Which one of the following systems forms a chemical mediator that is involved in the mechanism of pain during inflammation?
Kininogen-Bradykinin system
Understanding Pain During Inflammation
Inflammation is the body's natural response to injury, infection, or irritation. It involves a series of events aimed at protecting the body, removing harmful stimuli, and initiating the healing process. Key features of inflammation include redness, swelling, heat, and pain. Pain during inflammation is caused by the release of specific chemical mediators that activate nerve endings.
Kininogen-Bradykinin System and Pain
The Kininogen-Bradykinin system is a biological system that plays a significant role in inflammation and pain sensation. It involves plasma proteins called kininogens and enzymes called kallikreins.
- High molecular weight kininogen (HMWK) and low molecular weight kininogen (LMWK) are precursors.
- Plasma kallikrein acts on HMWK to produce Bradykinin.
- Tissue kallikrein acts on LMWK to produce Kallidin, which is then converted to Bradykinin.
Bradykinin is the primary chemical mediator produced by this system that contributes to pain during inflammation. It acts on specific receptors (B2 receptors) located on sensory nerve fibers, leading to their activation and the transmission of pain signals to the brain. Bradykinin also causes vasodilation (widening of blood vessels) and increases vascular permeability, contributing to the redness and swelling seen in inflammation.
Why Other Systems Are Less Directly Involved in Acute Inflammatory Pain
Let's look at the other options and why they are not the primary systems responsible for producing chemical mediators of pain during acute inflammation:
- Activated blood clotting cascade: This system is primarily involved in hemostasis, the process of stopping bleeding by forming blood clots. While clotting factors can interact with inflammatory pathways, their main chemical mediators are not the primary cause of inflammatory pain.
- Plasmin - Fibrinolytic system: This system is mainly responsible for breaking down blood clots. Its primary enzyme is plasmin. While it interacts with other systems like the kinin system, its direct role in producing a main pain mediator like Bradykinin is limited compared to the Kininogen-Bradykinin system.
- B-cell activation: B-cells are part of the adaptive immune system. Their primary role is to produce antibodies. While antibodies are involved in the overall immune response during inflammation, B-cell activation itself does not directly produce chemical mediators like Bradykinin that cause acute inflammatory pain.
Therefore, the Kininogen-Bradykinin system is the specific pathway that generates Bradykinin, a key chemical mediator involved in the mechanism of pain during inflammation.
Important Questions from Immune System
Bacterial infections are generally divided into two broad classes: intracellular and extracellular bacterial infections. Given below are some of the properties which are applicable for bacterial infections.
A. Humoral immune response is the main protective response against extracellular bacteria.
B. Innate immunity is not effective against intracellular bacterial pathogens.
C. Bacterial endotoxins do not induce an innate immune response.
D. Intracellular bacterial infections generally induce a cell-mediated immune response resulting in secretion of cytokines which activate macrophages.
Which one of the following combination of statements is correct?
The immunoglobulin heavy-chain that is rearranged first and is displayed on the surface of early stages of B-cell development is associated with:
Dr. Ralph M. Steinman was awarded Nobel Prize for his discovery on:
Suresh was bitten by a poisonous snake and was immediately treated with anti-venom human immunoglobulin and was saved. A year later he was bitten by the same type of snake second time. Predict his response to the venom from second bite from the following:
An antigen was injected into a mouse. Macrophages and antigen primed TH cells were isolated from this mouse to perform the following in vitro experiments:
A. Macrophages were treated with the antigen for an hour and then incubated with TH cells.
B. Macrophages were treated with paraformaldehyde first and then treated with the antigen for an hour. These macrophages were then incubated with T H cells.
C. Macrophages were treated with paraformaldehyde first then treated with the digested (proteolytically cleaved) antigen for an hour. These macrophages were then incubated with T H cells.
D. Macrophages were treated with the antigen for an hour and then treated with paraformaldehyde. These macrophages were then incubated with TH cells.
Which of the above experiments would lead to TH cells proliferation?
