Inflammation
- If the following features of the acute inflammatory reaction were placed in
chronological order which would come fourth?
A. Arteriolar contraction.
B. Blood flow slows.
C. Dilatation of arterioles.
D. Emigration of leucocytes from blood vessels.
E. Protein rich fluid escapes from blood vessels.
The answer is B. In the acute inflammatory response the injury results in an initial
contraction of arterioles (A) followed rapidly by arteriolar dilatation (C) in the process of
active hyperaemia; as a result of the hyperaemia the inflammatory exudate is formed (E) and
is responsible for swelling and pain; the microcirculation remains engorged, but blood flow
slows down (B) with associated emigration of leucocytes (D). - Which ONE of the following ultrastructural features is believed to allow for the
increased permeability of the vascular endothelium in acutely inflamed tissue?
A. Cytoplasmic micropinocytotic vesicles.
5
B. Gaps in endothelial tight junctions.
C. Gaps in the basement membrane.
D. Increase in number of phagolysosomes.
E. No morphological changes.
The answer is B. There is experimental evidence that gaps appear between vascular
endothelial cells during acute inflammation caused by injury and by chemical mediators.
These gaps are temporary. Micropinocytotic vesicles (A) do transfer material across cells but
are not increased in inflammation. - For each of the phases of increased vascular permeability in the acute inflammatory
reaction noted on the left choose the most suitable association from those on the right.
a. Immediate sustained response.
b. Immediate transient response.
c. Delayed prolonged leakage.
A. Endothelial cells elongate.
B. Leakage occurs through vascular endothelium.
C. Leakage occurs through venules and capillaries.
D. Secretion of exogenous mediators by endothelial cells.
E. Surrounding tissue and endothelium damaged.
The answer is E, B, C. Immediate sustained response – surrounding tissue and
endothelium damaged. This occurs in more severe injury in which vascular damage may be
so great as to cause thrombosis and even infarction of the tissues.
Immediate transient response – Leakage occurs through vascular endothelium. In the
experimental models only venular leakage occurs in this phase; this suggests endogenous
mediator activity.
Delayed prolonged leakage – Leakage occurs through venules and capillaries. Both
capillaries and venules leak in this phase, but leakage is confined to the zone of injury
suggesting that this is due to direct endothelial injury. - Which ONE of the following is not an endogenous mediator of increased vascular
permeability?
A. Angiotensin.
B. C3a and C5a.
C. 5-hydroxytryptamine.
D. Kallikrein.
E. Prostaglandin E2.
The answer is A. Angiotensin is produced by the action of renin on angiotensinogen
and is involved in the secretion of aldosterone and in pressor effects.
6
C3a and C5a (B) are part of the complement cascade and are activated C3 and C5;
they act by liberating histamine from mast cells.
5-hydroxytryptamine (C) or serotonin causes increased vascular permeability in rodents
but not in man.
Kallikrein (D) is produced by the activation of Hageman factor (factor XII) producing
prekallikrein activator which converts prekallikrein to kallikrein.
Prostaglandin E2 (E) is secreted by polymorphs which are phagocytically active, it
does not cause increased permeability itself but potentiates the activity of other factors. - Which ONE of the following is not a useful effect of acute inflammation?
A. Dilution of toxins.
B. Formation of fibrin.
C. Phagocytosis.
D. Stimulation of immune response.
E. Swelling of tissues.
The answer is E. Tissue swelling may result in obstruction of a vital passageway, i.e.,
larynx, or may cause ischaemic necrosis within an enclosed space, i.e., testis.
The others are all useful but some people may have an inappropriate immune response
and may therefore develop a pathological condition as part of their physiological response,
i.e., asthmatics. There is also a rare condition in which a deficiency of a complement
activation controlling factor (C1-inhibitor) allows complement activation to occur (angioneurotic oedema). - Which ONE of the following is not an acceptable characteristic of a granuloma.
A. Composed of altered macrophages.
B. Composed of fused macrophages (giant cells).
C. Composed of epithelioid cells.
D. Composed of a mixture of chronic inflammatory cells.
E. Composed of polymorphonuclear leucocytes, cellular debris and fibrin.
The answer is E. Composed of polymorphonuclear leucocytes, cellular debris and
fibrin – This is a description of pus as would be found in an abscess. Polymorphonuclear
leucocytes and nuclear debris can be found in a true granuloma if there is a focus of
suppuration: an infective granuloma.
The definition of ‘granuloma’ is controversial; it may be used to mean a chronic
inflammatory lesion forming a tissue mass or it may be restricted to a lesion composed of
macrophages or even of altered macrophages (epithelioid cells). - For each of the cell type listed on the left choose the most appropriate association
from those on the right.
7
a. Alveolar macrophages.
b. Kupffer cells.
c. Langhans’ giant cells.
A. CNS phagocytes.
B. Digest bone matrix.
C. Lining cells of hepatic sinusoids.
D. Nuclei arranged peripherally in the cytoplasm.
E. Phagocytic activity dependent on oxygen.
The answer is E, C, D. Alveolar macrophages – phagocytic activity dependent on
oxygen. The alveolar macrophages illustrate the point that local environment may influence
cellular function; unlike other phagocytic cells these cells require high oxygen tension for full
activity.
Kupffer cells – lining cells of hepatic sinusoids. The Kupffer cell lines the hepatic
sinusoids and is active in phagocytosis of particulate matter in the liver.
Langhans’ giant cell – nuclei arranged peripherally in the cytoplasm. The Langhans’
giant cell characteristically has a large number of peripherally arranged nuclei; this cell is
typical of the tuberculous granuloma.
Central nervous system phagocytes. The representative of the mononuclear phagocyte
system in the CNS (A) is the microglial cell.
Digest bone matrix. Osteoclasts are derived from bone marrow precursors and digest
matrix (B).
