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Questions and Answers

What type of damage can occur to DNA as a result of exposure to various agents?

Temporary damage

Repairable damage

Irreparable damage (correct)

Reversible damage

What is one site where protein synthesis occurs and can be affected by damage?

Golgi Apparatus

Nucleus

Mitochondria

Endoplasmic Reticulum (ER) (correct)

What is the structure that provides scaffolding and 'motor' functions for cells?

Cytoskeleton (correct)

Nucleolus

Cytoplasm

Cell Membrane

What is the process by which cells undergo programmed cell death?

Apoptosis Signup and view all the answers

What are the cellular components that suffer damage upon exposure to various agents?

Other cellular components, including the ER and cytoskeleton Signup and view all the answers

What is the term for the process of protein synthesis that occurs after transcription?

Post-translational processing Signup and view all the answers

What is the term used to describe the process of self-eating in cells?

Autophagy Signup and view all the answers

What is the main difference between autophagy and necrosis?

Autophagy is a natural process, while necrosis is a pathological process Signup and view all the answers

What is the term used to describe the appearance of cells undergoing autophagy?

Vacuolization Signup and view all the answers

What is the purpose of autophagy in cells?

To recycle cellular components and maintain cellular health Signup and view all the answers

What happens to the cellular components during autophagy?

They are degraded by lysosomes Signup and view all the answers

What is the role of lysosomes in autophagy?

To fuse with vacuoles and degrade cellular components Signup and view all the answers

What is the consequence of impaired autophagy?

Impaired cellular homeostasis Signup and view all the answers

What is the term used to describe the condensed chromatin in cells undergoing autophagy?

Pyknosis Signup and view all the answers

What is the result of damage to lysosomal membranes?

Leakage of enzymes Signup and view all the answers

What is the primary source of energy for energy-dependent cellular functions?

ATP Signup and view all the answers

What is the consequence of damage to cellular membranes?

Impaired transport functions Signup and view all the answers

Which of the following can cause DNA damage?

All of the above Signup and view all the answers

What is the result of necrosis?

Inflammation and tissue damage Signup and view all the answers

Which of the following is a consequence of radiation?

Mutations Signup and view all the answers

What is the result of apoptosis?

Programmed cell death Signup and view all the answers

What is the consequence of hypoxia/ischemia?

DNA damage and cell injury Signup and view all the answers

What is the function of the sensors in the ER membrane?

To detect the presence of misfolded proteins Signup and view all the answers

What happens when the amount of misfolded proteins is too great to be corrected?

The mitochondrial pathway of apoptosis is induced Signup and view all the answers

What is the purpose of the unfolded protein response?

To protect the cell from the harmful consequences of misfolded proteins Signup and view all the answers

What type of proteins are involved in detecting misfolded proteins in the ER?

BH3-only proteins Signup and view all the answers

What is the outcome of the terminal unfolded protein response?

Cell death Signup and view all the answers

Where do the sensors that detect misfolded proteins reside?

ER membrane Signup and view all the answers

What is the result of defective DNA repair?

Accumulation of misfolded proteins Signup and view all the answers

What is the consequence of mutations in DNA replication?

Increased cellular aging Signup and view all the answers

What is the role of insulin/IGF signaling in cellular aging?

It counteracts cellular aging Signup and view all the answers

What is the result of decreased protein synthesis?

Increased cell loss Signup and view all the answers

What is the consequence of cellular protein accumulation?

Increased cellular dysfunction Signup and view all the answers

What is the role of TOR in cellular aging?

It promotes cellular aging Signup and view all the answers

What is the result of decreased cell functions?

Increased cellular aging Signup and view all the answers

What is the consequence of altered transcription?

Decreased cellular functions Signup and view all the answers

DNA damage can be repaired in cells.

False Signup and view all the answers

The endoplasmic reticulum (ER) is involved in post-translational protein processing.

True Signup and view all the answers

Cytoskeleton is responsible for scaffolding and motor functions in cells.

True Signup and view all the answers

Apoptosis is a type of programmed cell death.

True Signup and view all the answers

Lysosomes are involved in protein synthesis.

False Signup and view all the answers

Autophagy is a process of cellular self-eating.

True Signup and view all the answers

Superoxide is converted to hydrogen peroxide spontaneously and by the action of the enzyme superoxide dismutase.

True Signup and view all the answers

The degree of injury from any injurious stimulus always remains the same.

False Signup and view all the answers

Intermediates are generated when oxygen is only partially reduced.

True Signup and view all the answers

The production of misfolded proteins can increase the production of normal proteins.

False Signup and view all the answers

Cellular injury and death are always irreversible.

False Signup and view all the answers

Telomerase is an enzyme that can repair DNA damage.

False Signup and view all the answers

Mutations can result in the production of abnormal proteins.

True Signup and view all the answers

Hydrogen peroxide is a reactive oxygen species that can cause cellular damage.

True Signup and view all the answers

Superoxide dismutase is an enzyme that converts hydrogen peroxide to water and oxygen.

False Signup and view all the answers

Enzymes are responsible for repairing DNA mutations.

False Signup and view all the answers

The extent of cellular injury depends on the severity of the injurious stimulus.

True Signup and view all the answers

The accumulation of misfolded proteins can lead to cell death.

True Signup and view all the answers

Reactive oxygen species are always beneficial to cellular metabolism.

False Signup and view all the answers

Cell injury can result from abnormalities in one or more essential cellular components.

True Signup and view all the answers

Decreased protein synthesis can lead to cellular aging.

True Signup and view all the answers

Autophagy is a process that occurs in response to DNA damage.

False Signup and view all the answers

The enzyme myeloperoxidase is responsible for converting hypochlorous acid into a reactive compound.

True Signup and view all the answers

Impaired autophagy can lead to inflammation and tissue damage.

True Signup and view all the answers

The progression of cellular aging is influenced by the rate of telomere shortening.

True Signup and view all the answers

Mitochondria are not involved in the process of cell injury.

False Signup and view all the answers

Hypoxia can lead to cell injury by causing oxidative stress and mitochondrial dysfunction.

True Signup and view all the answers

The nucleus is not a site of protein synthesis.

False Signup and view all the answers

Inflammation is a consequence of impaired autophagy.

True Signup and view all the answers

Cell injury can occur due to abnormalities in the lysosomal membrane.

True Signup and view all the answers

Calorie restriction can activate various signaling pathways and transcription factors that counteract cellular aging.

True Signup and view all the answers

Reactive oxygen species (ROS) are involved in promoting cellular aging.

True Signup and view all the answers

The target of rapamycin (TOR) is a signaling pathway that promotes cellular aging.

True Signup and view all the answers

Decreased protein synthesis can lead to cellular protein accumulation.

False Signup and view all the answers

Insulin-like growth factor (IGF) signaling is involved in promoting cellular aging.

True Signup and view all the answers

DNA damage can cause cardiovascular disease.

True Signup and view all the answers

Replicative senescence is a mechanism of cellular aging caused by telomere shortening.

True Signup and view all the answers

Defective protein homeostasis can lead to cardiovascular disease.

True Signup and view all the answers

What is the characteristic feature of apoptotic cells' nuclei?

Fragmented nuclei with condensed chromatin Signup and view all the answers

What is the effect of the preparative regimen for colonoscopy on epithelial cells?

Induces apoptosis Signup and view all the answers

What type of molecules are free radicals?

Reactive molecules Signup and view all the answers

What is the term used to describe the process of cellular self-eating?

Autophagy Signup and view all the answers

What is the consequence of radiation on cells?

Induces apoptosis and oxidative stress Signup and view all the answers

What are the primary cellular targets of injurious stimuli?

Mitochondria, cellular membranes, or nuclear DNA Signup and view all the answers

What is the role of reactive oxygen species (ROS) in cellular damage?

Causes oxidative stress and damage to cellular components Signup and view all the answers

What is the characteristic feature of apoptotic cells' bodies?

Shrunken cell bodies Signup and view all the answers

What type of damage can reactive oxygen species (ROS) cause?

Damage to lipids, proteins, and DNA Signup and view all the answers

What is the consequence of ATP depletion in cells?

Impaired cellular functions Signup and view all the answers

What is the normal process by which molecular oxygen is reduced to generate water during mitochondrial respiration?

Reduction-oxidation (redox) reaction Signup and view all the answers

What is the consequence of impaired autophagy?

Accumulation of damaged or dysfunctional cellular components Signup and view all the answers

What is the result of ischemia/hypoxia?

Reduced ATP production and increased ROS production Signup and view all the answers

What is the result of impaired reduction of molecular oxygen during mitochondrial respiration?

Reactive oxygen species (ROS) are produced Signup and view all the answers

What is the site where reactive oxygen species (ROS) are normally produced in small amounts during mitochondrial respiration?

Mitochondria Signup and view all the answers

What is the role of enzymes such as glutathione peroxidase in cells?

To reduce oxidative stress by converting hydrogen peroxide to water Signup and view all the answers

What is the consequence of nuclear DNA damage?

Genetic mutations and potential cell death Signup and view all the answers

What is the consequence of the accumulation of reactive oxygen species (ROS) in cells?

Cellular damage or injury Signup and view all the answers

What is the primary source of energy for energy-dependent cellular functions?

ATP Signup and view all the answers

What is the result of cellular membrane damage?

Disruption of cellular functions and potential cell death Signup and view all the answers

What is the normal process that occurs during mitochondrial respiration to generate energy?

Reduction-oxidation (redox) reaction Signup and view all the answers

What is the result of injury due to hypoxia?

Impaired oxidative phosphorylation Signup and view all the answers

What is the role of enzymes in the reduction of molecular oxygen during mitochondrial respiration?

To facilitate the sequential transfer of electrons Signup and view all the answers

What is the consequence of mitochondrial damage?

Impaired energy production and potential cell death Signup and view all the answers

What is the role of superoxide in cellular injury?

It can generate reactive oxygen species (ROS) Signup and view all the answers

What is the result of the incomplete reduction of molecular oxygen during mitochondrial respiration?

Reactive oxygen species (ROS) are produced Signup and view all the answers

What is the consequence of impaired oxidative phosphorylation?

Decreased ATP production Signup and view all the answers

What is the primary function of mitochondrial respiration?

To generate energy for the cell Signup and view all the answers

What is the result of radiation?

Generation of reactive oxygen species (ROS) Signup and view all the answers

What is the role of oxidative phosphorylation in cellular function?

It generates ATP Signup and view all the answers

What is the consequence of mitochondrondrial damage?

Impaired oxidative phosphorylation Signup and view all the answers

What is the result of ischemia?

Impaired oxidative phosphorylation Signup and view all the answers

What happens to cellular components when the ER membrane is damaged, leading to a decline in protein synthesis?

Enzymes and other components in the ER are damaged, causing a decrease in protein synthesis. Signup and view all the answers

How does p53 respond to damaged DNA?

p53 arrests cells in the G1 phase, allowing for DNA repair mechanisms to activate. Signup and view all the answers

What is the purpose of DNA repair mechanisms?

To correct DNA damage and allow cells to survive. Signup and view all the answers

What happens to cells when the unfolded protein response is triggered?

Cells undergo programmed cell death (apoptosis) if the unfolded protein response is triggered. Signup and view all the answers

What is the outcome of defective DNA repair?

Defective DNA repair can lead to mutations and tumorigenesis. Signup and view all the answers

What is the role of the unfolded protein response in cellular aging?

The unfolded protein response helps to prevent cellular protein accumulation and maintain protein homeostasis. Signup and view all the answers

What is the consequence of impaired autophagy?

Impaired autophagy can lead to cellular protein accumulation and cellular aging. Signup and view all the answers

What is the role of p53 in regulating cellular aging?

p53 triggers apoptosis in cells with damaged DNA, preventing further damage and promoting cellular aging. Signup and view all the answers

The generation of ______ is increased by exposure to reversible injury but larger doses of the toxin or more prolonged ischemia.

radicals Signup and view all the answers

UV light, ______ and toxins, and during normal cellular aging, may cause necrosis.

radiation Signup and view all the answers

Stretched muscle in the leg survives ______ for 2 hours.

ischemia Signup and view all the answers

Oxygen deprivation for 3 hours, whereas cardiac muscle, which has higher metabolic needs, dies.

Signup and view all the answers

This also leads to ROS production because of incomplete ______ of oxygen.

reduction Signup and view all the answers

The genetic makeup of the individual may also determine the reaction to ______ agents.

injurious Signup and view all the answers

The human body needs to burn ___________ kg of ATP every day.

50 to 75 Signup and view all the answers

After 20 to 30 minutes of ______, the gene expression of the individual.

ischemia Signup and view all the answers

Ischemia is a condition of ___________ deprivation.

oxygen Signup and view all the answers

This may also determine the reaction to ______ and further damage to cellular components.

injurious Signup and view all the answers

Damages to ATP can cause ___________ to many cellular components.

depletion Signup and view all the answers

Insulin/ ______ signaling plays a role in cellular aging.

IGF Signup and view all the answers

Defective ______ repair can lead to cellular aging.

DNA Signup and view all the answers

The reduction of ATP-dependent Na-K pump activity results in ___________ influx of Na and water.

an Signup and view all the answers

The ER is affected by the reduction of ATP-dependent Na-K pump activity, leading to ___________ and dilation.

cell Signup and view all the answers

Mutations in ______ replication can lead to misfolded proteins.

DNA Signup and view all the answers

Accumulation of cellular proteins can lead to ______ cellular functions.

decreased Signup and view all the answers

The reduction of ATP-dependent Na-K pump activity can cause ___________ and damage to the ER.

swelling Signup and view all the answers

______ signaling can counteract cellular aging.

TOR Signup and view all the answers

The ATP-dependent Na-K pump plays a crucial role in maintaining the ___________ of the plasma membrane.

integrity Signup and view all the answers

Hypoxia and ___________ can cause damage to ATP and affect cellular functions.

ischemia Signup and view all the answers

Altered ______ can lead to cellular aging.

transcription Signup and view all the answers

Cellular protein accumulation can lead to ______ cellular proteins.

misfolded Signup and view all the answers

Decreased protein synthesis can lead to ______ cellular functions.

decreased Signup and view all the answers

In some cases, pers pa o c med ors, such as hormone-induced of the breast, and hyperp sia, affect end rium.

onal, th, io, iators, the, enlargement, and, hyperplasia Signup and view all the answers

stress can cause in bone and muscle cells.

mechanical, changes Signup and view all the answers

adaptations are responses to mutations and oncogenic formation.

Pathologic, transformation Signup and view all the answers

allows cells to their structure and function and thus __.

stress, modify, survive Signup and view all the answers

is a decrease in the number of cells and, hence, may cause an injury.

Atrophy, escape Signup and view all the answers

and organ can occur as a result of __ function.

Physiologic, shrink, abnormal Signup and view all the answers

injury can occur at the expense of normal function.

Atrophy, cellular Signup and view all the answers

is caused by normal function, leading to __ injury.

Atrophy, loss, cellular Signup and view all the answers

Hyperp___a can be psychological or pathological and, in naming by insulin-like growth factor, so cells cycle less and suffer boon_s and suffer various biochemical sous_____ons.

lasia Signup and view all the answers

Grow_ factors are produced by a variety of cell types. Pos_orum

th Signup and view all the answers

In addition to these intrinsic abnormalities, damaged and dying en_gnt of the breast due to increased production of ductular cells induce low-_ inflammation, and chronic inflammation pre-

largement Signup and view all the answers

Grow_______ factors are responsible for stimulating production of ductular cells and, and some types of cancer.

th Signup and view all the answers

Surviving cells after death or removal of some of the cells in an organ is called comp_satory ___a.

ensatory hyperplasia Signup and view all the answers

Damaged and dying cells can induce _________ inflammation, and chronic inflammation pre-.

low-grade Signup and view all the answers

Grow_ factors are responsible for stimulating production of ductular cells and, and some types of ___.

cancer Signup and view all the answers

Hyperp___a can be psychological or pathological and, in naming by _-like growth factor, so cells cycle less and suffer boon_s and suffer various biochemical sous_____ons.

insulin Signup and view all the answers

Match the following cellular components with their effects when damaged:

Plasma membrane = Releases enzymes and leads to necrosis Nucleus = Disrupts transcription-dependent cellular functions Lysosomal membranes = Releases ROS or other agents Cytoskeleton = Disrupts scaffolding and motor functions Signup and view all the answers

Match the following cellular processes with their effects:

Necrosis = Results in cellular death Autophagy = Removes damaged cellular components Apoptosis = Results in programmed cell death Protein synthesis = Results in production of normal proteins Signup and view all the answers

Match the following reactive oxygen species with their effects:

Superoxide = Can cause cellular damage Hydrogen peroxide = Can cause cellular damage ROS = Can cause cellular damage Reactive oxygen species = Can cause cellular damage Signup and view all the answers

Match the following cellular components with their functions:

Endoplasmic reticulum = Involved in post-translational protein processing Lysosomes = Involved in protein synthesis and autophagy Cytoskeleton = Involved in scaffolding and motor functions Nucleus = Involved in transcription-dependent cellular functions Signup and view all the answers

Match the following cellular processes with their effects on cellular components:

Autophagy = Removes damaged cellular components Apoptosis = Removes damaged cellular components Necrosis = Results in cellular death Protein synthesis = Produces normal proteins Signup and view all the answers

Match the following cellular components with their effects on cellular functions:

Mitochondria = Provides energy for cellular functions Lysosomes = Involved in protein synthesis and autophagy Cytoskeleton = Involved in scaffolding and motor functions Nucleus = Involved in transcription-dependent cellular functions Signup and view all the answers

Match the following cellular processes with their effects on cellular injury:

Necrosis = Results in cellular death Autophagy = Reduces cellular injury Apoptosis = Results in programmed cell death Protein synthesis = Produces normal proteins Signup and view all the answers

Match the following cellular components with their effects on cellular death:

Lysosomes = Results in cellular death Nucleus = Results in cellular death Cytoskeleton = Results in cellular death Mitochondria = Results in cellular death Signup and view all the answers

Match the following terms with their corresponding descriptions:

Hypoxia = Oxygen deficiency Ischemia = Reduced blood flow ATP = Energy source for cellular functions Oxidative phosphorylation = Process of generating ATP in mitochondria Signup and view all the answers

Match the following cellular processes with their effects:

Hypoxia/Ischemia = Reduced ATP generation Oxidative phosphorylation = Increased ATP production Energy-dependent cellular systems = Failure of cellular functions Membrane transport = Disruption of cellular processes Signup and view all the answers

Match the following terms with their corresponding cellular components:

Mitochondria = Site of ATP production Lysosomes = Involved in cellular recycling ER = Site of protein synthesis Cytoskeleton = Provides scaffolding and motor functions Signup and view all the answers

Match the following terms with their corresponding cellular processes:

Synthesis = Production of proteins Turnover = Breakdown of proteins Membrane transport = Movement of molecules across membranes Scavenging = Removal of damaged cellular components Signup and view all the answers

Match the following terms with their corresponding effects on cellular systems:

Severe drop in blood pressure = Shock Reduced oxygen supply = Hypoxia Inadequate ATP production = Cellular dysfunction Impaired autophagy = Accumulation of damaged cellular components Signup and view all the answers

Match the following terms with their corresponding descriptions:

Cerebral artery disease = Narrowing or blockage of arteries supplying the brain Coronary artery disease = Narrowing or blockage of arteries supplying the heart Myocardial infarction = Death of heart muscle due to lack of oxygen Stroke = Blockage or rupture of blood vessels in the brain Signup and view all the answers

Match the following cellular processes with their corresponding consequences:

Impaired energy-dependent cellular systems = Cellular dysfunction Disrupted membrane transport = Cellular injury Inadequate ATP production = Cellular dysfunction Impaired autophagy = Accumulation of damaged cellular components Signup and view all the answers

Match the following terms with their corresponding descriptions:

Radicals = Highly reactive molecules that can cause cellular damage Oxidative stress = Imbalance between oxidants and antioxidants Reactive oxygen species = Molecules that can cause oxidative stress Antioxidants = Molecules that counteract oxidative stress Signup and view all the answers

Match the following reactive oxygen species (ROS) with their formation process:

Hydrogen peroxide = Partial reduction of oxygen Superoxide = Spontaneous conversion from oxygen Water = Complete reduction of oxygen Oxygen = Reduction-oxidation reaction Signup and view all the answers

Match the following cellular components with their functions:

Mitochondria = Energy generation Lysosomes = Protein synthesis Endoplasmic reticulum = Post-translational protein processing Cytoskeleton = Cellular scaffolding and motor functions Signup and view all the answers

Match the following cellular processes with their outcomes:

Apoptosis = Programmed cell death Autophagy = Cellular self-eating Necrosis = Unprogrammed cell death Protein synthesis = Production of new proteins Signup and view all the answers

Match the following enzymes with their functions:

Superoxide dismutase = Conversion of superoxide to hydrogen peroxide Telomerase = Repair of DNA damage Enzymes in mitochondria = Reduction of oxygen to water Sensors in ER membrane = Detection of misfolded proteins Signup and view all the answers

Match the following cellular responses with their triggers:

Unfolded protein response = Accumulation of misfolded proteins Autophagy = Nutrient deficiency Apoptosis = DNA damage Cellular injury and death = Injurious stimulus Signup and view all the answers

Match the following cellular structures with their roles in protein processing:

Mitochondria = Protein synthesis Endoplasmic reticulum = Post-translational protein processing Lysosomes = Protein degradation Cytoskeleton = Protein transport Signup and view all the answers

Match the following cellular processes with their effects on cellular components:

Autophagy = Degradation of damaged cellular components Apoptosis = Death of entire cell Necrosis = Uncontrolled cell death Protein synthesis = Production of new cellular components Signup and view all the answers

Match the following cellular processes with their consequences:

Impaired autophagy = Accumulation of damaged cellular components Defective DNA repair = Mutation accumulation Altered transcription = Changes in gene expression Inhibited protein synthesis = Reduced cellular growth Signup and view all the answers

Match the following cellular components with their functions:

Cytoskeleton = Provides scaffolding and motor functions for cells Lysosomes = Involved in protein synthesis Endoplasmic Reticulum = Involved in post-translational protein processing Autophagy = Process of cellular self-eating Signup and view all the answers

Match the following cellular responses with their descriptions:

Cellular swelling = Result of influx of Ca and efflux of K Loss of microvilli = Damage to cellular membranes Blebs = Formation of balloon-like structures on the cell surface ER swelling = Consequence of protein misfolding Signup and view all the answers

Match the following cellular processes with their consequences:

Apoptosis = Programmed cell death Autophagy = Cellular self-eating Necrosis = Unprogrammed cell death DNA damage = Mutations and altered transcription Signup and view all the answers

Match the following cellular components with their roles in cellular injury:

Lysosomes = Involved in protein degradation Mitochondria = Primary source of energy for cellular functions Endoplasmic Reticulum = Involved in post-translational protein processing DNA = Stores genetic information Signup and view all the answers

Match the following cellular components with their functions:

Mitochondria = Generate energy for the cell Lysosomes = Involved in protein degradation Endoplasmic reticulum (ER) = Involved in protein synthesis and folding Microvilli = Increase the surface area of the cell Signup and view all the answers

Match the following cellular processes with their triggers:

Apoptosis = DNA damage and cellular stress Autophagy = Nutrient deprivation and cellular stress DNA repair = DNA damage Unfolded protein response = Misfolded proteins in the ER Signup and view all the answers

Match the following cellular processes with their outcomes:

Ischemia-Reperfusion Injury = Restoration of blood flow to an ischemic tissue with increased ROS production Autophagy = Recycling of damaged cellular components Necrosis = Unprogrammed cell death Glycogen synthesis = Storage of glucose in the liver and muscles Signup and view all the answers

Match the following cellular responses with their triggers:

Influx of Ca = Damage to cellular membranes Efflux of K = Increased production of ROS ER stress = Accumulation of misfolded proteins Cellular swelling = Decreased blood flow to the tissue Signup and view all the answers

Match the following reactive oxygen species with their effects:

Superoxide = Can cause cellular damage Hydrogen peroxide = Can cause cellular damage ROS = Can cause DNA damage and mutations Oxygen = Essential for cellular respiration Signup and view all the answers

Match the following cellular components with their functions in protein synthesis:

Endoplasmic reticulum (ER) = Involved in protein folding and modification Lysosomes = Involved in protein degradation Mitochondria = Generate energy for protein synthesis Golgi apparatus = Modifies and packages proteins for secretion Signup and view all the answers

Match the following cellular processes with their results:

Mutations = Abnormal protein production DNA damage = Altered transcription and cellular injury Autophagy = Recycling of cellular components Apoptosis = Cell death Signup and view all the answers

Match the following cellular responses with their consequences:

Increased ROS production = Cellular damage and injury Protein misfolding = ER stress and unfolded protein response Cellular swelling = Decreased cellular function Autophagy = Recycling of damaged cellular components Signup and view all the answers

Match the following cellular processes with their descriptions:

Glycogen synthesis = Storage of glucose in the liver and muscles Lactic acid synthesis = Energy production in the absence of oxygen Protein synthesis = Production of new proteins in the cell Autophagy = Recycling of damaged cellular components Signup and view all the answers

Match the following cellular components with their roles in cellular injury:

Lysosomes = Involved in protein degradation and removal of damaged cellular components Mitochondria = Generate energy for the cell, but can also produce ROS Endoplasmic reticulum (ER) = Involved in protein synthesis and folding, and can be damaged by misfolded proteins Cell membrane = Regulates the flow of molecules into and out of the cell Signup and view all the answers

Study Notes

Autophagy

Autophagy is a form of "self-eating" (Greek, phaga = to eat) where cells digest their own organelles and recycle them to provide energy for survival.
In H&E-stained sections, the nucleus appears materlike to provide energy for survival.

Autophagy vs. Necrosis

Autophagy differs from necrosis in that cells survive by recycling their own organelles.
In necrosis, cells die due to irreversible damage.
In H&E-stained sections, autophagic cells appear with shrunken, pyknotic nuclei, and vacuoles containing cellular debris.

Cellular Components and Damage

Other cellular components that suffer damage upon exposure to various injurious agents include:
- Endoplasmic Reticulum (ER) involved in protein synthesis and post-translational processing
- Cytoskeleton providing structural support and motor functions
- Mitochondria responsible for energy production
- Cellular membranes vulnerable to leakage and damage

Mechanisms of Cell Injury and Death

Hypoxia/ischemia, radiation, and other injurious agents can cause cell injury and death.
Mitochondrial damage leads to reduced ATP production, increased ROS, and activation of caspases, ultimately resulting in apoptosis.
DNA damage triggers apoptosis, while mutations can lead to cellular aging and death.
ER stress triggers an unfolded protein response, which can protect the cell from misfolded proteins or induce apoptosis if the damage is irreversible.

Cell Death Pathways

Necrosis: irreversible cell damage and death
Apoptosis: programmed cell death in response to internal or external signals
Autophagy: self-eating and recycling of cellular components to provide energy for survival

Mechanisms of Cell Injury and Death

Irreparable DNA damage can occur due to exposure to various injurious agents, leading to cellular injury and death.
Other cellular components, such as the ER and cytoskeleton, can also suffer damage upon exposure to injurious agents.

Cellular Components Prone to Damage

Mitochondria, membranes, and the nucleus are essential cellular components that can be damaged, leading to cellular injury and death.
The degree of injury from any stimulus varies depending on the degree of abnormality in one or more of these essential cellular components.

Mechanisms of DNA Damage

Superoxide, a reactive oxygen species, can be converted to hydrogen peroxide (H2O2) spontaneously or by the action of the enzyme superoxide dismutase.
Hydrogen peroxide can be converted to a highly reactive compound, hypochlorous acid, by the enzyme myeloperoxidase present in leukocyte granules.
This reactive compound can cause DNA damage and disrupt cellular function.

Consequences of Cellular Damage

Decreased cell replication due to progressive loss of cellular function can lead to tissue damage and organ injury.
Abnormalities in cellular components can lead to increased production of misfolded proteins, which can accumulate and cause cellular damage.
Decreased telomerase activity, which maintains telomere length, can lead to cellular senescence and aging.

Aging and Cellular Damage

DNA damage, replicative senescence, and decreased and misfolded proteins are among the best-described mechanisms of cellular aging.
Environmental stresses, such as calorie restriction, can counteract aging by activating various signaling pathways and transcription factors.
Cellular aging can lead to tissue damage and organ injury, and can also increase the risk of age-related diseases.

Apoptotic Cells and Free Radicals

Apoptotic cells in the colonic epithelium are shown, which are induced by the preparative regimen for colonoscopy.
Free radicals are highly reactive molecules that can cause apoptosis in epithelial cells.
Apoptotic cells are characterized by fragmented nuclei, condensed chromatin, and shrunken cell bodies.

Free Radicals and ROS

ROS (Reactive Oxygen Species) are produced normally in small amounts in cells during redox reactions.
ROS are highly reactive molecules that can cause oxidative damage to cellular components.
ROS include oxygen radicals, such as superoxides, hydroxyl radicals, and hydrogen peroxide.

Mitochondria and ROS

Mitochondria are the sites where ATP is produced, and ROS are produced as a byproduct.
ROS can damage mitochondrial components, leading to the production of more ROS.
Mitochondrial dysfunction can lead to the release of ROS, which can cause apoptosis.

Cellular Targets of Injurious Stimuli

Most injurious stimuli affect mitochondria, cellular membranes, or nuclear DNA.
Injury to these structures can progress to necrosis or apoptosis.
ATP, adenosine triphosphate, is a key player in cellular energy metabolism.

ROS and Cellular Damage

ROS can damage lipids, proteins, and DNA, leading to cellular damage.
Peroxidation of lipids, oxidation of proteins, and breaks in DNA can occur due to ROS.
ROS can also affect cellular components, such as enzymes, and lead to the accumulation of damaged proteins.

DNA Damage and Repair

Damaged DNA can activate p53, which arrests the cell cycle in the G1 phase to allow for DNA repair.
DNA repair mechanisms can correct DNA damage, but if the damage is severe, p53 can trigger apoptosis.
The accumulation of DNA damage can lead to the activation of DNA repair mechanisms, which can prevent further damage.

Cellular Response to Damage

Cells can respond to damage by activating repair mechanisms or undergoing apoptosis.
The choice between repair and apoptosis depends on the severity of the damage and the cellular context.
Apoptosis is a mechanism to eliminate damaged cells, which can prevent further damage to the organism.

Ischemia and Oxidative Stress

Ischemia leads to oxygen deprivation, which increases oxidative stress and ROS production.
This causes damage to cellular components, including the plasma membrane, and disrupts ATP-dependent Na-K pumps.

Cellular Effects

Reduced cellular activity and ATP production occur due to oxidative stress.
Decreased ATP production damages many cellular components, leading to:
- Reduced activity of the plasma membrane ATP-dependent Na-K pump.
- Influx of Na and water, causing cell swelling and damage.
- Disruption of ER function, leading to protein misfolding and aggregation.

Genetic Effects

Oxidative stress and DNA damage lead to:
- Mutations in DNA replication.
- Defective DNA repair.
- Altered gene transcription.

Cellular Aging

Decreased cellular function and increased DNA damage contribute to cellular aging.
Counteracting cellular aging requires maintaining protein homeostasis and promoting DNA repair.

Hyperplasia

Hyperplasia can be physiological or pathological and is induced by growth factors.
It can lead to increased cell proliferation and protein synthesis.
Examples of hyperplasia include:
- Insulin/IGF signaling pathway.
- TOR pathway.
- Hormone-induced hyperplasia.

Pathological Consequences

Hyperplasia can lead to various diseases, including:
- Atherosclerosis.
- Type 2 diabetes.
- Cancer.
It can also cause chronic inflammation and tissue damage.

Compensatory Mechanisms

Compensatory mechanisms, such as hyperplasia, can occur in response to tissue damage or stress.
Examples include:
- Compensatory hyperplasia in response to hormonal changes.
- Compensatory hyperplasia in response to mechanical stress.

Cellular Damage and Necrosis

Damage to cell membranes can lead to the release of enzymes, causing cell injury and necrosis
ROS (Reactive Oxygen Species) can damage cell membranes, leading to cell injury and necrosis
Plasma membrane damage can result in cell death, leading to necrosis

Nuclear Damage

Nuclear DNA is damaged, disrupting transcription-dependent cellular functions (e.g., protein synthesis)
Nuclear damage can disrupt gene expression, leading to cell injury and death

ROS Production

ROS are produced normally in small amounts during cellular respiration and metabolism
ROS can trigger apoptosis (cell death) by damaging mitochondria
Increased ROS production can contribute to coronary artery disease and stroke

Cellular Response to Injury

Hypoxia and ischemia can lead to reduced ATP production, causing energy-dependent cellular systems to fail
Cellular swelling, loss of microvilli, and bleb formation can occur in response to injury
ER swelling and increased ROS production can exacerbate tissue injury

Consequences of Cellular Injury

Accumulation of mutations in DNA can occur naturally and can be enhanced by ROS and environmental mutagens
Influx of calcium and sodium ions can contribute to cellular injury and death
Efflux of potassium ions can lead to cellular injury and death

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Description

Learn about autophagy, a process of self-eating, and its connection to apoptosis, a form of cell death. Understand the morphological appearance and distinct differences between these two cellular processes.