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Flashcards in Terminology and Cell ID Deck (22):
1

AGONAL CHANGES

Immediately before death
1. Passive congestion
2. Pulmonary oedema
3. Pulmonary alveolar emphysema
4. Stomach contents in oesophagus/trachea, due to regurgitation and aspiration.

2

EUTHANASIA EFFECTS

Due to drug used. Crystal formation in serosa and endothelium.

3

POST MORTEM CHANGES

Occur after death. Breakdown of cells and tissues.

BLOAT/EMPHYSEMA seen.

4

WHAT CAUSES POST MORTEM CHANGES?

1. Autolysis of cells from respiratory failure. Proteolysis by lysosomal enzymes.

2. Bacterial growth (partly physiological bacteria)

5

EXTENT OF POST MORTEM CHANGES?

Depends on:
1. Tissue of origin
2. Temperature at death.
3. Fleece/fur thickness.
4. Bacterial flora.
5. Interval between death and necropsy.

6

ALGOR MORTIS

Cooling

7

RIGOR MORTIS

Rigidity, seen 1-6 hours after death, lasts for 1-2 days. Muscles are contracted.
Starts in HEART.
Spreads to HEAD AND NECK MUSCLES, then to EXTEMITITES.
More pronounced in muscular animals.
Excitement accelerates onset.
May fail to develop if animal is extremely malnourished, due to insufficient energy stores in muscles- Myofibres do not contract. Heart remains full of blood.

8

TEXTURE CHANGES

1. Corneal opacity- Reduced turgor
2.Gas formation in liver and gut (spongy appearance of liver)
3. Softening of liver, kidney, pancreas
4. Drying of tissue surfaces.

9

TISSUE DETACHMENT

Mucosa of rumen, reticulum, omasum.
'Hairslip'- Loss of hair.

10

COLOUR CHANGES

-Dark red- Due to hypostatic congestion (blood settling)

-Diffuse reddish stain- Serosa, intima, serosal fluids- Due to haemoglobin imbibition (displacement). Hb moves in to tissues from blood.

-Greenish-yellow due to bile staining tissues near gall bladder.

-Green-black- Hydrogen sulphide from bowel organisms and sulfmethaemoglobin (from Hb)

11

CLOTTING

Post mortem clots are rubbery and homogenous, forming perfect casts of the vessels they are in.

12

CURRANT JELLY CLOT

Red blue, contains red blood cells

13

CHICKEN FAT CLOT

Clear yellow, serum clot. Not just in chicken!

14

DECOMPOSITION

AUTOLYSIS plus PUTREFACTION

15

AUTOLYSIS

Tissue breakdown due to lack of oxygen. Minimised by chilling.

16

PUTREFACTION

Generalised, advanced decomposition of viscera.

*Clostridial myositis can look similar, but it is localised to affected muscles. Putrefaction happens EVERYWHERE.

17

ARTEFACT

A structure or appearance that is not natural but is due to man made manipulation

18

FREEZING

Causes crystallisation and cell disruption- artefacts

19

IMPERFECT BLEEDING

Causes artefacts- Backbleeding in to thorax if angle of knife is incorrect.
Inhalation in to lungs if trachea is nicked.
Mostly pigs

CORRECT BLEEDING- Jugular veins and carotid arteries should be severed simultaneously.

20

BLOOD SPLASHING

Artefacts- Multiple pinpoint haemorrhages in lungs, muscle, heart and other organs. In sheep and pigs, caused by electrical stunning.
Can be localised in an organ (ie. on one part of that organ), or diffuse (all over organ)

21

EMPHYSEMA

Can be an artefact (also seen as a post mortem change) due to terminal gasping- Especially in old thin cows.

22

SPLENOMEGALY

Artefact caused by anaesthesia or barbiturate anaesthesia

Barbiturates may also cause CRYSTALLISATION