Cellular Response to Stress and Toxic Insults Flashcards Preview

PoD Test 1 > Cellular Response to Stress and Toxic Insults > Flashcards

Flashcards in Cellular Response to Stress and Toxic Insults Deck (23)
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1
Q

What are four types of cellular adaptations to stress?

A

Atrophy - shrinkage of cells

Hypertrophy - increase in the size of cells which results in enlargement of the organs

Hyperplasia - increased number of cells in an organ or tissue

Metaplasia - transformation or replacement of one adult cell type with another

2
Q

What are the mechanisms of atrophy?

A

Increased catabolism of cell organelles

Decreased protein synthesis

Increased protein degradation via ubiquitin-proteasome pathway

Increased autophagy

3
Q

What is Brown atrophy?

A

During atrophy, undigested lipids are stored as residual bodies called Lipofuscin granules that impart a brown coloration to the tissue

4
Q

What causes hypertrophy?

A

Response to increased workload; induced by growth factors produced in response to mechanical stress or other stimuli

Occurs in tissues incapable of cell division

5
Q

What triggers the molecular pathogenesis of cardiac hypertrophy?

A

The integrated actions of mechanical sensors (triggered by increase workload), growth factors, and vasactive agents

These activate complex signal transduction pathways

6
Q

What is the result of the activation of the signal transduction pathways associated with cardiac hypertrophy?

A

Muscle cell synthesize more proteins and the number of myofilaments increases

a isoform of myosin heavy chain is replaced by B form

Atrial natriuretic factor is re-induced, causing decrease in blood volume

7
Q

What is physiologic hyperplasia?

A

Caused by the action of hormones or growth factors that occurs:

when there is a need to increase functional capacity

or when there is a need for compensatory increase after damage or resection

8
Q

What is pathologic hyperplasia?

A

Usually due to excessive hormonal stimulation and/or effects of growth factors

9
Q

What is the cause of metaplasia?

A

Usually results from chronic irritation

Seem to precede development of cancer

Thought to arise from reprogramming of undifferentiated cells

10
Q

When does metaplasia from columnar to squamous occur?

A

Occurs in respiratory tract in response to chronic stress (e.g. smoking) and vitamin A deficiency

Stones in excretory ducts can also cause this type of metaplasia

11
Q

What is Barrett esophagus?

A

Esophageal squamous epithelium is replaced by intestinal-like columnar cells under the influence of refluxed gastric acid

12
Q

What is Connective tissue metaplasia?

A

Formation of cartilage, bone, or adipose tissue in tissues that normally do not contain these elements

13
Q

What is cellular adaptation?

A

Cells are capable of adjusting their structure and functions in response to various physiological and pathological conditions

14
Q

What are four ways that cell injury can result from oxygen deprivation?

A

Hypoxia

Ischemia

Hypoxemia

Perfusion defects

15
Q

What are the four principal targets and biochemical mechanisms of cell injury?

A

Mitochondria and their ATP and ROS under pathologic conditions

Damage to cellular membranes

Disturbance in calcium homeostasis

Damage to DNA and misfolding of proteins

16
Q

What are the hallmarks of reversible cell injury?

A

Reduced oxidative phosphorylation with resultant depletion of ATP

Cellular swelling caused by changes in ion concentration and water influx

17
Q

What nuclear changes are associated with cell death?

A

Karyolysis - fading of basophilic chromatin of the nucleus

Pyknosis - nuclear shrinkage and increased basophilia

Karyorrhexis - break up and fragmentation of the nucleus

18
Q

What is coagulative necrosis?

A

Cell outline is preserved due to denaturation of proteins by acidosis, cells are eosinophilic, coagulated and anucleated

Usually occurs in conditions of ischemia

19
Q

What is liquefactive necrosis?

A

Digestion of tissue by hydrolytic enzymes causing it to be completely liquified

Occurs with abscess and fungi of any organ and ischemic brain infarction

20
Q

What is enzymatic fat necrosis?

A

Lipases released from the pancreas during pancreatitis split the triglyceride esters contained in fat cells

The fatty acids combine with calcium to produce chalky-white areas (fat saponification)

21
Q

What is Fribinoid necrosis?

A

Prominent when complexes of antigens and antibodies are deposited in the walls of arteries

22
Q

What is Caseous necrosis?

A

Distinct form of coagulative necrosis

Composed of fragmented or lysed cells and amorphous granular debris enclosed within ditinctive inflammatory debris

No cell outline, surrounded by granulomatous inflammation

23
Q

What is Gangrenous necrosis?

A

Coagulative necrosis superimposed with bacterial infection causing liquefactive necrosis due to actions of degradative enzymes in bacteria