[A] 1.38 Necrosis & Apoptosis Flashcards
(36 cards)
1
Q
Give the forms of necrosis
A
- Death
- Necrosis
- Necrobiosis
- Apoptosis (active process)
2
Q
Necrosis
A
Localised irreversible cessation of life in the living organism
- Morphological changes due to enzymatic degradation process in the injured cells
3
Q
Responses of cells to injury is dependent on…
A
- Cell type
- Injury type
4
Q
Give the responses of cells to injury
A
- Adaptation
- Degeneration
- Cell death
5
Q
Responses to injuries: Degeneration of the cell may be due to…
A
- Damage beyond adaptation capacity
- Severe/longlasting injury
- Malnutrition
- Mutation in important cell elements
6
Q
Stages of cell reaction
A
- Reversible stage: Can be repaired, normal function returns
- Irreversible stage: “Point of no return” → Cell death
7
Q
Give the types of cell death
A
- Physiological
- Passive
- Regulated
- Active
8
Q
When is physiological cell death seen?
A
- Embryonic development
- In skin cells & enterocytes
9
Q
Passive cell death
A
Necrosis
- The cell stops the vital functions
- Due to stimuli
10
Q
Regulated cell death
A
Necrobiosis
11
Q
Active cell death
A
Apoptosis
- Elimination of unwanted cell
- “Suicide” of the damaged cell
12
Q
What can necrosis affect?
A
- Cell elements
- Single cells
- Tissue parts
- Whole tissues
- Circumscribed areas of organs
- Whole organs
- Body parts
- Damaged tissues
13
Q
Give the categories of necrosis localisation
A
- Focal
- Regional
- Multifocal
- Massive
- Zonar
14
Q
Causes of necrosis
A
- Acquired - External/Internal
- Genetically programmed
15
Q
Acquired external necrosis
A
- Mechanical trauma (Blood vessels)
- Thermal effects (Burns & frostbites)
- Chemical (Acids & bases)
- Coagulation & colliquation of proteins
- Toxins
- Inhibition of enzymes
- Pathogens
16
Q
Acquired internal necrosis
A
- Hypoxia
- Ischaemia, hypoxaemia, prestasis, stasis
- Trophoneurotic disorders
- Injury, paralysis of nerves
- Pancreatic enzymes (lipase)
17
Q
Ultrastructural signs of necrosis
A
- Ribosomes detach from ER
- Mitochondria and other organelles are swollen
- Membranes are fragmented
- Reduced density of chromatin
18
Q
Histopathological signs of necrosis
- Nucleus
- Hyperchromatosis of membrane
- Karyopycinosis
- Karyorrhexis
- Karyolysis
- Cytoplasm
- Glycogen disappears
- Increased eosinophilia
- Cytoplasmolysis
A
19
Q
Necrosis: Macroscopic changes
A
- Coagulation necrosis and special forms
- Zenker necrosis
- Caseation
- Liponecrosis
- Colliquation necrosis
20
Q
Coagulation necrosis
A
- In the cytoplasm: Protein denaturation
- IC space: Denaturation due to lysosomal enzymes leaving cels
- Nuclear changes
- Occurence:
- Liver, Kidney & spleen
- Causes:
- Bacterial toxins
21
Q
Pathological signs of coagulation necrosis
A
- Sharp edges
- Elevated surface
- Dry cut surface
- Driable
- Colour: Dependent on blood content
22
Q
Special forms of coagulation necrosis
A
- Zenker necrosis
- Caseation
- Liponecrosis
- Blackleg disease (muscles & clostridia)
23
Q
Zenker necrosis: Characters
A
Necrosis of the contractile elements of muscle cells
- Cooked meat-like
- Pale & dry
24
Q
Zenker necrosis: Causes
A
- Nutrition
- Se or Vit. E deficiency
- Inproper circulation
- Vasoconstriction
- Improper functional hyperaemia
- Physical effects
- Burns, frost & trauma
25
Caseation
* Fatty infiltration before necrosis
* Lipochromes stain the necrotic mass
* *Tuberculosis & Pseudotuberculosis*
26
Colliquation necrosis
* Enzymatic effect following the disintegration of cells
* Not too much protein
* Necrotic area:
* Pulpy
* Smeary
27
Colliquation necrosis can be caused by...
Strong alkalic pH
28
Coagulation necrosis *+ Secondary colliquation (heterolysis)* →
Colliquation necrosis
29
Give the consequences of necrosis
1. Regeneration
2. Calcification
3. Sequestration
4. Cicatrix (organisation)
5. Lysis
6. Desquamation, erosion & ulceration
7. Secondary infection
30
Apoptosis: Causes
* Physiological:
* Removal of unnecessary cells & tissue homeostasis
* Removal of defective cells (genetic defects)
* Biochemical Effects:
* Activated caspases (cysteine proteases)
31
* Necrosis: Swollen
* Apoptosis: Shrunken
32
* Necrosis: Pyknosis → Karyorrhexis → Karyolysis
* Apoptosis: Breaks into fragments
33
* Necrosis: Damaged
* Apoptosis: Intact, different structure
34
* Necrosis: Enzymatic lysis, get out of the cell
* Apoptosis: Intact, inside apoptotic bodies
35
* Necrosis: Often
* Apoptosis: None
36
* Necrosis: Always pathologic
* Apoptosis:
* Often physiological, elimination of extra cells
* Pathologic after cell damage
