Pathology Flashcards
Definition of Inflammation
A reaction to injury/infection that involved cells such as neutrophils and macrophages
Is infectious mononucleosis chronic or acute?
Chronic from the start
Characteristics of acute inflammation
Sudden onset, short duration and usually resolves. Cells include neutrophils.
Characteristics of chronic inflammation
Slow onset, long duration and may never be resolved. Cells include macrophages and lymphocytes
Neutrophil polymorphs characteristics
Lots of enzymes in vacuoles in cytoplasm. Can phagocytose. Short lived and first cells on scene of acute inflammation. Usually die at scene (yellow pus) and release cytokines that attract other inflammatory cells
Macrophage characteristics
Non-discript nucleus with bags of enzymes in cells. Long lived and can phagocytose. APC cells
Lymphocyte characteristics
Long lived and have immunological memory
What are endothelial cells coated with?
Nitric acid
What do fibroblast do?
Make collagen - contain ER and are long lived
What are granulomas?
Lump of macrophages surrounded by lymphocytes. Occurs in sarcoidosis, leprosy and TB
Definition of resolution?
Where damaging factor is removed, tissue is undamaged and able to regenerate eg LIVER
IT GOES AWAY
Definition of repair
Damaging factor is present but there is tissue damage this tissue cannot regenerate
Can pneumocystis regenerate?
Type 2 pneumocystis are known to produce surfactants and regenerate alveolar epithelium after injury
Healing by 1st intentions steps?
Incision, no tissue loss, fibrinogen release, edges joined by fibrin and replaced by collage (little scar tissue) - structure and functions restored
Healing by second intention steps?
Loss of tissue, gap filled with it granulomatous tissue and edges don’t come together. Fibrosis formation which leads to a big scar
Inadequate wound healing characteristics?
Por blood supply, poor nutrition, wound infection, immunosuppression, diabetes and old age
Excessive wound healing characteristics?
Hypertrophic scars due to excessive collagen, stays within wound site. Keloid scars -> excessive granulation tissue that expands beyond wound edges
What tissues regenerate?
Hepatocytes, pneumocytes, blood cells, gut cells, skin cells and oesteocytes
Non regenerating cells?
Heart cells, brain cells and spinal cord
types of autopsy
hospital
medico-legal
hospital autopsy %
<10%
medico-legal autopsy % and types
> 90%
coronial autopsy - where death is not due to unlawful actions
forensic autopsy - where death is unlawful eg, murder
why deaths are referred to coroner
when death is presumed natural (cause not known), presumed iatrogenic and presumed unnatural
external examination for autopsy
look for any ID, diseases and treatments, injuries and then perform evisceration
what is evisceration
Y shaped (from behind ears down to clavicles and then down midline incision) where al body cavities are opened and examined. Brain is also removed.
suppuration definition
pus formation eg, abscess
why does rubor occur in inflammation?
due to dilation of small blood vessels within damaged area
why is calor seen in inflammation?
hyperaemia (increased blood flow) and vascular dilation delivers warm blood to area
also systemic fever can result due to chemical mediators of inflammation
why is there dolor in inflammation?
pain from stretching and distortion of tissue due to inflammatory oedema and pus
some chemical mediators eg, bradykinin, PG and serotonin can induce pain
vascular changes in acute inflammation
pre-capillary sphincters relax and this increases blood flow through capillaries causing rubor and calor
arteriole dilate and causes increased vascular permeability (fluid exudation)
stages of neutrophil polymorph emigration
1 - margination of neutrophils
2- adhesion of neutrophils
3- neutrophil emigration
4- diapedesis
what does histamine do
- chemical mediator in acute inflammation
- causes vascular dilation and increases basilar permeability
- able to have immediate affect due to it being stored in granules (mast cells)
- histamine release is stimulated by C3a and C5a
what are the 4 systems of chemical mediators
complement, kinins, coagulation factors and fibrinolytic systems
what is the kinin system activated by?
factor XII and plasmin activate conversation of prekalilkin to kallikrenin. This then stimulates conversion of kinonogens to kinins eg, bradykinin
what do IL-1 and TNF alpha do?
causes endothelial cells, fibroblasts and epithelial cells to secrete MCP1 (chemotactic protein) to attract neutrophil polymorphs
which cell is present first at the sight of inflammation?
macrophages
why can acute inflammation be bad?
- enzymes such as collagensases and proteases may digest normal tissue
- inappropriate swelling
- inappropriate inflammatory responses (hypersensitivity reactions)
what is organisation in acute inflammation.
Organisation of tissues is their replacement by granulation tissue
(tissue forming in response to injury, contains many new blood vessels (TGF beta) and, in its later stages, large numbers of fibroblasts (produces collagen and other fires) as part of the process of repair (so possible scar formation)