PROSES TERJADINYA APOPTOSIS | PATOLOGI DASAR KEDOKTERAN

Summary

This video explains apoptosis, the programmed cell death process, and how it differs from necrosis. Apoptosis occurs in response to both physiological and pathological stimuli and involves the activation of enzymes that break down the cell. It is essential for eliminating unwanted cells, maintaining tissue balance, and preventing diseases like cancer. The video also explores the two major apoptosis pathways—the intrinsic and extrinsic pathways—and highlights the microscopic features of cells undergoing apoptosis. The clear distinction between apoptosis and necrosis is also emphasized, focusing on their different effects on cell structure and surrounding tissues.

Takeaways

• 😀 Apoptosis is a programmed cell death pathway activated by enzymes that break down the cell.
• 😀 Apoptosis can be triggered by pathological (e.g., infections, mutations) or physiological stimuli (e.g., shedding of endometrial cells).
• 😀 The apoptosis process is regulated by genes that code for enzymes responsible for cell fragmentation and removal by macrophages.
• 😀 Necrosis and apoptosis are different forms of cell death. Necrosis leads to cell swelling and rupture, while apoptosis results in cell shrinkage and fragmentation.
• 😀 In apoptosis, the cell's nucleus fragments into smaller pieces, while in necrosis, the nucleus dissolves and the cell membrane breaks down, causing inflammation.
• 😀 Apoptosis is often physiological and helps eliminate unwanted cells, whereas necrosis is usually pathological and can lead to irreversible damage and inflammation.
• 😀 Apoptosis can occur in various contexts, such as embryogenesis, hormone-dependent tissue involution, and the removal of cells that have completed their function (e.g., lymphocytes).
• 😀 Pathological apoptosis is important for eliminating genetically damaged cells, preventing tumor formation, and managing abnormal protein accumulation.
• 😀 There are two main apoptosis pathways: the mitochondrial (intrinsic) pathway and the death receptor (extrinsic) pathway. Both lead to the activation of caspases and cell fragmentation.
• 😀 The mitochondrial pathway is triggered by stress signals, such as DNA damage or lack of growth factors, leading to the release of cytochrome c and activation of apoptosis.
• 😀 In the death receptor pathway, activation of receptors like Fas and TNF receptor on the cell surface initiates caspase activation, leading to apoptosis and subsequent phagocytosis by macrophages.

Q & A

What is apoptosis?

Apoptosis is a programmed cell death process in which enzymes are activated to break down the cell. It is a pathway designed to eliminate unwanted cells, either for physiological or pathological reasons.

What triggers apoptosis in cells?

Apoptosis can be triggered by various stimuli, both physiological (e.g., endometrial shedding during menstruation) and pathological (e.g., DNA mutation, radiation exposure, chemical damage, or infection).

How does apoptosis differ from necrosis?

Apoptosis involves the shrinkage and fragmentation of the cell, with the intact plasma membrane, whereas necrosis leads to cell swelling, membrane rupture, and inflammation due to the leakage of cell contents.

What happens to the cell during necrosis?

During necrosis, the cell swells, the plasma membrane ruptures, and the cell contents leak out, which can lead to inflammation in the surrounding tissue.

What happens to the cell during apoptosis?

In apoptosis, the cell shrinks, its nucleus fragments into small pieces, and apoptotic bodies are formed. These bodies are then cleared by macrophages without causing inflammation.

Why is apoptosis considered to be physiologically important?

Apoptosis plays a critical role in removing unnecessary or damaged cells, maintaining tissue homeostasis, and preventing abnormal cell growth. It is essential for processes like embryogenesis, hormone-regulated tissue involution, and immune system regulation.

Can apoptosis occur in response to disease or genetic damage?

Yes, apoptosis is an important mechanism for eliminating cells that have undergone genetic damage or mutations, helping to prevent the development of tumors or further damage to the tissue.

What are some physiological examples of apoptosis?

Examples include the removal of excess cells during embryogenesis, the elimination of damaged cells after immune response, and involution of hormone-dependent tissues like the endometrium during menstruation.

What is the role of caspases in apoptosis?

Caspases are enzymes activated during apoptosis that initiate the breakdown of cellular structures, including DNA fragmentation and disassembly of the cytoskeleton, leading to the cell’s death.

What are the main pathways for inducing apoptosis?

There are two main apoptosis pathways: the mitochondrial (intrinsic) pathway, which is triggered by cellular stress, and the receptor (extrinsic) pathway, which is activated through interactions between cell surface receptors and ligands, such as Fas ligand and TNF.