Basic Sciences Flashcards
What feature is not shown on an FNAC study?
Perivascular invasion
Invasion of basement membrane
What are the recognised forms of cell death?
1) Necrosis
2) Apoptosis
What are the features of necrosis?
Induction:
- Pathological stimuli
Extent:
- Groups of cells
Biochemical:
- Ion homeostasis imparied/stopped
- Lysosomal leak lytic enzymes
Cell membrane integrity:
- Lost
Morphology:
- Cell swelling and lysis
Inflammatory response:
- Present
Fate of dead cells:
- Phagocytosed by neutrophils and macrophages
What are the features of apoptosis?
Induction:
- Physiological / Pathological stimuli
Extent:
- Single cells
Biochemical:
- Energy-dependent fragmentation of DNA by endogenous endonucleases
- Lysosomes intact
Cell membrane integrity:
- Preserved
Morphology:
- Cell shrinkage & breakdown ==> apoptotic bodies & dense chromatin
Inflammatory response:
- Absent
Fate of dead cells:
- Phagocytosed by neighbouring cells
What are the mediators of apoptosis?
1) p53
2) bcl-2
3) fas (CD 95)
4) Caspases
What local factors affect wound healing?
1) Type, size, site
2) Local blood supply
3) Infection
4) Foreign bodies/contamination
5) Radiation damage
What systemic factors affect wound healing?
1) Age
2) Co-morbidities (DM/CVD)
3) Nutritional deficiencies
4) Obesity
What are the stages of wound healing?
1) Haematoma
2) Inflammation
3) Proliferation
4) Remodelling
What are the histological features of malignancy?
1) Distorted architecture
2) Involvement of basement membrane
3) Increased angiogenesis
4) Areas of haemorrhage & necrosis
5) Peri-neural/vascular/lymphatic invasions
What characteristics of a benign tumour?
1) Localised at site of origin
2) Does not invade adjacent tissues
3) Slow growth
4) Remains encapsulated
5) Not metastatic
6) Fully differentiated
Can benign tumours be significant?
Only if they cause mass effect/pressure onto adjacent structures within an enclosed space
What characteristics of a malignant tumour?
1) High rate of cell division/proliferation
2) Invades surrounding tissues
3) Metastatic / paraneoplastic syndromes
4) Not encapsulated/contained
5) Poorly differentiated/ anaplastic
6) Can cause complications e.g. erosion into blood vessel/bone/nerve
7) Mass effect
Examples of paraneoplastic syndromes?
1) Cushing’s syndrome
2) Hypercalcaemia
3) Polycythemia
4) Hypoglycaemia
5) Carcinoid syndrome
Explain the following paraneoplastic syndrome mechanisms:
1) Cushing’s syndrome
2) Hypercalcaemia
3) Hyponatraemia
4) Polycythemia
5) Hypoglycaemia
6) Carcinoid syndrome
7) Trousseau’s syndrome
1) ACTH-like substance
2) PTH-related protein
3) Innapropriate ADH secretion
4) EPO
5) Insulin-like substance
6) 5-HIAA
7) Hypercoagulable state
What are the stages of secondary fracture healing?
1) Haematoma & Inflammation (Day 1 - 5)
- Haematoma
- Macrophages, neutrophils & platelets release cytokines
- Fibroblasts & mesenchymal cells migration
- Osteoblasts & fibroblasts proliferate
- Inhibiton of COX-2 => crucial for osteoblastic differentiation
2) Callous formation
Soft callous (Day 5 - 10)
- VEGF further proliferates & brings in mesenchymal cells
- These differentiate into fibroblasts, chondroblasts & osteoblasts
- Chondrogenesis & woven bone laid down
Hard Callous ( Day 10 - 28)
- cartilagenous bone forms into endochondral ossification
- RANK-L expressed => further differentiation of osteoblasts/clasts & chondroblasts/clasts
- Resorption of cartilagenous bone => calcify
- Woven bone laid down, further proliferation of vessels & mesenchymal cells
- Immature bone formation
3) Remodelling (Day 18 - onwards months/years)
- Continuous migration of osteoblasts/clasts
- Undergoes repeated remodelling
Both bone resorption by osteoclasts & bone building by osteoblasts
- Centre of callous replaced by compact bone
- Edges of callous replaced by lamellar bone
