Page 70 - Concise Pathology for Exam Preparation ( PDFDrive )

3 Healing and Repair 55

Injury

Vascular and cellular response

Acute inflammatory exudation
Stimulus destroyed Persistent stimulus

None or minimal necrosis of cells
Tissue of Tissue of
Exudates resolved Exudates organized stable or permanent
labile origin origin
Return to original Scarring
structure No regeneration

Framework intact Framework destroyed

Regeneration; normal Scarring
structure regained
FLOWCHART 3.1. Pathways of reparative response following injury.

Q. Write briefly on cell cycle.

Ans. During differentiation, mammalian cells alternate between a phase of division
(mitosis) and a resting phase (interphase). The sequence of events that control DNA
replication and mitosis and, hence, cellular proliferation is labelled cell cycle (Fig. 3.2).

Labile cells

S G 2

G /S G /M
2
1
checkpoint checkpoint

G 1 M

Quiescent cells

G 0
Permanent cells Cell division
FIGURE 3.2. Cell cycle.

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