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Flashcards in Injuries to cells Deck (18)
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Define hyperplasia

Increase in number of cells = increase in size of organ eg. menstrual cycle


Define hypertrophy

Increase in size of cells = increase in size or organ eg. body builders, heart in hypertension


Define metaplasia

One adult cell type is replaced by another, reversible, may be able to withstand new stress eg. chronic gastro-oesophageal reflux


Define atrophy

Decrease in size of cell by loss of cell substance due to loss of blood, lack of nutrition, loss of hormonal stimulation, ageing


What are the causes of cell injury

Hypoxia, ischaemia, chemical exposure (alcohol, cigs), infection, radiation, lack of nutrition, ageing


What is necrosis?

Cell death which is always pathological
Damage to membrane allows enzymes to digest cell
Causes local inflammation


What are the 4 types of necrosis?

Liquefactive eg stroke
Caseous eg TB
Fat eg breast (mistaken for cancer)


What is apoptosis?

Programmed cell death by Killer T cells- irreparable damage to cells proteins & DNA
Bits of cell break off, rapidly removed by phagocytosis
Can be physiological:
-elimination of cells that have served their purpose & harmful self-reactive lymphocytes
- embryogenesis
Can be pathological:
-DNA damage - accumulation of misfolded proteins
- caused by certain infections, occurs in parenchymal organs after duct obstruction


What is neoplasia?

Mild DNA damage by gene mutation
- damage to genes controlling DNA repair - further change
- damage to genes controlling cell division = excess division
-mutation accumulate = abnormal cells = CANCER


Define inflammation and its aims

Response to tissue damage by a wide range of stimuli
Protective, aims to remove/contain pain, initiates repair and reinstate useful action, essential for wound healing


Vascular reaction of inflammation

Maximises movement of plasma proteins and circulating cells to cite of injury by:
> changing vessel and flow
> increasing vascular permeability
Results in hyperaemia (excess blood in vessels), stasis and fluid exudation


Cellular reaction of inflammation

Leukocyte (neutrophils) extravasation
- margination, rolling, adhesion to endothelium
- transmigration
- migration through tissue


5 cardinal signs of inflammation

Heat, Redness, Swelling, Pain, Loss of function


Signs and symptoms of inflammation

Fever, increase pulse and BP, increase WCC and CRP count


Acute inflammation

Rapid response, short lived
Neutrophils predominant
Aim to complete resolution, healing by fibrosis (scar formation)
Can lead to chronic


Chronic inflammation

Prolonged (weeks/months)
Due to persistant infections, prolonged exposure to toxins, autoimmune reactions
Lymphocytes and macrophages predominant
Causes tissue destruction
Attempts at healing = proliferation of blood vessels, fibrosis & necrosis
eg. TB transplant rejection, autoimmunity


Treatment of inflammation



What happens if a person has no inflammation response?

Increase susceptibility of infection
Delayed wound healing
Tissue damage
eg. post chemo