Cell injury and death

gen. pathology dmd3

What are the causes of cell injury?

• oxygen deprivation

• chemical agents

• infectious agents

• immunologic reactions

• genetic defects

• nutritional imbalance

• physical agents

• aging

What is hypoxia?

oxygen deficiency

interferes with aerobic oxidative respiration

pneumonia, anemia, or carbon monoxide poisoning is what type of condition?

hypoxia

what is the most common cause of hypoxia?

ischemia

what are some chemical agents that can cause cell injury or death?

-glucose

-salt

-oxygen

what are some infectious agents that can cause cell injury or death?

bacteria

fungi

protozoans

what are some immunologic reactions that can cause cell injury or death?

autoimmune reactions against own’s tissues and allergic reactions

what are some genetic defects that can cause cell injury or death?

congenital malformations in Down syndrome, hemoglobin S and sickle cell anemia, deficiency of functional proteins, and damage or misfolded DNA.

what are some nutritional imbalances that can cause cell injury or death?

protein-calorie insufficiency, vitamin deficiencies, excess of animal fat, etc.

what are some physical agents that can cause cell injury or death?

-trauma

-extreme temperatures

-radiation

-electric shock

-sudden change in atmospheric pressure

what is cellular senescence

a state where cells stop dividing but remain metabolically active (aging)

-diminished ability to respond to damage

cellular injury results from?

functional and biochemical abnormalities in one or more of several essential cellular components.

What are some essential cellular components?

• mitochondria

• cell membrane

• protein synthesis

• cytoskeleton

• genetic apparatus

What are the importance of ATP

oxidative phosphorylation and glycolytic pathway

What causes ATP depletion?

-reduced supply of oxygen and nutrients

-mitochondrial damage

-actions of some toxins

What happens when there is an increase pf cytosolic Ca2+

it activates a number of enzymes with potentially deleterious cellular effects

phospholipases causes?

membrane damage

proteases break down both?

membrane and cytoskeletal proteins

endonucleases for?

DNA and chromatin fragmentation

adenosine triphosphatases hastes?

ATP depletion

increased intracellular Ca2+ levels results in the induction of?

apoptosis

depleting extracellular Ca2+ delays?

cell death after hypoxia and exposure to some toxins

what are free radicals?

chemical species with a single unpaired electron in an outer orbital; highly reactive

what is oxidative stress?

excess of free radicals

what is reperfusion?

the restoration of blood flow to a tissue or organ that has been deprived of circulation (ischemia)

plasma membrane can be damaged by?

-ischemia

-microbial toxins

-lytic complement components

-physical and chemical agents

what is autophagy

lysosomal digestion of cell’s own components

survival mechanism during nutrient deprivation

what is heterophagy

cell ingests substances from the outside for intracellular destruction

what are residual bodies

undigested debris persistent within the cell

examples of residual bodies

lipofuscin pigments

carbon particles

tattoo pigments

what is hemosiderin

a hemoglobin-derived granular pigment that is golden yellow to brown and accumulates in tissues when there is a local or systemic excess of iron

iron is normally stored within?

apoferritin

apoferritin forms?

ferritin micelles

large aggregates of ferritin micelles are seen as?

hemosiderin pigment

hemosiderosis is?

a condition characterized by the excessive accumulation of hemosiderin, an iron-storage complex, in tissues.

if there is an impressive accumulation of systemic hemosiderosis what happens?

the iron pigment does not damage the parenchymal cells or impair organ function

what is pathologic calcification?

the abnormal deposition of calcium salts, together with smaller amounts of iron, magnesium, and other minerals

when calcification occurs in dead or dying tissues it is called?

dystrophic calcification

deposition of calcium salts in normal tissues called?

metastatic calcification

when does dystrophic calcification occur?

occurs in the absence of calcium metabolic derangements

metastatic calcification reflects derangement in ?

in calcium metabolism (hypercalcemia)

true or false

necrotic cells are unable to maintain membrane integrity, and their contents often leak out

true

the enzymes responsible for digestion of the cell are derived from?

lysosomes

what are the patterns of tissue necrosis?

• coagulative necrosis

• liquefactive necrosis

• gangrenous necrosis

• caseous necrosis

• fat necrosis

• fibroid necrosis

tissue necrosis in which the component cells are dead but the basic tissue architecture is preserved for at least several days

coagulative necrosis

coagulative necrosis is characteristics of infarcts in all solid organs except?

the brain

areas of tissue that have undergone necrosis due to a blockage in the local blood supply, leading to a lack of oxygen and nutrients

infarcts

a type of necrosis where the necrotic tissue is transformed into a liquid or viscous mass, often due to enzymatic digestion

liquefactive necrosis

necrosis seen in focal bacterial or fungal infections

liquefactive necrosis

hypoxic death of cells within the central nervous system often evokes…

liquefactive necrosis

true or false

liquefaction digests the dead cells partially

false

liquefaction completely digests the dead cells

if liquefactive necrosis was initiated by acute inflammation what happens to the material?

the material is frequently yellow = pus

necrosis that is the result from the loss of blood supply and has undergone coagulative necrosis involving multiple tissue layers

gangrenous necrosis

gangrenous necrosis is usually applied to?

a limb (usually lower leg)

gangrenous necrosis and liquefactive action is called

wet gangrene

necrosis characterized by a cheese-like appearance of the affected tissue; yellow-white

caseous necrosis

necrosis most often in foci of tuberculous infection

caseous necrosis

on microscope caseous necrosis appears as?

a collection of fragmented or lysed cells with an amorphous granular appearance

caseous necrosis often enclosed within a distinctive inflammatory border called?

granuloma

a special form of necrosis usually seen in immune reactions involving blood vessel

fibrinoid necrosis

deposits of immune complexes together with fibrin that leaked out of vessel resulting in a bright pink and amorphous appearance in H&E stains called?

fibrinoid

what is the programmed destruction of cells during embryogenesis

apoptosis

cell death kind involving endometrial cell breakdown in menstruation

apoptosis

kind of cell death regression of lactating breast after weaning

apoptosis