Formative Flashcards
During ischaemia cells swell. Why is this? Is this change reversible or
irreversible?
Loss of function of energy-dependant membrane pumps, therefore
sodium and water accumulate in cytoplasm.
The change is reversible.
Describe the differences between oncosis/necrosis & apoptosis
Oncosis/Necrosis: Sheets of cells affected Associated inflammation Cell swelling Always pathological Membrane breaks down Diffuse/random DNA cleavage
Apoptosis: Single cells affected No associated inflammation Cell shrinkage Can be pathological or physiological Membrane remains intact Internucleosomal DNA cleavage
Name the 4 “cardinal” clinical features of acute inflammation.
Pain (dolor)
Swelling (tumor)
Redness (rubor)
Heat (color)
Why is swelling seen in an acutely inflamed area
Chemical mediators, such as histamine, serotonin and bradykinin, are
released and formed.
They cause arterioles to dilate and endothelial cells to contract (resulting in the formation of spaces between the endothelial cells).
Arteriolar dilatation results in increased hydrostatic pressure within the
capillaries and venules and fluid (with the plasma proteins that it contains) is pushed out of the venules through the gaps between the endothelial cells into the tissue spaces.
As the concentration of protein within the tissue spaces is increased, the osmotic pressure of the tissue spaces increases which serves to pull further fluid into the tissue spaces and to hold it there.
Give some functions of the complement system
Killing bacteria by forming the membrane attack complex which punches holes in them
Some components act as chemical mediators. C5a and C3a are
chemotaxins.
Opsonisation. C3b is an opsonin.
What is the molecular abnormality in inherited angio-oedema? Briefly
describe the main clinical features.
Absence of C1 esterase inhibitor (a component of the complement
system).
Attacks of non-itchy cutaneous angio-oedema (rapid oedema of the dermis, subcutaneous tissue, mucosa and submucosal tissues) especially of the face and airway.
Recurrent abdominal pain which is due to intestinal oedema.
Often a family history of sudden death due to laryngeal involvement.
Give some functions of macrophages in chronic inflammation
Phagocytosis of bacteria and other particles
Secretion of chemical mediators
Presenting antigens to the immune system and initiation of the immune response
Stimulating angiogenesis
Inducing fibrosis
Inducing fever, acute phase reaction and cachexia (loss weight, musc atrophy, weakness)
What is a granuloma?
Name the types of multinucleated giant cell that can be found in a granuloma and describe each.
A granuloma is a chronic inflammatory response.
It is a collection of cells (macrophages (some of which are modified to form epithelioid histiocytes), giant cells, fibroblasts and sometimes lymphocytes) which surrounds and attempts to destroy difficult to eliminate microorganisms and particles.
Multinucleated cells seen in granulomas:
Langhans giant cells – nuclei arranged around the periphery of the giant cell
Foreign body giant cells – nuclei arranged randomly in the cell,
Touton giant cells – nuclei arranged in a ring towards the centre of the cell.
What is sarcoidosis?
Name 2 organs that are commonly affected
Sarcoidosis is an inflammatory disease with an unknown cause in which granulomas are formed in organs throughout the body.
It commonly affects the lungs and lymph nodes.
Name some ways that sarcoidosis can be distinguished from TB (microscopically or in lab tests)
• Tuberculous granulomas often show central caseous necrosis and more frequently contain Langhans type giant cells than do sarcoid granulomas
• Mycobacteria may be seen in tuberculous granulomas with Ziehl-Neelsen stain
• Mycobacterial DNA can be identified from tuberculous granulomas using PCR (polymerase chain reaction)
• Mycobacterium tuberculosis may be cultured from infected tissues
• Hypercalcaemia is often seen in sarcoidosis
• Serum angiotensin converting enzyme (ACE) levels are often raised in
sarcoidosis
Why must the myocardium always heal with a scar
Cardiac myocytes are permanent cells and no stem cells are present in the myocardium, therefore no regeneration is possible.
Granulation tissue is important in the healing of the myocardium. Name its principal cellular constituents.
Fibroblasts and myofibroblasts
Endothelial cells/capillaries
List some local factors that can impair the healing of a wound
- Large size of wound
- Poor blood supply
- Local infection
- Presence of foreign bodies
- Large haematoma or large amount of necrotic tissue
- Mechanical stress on the healing tissue
- Poor surgical technique
Give 2 important functions of (myo)fibroblasts in the healing of a wound
Production of extracellular matrix
Wound contraction
Describe the route of a typical thrombo-embolism from the leg veins to the lungs taking care to give vessel types i.e. artery or vein. Detailed vessel names are not needed.
Deep veins of calf iliac veins inferior vena cava right atrium right ventricle pulmonary artery
How does a thrombosis differ from clotting?
Thrombosis is a pathological process. It is the inappropriate formation of a solid mass from the constituents of the blood within a vessel during life.
Clotting is the physiological process whereby blood forms a solid mass which controls bleeding when blood vessels are severed. It occurs outside of vessels.
