Cell Injury Flashcards by Steven Marincel

How do cells adapt to changes in their environment?

Change in size, number, or appearance

How well did you know this?

Not at all

Perfectly

What is hyperplasia?

increase in the number of cells

How well did you know this?

Not at all

Perfectly

What is hypertrophy?

Increase in the size of a cell due to increased cellular substance

How well did you know this?

Not at all

Perfectly

What is atrophy?

Decrease in the size of a cell due to a loss of cellular substance

How well did you know this?

Not at all

Perfectly

What is metaplasia?

Substitution of one type of adult cell for another type of adult cell (smoking changing tracheal epithelia from columnar to squamous)

How well did you know this?

Not at all

Perfectly

What are two features of irreversible cell injury?

Non-repairable mitochondrial dysfunction

Profound membrane dysfunction

How well did you know this?

Not at all

Perfectly

What are 4 main biochemical systems that can lead to cell injury?

Mitochondria

Cellular Ca changes

Integrity of membranes

Integrity of genetic material

How well did you know this?

Not at all

Perfectly

What is hypoxia?

a deficiency in the amount of oxygen reaching a tissue

How well did you know this?

Not at all

Perfectly

What is hypoxemia?

Hypoxia due to oxygen deficiency (low Hb, low artO2)

How well did you know this?

Not at all

Perfectly

What is ischemia?

Hypoxia due to a loss of blood supply

How well did you know this?

Not at all

Perfectly

Describe the hypoxic injury model

Ischemia will lead to mitochondrial damage, due to decreased oxidative phosphorylation. This will result in decreased ATP which will have three distinct results.

decrease Na pump which results in an influx of Ca, H20, and Na and an efflux of K. This leads to ER/cellular swelling, and blebs
increased anaerobic glycolysis leading to decreased glycogen, increased lactic acid, and decreased pH
detachment of ribosomes resulting in decreased protein synthesis and lipid deposition

How well did you know this?

Not at all

Perfectly

A loss of energy results in increased cellular Ca, which leads to what?

altered membrane permeability and activation of intracellular enzymes

How well did you know this?

Not at all

Perfectly

What happens when membrane permeability is altered?

intracellular enzymes can leak from cell into vascular compartment

How well did you know this?

Not at all

Perfectly

How can we confirm a clinical diagnosis of a disease?

measure elevated levels of intracellular enzymes

How well did you know this?

Not at all

Perfectly

What intracellular enzymes would be elevated from myocardial cells in an acute MI?

CK or troponin

How well did you know this?

Not at all

Perfectly

What intracellular enzymes would be elevated from hepatocytes in hepatitis?

AST/ALT

How well did you know this?

Not at all

Perfectly

What would be elevated in shock? Why?

Lactic acid levels would be increased (metabolic acidosis) as a byproduct of anaerobic glycolysis

How well did you know this?

Not at all

Perfectly

What are the pathologic effects of free radicals?

lipid peroxidation - membrane damage

protein modifications - breakdown, misfolding

DNA damage - mutations

How are free radicals normally removed?

conversion to H2O2 by SOD

decomposition to H20 by glutathione peroxidase and catalase

What is the morphology of reversible cell injury?

Cellular swelling
Steatosis
Myelin figures
Endoplasmic reticulum swelling
Membrane blebs

What is necrosis characterized by?

presence of leukocytes (especially neutrophils) infiltrating dead tissue from adjacent living tissue

What are some morphologic patterns of necrosis?

Coagulation necrosis
Liquefactive necrosis
Caseous necrosis
Enzymatic fat necrosis
Gangrene

describe coagulation necrosis

Pattern of necrosis associated with severe ISCHEMIA

In solid organs (heart, kidney)

What does coagulation necrosis look like histologically?

Ghost-like remnants of intact cells which lack nuclei. The cell outline is preserved. The cytoplasm stains intense pink (eosinophilia)

What are some examples of coagulation necrosis?

MI, renal infarct

describe liquefactive necrosis

Pattern of necrosis often associated with bacterial infections

describe the microscopic and macroscopic patterns of liquefactive necrosis

Microscopic: Bacteria release enzymes causing a rapid loss of cellular structure and a collection of liquid, amorphous debris Macroscopic: creamy yellow material (ABSCESS = collection of neutrophils, dead cells, liquid)

What kind of necrosis do you typically see in brain hypoxia/infarct?

liquefactive

describe caseous necrosis

Pattern of necrosis associated with an inflammatory reaction called “granuloma”

describe the histological and macroscopic features of caseous necrosis

Histologically: amorphous, granular debris (dead cells) in the center of granulomatous cell reaction Macroscopically: necrotic tissue is soft, white, friable

Describe enzymatic fat necrosis

Term commonly used to describe cell death in the pancreas and adjacent fat

What is an example of enzymatic fat necrosis?

Acute pancreatitis

How does enzymatic fat necrosis occur?

FFA + Ca leads to calcium salts

What is gangrene?

A clinical term that represents coagulation (ischemic) necrosis, usually of an extremity, bowel, gallbladder

What is wet gangrene?

If bacteria contaminate dying tissue, superimposing liquefactive necrosis, the process is referred to as wet gangrene.

What is apoptosis?

Regulated pattern of cell death characterized by nuclear condensation and fragmentation coupled with fragmentation of cytoplasm into “apoptotic bodies”

is apoptosis associated with an inflammatory reaction?

no!

What are dead cells removed by?

phagocytes

What is apoptosis initiated by?

Caspases (initiated by p53)

Ischemic injury to the central nervous system from right internal carotid arterial occlusion suffered by a 72 year old man will result in what pattern of necrosis?

Liquefactive necrosis (ischemic injury to the brain)

Which are the major mechanisms which result in membrane damage typical for a reperfusion injury following myocardial ischemia in a 68 year old woman?

ROS as a result of reperfusion injury

Scattered acidophilic bodies are found in the liver of a 57 year old man who has recently developed nausea, vomiting, and scleral icterus. His serologic test for viral hepatitis A is positive. What is the most likely pattern of tissue alteration?

Apoptotic

An endocervical biopsy in a 23 year old woman demonstrates the presence of squamous epithelium (not columnar epithelium). What process has occurred? Why?

Metaplasia, due to something in the environment that forces the adaptation