Cell Response To Injury Flashcards
(29 cards)
LOOK AT ALL THE LECTURE SLIDES
How a cell responds depends on:
Type, duration and severity of the stimulus
Type, status, capability and genetic makeup of the cell
Example of how a normal cardiac monocyte would react :
Either adaptation or death
Pathology is conditions associated with a disease
Physiological is the mechanisms within an organism
What is hyperplasia and where does it occur?
What is a pathological example?
Hyperplasia is the increase in the number of cells in tissue/ organ WITHOUT an increase in the size of cells
It occurs in tissues capable of cell division
Pathological hyperplasia = chronic hyperplastic candidosis
prostate increase in number of cells due to hormone imbalance
What is hypertrophy?
Where does it occur?
Hypertrophy is an increase in the size of cells WITHOUT an increase in the number of cells
It occurs in cells that are NOT capable of cell division such as skeletal or cardiac muscle
Pathological example = Left cardiac ventricle hypertrophy after heart failure
(It is difficult to differentiate between hypertrophy and hyperplasia as they usually occur side by side)
What is atrophy?
What is a pathological example?
Atrophy is a decrease in the size of an organ as a result of a decrease in the size and number of cells.
Pathological example is Lichen planus
What is a metaplasia?
Example?
Metaplasia is the change from one differentiated cell type to another differentiated cell type
Eg in bladder with a catheter
Oral cavity - minor salivary gland ducts if there is trauma , cells will undergo metaplasia from simple cuboidal to stratified squamous
What is dysplasia?
Dysplasia is disordered stratification and disordered maturation
Eg a response to carcinogenic agents
What are the causative agents of cell damage?
Ie what causes cell damage?
What are some mechanisms of cell injury?
Disruption of metabolism
Nutrient/growth factor deprivation
Free radical/ROS formation
DNA Damage
Inflammation
Membrane disruption
Necrosis
Cell death can occur by necrosis OR apoptosis
Necrosis is not reversible
Normally characterised by cell swelling
What is pyknosis
What is karyorrhexis
Pyknosis is condensation of the nucleus - seen in necrosis and apoptosis
In necrosis, pyknosis is succeeded by karyorrhexis
Karyorrhexis is fragmentation of the nucleus and then leads to karyolysis
In necrosis:
What is coagulative necrosis?
What are two common causes of coagulative necrosis?
Most common type of necrosis
It is when the structural pattern of the necrotic tissue is maintained
Ischaemia and infarction are two common causes of coagulative necrosis
Liquefactive necrosis
Where is it common?
In liquefactive necrosis, changes in the organ and tissues results in a collection of liquid viscous material.
No cell outlines are discernible
Common in necrosis in central nervous tissue eg brain or where there is bacterial or fungal infection
Caseous necrosis
Where is it common?
Resembles cheese
Common in TB - granuloma formation
What is apoptosis?
Examples of where it occurs?
Regulated and targeted programmed cell death
(Energy dependant)
Physiological apoptosis occurs during embryogenesis
Pathological apoptosis in DNA damage or protein misfolding or viral infection
What are the two pathways that apoptosis in induced?
1) extrinsic
2) intrinsic
What happens in the extrinsic pathway of apoptosis?
When is it intitiated?
A death ligand binds to a death receptor and causes activation of caspases.
Activation of caspase 8 results in activation of caspase 3 which then causes execution of apoptosis through dismantling of DNA and cytoskeletal proteins
Initiated in cytotoxic T cell mediated cell death
What happens in the intrinsic pathway of apoptosis?
When is it intitiated?
Also known as the mitochondrial dependant pathway.
Usually DNA damage- release of cytochrome C causes activation caspase 9 which then causes activation of caspase 3
Initiated in DNA damage
Apoptosis
