumping of nuclear chromatin
- mitochondrial and ER swelling
What are the two main types of necrosis? (And name the other two)
Coagulative
- ischaemia of solid organs e.g. kidney, liver, heart.
- due to protein desaturation.
Liquefaction necrosis
- ischaemia in loose tissues e.g brain and lungs
- presence of many neutrophils
- due to enzyme release
Also there’s caseous and fat necrosis.
What does coagulative necrosis look like?
- cells architecture is sort of preserved
- darker staining
- looks more wiggly
- lots of dots between layers = neutrophils mopping up dead tissue
- nuclei have undergone karyolyse
What is the difference between oncosis and necrosis?
- oncosis = the process of cell death with swelling.
- necrosis= when the cell is actually dead. What you see after it dies e.g karyolysis.
What is caseous necrosis and what does it look like?
- contains structureless debris
- particularly associated with infections, especially tuberculosis
- appears dense like a ball
- in a fixed tissue appears lighter, like cheese (caseous = cheese in Latin)
Define the terms
- gangrene
- infarction
- infarct
Gangrene = a necrosis visible to the naked eye
Infarction = necrosis caused by reduction in arterial blood flow. Can lead to gangrene.
Infarct = an area of necrotic tissue which is a result of loss of arterial blood supply. An area of ischaemic necrosis.
What is the difference between dry and wet gangrene?
Dry = necrosis modified by exposure to air (coagulative necrosis)
Wet = necrosis modified by infection (liquefactive necrosis)
Why are some infarcts white and why are some red?
White
- anaemic infarcts
- solid organs with occlusion of end artery
- coagulative necrosis
Red
- haemorrhaging infarct
- loose tissue
- Dual blood supply
What is ischaemia reperfusion injury?
if blood flow is returned to a damaged by not yet necrotic tissue, damage sustained can be worse than if blood flow hadn’t been returned.
Possible causes include:
- increased production of oxygen free radicals with reoxygenation
- increase number of neutrophils resulting in more inflammation and increased tissue injury
- delivery of complement proteins and activation of complement pathways.
What apoptosis and When may it occur?
Apoptosis = cell death with shrinkage that is regulated and characteristics.
Occurs physiologically when trying to maintain a steady state and embryogenesis.
Occurs pathologically when cytotoxic T cells acting on virus infected or neoplastic cells, when cells have damaged DNA etc.
