Hypoxia & cellular injury - causes, symptoms, diagnosis, treatment & pathology

Summary

The transcript explains the critical role of oxygen in cellular function, particularly in ATP production through oxidative phosphorylation in mitochondria. When oxygen is scarce, a condition known as hypoxia occurs, halting ATP synthesis. This cessation affects essential cellular processes, leading to swelling, disrupted protein synthesis, and eventual cell damage. Although cells can partially compensate via anaerobic glycolysis, it produces lactic acid, worsening the acidic environment and causing further harm. Accumulation of calcium triggers enzymes that damage cellular structures and may lead to apoptosis, underscoring the severe consequences of oxygen deprivation.

Takeaways

• 😀 Oxygen is essential for every cell in the body to survive and produce energy.
• 😀 ATP (adenosine triphosphate) is crucial for cellular functions, often referred to as the molecular unit of currency.
• 😀 The mitochondrion acts as the cell's payroll department, using oxygen to produce ATP through oxidative phosphorylation.
• 😀 Hypoxia occurs when cells do not receive enough oxygen, leading to a lack of ATP production.
• 😀 The sodium-potassium pump is vital for maintaining ion balance; without ATP, it cannot function properly, leading to cell swelling.
• 😀 When cells swell, their microvilli and rough endoplasmic reticulum are affected, which reduces their ability to absorb molecules and synthesize proteins.
• 😀 Anaerobic glycolysis can produce ATP without oxygen, but it is less efficient and results in lactic acid buildup.
• 😀 An acidic environment can damage proteins and enzymes within the cell, contributing to cellular dysfunction.
• 😀 Calcium buildup due to pump failure can activate destructive enzymes, harming the cell's cytoskeleton and DNA.
• 😀 Mitochondrial damage and calcium leakage can trigger apoptosis, or programmed cell death, indicating severe cellular distress.

Q & A

What is the primary role of oxygen in the body's cells?

Oxygen is essential for cells to produce ATP (adenosine triphosphate), which is the energy currency that powers various cellular functions.

What is oxidative phosphorylation and where does it occur?

Oxidative phosphorylation is a process that occurs in the mitochondrion, where oxygen is used as the final electron acceptor to produce ATP.

What happens to the cell during hypoxia?

During hypoxia, there is a lack of oxygen, which disrupts ATP production, leading to cellular swelling, impaired function, and potential cell death.

How does the sodium-potassium pump function in maintaining cell integrity?

The sodium-potassium pump maintains the concentration gradient by pumping sodium out of the cell, which prevents excessive sodium accumulation and water retention that can cause cell swelling.

What role does anaerobic glycolysis play when oxygen is scarce?

Anaerobic glycolysis provides an alternative, albeit less efficient, way to produce ATP without oxygen, generating a net of about 2 ATP molecules per glucose, along with lactic acid as a byproduct.

What are the consequences of lactic acid buildup in the cell?

Lactic acid buildup lowers the pH inside the cell, which can denature proteins and enzymes, leading to cellular damage and impaired function.

What cellular changes occur when the rough endoplasmic reticulum swells?

When the rough endoplasmic reticulum swells, ribosomes detach from its surface, leading to a decrease in protein synthesis, which is vital for cell function.

How does calcium accumulation affect the cell during hypoxia?

Calcium accumulation can activate destructive enzymes that damage proteins, the cytoskeleton, and DNA, further contributing to cellular damage and dysfunction.

What triggers apoptosis in cells experiencing prolonged hypoxia?

Apoptosis, or programmed cell death, is triggered by the release of cytochrome c from the mitochondria, which signals that the cell is in distress due to a lack of ATP and increased calcium levels.

Can the changes caused by hypoxia be reversed, and under what conditions?

Yes, the changes caused by hypoxia can be reversible if oxygen levels are restored quickly enough; however, prolonged hypoxia can lead to irreversible cellular damage.