pathology and immunology Flashcards
Acute inflammation:
neutrophil polymorph action?
- Short lived cells
- First on the scene of acute inflammation
- Cytoplasmic granules full of enzymes that kill bacteria
- Usually die at the scene of inflammation
- Release chemicals that attract other inflammatory cells such as macrophages
Acute inflammation:
acute vs chronic?
Acute:
- sudden onset
- short lived
- usually resolves
Chronic:
- slow onset or sequel to acute
- long duration
- may never resolve
Exudate vs transudate?
Exudate
- fluid buildup outside vessels
- the protein-rich fluid that leaks out from blood vessels
- due to e.g. inflammation or local cellular damage
- accumulation of neutrophil polymorphs outside the vessel in the extracellular space (they squeeze through gaps in endothelial cell layer)
Transudate
- fluid buildup outside
- due to changes in blood pressure in blood vessels
- causing fluid to leave vascular system
Acute inflammation:
causes?
- microbial infections, e.g. pyogenic bacteria, viruses
- hypersensitivity reactions, e.g. parasites, tubercle bacilli
- physical agents, e.g. trauma, ionising radiation, heat, cold
- chemicals, e.g. corrosives, acids, alkalis, reducing agents,
- bacterial toxins
- tissue necrosis, e.g. ischaemic infarction
Acute inflammation:
essential macroscopic appearances of inflammation?
- calor (Heat) - increased blood flow (hyperaemia) through the region, resulting in vascular dilatation and the delivery of warm blood to the area
- rubor (redness) - vasodilation of small blood vessels in damaged area
- tumor (swelling) - exudate but also to a lesser extent migration of neutrophil polymorphs to area
- dolor (pain) - stretching and distortion of tissues due to inflammatory oedema but also bc of pus under pressure in an abscess
- loss of function - movement of an inflamed area will consciously and reflexively be inhibited and severe swelling will also immobilise the tissues
Acute inflammation: describe macrophages?
- Long lived cells (weeks to months) • Phagocytic properties
- Ingest bacteria and debris
- May carry debris away
- May present antigen to lymphocytes
Acute inflammation: lymphocytes?
- Long lived cells (years)
- Produce chemicals which attract in other inflammatory cells
- Immunological memory for past infections and antigens
Acute inflammation: endothelial cells?
- Line capillary blood vessels in areas of inflammation
- Become sticky in areas of inflammation so inflammatory cells adhere to them
- Become porous to allow inflammatory cells to pass into tissues
- Grow into areas of damage to form new capillary vessels
Acute inflammation:
4 outcomes of inflammation?
- Resolution
- Suppuration e.g. abscess formation/discharge of pus
- Organisation
- Progression to chronic inflammation
Acute inflammation:
5 signs of inflammation?
- Redness (rubor).
- Swelling (tumor).
- Pain (dolor).
- Heat (calor).
- Loss of function.
Chronic inflammation:
Causes of chronic inflammation?
- Primary chronic inflammation.
- Transplant rejection.
- Recurrent acute inflammation.
- Progression from acute inflammation.
chronic inflammation:
essential macroscopic features?
- Chronic ulcer.
- Chronic abscess cavity.
- Granulomatous inflammation.
- Fibrosis.
The activity of what enzyme in the blood can act as a marker for granulomatous disease?
Angiotensin converting enzyme.
Name 2 types of cells that are incapable of regeneration.
- Myocardial cells.
2. Neuronal cells.
Healing by first intention?
incision → no tissue loss → fibrinogen release → edges joined by fibrin [which forms a clot] → replaced by collagen [little scar tissue] → structure & function restored
Healing by 2nd intention?
loss of tissue → gap filled w/ granulomatous tissue → adhesion of edges → organisation & fibrosis formation [areas of fibrous tissue leads to a big scar]
Resolution vs repair?
Resolution:
when tissue is undamaged and able to regenerate (liver)
Repair:
Replacement of damaged tissue by fibrous tissue (tissue damage so can’t regenerate)
Thrombosis:
Definition?
Caused by?
solid mass of blood constituents formed within intact vascular system during life
Caused by:
- change in vessel wall [endothelial injury by smoking]
- change in blood flow [stasis]
- change in blood constituents [which causes platelet aggregation, thrombus formation & fibrin deposition]
- change in 2/3 of the Virchow’s triad;
Virchow’s triad?
Change in blood flow (stasis)
— endothelial injury (change in vessel wall)
— Change in blood constituents (hypercoaguability)
Atrophy?
decrease in size of a tissue caused by a decrease in number of the constituent cells or a decrease in their size
Hypertrophy?
Increase in size of a tissue caused by an increase in size of the constituent cells
Hyperplasia?
Can only do this in which tissues?
increase in size of a tissue caused by an increase in number of the constituent cells
- Can only do this in tissues capable of regeneration
Metaplasia?
change in differentiation of a cell from one fully-differentiated type to a different fully-differentiated type
Dysplasia?
imprecise term for the morphological changes seen in cells in the progression to becoming cancer