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→Hyaline Degeneration
===Hyaline Degeneration===
===Hyaline Degeneration===
Hyaline degeneration - a descriptive term meaning 'glassy'' and applied to several
types of degeneration or infiltration. Some are extracellular e.g. protein hyaline casts in the
renal tubules, while others are intracellular e.g. hyaline degeneration of skeletal muscle. The
word hyaline is used in pathology when material appears structureless in section and stains
red with eosin. Hyaline degeneration is really a descriptive term of a variety of
conditions in which structureless materials are present.
Instances of 'hyaline' degeneration:
a. renal intratubular casts from excessive protein passing through glomerulus: When fresh
urine is examined under the microscope, they may be seen as elongated glassy tubes.
b. proteinaceous effusions into pulmonary alveoli are known as hyaline membranes: they
prevent gaseous exchange.
c. hyaline degeneration of muscle in deficiency of Vit. E/ Selenium.
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Two forms of hyaline change deserve mention on their own. One is fibrinoid degeneration
and the other is amyloid infiltration.
====Fibrinoid Degeneration====
====Fibrinoid Degeneration====
Fibrinoid degeneration
This implies that there is a
material which is fibrin-like,
and is essentially a focal death
of cells in the walls of small
blood vessels, usually
arterioles. Parts of the vessel
wall become replaced by a
homogenous or granular
eosin-staining material, which
has some of the appearance
and staining properties of
fibrin. This pinkish-red
material consists partly of
degenerated muscle and elastic
fibres, and partly of an
increased amount of protein ground substance around the degenerated fibres. Its main
importance is that it may suggest either a local hypersensitivity reaction or hypertension in
the blood vessels. When viewed histologically, the fibrinoid degeneration is like a red
smudge in part of the vessel wall.
====Amyloidosis====
====Amyloidosis====
Amyloid infiltration - Amyloidosis
It is the deposition of a proteinaceous
hyaline substance extracellularly in
specific tissues. The sites of
deposition vary with the species. The
kidney is a common site. Here the
amyloid is deposited under the
capillary endothelium and
progressively increases in volume.
Various categories of amyloid exist.
It is essentially an abnormal protein
produced in the body. In most natural
cases in domestic animals, it is
produced in response to sustained
antigenic stimulation in the body caused by a chronic suppurative process such as a foot
abscess, mastitis, etc.
It is a relatively inert substance and when it accumulates, it is not easily removed.
===Glycogen Infiltration===
===Glycogen Infiltration===
===Cellular Inclusions===
===Cellular Inclusions===