Mechanisms of Cell Death

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Questions and Answers

What is the significance of tumor necrosis factor (TNF) in the immune response?

It helps in the activation of B cells.

It is responsible for initiating phagocytosis.

It promotes the production of pus.

It serves as an important mediator in inflammation. (correct)

Which cells are primarily involved in the early and later responses of edema during inflammation?

Mast cells and eosinophils. (correct)

T cells and B cells.

Fibroblasts and endothelial cells.

Neutrophils and macrophages.

What characterizes a granuloma in the context of inflammation?

Macrophages surrounded by T cells. (correct)

A thickening of the skin due to fibrosis.

An accumulation of pus and dead bacteria.

A collection of lymphocytes around a necrotic center.

When does the immune response typically conclude?

When all antigens are eliminated and T cell stimulation ceases. Signup and view all the answers

Which of the following best describes pyogenic inflammation?

Resulting in accumulation of dead bacteria and white blood cells in pus. Signup and view all the answers

What term refers to the cause of a disease?

Etiology Signup and view all the answers

Which of the following is NOT a form of necrosis?

Apoptotic necrosis Signup and view all the answers

What is one characteristic feature of necrosis?

Cell breakdown and explosion Signup and view all the answers

Which process involves the controlled disassembly of cells?

Apoptosis Signup and view all the answers

What type of necrosis is described as having a viscous mass due to cell digestion?

Liquefactive necrosis Signup and view all the answers

Which of the following is a sign of cellular injury?

Intracellular accumulations Signup and view all the answers

What is necroptosis?

Regulated necrosis Signup and view all the answers

Which of the following causes of necrosis involves overwhelming damage to cellular components?

Nutrient withdrawal Signup and view all the answers

What is the process that results in the destruction of self-reactive lymphocytes to prevent autoimmunity?

Pyroptosis Signup and view all the answers

Which of the following is NOT a major morphological feature of apoptosis?

Swelling of the cell Signup and view all the answers

What initiates the extrinsic apoptotic signaling pathway?

Death receptors on the plasma membrane Signup and view all the answers

What is the role of caspases in apoptosis?

To disassemble the cell Signup and view all the answers

During which physiological process do endometrial cells undergo breakdown?

Menstrual cycle Signup and view all the answers

Which of the following can act as an initiator caspase?

Caspase 8 Signup and view all the answers

What is the result of unresolved stress in cells?

Apoptosis Signup and view all the answers

Which cytokine is known to be involved in the initiation of apoptosis?

Tumor Necrosis Factor (TNF) Signup and view all the answers

What characterizes the muscle phase of infection?

Disruption of myofibrils Signup and view all the answers

Which immune response is primarily involved during the enteric phase of infection?

T helper cell cytokine production Signup and view all the answers

Which of the following is NOT a symptom of the enteric stage?

Myalgia Signup and view all the answers

What is the hallmark histological feature of psoriasis?

Elongated rete ridges Signup and view all the answers

Which cytokine is NOT typically overexpressed in psoriasis?

IL-10 Signup and view all the answers

What is a common pathogenetic factor associated with verrucae?

Human papillomavirus Signup and view all the answers

What mechanism causes blisters in pemphigus?

Autoantibodies targeting intercellular junctions Signup and view all the answers

Which form of pemphigus results in a suprabasal lesion?

Pemphigus vulgaris Signup and view all the answers

Which factor is NOT associated with angiogenesis in psoriatic lesions?

Epidermal Growth Factor Signup and view all the answers

Which statement about verrucae is true?

They can be transmitted through contact. Signup and view all the answers

Which subfamily of the Death Domain superfamily primarily involves the autocatalytic activation of initiator caspases?

Caspase Recruitment Domain (CARD) subfamily Signup and view all the answers

What components are involved in the formation of the Death-Inducing Signaling Complex (DISC)?

Fas, FADD, caspase-8 or -10 Signup and view all the answers

Which of the following is a function of p53 in cellular processes?

Acts as a transcription factor for apoptosis promoting genes Signup and view all the answers

Which apoptotic factor is activated by caspases through tBid?

Bax Signup and view all the answers

What is the role of the Apoptosome in apoptosis?

It facilitates the autocatalysis of caspase-9. Signup and view all the answers

What triggers the PIDDosome formation?

Genotoxic stress Signup and view all the answers

Which of the following processes can lead to cell death due to ER stress?

Accumulation of misfolded proteins Signup and view all the answers

Which two caspases are primarily involved in Complex II of the Death Domain superfamily?

Caspase-8 and caspase-10 Signup and view all the answers

What is a characteristic feature of mitochondrial pro-apoptotic factors like Bid?

They sequester anti-apoptotic Bcl-2 members. Signup and view all the answers

What type of binding does the Death Domain superfamily utilize for protein complex assembly?

Homotypic binding Signup and view all the answers

Which statement about the intrinsic apoptotic pathway is true?

It relies on the release of cytochrome c from mitochondria. Signup and view all the answers

Which protein is first mentioned in relation to the Bcl-2 family?

Bcl-2 Signup and view all the answers

Which component is NOT part of the signalling complexes mentioned for the Death Domain superfamily?

ASC Signup and view all the answers

What is one consequence of a failed stress response in cells?

Induction of ferroptosis Signup and view all the answers

What does the Unfolded Protein Response aim to achieve under ER stress conditions?

Promote degradation of misfolded proteins Signup and view all the answers

Study Notes

Pathology Terminology

Etiology: Refers to the cause of a disease.
Pathogenesis: Involves biochemical and molecular mechanisms in disease development.
Morphology: Describes the structural appearance of cells, tissues, and organs.
Clinical features: Functional consequences of morphological changes observed in diseases.

Cell Death

Causes include lack of resources (hypoxia, nutrient deprivation, withdrawal of growth factors), toxin exposure, aging cell removal, and immune system attacks (infection, autoimmunity).

Signs of Cellular Injury

Intracellular accumulations may include fatty deposits, lipofuscin, and proteins that can indicate cell damage.

Modes of Cell Death

Necrosis: Unregulated, pathological cell death that results in cell rupture and inflammation.
Apoptosis: Regulated, physiological cell death involving controlled disassembly and phagocytosis of cell components.
Alternatives: Include necroptosis, anoikis, and ferroptosis.

Necrosis Types

Coagulative: Loss of cell architecture without tissue architecture change.
Liquefactive: Digestion of cells leading to a viscous mass.
Caseous: Fragmented cells with inflammatory responses.
Fibrinoid: Accumulation of immune complexes and fibrin in blood vessel walls.

Causes of Necrosis

Resulting from overwhelming damage due to toxins, excessive calcium, mitochondrial and endoplasmic reticulum damage, reactive oxygen species, ischemia, membrane damage, or nutrient withdrawal.

Apoptosis

Involved in physiological events like embryogenesis and removal of unnecessary cells during tissue regeneration.
Hormonal fluctuations cause specific cells (e.g., endometrial cells, ovarian cells) to undergo apoptosis.
Deletion of auto-reactive lymphocytes prevents autoimmunity.

Apoptotic Initiators

Triggered by factors like viral infections, ionizing radiation, chemical damages, cytokines, mitochondrial damage, and unresolved cellular stress.

Morphological Features of Apoptosis

Characterized by cell rounding, nuclear fragmentation, membrane blebbing, and formation of apoptotic bodies.

Apoptotic Signaling Paths

Extrinsic: Involves activation of death receptors on the cell membrane leading to caspase activation.
Intrinsic: Initiated by mitochondrial signals that release pro-apoptotic proteins activating caspases.

Caspases

Specific proteases essential for the disassembly of cells during apoptosis.
Two classes: initiator caspases (2, 8, 9, 10) and executioner caspases (3, 6, 7).

Death Domain Superfamily

Comprises various subfamilies (DD, DED, CARD, PYD) that help in forming protein complexes for signaling pathways involved in apoptosis.

p53 and Cellular Response to Stress

Acts as a crucial factor in DNA repair and apoptosis regulation.
Addresses DNA damage and balances cell cycle progression and apoptosis promoting genes.

Unfolded Protein Response (UPR)

A mechanism that deals with endoplasmic reticulum stress due to misfolded proteins, which can lead to cell death if unresolved.

Skin and Infectious Diseases

Immune response characterized by inflammation and clinical manifestations like redness, swelling, and pus.
Common conditions include meningitis, parasitic infections, and skin disorders such as psoriasis and pemphigus.

Psoriasis

An inflammatory skin disease displaying thickened epidermis, elongated rete ridges, and neutrophil infiltration.
Linked to overexpression of cytokines like TNF and genetic factors related to HLA-C.

Verrucae (Warts)

Benign epidermal growths caused by human papillomaviruses (HPV).
Characterized by squamoproliferative lesions and potential progression to malignancy.

Pemphigus

An autoimmune disorder causing blister formation due to autoantibodies attacking intercellular junctions in the epidermis.
This condition can be classified into types based on the level of separation in the skin layers (e.g., foliaceus, vulgaris).

Cellular Mechanisms and Pathways

Highlight various mechanisms leading to cell death, emphasizing apoptosis pathways, signaling complexities, and immune responses in different disease contexts.

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Description

Explore the critical mechanisms of cell death in relation to disease. This quiz delves into etiology, pathogenesis, morphology, and the clinical features resulting from cellular changes. Test your understanding of how and why cells die, including factors like hypoxia and nutrient deficiency.

Mechanisms of Cell Death - Pathology

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