Regressive lesions - 1 Flashcards
Atrophy def:
Atrophy of any organ is defined as shrinkage in the size of the cell by the loss of cell substance.
Frequently, this condition is manifested by shrinkage (reduced size) of affected organ.
However, shrinking parenchymal cells are in some cases replaced by connective or fat tissue the dimension of atrophic organ remaining unchanged
Atrophy depends on the underlying cause and can be ……
local or generalized
The common causes of atrophy are the following:
- diminished blood supply
- decreased workload (atrophy of disuse)
- inadequate nutrition
- loss of endocrine stimulation
- pressure
- loss of innervation (denervation atrophy)
Atrophy- morphologic classification:
- Reference to cells
- Reference to stroma
- Reference to an entire organ
Reference to cells:
Atrophy- morphologic classification
e.g. simple atrophy
Reference to stroma:
Atrophy- morphologic classification
- normal stroma ( e.g. simple atrophy)
- increased stroma (e.g. due to excess of collagen „fibrous a.”, due to accumulation lymphocytes)
Reference to an entire organ:
Atrophy- morphologic classification
- concentric atrophy:
diminution of an organ - eccentric atrophy:
diminished mass of an organ while its size is normal or even increased (pulmonary emphysema, hydronephrosis, osteoporosis, lipomatous atrophy of the pancreas)
Increased stroma
e.g. due to excess of collagen „fibrous a.”, due to accumulation lymphocytes
Concentric atrophy
diminution of an organ
Eccentric atrophy:
diminished mass of an organ while its size is normal or even increased (pulmonary emphysema, hydronephrosis, osteoporosis, lipomatous atrophy of the pancreas)
Pulmonary emphysema:
Emphysema pulmonum essentiale
The term pulmonary emphysema….
is applied to a condition characterized by abnormal distention of air spaces distal to the terminal bronchioles with destruction of interalveolar septa.
The term „overinflation”……..
refers to dilatation of air spaces which is not accompanied by destruction of their walls.
Emphysema (besides chronic bronchitis and small airways disease) is included in a group of pulmonary disorders, referred to as…….
Chronic Obstructive Pulmonary Disease (COPD)
The most important factors contributing to development of pulmonary emphysema:
- smoking
- inherited susceptibility
- frequent respiratory tract infections (especially in childhood)
What is the clinically presenting symptom of pulmonary emphysema?
dyspnea is the presenting symptom.
It results from loss of elastic recoil properties and reduction of gas exchanging surface.
MORHOLOGICALLY, emphysema is classified according to the distribution of changes within pulmonary acini.
- Centrilobular (centriacinar)
- Paraseptal
- Panacinar
Centrilobular (centriacinar):
- proximal acinar
- involving respiratory bronchioles
- result of cigarette smoking!
Paraseptal
- distal acinar
- involving alveoli and alveolar ducts
Panacinar
- panlobular
- involving pulmonary acini uniformly
Centriacinar (centrilobular)
- result of cigarette smoking
- Distal alveoli are spared and respiratory bronchioles are involved (both distended and normal airspaces are present)
- upper lobes
- spaces that exceed 1 cm in size – „bullae”
Panacinar:
- inherited alpha-1 antitrypsin deficiency
- Develops usually early in life (third decade)
- respiratory bronchioles and terminal alveoli are involved
- lower lobes
The protease-antiprotease imbalance
The destructive effect of high protease activity (cellular proteases from neutrophils) in subjects with low antiprotease activity (low levels of serum α1-antitrypsin)
- elastic tissue destruction is unchecked and emphysema
results.
