Cell Injury and Free Radical Mediation

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Questions and Answers

What is one of the main characteristics of fatty change in liver and myocardial cells?

Absence of mitochondria

Increased ribosome attachment

Presence of necrotic tissue

Accumulation of fat due to hypoxia (correct)

Which type of necrosis is characterized by the preservation of structural outlines of the tissue for several days?

Liquefactive necrosis

Necrotizing fasciitis

Caseous necrosis

Coagulative necrosis (correct)

In which organ does coagulative necrosis NOT typically occur?

Lung

Liver

Heart

Brain (correct)

What are the key indicators of karyorrhexis?

Fragmentation of the pyknotic nucleus Signup and view all the answers

Which necrosis type is associated with acidophilic coagulated anucleated cells?

Coagulative necrosis Signup and view all the answers

What causes liquefactive necrosis?

Bacterial or fungal infection Signup and view all the answers

What distinguishes caseous necrosis?

Presence of cheesy white necrotic area Signup and view all the answers

Which type of necrosis is often referred to as wet gangrene?

Gangrenous necrosis Signup and view all the answers

What characterizes fat necrosis following acute pancreatitis?

Destruction of fat due to digestive enzyme activity Signup and view all the answers

Which process does NOT typically involve apoptosis?

Acute inflammation Signup and view all the answers

What is the result of karyorrhexis during apoptosis?

Nuclear fragmentation Signup and view all the answers

Which of the following stimuli can initiate apoptosis?

Engagement of specific receptors Signup and view all the answers

What describes the appearance of cells undergoing apoptosis on H&E stained sections?

Round masses with eosinophilic cytoplasm Signup and view all the answers

Which category does NOT belong to intracellular accumulations?

Excessive nutrient absorption Signup and view all the answers

What is a consequence of activating intracellular proteases during apoptosis?

Degradation of the cytoskeleton Signup and view all the answers

What happens during the apoptosis of autoreactive T cells?

Deleted due to programmed cell death Signup and view all the answers

What primarily causes fatty change (steatosis) in cells?

Abnormal accumulation of triglycerides Signup and view all the answers

Which of the following organs is least likely to exhibit fatty change?

Spleen Signup and view all the answers

What role do hepatotoxins play in fatty change?

They alter mitochondrial and SER function. Signup and view all the answers

What condition causes macrophages to appear as foamy cells?

Necrotic cell debris Signup and view all the answers

Which of the following is NOT a mechanism through which free radicals can cause cell injury?

Protein synthesis enhancement Signup and view all the answers

Which pigment results from the accumulation of hemoglobin-derived granules?

Hemosiderin Signup and view all the answers

What does pathologic calcification involve?

Abnormal accumulation of calcium salts Signup and view all the answers

What type of cell injury is characterized by clear vacuoles in the cytoplasm?

Reversible cell injury Signup and view all the answers

Which species can be generated by the reduction-oxidation reactions involving oxygen?

Superoxide radicals Signup and view all the answers

What is a visible indicator of fatty change in cells under a light microscope?

Presence of clear spaces displacing the nucleus Signup and view all the answers

Which of the following is least likely to cause fatty change?

Increased physical activity Signup and view all the answers

What is a consequence of carbon tetrachloride (CCl4) exposure in the liver?

Rapid breakdown of endoplasmic reticulum Signup and view all the answers

Which of the following free radicals reacts with thymine in DNA?

Hydroxyl radical Signup and view all the answers

How does mercury cause cellular injury?

By binding to sulfhydryl groups Signup and view all the answers

What role does xanthine oxidase play in free radical generation?

It generates superoxide radicals Signup and view all the answers

Which of the following options is associated with oxidative stress in cells?

Formation of free radicals Signup and view all the answers

What is dystrophic calcification characterized by?

Normal serum calcium levels Signup and view all the answers

Where can metastatic calcification occur?

In normal tissues with hypercalcæmia Signup and view all the answers

What is the primary cause of atrophy?

Inadequate nutrition Signup and view all the answers

What is a characteristic of hypertrophy?

Increase in cell size Signup and view all the answers

Which condition does NOT typically lead to hypercalcæmia?

Excessive blood supply Signup and view all the answers

What physiological adaptation is seen in the induction of breast growth?

Hypertrophy Signup and view all the answers

What is the likely outcome of extensive nephrocalcinosis?

Minor impairment of organ function Signup and view all the answers

Which of the following is considered a pathologic adaptation?

Cellular response to injury Signup and view all the answers

Study Notes

Free Radical Mediation of Cell Injury

Free radicals are unstable molecules with an unpaired electron.
They readily react with organic and inorganic chemicals.
Free radicals are implicated in chemical, radiation, and oxygen toxicity, cellular aging, microbial killing, inflammatory damage, and tumor killing.
They are generated during normal physiological processes and by exposure to radiation and certain chemicals.
Free radical generation occurs through the reduction of oxygen, enzymatic catabolism, absorption of radiant energy, and reactions with metals like copper and iron.
Free radicals can damage lipid, DNA, and proteins.

Reversible Cell Injury

Light microscopic changes include cell swelling, cytoplasmic eosinophilia, and fatty change.
Ultrastructural changes involve the plasma membrane, mitochondria, endoplasmic reticulum, and nucleus.

Necrosis

Characterized by morphological changes that follow cell death.
Manifestations result from enzymatic digestion and protein denaturation.
Types include coagulative, liquefactive, gangrenous, caseous, and fat necrosis.

Coagulative Necrosis

Cell structure is preserved, but enzymes are denatured.
Common in myocardial infarction.
Occurs in hypoxic tissues except the brain.

Liquefactive Necrosis

Results from bacterial or fungal infection.
Occurs in the CNS due to hypoxia.
Leads to the formation of a liquid mass.

Gangrenous Necrosis

Ischemic coagulative necrosis with superimposed infection.
Often referred to as "wet gangrene".

Caseous Necrosis

Characterized by a cheese-like appearance.
Seen in tuberculosis.
Microscopically composed of granular debris within granulomatous inflammation.

Fat Necrosis

Caused by the release of pancreatic enzymes.
Occurs in the peritoneum following pancreatitis.
Leads to the hydrolysis of triglyceride esters within fat cells.

Apoptosis

Programmed cell death.
Seen in physiological and pathological conditions.
Apoptosis involves single cells or clusters of cells and can be initiated by withdrawal of growth factors, engagement of specific receptors, injury, and intrinsic protease activation.

Intracellular Accumulations

Normal cells may accumulate abnormal substances.
Accumulations can be normal endogenous substances, abnormal endogenous substances, or abnormal exogenous substances.
Accumulations may be harmful or injurious.

Fatty Change (Steatosis)

Accumulation of triglycerides within cells.
Most commonly seen in the liver, although it can occur in other organs.

Cholesterol and Cholesterol Esters

Accumulation can lead to fatty cells, atherosclerosis, and xanthomas.

Proteins

Uncommon accumulation, but can be observed in glomerular diseases.

Glycogen

Accumulates in cases of abnormal glucose or glycogen metabolism.

Pigments

Colored substances either exogenous or endogenous.
Examples include melanin, hemosiderin.

Pathologic Calcification

Abnormal deposition of calcium salts.
Dystrophic calcification occurs in dead or dying tissues.
Metastatic calcification occurs in normal tissues due to hypercalcemia.

Cell Adaptations of Growth and Differentiation

Cells adapt to changes in their environment.
Physiological adaptations are responses to hormones or endogenous chemicals.
Pathological adaptations are often responses to stress or injury.

Atrophy

Shrinkage in cell size.
Can involve the entire organ.
Causes include decreased workload, loss of innervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging.

Hypertrophy

Increased cell size.
Results from increased synthesis of structural proteins and organelles.
Associated with increased workload.

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Description

This quiz explores the mechanisms and effects of free radicals on cell injury, reversible injury, and necrosis. It covers fundamental concepts such as the generation of free radicals and the morphological changes associated with cell death. Test your understanding of cellular responses to injury and the role of free radicals in various pathological processes.