Cedera dan kematian sel MK Patologi Farmasi ULM

Summary

This lecture focuses on cell injury and death, beginning with the causes such as hypoxia, ischemia, physical agents, and toxins. It explores reversible and irreversible cell injuries, highlighting their microscopic manifestations and how they impact cellular function. The key mechanisms of cell death—necrosis and apoptosis—are explained, emphasizing their differences in terms of causes and outcomes. The process of autophagy, especially in aging cells, is also discussed. A case study of a patient injured by an electric shock provides a practical application of the material, illustrating the body’s response to cellular injury and repair processes.

Takeaways

• 😀 Cells interact with their environment and can adapt to harmful stimuli, but failure to adapt leads to injury and potentially death.
• 😀 Cell injury is the basis of all diseases, with potential causes including hypoxia, ischemia, physical agents, chemicals, microbiological agents, and genetic defects.
• 😀 Hypoxia refers to a lack of oxygen, while ischemia involves a reduced blood supply, both causing oxygen deprivation in tissues.
• 😀 Physical agents like trauma, extreme temperatures, and radiation can alter cell structures and functions, leading to cell damage.
• 😀 Chemical agents, such as drugs (e.g., NSAIDs), can cause cell injury, with examples like peptic ulcers resulting from prolonged use.
• 😀 Microbiological agents, such as bacteria, viruses, fungi, and protozoa, can invade cells and cause infections, resulting in cell damage.
• 😀 Genetic defects and nutritional imbalances, such as protein or vitamin deficiencies, can lead to cellular dysfunction and injury.
• 😀 Cell aging contributes to injury by reducing the cell's ability to perform vital functions, such as protein synthesis and DNA repair.
• 😀 Reversible cell injury includes signs like swelling (hydropic degeneration) and fat accumulation (fatty degeneration), which can reverse once the harmful stimulus is removed.
• 😀 Irreversible cell injury results in severe damage, including mitochondrial dysfunction, membrane integrity loss, and DNA damage, ultimately leading to cell death.
• 😀 Two main forms of cell death are necrosis (uncontrolled cell death causing inflammation) and apoptosis (programmed cell death without inflammation).

Q & A

What is the main topic discussed in the pathology lecture?

The main topic discussed in the lecture is cellular injury and cell death, including the mechanisms and causes behind them, and their relevance to disease processes.

What are the common causes of cellular injury?

Common causes of cellular injury include hypoxia, ischemia, physical agents (e.g., trauma, radiation), chemical agents (e.g., drugs like NSAIDs), infections, immunologic reactions, genetic disorders, nutritional imbalances, and aging.

How does hypoxia differ from ischemia in terms of cellular injury?

Hypoxia refers to a lack of oxygen supply to tissues, while ischemia refers to reduced blood supply, which leads to both a lack of oxygen and nutrients, causing more severe damage to tissues.

What is reversible cellular injury and how can it be identified?

Reversible cellular injury occurs when cells experience dysfunction but can return to normal if the harmful stimulus is removed. It can be identified by changes such as hydropic swelling (water accumulation) and fatty change (lipid buildup within cells).

What is irreversible cellular injury?

Irreversible cellular injury occurs when the damage is severe or prolonged, causing permanent cell damage. This includes loss of mitochondrial function, damage to cell membranes, and DNA fragmentation, often leading to cell death.

What are the differences between necrosis and apoptosis?

Necrosis is uncontrolled cell death caused by severe injury, characterized by swelling, membrane rupture, and inflammation. Apoptosis is a programmed, controlled form of cell death, where damaged cells are eliminated without triggering inflammation.

What are the morphological changes associated with necrosis?

Morphological changes in necrosis include cell swelling, membrane rupture, and the disintegration of the nucleus, with signs such as pyknosis (shrinkage), karyorrhexis (nuclear fragmentation), and karyolysis (nuclear dissolution).

What role does apoptosis play in the body?

Apoptosis plays a crucial role in eliminating unnecessary or damaged cells, such as during embryonic development (e.g., separating fingers) and in maintaining tissue homeostasis.

How does aging contribute to cellular injury?

Aging leads to a progressive decline in cell function, including decreased synthesis of proteins and enzymes, reduced ATP production, and a decrease in the cell's ability to respond to stress, making cells more vulnerable to injury.

How is the body likely to respond to the electric shock injury described in the case study?

In response to the electric shock injury, the body would initiate an inflammatory response to contain and repair the damage, but if the injury is severe, it may lead to necrosis of affected cells and tissues.