Cell Injury and Cell Death — MCQs
Apoptosis is characterized by all of the following except which of the following?
Which of the following is not a cause for reversible dementia?
Coagulative necrosis is due to which of the following?
Which of the following is a sign of reversible injury in alcoholic liver disease?
Which of the following is an example of programmed cell death?
Which of the following ions is important in irreversible cell injury?
Radiation causes cell death by:
All of the following are true about apoptosis except:
Which of the following statements is false about apoptosis?
Which of the following statements about apoptosis is not true?
Cell Injury and Cell Death Indian Medical PG Practice Questions and MCQs
Question 1: Apoptosis is characterized by all of the following except which of the following?
- A. Chromatin condensation
- B. Cell shrinkage
- C. DNA fragmentation
- D. Cell proliferation (Correct Answer)
Explanation: ***Inflammation*** - Apoptosis is a programmed cell death process that **does not induce inflammation**, contrasting with necrosis, which does [1]. - It is characterized by its **clean uptake** by surrounding cells without eliciting an immune response [1]. *DNA fragmentation* - A hallmark of apoptosis, where **DNA is cleaved** into smaller fragments as part of the intrinsic cell death pathway [2]. - This fragmentation can be detected via techniques such as **agarose gel electrophoresis**. *Cell shrinkage* - In apoptosis, cells exhibit **shrinkage**, also known as **pyknosis**, as they lose their volume and adopt a condensed morphology. - This shrinkage is due to changes in the cytoskeleton and loss of intracellular water. *Chromatin condensation* - One of the early features of apoptosis is **chromatin condensation**, which leads to the formation of dense nuclear material [3]. - This process is part of the typical morphology seen during programmed cell death. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 67-69. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 64-65. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 80-81.
Question 2: Which of the following is not a cause for reversible dementia?
- A. Hypothyroidism
- B. Subdural hematoma
- C. Multi infarct dementia (Correct Answer)
- D. Toxic dementia
Explanation: ***Multi infarct dementia*** - This form of dementia results from **multiple small strokes** causing cumulative brain damage, which is typically **irreversible**. - While progression can sometimes be slowed by managing vascular risk factors, the existing brain damage and associated cognitive decline are **not fully reversible**. *Hypothyroidism* - **Severe or untreated hypothyroidism** can cause cognitive impairment, including memory loss and slowed thinking, mimicking dementia. - With **thyroid hormone replacement therapy**, these cognitive symptoms are often **reversible**. *Subdural hematoma* - A **chronic subdural hematoma** can cause slowly progressive neurological symptoms, including cognitive decline due to compression of brain tissue [1]. - **Surgical evacuation** of the hematoma can lead to **significant improvement or complete resolution** of dementia symptoms [1]. *Toxic dementia* - **Exposure to neurotoxins**, drugs (e.g., anticholinergics, sedatives), or alcohol can induce acute or chronic cognitive impairment [1]. - If the causative agent is identified and eliminated, the cognitive deficits are often **partially or fully reversible** [1].
Question 3: Coagulative necrosis is due to which of the following?
- A. Denaturation of protein (Correct Answer)
- B. Enzymatic digestion
- C. Infection
- D. Increased enzymatic activity
Explanation: ***Denaturation of protein*** - Coagulative necrosis primarily results from the **denaturation of proteins** within cells, which leads to cell membrane stability loss [1]. - Commonly associated with **ischemia** or **hypoxia**, causing localized tissue damage while preserving the basic structure of the necrotic tissue [1]. *Infection* - Infection can lead to **other forms of necrosis** such as liquefactive necrosis, but **not coagulative necrosis** directly. - Typically involves microbial agents that induce inflammation, instead of mere protein denaturation. *Enzymatic digestion* - Enzymatic digestion is characteristic of **liquefactive necrosis** where **enzymes degrade cellular structures**, leading to a liquid mass. - This process is not relevant to coagulative necrosis, which is marked by solid tissue with preserved outlines. *None* - The statement "None" doesn't accurately reflect the mechanism of coagulative necrosis, which **specifically involves protein denaturation**. - This oes not acknowledge the pathogenic factors involved in coagulative necrosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 53-55.
Question 4: Which of the following is a sign of reversible injury in alcoholic liver disease?
- A. Cytoplasmic vacuole (Correct Answer)
- B. Pyknosis (nuclear shrinkage)
- C. Loss of cell membrane integrity
- D. Nuclear karyolysis (nuclear dissolution)
Explanation: ***Cytoplasmic vacuole*** - The presence of **cytoplasmic vacuoles** in liver cells indicates fatty change, which is a **reversible injury** in alcoholic liver disease [1][2]. - This injury allows the liver to recover if **alcohol consumption** is ceased, highlighting its reversible nature [1]. *Nuclear karyolysis* - **Nuclear karyolysis** signifies severe cellular damage and necrosis, indicating an irreversible process [2]. - This feature involves the dissolution of the nucleus, which does not align with reversible injury. *Loss of cell membrane* - Loss of the **cell membrane** indicates irreversible damage, leading to cell death rather than a reversible condition [2]. - This change is associated with significant cellular impairment, contrary to the concept of recovery. *Pyknosis* - **Pyknosis**, the condensation of chromatin in the nucleus, suggests irreversible cellular injury and impending necrosis [2]. - It is often a precursor to cell death and is not indicative of reversible damage in liver pathology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 848-850. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 51-53.
Question 5: Which of the following is an example of programmed cell death?
- A. Apoptosis (Correct Answer)
- B. Cytolysis
- C. Necrosis
- D. Autophagy
Explanation: ***Apoptosis*** - Apoptosis is a form of **programmed cell death** [1], essential for normal cellular turnover and development. - It is characterized by cellular shrinkage, chromatin condensation, and membrane blebbing, without provoking an inflammatory response [4]. *Cytolysis* - Cytolysis refers to the **destruction of cells by external agents**, such as toxins or pathogens, leading to membrane rupture. - It typically results in **inflammation** and is not a programmed or controlled process like apoptosis. *Necrosis* - Necrosis is an **uncontrolled form of cell death** resulting from acute cellular injury, leading to inflammation and damage to surrounding tissues. - Unlike apoptosis, necrosis involves rapid cell swelling and bursting of cell membranes, causing inflammation. However, some forms of necrosis can be programmed, such as necroptosis [2][3]. *Proptosis* - Proptosis refers to **eye bulging** (exophthalmos), often due to thyroid disease or certain tumors, and is not related to cell death. - It does not involve a process of cell death but rather anatomical displacement of the eyeball. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 63-64. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 71. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 69-71. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 67-69.
Question 6: Which of the following ions is important in irreversible cell injury?
- A. Sodium
- B. Chloride
- C. Calcium (Correct Answer)
- D. Potassium
Explanation: ***Calcium*** - An increase in intracellular **calcium** concentration is a critical event in irreversible cell injury, activating various destructive enzymes like **phospholipases**, **proteases**, **endonucleases**, and ATPases [1]. - This influx of calcium can occur due to mitochondrial dysfunction (leading to impaired calcium sequestration) or damage to the plasma membrane [1]. *Sodium* - While important for maintaining **osmotic balance** and cell volume, dysregulation of sodium primarily contributes to **cellular swelling** (hydropic change), which is an early and often reversible sign of cell injury [1]. - Increased intracellular sodium typically leads to water influx, but its direct role in irreversible damage is secondary to calcium. *Chloride* - Changes in chloride ion distribution are often secondary to sodium dysregulation and play a role in maintaining **charge neutrality** and osmotic balance across the cell membrane. - It is not directly implicated as a primary mediator of the **enzyme activation cascade** that leads to irreversible cell damage. *Potassium* - **Potassium** is the major intracellular cation; its leakage out of the cell is a consequence of cell membrane damage, indicating loss of membrane integrity. - While significant **potassium efflux** is a sign of severe injury, it is not the initiator of the irreversible damage pathway, unlike calcium. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 57-62.
Question 7: Radiation causes cell death by:
- A. Charring of nucleoproteins
- B. Ionization (Correct Answer)
- C. Disruption of cytosol
- D. Destroying their mitochondria
Explanation: ***Ionization*** - Radiation, particularly **ionizing radiation**, causes cell death by directly or indirectly damaging cellular components through the process of **ionization**. [1] - This involves the removal of electrons from atoms or molecules, leading to the formation of highly reactive **free radicals** (especially hydroxyl radicals from water radiolysis) that can damage DNA, proteins, and lipids. [1] - The most critical lethal lesion is **DNA double-strand breaks**, which are difficult to repair and trigger apoptosis or mitotic catastrophe. [1] *Charring of nucleoproteins* - **Charring** typically refers to the combustion or burning of organic matter, which is not the mechanism of cell death caused by therapeutic radiation doses. - While radiation can cause protein denaturation, it does not lead to the macroscopic charring of nucleoproteins within cells. *Disruption of cytosol* - While severe radiation damage can impact the entire cell, direct and selective **disruption of the cytosol** is not the primary or most impactful mechanism of radiation-induced cell death. - The critical targets for radiation-induced cell death are primarily the **nucleus** and its DNA, not the cytoplasm. [2] *Destroying their mitochondria* - Although radiation can induce **mitochondrial dysfunction** and contribute to cell death through apoptosis, it is not the initial or primary mechanism of cell destruction. - The most critical and direct damage leading to cell death is inflicted upon the **DNA** in the nucleus, particularly causing double-strand breaks. [1] **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 100-102. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Central Nervous System Synapse, pp. 438-439.
Question 8: All of the following are true about apoptosis except:
- A. No inflammation
- B. Plasma membrane intact
- C. Organelle swelling (Correct Answer)
- D. Affected by dedicated genes
Explanation: ***Organelle swelling*** - **Organelle swelling** is characteristic of **necrosis**, where cellular contents are released due to membrane rupture [1]. - In **apoptosis**, organelles generally maintain their morphology or shrink, and the cell is packaged into apoptotic bodies [3]. *No inflammation* - This statement is **true regarding apoptosis** because the cell contents are neatly packaged into **apoptotic bodies** and phagocytosed without releasing inflammatory mediators [3]. - The lack of cellular contents spilling into the extracellular space prevents activation of the immune system [3]. *Plasma membrane intact* - This statement is **true regarding apoptosis** as the plasma membrane remains intact, preventing the leakage of cellular contents and subsequent inflammation [3]. - The integrity of the membrane is maintained throughout the process until **apoptotic bodies** are formed [3]. *Affected by dedicated genes* - This statement is **true regarding apoptosis** because it is a tightly regulated process controlled by a cascade of genes, including those encoding **caspases** and **Bcl-2 family proteins** [2]. - These genes ensure the orderly dismantling of the cell without causing harm to neighbouring cells [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 69-71. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 64-65. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 67-69.
Question 9: Which of the following statements is false about apoptosis?
- A. Swelling of organelles (Correct Answer)
- B. No inflammation
- C. Affected by dedicated genes
- D. Intact plasma membrane
Explanation: ***Swelling of organelles*** - **Swelling of organelles** is a characteristic feature of **necrosis**, not apoptosis, which involves cellular shrinkage [1]. - In apoptosis, the cell undergoes controlled **shrinkage** and fragmentation into apoptotic bodies, maintaining organelle integrity until later stages. *No inflammation* - Apoptosis is a programmed cell death process that does not induce an **inflammatory response** because the cellular contents are neatly packaged and cleared by phagocytes [4]. - This lack of inflammation distinguishes apoptosis from necrosis, where cell lysis releases intracellular components that trigger inflammation [4]. *Affected by dedicated genes* - Apoptosis is a highly regulated process controlled by a complex network of **genes** and proteins, including the Bcl-2 family and caspases [2]. - Genes like **p53** can also initiate apoptosis in response to DNA damage, ensuring proper cellular function and preventing uncontrolled cell growth [3]. *Intact plasma membrane* - During apoptosis, the **plasma membrane** generally remains intact, although with altered permeability and surface changes that facilitate recognition by phagocytes [4]. - This maintains the cell's internal environment and prevents the leakage of cellular contents, thereby *avoiding local inflammation* [4]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 69-71. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 64-65. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 310. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 67-69.
Question 10: Which of the following statements about apoptosis is not true?
- A. Cellular swelling (Correct Answer)
- B. Nuclear compaction
- C. Intact cell membrane
- D. Formation of apoptotic bodies
Explanation: ***Cellular swelling*** - **Apoptosis**, or programmed cell death, is characterized by cell shrinkage, not cellular swelling. - **Cellular swelling** is typically seen in **necrosis**, which is an uncontrolled form of cell death often due to injury. *Nuclear compaction* - **Nuclear compaction**, or **pyknosis**, is a hallmark feature of apoptosis where the nucleus condenses and fragments. - This process is crucial for the organized dismantling of the cell during programmed cell death. *Intact cell membrane* - In apoptosis, the **cell membrane** generally remains intact until the very late stages, preventing the release of cellular contents and subsequent inflammation. - This intactness differentiates apoptosis from necrosis, where the cell membrane ruptures early. *Formation of apoptotic bodies* - The cell fragments into small, membrane-bound structures called **apoptotic bodies**, which are then readily engulfed by phagocytes. - This mechanism allows for the efficient removal of dying cells without triggering an inflammatory response.
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