Inflammation and Repair Practice Questions

Q: What is responsible for regeneration of liver cells?

HGF. **HGF** - **Hepatocyte growth factor (HGF)** is the primary growth factor responsible for stimulating hepatocyte proliferation and migration, playing a crucial role in **liver regeneration** after injury or resection. - It acts as a potent **mitogen** for hepatocytes, promoting their entry into the cell cycle and division. *VEGF* - **Vascular endothelial growth factor (VEGF)** is primarily involved in **angiogenesis**, the formation of new blood vessels. - While important for tissue repair, it does not directly stimulate the proliferation of liver cells themselves. *TGF-beta* - **Transforming growth factor-beta (TGF-β)** is generally considered an **inhibitor of cell proliferation** and a promoter of fibrosis in the liver. - It can suppress hepatocyte growth and promote the differentiation of stellate cells into myofibroblasts, leading to **scar formation**. *IFN-γ* - **Interferon-gamma (IFN-γ)** is a cytokine primarily involved in **immune responses** and has anti-proliferative and pro-apoptotic effects on various cell types. - It does not promote liver cell regeneration; instead, it can be involved in liver injury and fibrosis during chronic inflammation.

Q: All of the following cell types undergo cell division, EXCEPT:

Cardiac muscle cell. ***Cardiac muscle cell*** - **Cardiac muscle cells** are terminally differentiated and largely lose their ability to divide shortly after birth. - While some limited regenerative capacity exists, they do not undergo significant cell division for repair or growth in the adult heart. *Pericyte* - **Pericytes** are multipotent cells associated with capillaries and postcapillary venules and are involved in angiogenesis and tissue repair. - They can differentiate into **fibroblasts, smooth muscle cells, osteoblasts, and adipocytes**, and their proliferative capacity is crucial for these functions, especially after injury. *Smooth muscle cell* - **Smooth muscle cells** retain their ability to divide throughout life and can proliferate in response to injury or hormonal stimuli. - This proliferative capacity is important for the growth and repair of organs like the uterus and blood vessels, and can contribute to conditions like **atherosclerosis**. *Satellite cell of skeletal muscle* - **Satellite cells** are quiescent muscle stem cells located between the basal lamina and sarcolemma of muscle fibers. - Upon muscle injury, they become activated, proliferate, and differentiate into new muscle fibers, playing a critical role in **skeletal muscle regeneration** and repair.

Q: Nuclei are arranged at the cell periphery in which type of cell?

Langhans giant cells. ***Langhans giant cells*** - These are **multinucleated giant cells** formed by the fusion of multiple epithelioid macrophages. - Their nuclei typically form a **horseshoe or ring-like arrangement** at the periphery of the cell cytoplasm. *Merkel cells in the skin* - Merkel cells are **neuroendocrine cells** found in the basal layer of the epidermis. - They possess a **single, irregularly lobed nucleus** and are associated with touch sensation, not multiple peripheral nuclei. *Natural Killer (NK) cells* - NK cells are **lymphocytes** characterized by a **single, round nucleus** and granular cytoplasm. - Their primary function is to kill infected or cancerous cells, and their nuclear arrangement is not peripheral. *Neutrophils in the immune response* - Neutrophils are **polymorphonuclear leukocytes** with a characteristic **multi-lobed nucleus**. - While the nucleus is segmented, it is not arranged peripherally in a ring, but rather centrally within the cell.

Q: Normal time for wound healing to transition from proliferative to maturation phase after injury is?

3 weeks. ***4 weeks*** - The normal time for scar formation is generally around **4 weeks**, allowing for significant collagen deposition and remodeling [1]. - This timeframe signifies the transition from initial wound healing to the maturation phase where the scar solidifies. *2 weeks* - At 2 weeks, the healing is in the **inflammatory** and early proliferative phase, not fully developed into a scar. - Scar formation generally requires a longer duration for sufficient **collagen synthesis** and tissue remodeling. *3 weeks* - By 3 weeks, the wound is progressing, but it still lacks the **structural integrity** of a mature scar. - Scar formation typically reaches its recognizable stage by **4 weeks**, with formal remodeling continuing thereafter. *5 weeks* - While healing continues past 4 weeks, **5 weeks** is longer than the typical duration for initial scar formation, possibly suggesting delayed healing. - By this point, the scar should be present, but significant remodeling will still occur beyond this period. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119.

Q: Which of the following cytokines stimulate acute phase reactants?

All of the options. ***All of the above*** - Acute phase reactants are stimulated by various **cytokines**, including IL-6, TNF-α, and IL-1, highlighting a coordinated immune response [1]. - The presence of multiple cytokines indicates that a range of **inflammatory processes** contributes to the activation of the acute phase response [1]. *IL-6* - While IL-6 is indeed a **key mediator** in acute phase reactions, it is not the only cytokine responsible for stimulating this response [1]. - Other cytokines like **TNF-α** and **IL-1** also play significant roles, making this option incomplete [1][2]. *TNF-a* - TNF-α is a crucial cytokine that can stimulate acute phase reactants, but it does not act alone in this process [2]. - The role of **multiple cytokines** (including IL-6 and IL-1) makes this option insufficient on its own [1]. *IL-1* - IL-1 is known to activate acute phase reactants, but similar to the others, it is **not the sole factor** and works in conjunction with other cytokines [2]. - Therefore, like TNF-α and IL-6, its contribution alone does not capture the complete picture [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 97-99. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 110-111.

Q: Leukocyte adhesion to endothelium is mediated by all except?

VCAM-4. ***VCAM 4*** - **VCAM-4** is not a recognized mediator for leukocyte adhesion; instead, **VCAM-1** plays a significant role in this process. - Adhesion is primarily mediated by interactions between leukocyte integrins and endothelial **selectins** and **VCAM-1** [1]. *E selectin* - **E selectin** is involved in the adhesion of leukocytes to endothelium, particularly during inflammation [1]. - It helps in the adhesion process during the **rolling** phase of leukocyte extravasation [2]. *L selectin* - **L selectin** is crucial for the initial adhesion of leukocytes to the **high endothelial venules** in lymphoid tissues [1]. - It facilitates leukocyte **homing** to lymphoid organs, aiding in a variety of immune responses. *VCAM 1* - **VCAM-1** is a key adhesion molecule that facilitates the binding of leukocytes to endothelial cells, particularly in inflammation [3]. - Interacts with the integrin **VLA-4** on leukocytes, promoting firm adhesion during the immune response. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 87. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Migration in the tissues toward a chemotactic stimulus, pp. 86-87. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 87-89.

Q: All of the following statements are true regarding neutrophil extracellular trapping (NET) except for which of the following?

Mitochondrial DNA is seen. ***Mitochondrial DNA is seen*** - NETs (Neutrophil Extracellular Traps) are made primarily of **nuclear chromatin**, not mitochondrial DNA [2]. - The main purpose of NETs is to trap and kill pathogens, focusing on **nuclear genetic material** rather than mitochondrial components. *It is detected in blood during sepsis* - NETs can indeed be found in the **circulation during sepsis**, serving as a defense mechanism against infections. - Their presence in blood indicates an **active immune response**, particularly in severe systemic infections. *It is produced in response to bacterial infection* - NET formation is a known response to **bacterial infections**, as neutrophils deploy them to capture and neutralize pathogens. - This process helps in controlling infections, showcasing the importance of NETs in **innate immunity**. *It is chromatin with antibacterial enzymes* - NETs consist primarily of **decondensed chromatin**, embedded with **antimicrobial proteins** and enzymes to combat pathogens [1][2]. - This characteristic underscores their role in targeting and eliminating invading microorganisms effectively. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 91-92. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 92-93.

Q: What is the main feature of chemotaxis as observed in white blood cells?

Unidirectional locomotion of neutrophils. ***Unidirectional locomotion of neutrophils*** - **Chemotaxis** refers to the **directional movement** of cells, such as neutrophils, towards a chemical attractant. - This process is crucial for recruiting immune cells to sites of infection or inflammation. *Increased random movement of neutrophils* - While neutrophils do exhibit random movement, **chemotaxis** specifically describes **directed movement** along a chemical gradient, not merely an increase in random motion. - **Random movement** without a specific direction does not effectively guide immune cells to a specific target. *Increased adhesiveness to intima* - **Adhesion to the intima** (endothelial cells) is an initial step in the process of leukocyte extravasation, allowing cells to roll and stick to vessel walls. - However, it is primarily mediated by adhesion molecules and is distinct from the **directional migration** defined by chemotaxis. *Increased phagocytosis* - **Phagocytosis** is the process by which cells engulf pathogens or cellular debris. - While essential for immune function, it is a separate function that occurs **after** the cell has migrated to its target via chemotaxis.

Question 1

What is responsible for regeneration of liver cells?

Accepted Answer

HGF

Answer

TGF-beta

Answer

VEGF

Answer

IFN-γ

Question 2

All of the following cell types undergo cell division, EXCEPT:

Accepted Answer

Cardiac muscle cell

Answer

Pericyte

Answer

Smooth muscle cell

Answer

Satellite cell of skeletal muscle

Question 3

Nuclei are arranged at the cell periphery in which type of cell?

Accepted Answer

Langhans giant cells

Answer

Merkel cells in the skin

Answer

Natural Killer (NK) cells

Answer

Neutrophils in the immune response

Question 4

Primary granules contain which enzyme?

Accepted Answer

Myeloperoxidase (MPO)

Answer

Hydrolases

Answer

Lactoferrin

Answer

Phospholipase A2

Question 5

Normal time for wound healing to transition from proliferative to maturation phase after injury is?

Accepted Answer

3 weeks

Answer

2 weeks

Answer

4 weeks

Answer

5 weeks

Question 6

Which of the following cytokines stimulate acute phase reactants?

Accepted Answer

All of the options

Answer

IL-1

Answer

IL-6

Answer

TNF-α

Question 7

Leukocyte adhesion to endothelium is mediated by all except?

Accepted Answer

VCAM-4

Answer

L-selectin

Answer

VCAM-1

Answer

E-selectin

Question 8

What is the definition of exudate?

Accepted Answer

Extravascular fluid that has a high protein concentration and contains cellular debris

Answer

Extravascular fluid that has a low protein concentration

Answer

Extravascular fluid with high glucose concentration

Answer

Extravascular fluid with low glucose concentration

Question 9

All of the following statements are true regarding neutrophil extracellular trapping (NET) except for which of the following?

Accepted Answer

Mitochondrial DNA is seen

Answer

It is detected in blood during sepsis

Answer

It is chromatin with antibacterial enzymes

Answer

It is produced in response to bacterial infection

Question 10

What is the main feature of chemotaxis as observed in white blood cells?

Accepted Answer

Unidirectional locomotion of neutrophils

Answer

Increased random movement of neutrophils

Answer

Increased adhesiveness to intima

Answer

Increased phagocytosis

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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