APOPTOSE (VIA INTRÍNSECA E VIA EXTRÍNSECA) - NECROSE - MORTE CELULAR - CITOLOGIA

Summary

In this educational video, Cleverson from 'Facilitando A Medicina' dives into the concepts of apoptosis and necrosis, both types of cell death. Apoptosis is a programmed, non-inflammatory process where damaged cells shrink and are safely eliminated, without causing disruption. In contrast, necrosis involves cells exploding and releasing their contents, triggering inflammation. The video explains the molecular mechanisms behind both processes, including the role of caspases and the pathways through which these cell deaths occur. Viewers also learn how these processes help prevent conditions like cancer by eliminating damaged cells.

Takeaways

• 😀 Apoptosis is a form of programmed cell death that occurs when a cell detects damage and decides to self-destruct.
• 😀 The process of apoptosis involves the shrinking of the cell, the condensation of chromatin, and the fragmentation of the nucleus.
• 😀 Apoptotic bodies are formed and later engulfed by macrophages, preventing inflammation.
• 😀 Caspases are key enzymes in apoptosis, with initiator caspases (types 8 and 9) activating executioner caspases (types 3, 6, and 7).
• 😀 Apoptosis can be triggered via two pathways: the extrinsic pathway (external signals) and the intrinsic pathway (internal cellular signals).
• 😀 The extrinsic pathway is initiated when external death signals, like Fas ligand, bind to the death receptor on the cell's surface.
• 😀 The intrinsic pathway is triggered internally when the cell's mitochondria release cytochrome c, activating the apoptosome and downstream caspases.
• 😀 Necrosis is another form of cell death, but it differs from apoptosis in that it causes cell contents to leak out, triggering inflammation.
• 😀 Unlike apoptosis, necrosis leads to a burst in the cell membrane, releasing its contents into the surrounding tissue, which causes inflammation.
• 😀 Both apoptosis and necrosis are responses to cell damage, but apoptosis is controlled and does not result in inflammation, whereas necrosis does.
• 😀 Proper cell death through apoptosis is crucial for preventing diseases like cancer, as damaged or mutated cells must be removed from the body.

Q & A

What is apoptosis?

Apoptosis is a form of programmed cell death, where a damaged cell intentionally undergoes death due to internal or external signals. It is a controlled and regulated process that involves shrinking of the cell and fragmentation of its nucleus and chromatin.

What happens during the process of apoptosis?

During apoptosis, the damaged cell begins to shrink, the nucleus condenses, and chromatin material becomes tightly packed. The nucleus disassembles, and the cell loses its shape, forming apoptotic bodies. These bodies are eventually phagocytosed by immune cells like macrophages.

What are caspases and what role do they play in apoptosis?

Caspases are enzymes that act as key regulators in the apoptosis process. There are initiator caspases (types 8 and 9) and executor caspases (types 3, 6, and 7). The initiators activate the executors, which then carry out the series of events leading to cell death.

How does apoptosis occur through the extrinsic pathway?

In the extrinsic pathway, external signals activate death receptors on the cell surface, such as the Fas receptor. These receptors then trigger the activation of initiator caspases (type 8), which in turn activate executor caspases (types 3, 6, and 7) to execute the cell death process.

What is the intrinsic pathway of apoptosis?

The intrinsic pathway of apoptosis occurs without external signals. It is initiated within the cell itself when it detects damage. In this pathway, the mitochondria release cytochrome c, which forms the apoptosome and activates initiator caspase 9. This leads to the activation of executor caspases, culminating in cell death.

What is the difference between apoptosis and necrosis?

The key difference is that apoptosis is a controlled process where the cell dies quietly without causing inflammation. In contrast, necrosis involves the uncontrolled rupture of the cell, releasing its contents into the surrounding tissue, causing inflammation.

Does apoptosis cause inflammation?

No, apoptosis does not cause inflammation. The cell's contents are contained and phagocytosed by other cells, so there is no inflammatory response.

Why does necrosis lead to inflammation?

Necrosis causes inflammation because when the cell dies, it ruptures and spills its contents into the extracellular space. This triggers an immune response and inflammation as the body attempts to clean up the spilled cellular material.

What is the role of mitochondria in apoptosis?

Mitochondria play a crucial role in the intrinsic pathway of apoptosis. When a cell detects damage, the mitochondria release cytochrome c, which helps form the apoptosome, leading to the activation of caspase 9 and the subsequent activation of executor caspases that carry out cell death.

Can apoptosis and necrosis be triggered by the same factors?

Yes, both apoptosis and necrosis can be triggered by similar factors such as cellular damage caused by radiation, chemicals, or mechanical stress. However, the outcomes differ significantly: apoptosis is a controlled and orderly process, while necrosis results in an uncontrolled rupture of the cell and inflammation.