7b Flashcards
Why Study General Cytotoxicity and Histopathology
- Represent the consequence for molecular changes
- Early warning system for individual level effects
- Allow for interpretations at the organism level (more ecologically relevant)
Define Histopathology
The study of changes in cells and tissues as a result of disease
What are the advantages of histopathology as a biomarker
- More ecologically relevant then enzyme activity at the level of the individual
- cost effective to show toxin action and exposure (biopsy or population screening methods)
What are the disadvantages of histopathology as a biomarker
- Variations of “Normal” may be poorly understood for sentinel species
- Most studies are not quantitative
- Further basic research is needed to fill knowledge gaps
What is apoptosis
Programmed cell death
What needs to be distinguished from pathology
Apoptosis (programmed cell death)
True or false: Apoptosis is often part of the developmental cycle
True
Define Necrosis
Cell death from disease or injury (Note: this is distinct from somatic death
Define somatic death
death of the organism
define lesions
pathological changes to cells, tissues or organs
what do lesions indicate
toxin exposure
what are lesions usually confined to
target tissue or organ
True or False: lesions may suggest mechanism of action for the toxin
true
Define pyknosis
a sign of cell death in which the chromatin condenses into a strongly basophilic irregularly shaped mass
What are the signs of necrosis
- pyknosis
- nuclear disintegration (karyorrhexis and karyolysis)
- acidophilic cytoplasm
- Swollen mitochondria
- increase in cytoplasmic granules
- cells may become displaced (sloughed) from tissue
Does the type of necrosis indicate possible different tocin actions
yes
What is coagulation necrosis
cell appears opaque as cytoplasmic proteins have denatured and aggregated
what is this an example of? ingestion of phenol or inorganic Hg will cause renal failure resulting in extensive coagulation of necrosis of the kidneys (this may also occur due to injury which cuts off blood flow
coagulation necrosis
what is Liquefactive (cytolytic) necrosis
Cell death due to rapid breakdown of cell contents by intracellular enzymes (fluid filled space left in tissue, often due to infection))
What are abscesses a classic example of?
Liquefactive necrosis
What is caseous necrosis
Cells disintegrate to a mass of fat and protein
Which type of caseous necrosis can cause lungs or other organs to have a cheesy appearance?
Caseous necrosis
What is Gangrenous necrosis
A combination of coagulation and liquefactive necrosis (often due to a puncture injury followed by infection)
What is fat necrosis
Deposits of alkali degraded fats into dead fat cells (looks like white chalky areas on the surface that look sometimes like soap)
What is Zenker’s necrosis
Similar to coagulation necrosis but only seen in skeletal muscle
What is inflammation and what is it useful for
- useful biomarker
- response made by body in an effort to isolate and destroy a damage causing agent (net result: healed tissue)
What are the signs of inflammation
- heat and redness (caused by vasodilation increasing blood flow to the area)
- Swelling (plasma passes into tissues of inflamed area, leucocytes enter area)
- pain caused by pressure due to swelling
What are long term signs of swelling?
- capillaries form
- connective tissue grows
- scar tissue may form
- fibroblasts (secrete collagen) move in and multiply
What does chronic inflammation lead to often?
tissue dysfunction due to collagen build up in the area
What is comatic risk
Damage to an individual which may lead to cancer (germ cells are not involved)
What is genetic risk
risk to progeny of an individual due to inheritable DNA damage
What may changes in DNA be associated with
- chromosomal breakage
- deletions
- translocations
- segregation failure
(many of these changes have catastrophic effects for the cells or zygote which inherit the DNA)
