Cell Injury, Inflammation, Tissue Healing Flashcards
What are morphological changes?
The structural alterations of a cell
What are the morphological changes divided into?
Gross or macroscopic appearance
Microscopic appearance
Which type of stain is used in routine pathology?
Hematoxylin & Eosin
Why is the H&E stain useful in pathology?
Hematoxylin is positively charged so it would helpful to identify the nucleus since it is negative
Eosin is negatively charged so it would help identify the enzymes in the cytoplasm which are positively charged
What colour does the cytoplasm become under the H&E stain?
Pink
What colour does the nucleus become under the H&E stain?
Blue
What is cell injury and when does it occur?
When a stress exceeds the cell’s ability to adapt
What might cause cell injury?
Infectious agents
Immunological reactions (autoimmune)
Physical agents
Genetic defects
Hypoxia (lack of oxygen)
Drugs (overdose)
Nutritional imbalance
Thermal sources (burns)
Chemical agents
What are the two types of cell injury?
Reversible (sub-lethal)
Irreversible (lethal)
What is reversible cell injury?
Short duration
Reversible effects
What is an example of short duration cell injury?
Hypoxia
What are the changes that occur inside the cell during reversible cell injury?
Partial damage to the Na+ pump
Swelling of cell and organelles
What is irreversible cell injury?
Long duration
Irreversible effects leading to necrosis
What are some changes in the cell during irreversible cell injury?
Cell membrane damage
Cytoplasmic leakage
Nuclear changes
What are the kinds of changes that the nucleus might experience during irreversible cell injury?
Pyknosis, Karyorrhexix and karyolysis
What happens to the nucleus during pyknosis?
Nucleus shrinks in size and condenses
What is the nuclear pattern in necrosis called where the nucleus breaks down into small fragments?
Karyorrhexis
What happens to the nucleus during karyolysis?
Nucleus looks fade
Why does the nucleus look fade during karyolysis?
Chromatin lysed and DNA is lost
Where is coagulative necrosis usually seen?
In hypoxic environments, for instance ischemia and infraction
What kind of tissues is coagulative necrosis usually seen in?
Kidney, heart, and adrenal glands
What would coagulative necrosis look like under a microscope?
The affected part would be more pale compared to normal tissue
What usually causes coagulative necrosis?
A blockage
What is liquefactive necrosis?
Digestion of dead cells resulting in transformation of the tissue into a liquid viscous
Which kind of necrosis is associated with pus or abscess?
Liquefactive necrosis
What usually causes liquefactive necrosis?
Bacterial and sometimes fungal infections
What is the difference between pus and abscess?
Pus is a discharge
Abscess is a pocket of pus; accumulated pus
What is gangrenous necrosis?
It is a type of coagulative necrosis
Where does gangrenous necrosis usually occur?
Lower limbs, affects mainly diabetic patients, and the GI tracts
When is gangrenous necrosis considered as liquefactive necrosis?
If a superimposed infection occurs, it causes wet gangrene
What is caseous necrosis?
It is considered as a combination of coagulative and liquefactive necrosis
What is the appearance of caseous necrosis?
Dead cells look like large granules since they are not completely digested, giving the appearance of clumped cheese.
What usually causes caseous necrosis?
Mycobacteria such as Tuberculosis
What is seen microscopically for caseous necrosis?
Giant cells that are formed by the fusion of epithelioid cells (macrophages)
What is fat necrosis?
Appears as yellowish-whitened firm deposits
Where does fat necrosis usually occur?
In organs with adipose tissue, such as the pancreas
What is seen microscopically for fat necrosis?
The necrotic cells have a cloudy appearance
What is the process of fat necrosis occurring?
Triglycerides –> fat acids (lipase)
Fat acids –> fat acids + Ca+
Fat acids + Ca+ –> White chalky deposits
What is fibrinoid necrosis>
Occurs in smooth muscle cells which allow fibrins to deposit in the area of necrosis
Where does fibrinoid necrosis occur?
In the arterial wall, for instance vasculitis
What does fibrinoid necrosis look like microscopically?
The wall of the artery is bright pink with dark neutrophils
What is apoptosis?
Programmed cell death to eliminate the unwanted cells
What is the process of apoptosis?
Normal cell shrinks, chromatin condenses
Membrane starts blabbing, organelles disintegrate
Nucleus and organelles collapse, and the membrane continues to bleb
Apoptotic bodies form
Macrophages phagocytose apoptotic bodies
No inflammation
What happens to the size of the cell during necrosis and apoptosis?
Necrosis: swelling (enlarges)
Apoptosis: shrinkage (reduces)
What happens to the nucleus during necrosis and apoptosis?
Necrosis: pyknosis, karyorrhexis, karyolysis
Apoptosis: fragmentation around nucleosome (in apoptotic bodies)
What happens to the plasma membrane during necrosis and apoptosis ?
Necrosis: disrupted
Apoptosis: intact
What happens to the cellular contents during necrosis and apoptosis?
Necrosis: enzymatic digestion, Amy leak out of cells
Apoptosis: intact; may be release in apoptotic bodies
Is there adjacent inflammation during necrosis and apoptosis?
Necrosis: frequent
Apoptosis: no
Are necrosis and apoptosis of a physiologic or pathologic role?
Necrosis: pathologic only
Apoptosis: pathologic or physiologic
What is inflammation?
It is a non-specific immune (part of the innate immune system) that helps the body fight infection and heal tissue damage
How is inflammation clinically denoted?
By the suffix -itis