Cell Death Overview and Necrosis
39 Questions
5 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which condition is characterized by a putrid and foul-smelling presentation with rapid proximal spread and no clear line of demarcation?

  • Dry Ischaemic gangrene
  • Apoptosis
  • Autophagy
  • Wet Ischaemic gangrene (correct)

What is a key physiological role of apoptosis?

  • Atrophy of organs following obstruction
  • Induction of immune cell proliferation
  • Promotion of tumor growth
  • Cell deletion in proliferating tissues (correct)

Which of the following is NOT associated with reduced apoptosis?

  • Neoplasia involving p53 mutations
  • Increased cell turnover (correct)
  • Bcl-2 overexpression
  • Cell accumulation

What type of cell death is characterized by the digestion of cellular organelles for energy, particularly in starving cells?

<p>Autophagy (D)</p> Signup and view all the answers

Which of the following diseases is associated with increased apoptosis leading to cell loss?

<p>AIDS (C)</p> Signup and view all the answers

What differentiates dry ischaemic gangrene from wet ischaemic gangrene?

<p>Sharp line of demarcation (B)</p> Signup and view all the answers

Which enzyme is primarily responsible for the fragmentation of DNA during apoptosis?

<p>Endonucleases (C)</p> Signup and view all the answers

What is the potential outcome if nutrients are not received by a cell undergoing autophagy?

<p>Apoptosis and cell death (B)</p> Signup and view all the answers

Which form of cell death is often linked with graft versus host disease?

<p>Apoptosis (A)</p> Signup and view all the answers

Which characteristic is NOT typically associated with necroptosis?

<p>Limited cellular ATP (D)</p> Signup and view all the answers

What is the primary mechanism that leads to liquefactive necrosis?

<p>Action of lytic enzymes (B)</p> Signup and view all the answers

Which condition is most commonly associated with caseative necrosis?

<p>Pulmonary tuberculosis (A)</p> Signup and view all the answers

What is one of the causes of fat necrosis?

<p>Enzymatic activity (C)</p> Signup and view all the answers

Which of the following cellular reactions is characterized by fragmented granular debris surrounded by epithelioid histiocytes?

<p>Caseative necrosis (B)</p> Signup and view all the answers

What pathological process primarily contributes to the formation of calcium soaps in fat necrosis?

<p>Release of lipases (A)</p> Signup and view all the answers

What distinguishes necroptosis from apoptosis?

<p>It can involve inflammation. (B)</p> Signup and view all the answers

Which tissue is particularly susceptible to liquefactive necrosis due to its high water content?

<p>Brain tissue (C)</p> Signup and view all the answers

In which scenario would you expect to see shadowy outlines of necrotic fat cells?

<p>Acute pancreatitis (A)</p> Signup and view all the answers

What type of cell death is characterized by the induction of inflammation due to cell lysis?

<p>Necroptosis (A)</p> Signup and view all the answers

Which of the following necrosis types is most commonly associated with acute pancreatitis?

<p>Fat necrosis (B)</p> Signup and view all the answers

Which process is characterized by the programmed death of cells without causing inflammation?

<p>Apoptosis (A)</p> Signup and view all the answers

Which type of necrosis features the preservation of the cell's basic shape but loss of the nucleus?

<p>Coagulative necrosis (A)</p> Signup and view all the answers

Which type of necrosis is most commonly associated with bacterial infections?

<p>Liquefactive necrosis (B)</p> Signup and view all the answers

Which type of cell death is specifically related to the formation of gas gangrene?

<p>Necroptosis (D)</p> Signup and view all the answers

What is the primary mechanism through which cellular components are degraded in autophagy?

<p>Lysosomal degradation (B)</p> Signup and view all the answers

Which statement correctly differentiates pyroptosis from other forms of cell death?

<p>It involves activation of caspases, leading to cell swelling and lysis. (A)</p> Signup and view all the answers

What is the main characteristic feature of gangrene?

<p>Death of tissue due to infection or lack of blood flow (D)</p> Signup and view all the answers

Which drugs or substances are most likely to induce apoptosis as a therapeutic mechanism?

<p>Chemotherapeutic agents (D)</p> Signup and view all the answers

Which physical factor can potentially lead to necrosis by causing damage through extreme conditions?

<p>Irradiation (A)</p> Signup and view all the answers

What type of cells are typically observed microscopically in traumatic fat necrosis?

<p>Foam cells and giant cells (B)</p> Signup and view all the answers

Which microbe is primarily associated with primary gas gangrene?

<p>Clostridium perfringens (D)</p> Signup and view all the answers

Which condition is NOT a cause of secondary or ischaemic gangrene?

<p>Clostridial infection (C)</p> Signup and view all the answers

What is the primary characteristic of gangrene?

<p>Bacterial digestion of dead tissue (B)</p> Signup and view all the answers

Which of the following best describes the process of gas gangrene?

<p>Anaerobic conditions leading to gas production (B)</p> Signup and view all the answers

What type of necrosis is characterized by a hard mass in fat tissue due to trauma?

<p>Traumatic fat necrosis (A)</p> Signup and view all the answers

Which factor is most closely linked to the development of secondary (ischaemic) gangrene?

<p>Vascular diseases such as diabetes (A)</p> Signup and view all the answers

What is a common sign of gas gangrene during physical examination?

<p>Presence of crepitance (B)</p> Signup and view all the answers

Which term refers specifically to necrosis accompanied by putrefaction due to bacterial action?

<p>Gangrene (B)</p> Signup and view all the answers

What type of bacteria is commonly involved in primary gangrene and associated with soil?

<p>Sporulating anaerobes (B)</p> Signup and view all the answers

Flashcards

Necrosis

The death of cells within a living organism caused by protein denaturation and/or enzymatic digestion. This is a breakdown of the cell from the inside out.

Autolysis

The process by which a cell is broken down by its own enzymes, specifically from lysosomes.

Gangrene

A condition where dead tissue is digested by bacteria, causing putrefaction in a body part.

Primary Gangrene

Gangrene caused by bacteria directly attacking and killing healthy tissue.

Signup and view all the flashcards

Secondary Gangrene

Gangrene caused by tissue death due to an underlying condition, followed by bacterial invasion.

Signup and view all the flashcards

Gas Gangrene

A type of primary gangrene caused by Clostridium perfringens, an anaerobic bacteria that releases toxins killing tissue.

Signup and view all the flashcards

Dry Gangrene

A type of gangrene where the affected area dries out. It's often caused by a lack of blood supply.

Signup and view all the flashcards

Wet Gangrene

A type of gangrene where the affected area becomes moist and infected. It's often caused by a lack of blood supply and bacterial infection.

Signup and view all the flashcards

Vascular disease

This type of gangrene is often caused by atherosclerosis, a condition that hardens arteries and restricts blood flow.

Signup and view all the flashcards

Embolism

This type of gangrene is often caused by blood clots traveling and blocking arteries.

Signup and view all the flashcards

Trauma to a major artery

This type of gangrene is often caused by injury to a major artery.

Signup and view all the flashcards

Frostbite

This type of gangrene is often caused by extreme cold, leading to vascular spasm and tissue death.

Signup and view all the flashcards

Liquefactive Necrosis

A type of necrosis where tissue is broken down and liquefied, often due to the action of lytic enzymes.

Signup and view all the flashcards

Brain Infarction and Liquefactive Necrosis

Liquefactive necrosis is a common outcome of brain infarction due to the brain's high water content.

Signup and view all the flashcards

Caseous Necrosis

A type of necrotic tissue that is soft, friable, and has a yellow-white appearance, similar to cheese.

Signup and view all the flashcards

Caseous Necrosis in Tuberculosis

Caseous necrosis is commonly found in tuberculosis infections due to a hypersensitivity reaction in the body.

Signup and view all the flashcards

Microscopic Features of Caseous Necrosis

Caseous necrosis is characterized microscopically by fragmented cellular debris surrounded by a granulomatous reaction, often with epithelioid histiocytes forming granulomas.

Signup and view all the flashcards

Fat Necrosis

Fat necrosis occurs when fat tissue is damaged, leading to the breakdown of fat cells and the release of fatty acids.

Signup and view all the flashcards

Enzymatic Fat Necrosis

Enzymatic fat necrosis can result from pancreatitis, a condition where pancreatic enzymes damage surrounding tissues.

Signup and view all the flashcards

Causes of Enzymatic Fat Necrosis

Pancreatitis can be caused by factors like alcohol abuse and bile reflux, leading to the release of destructive pancreatic enzymes.

Signup and view all the flashcards

Calcium Soaps in Fat Necrosis

Enzymatic fat necrosis results in the formation of calcium soaps, creating areas of visible necrosis in the pancreas and abdominal fat.

Signup and view all the flashcards

Traumatic Fat Necrosis

Traumatic fat necrosis occurs when fat tissue is injured, for example, during injections or trauma.

Signup and view all the flashcards

What is apoptosis?

A process of cell death where the cell actively induces its own destruction, involving programmed fragmentation of DNA and destruction of cellular proteins.

Signup and view all the flashcards

What does carbolic acid cause?

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. Carbolic acid is a chemical that can cause thrombosis.

Signup and view all the flashcards

What does ergot cause?

Vasospasm is a sudden narrowing of a blood vessel. Ergot is a chemical known to cause vasospasm.

Signup and view all the flashcards

Describe dry gangrene.

Dry gangrene is a type of gangrene characterized by a shriveled, mummified appearance, a sharp line of demarcation between dead and healthy tissue, and a black color due to iron sulfide formation.

Signup and view all the flashcards

Describe wet gangrene.

Wet gangrene involves rapid spread of infection, putrid odor, and a lack of clear demarcation between dead and healthy tissue. It is characterized by extensive tissue damage and fluid buildup.

Signup and view all the flashcards

What are the physiological functions of apoptosis?

Apoptosis plays a key role in normal development, removing unwanted cells during embryonic development and maintaining tissue homeostasis.

Signup and view all the flashcards

What are the pathological roles of apoptosis?

Apoptosis is involved in pathological conditions like tumor growth suppression by eliminating cancerous cells, immune cell regulation, and organ atrophy.

Signup and view all the flashcards

How can apoptosis be related to diseases?

Reduced apoptosis can lead to the accumulation of cells, contributing to conditions like cancer, where mutated cells survive and proliferate. Increased apoptosis can lead to excessive cell loss and contribute to conditions like atrophy, AIDS, and certain neurodegenerative disorders.

Signup and view all the flashcards

What is autophagy?

Autophagy is a process where cells break down their own components, such as organelles and macromolecules, to generate energy and nutrients for survival during starvation.

Signup and view all the flashcards

What happens if autophagy continues without nutrient restoration?

Autophagy is a survival mechanism, but if nutrients are not restored, the cell may eventually deplete all its resources and die.

Signup and view all the flashcards

Study Notes

Cell Death Overview

  • A lecture by Dr. Alessandro Aldera, Division of Anatomical Pathology, University of Cape Town, February 2024.
  • Topics covered include necrosis, gangrene, apoptosis, and new concepts.

Necrosis

  • Definition: Death of cells in a living organism due to protein denaturation and/or enzymatic digestion of the cell.

  • Autolysis: Cellular enzymatic degradation by catalytic enzymes from the lysosomes of dead cells.

  • Heterolysis: Enzymatic degradation by enzymes from immigrant and living cells such as neutrophils and macrophages.

  • Causes:

    • Ischemia (e.g., infarcts, center of tumors, hypoxia).
    • Toxins (e.g., snake venom, bacterial toxins).
    • Infections (e.g., viruses like polio, hepatitis; bacteria like diphtheria, typhoid).
    • hypersensitivity reactions (e.g., caseative necrosis in tuberculosis).
    • Chemical poisons (e.g., acids, alkalis, phenols)
    • physical factors, such as irradiation, high heat (>45°C), freezing (resulting in vasospasm and ice crystals)

  • Types of Necrosis:

    • Coagulative necrosis: preservation of basic cell shape, loss of nuclei, eosinophilic (pink/opaque) cytoplasm, due to protein denaturation (seen in most tissues except brain).
    • Liquifactive necrosis: liquefaction of tissues due to lytic enzymes, characteristic of brain infarcts and abscesses (neutrophils).
    • Caseous necrosis: friable, yellow-white debris similar to cheese, found in tuberculosis hypersensitivity reactions.
    • Fat necrosis: enzymatic (e.g., acute pancreatitis from alcohol or bile reflux/regurgitation), traumatic (e.g., from injections), or infectious; results in calcium soaps (saponification).

  • See different examples under each type for further details.

Gangrene

  • Definition: Necrosis with putrefaction of tissues (tissue digestion by bacterial action)

  • Classification:

    • Primary: Due to infection with pathogenic bacteria that kill tissues (exotoxins) and then invade/digest dead tissue (e.g., gas gangrene from Clostridium perfringens, intestinal commensal, found in soil).
    • Secondary/Ischemic: Tissue necrosis due to another cause, following ischemia (e.g., vascular disease, atherosclerosis, diabetes; embolism [e.g., left heart atrium, ventricle valves, infective endocarditis], trauma to major artery).

  • Types of Gangrene (illustrated in images):

    • Dry gangrene (ischemic): initially in toes, spreads proximally, shrivelled, dry, mummified, sharp line of demarcation, black (iron sulphide)
    • Wet gangrene (ischemic): foul smelling, rapid proximal spread, no clear line of demarcation.

Apoptosis

  • Definition: A programmed pathway of cell death that uses regulated intracellular programs to activate enzymes that destroy DNA and cell proteins.
  • Mechanism:
    • Energy-dependent fragmentation of DNA by endogenous endonucleases
    • Individual cell deletion of unwanted/defective cells due to physiological and pathological circumstances.
  • Function/Roles:
    • Physiological: Embryogenesis, hormone-dependent involution, cell deletion in proliferating tissues (e.g., intestine), prevents genome instability.
    • Pathological: Cell death in tumours, death of immune cells (B and T lymphocytes), atrophy of hormone-dependent and obstructed organs, cell death from cytotoxic T cells (e.g., graft rejection, graft vs. host disease), cell injury by viruses.
  • Illustrated examples of the process of Apoptosis

Autophagy

  • Proposed third mode of cell death: Cells generate energy and metabolites by digesting their own organelles and macromolecules. A starvation response can be used to allow a surviving cell and subsequently, may potentially digest all cellular substrates and die.

Necroptosis

  • Definition: A form of programmed cell death. Morphologically resembles necrosis and mechanistically resembles apoptosis. This mode is genetically programmed and caspase-independent.

Pyroptosis

  • Definition: Another form of programmed cell death marked by the release of fever-inducing pyrogens (IL-1)
  • Mechanism: Cells swell, cause a loss of plasma membrane integrity, and release inflammatory mediators.
  • Association/Occurrence: Primarily occurs in cells infected by microbes/pathogens.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Cell Death Lecture Outline PDF

Description

Explore the fundamental concepts of cell death, including necrosis, apoptosis, and gangrene in this informative quiz. Dive into definitions, types, causes, and relevant examples of necrosis as detailed by Dr. Alessandro Aldera. Enhance your understanding of these critical biological processes.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser