RGI 6 Notes

These flashcards cover key concepts related to the Gas Laws and Breathing, focusing on diffusion, alveolar function, surfactant properties, and osmosis.

What is diffusion in the context of respiration?

Diffusion is the process driven by random, elastic collisions between gas molecules, allowing gas exchange.

What drives diffusion in the respiratory system?

Random, elastic collisions between gas molecules.

What happens to gas molecules during elastic collisions?

No energy or momentum is lost, preventing molecules from liquefying at the bottom of their containers.

At what velocity do most gas molecules move under normal conditions?

Most gas molecules have velocities near the speed of sound (approximately 344 m/s).

How quickly is equilibrium established for O2 and CO2 during gas exchange?

Equilibrium is established within approximately 1 second.

What is Tidal Volume?

The amount of air exchanged during normal respiration, approximately 500ml.

What is Anatomical Dead Space?

The portion of inspired air that does not participate in gas exchange, around 150ml.

Why does snorkelling increase breathlessness?

It extends the Anatomical Dead Space by an additional 70-80ml, while Tidal Volume remains the same.

What is Laplace's equation's prediction regarding alveoli?

Smaller alveoli will collapse first during exhalation.

How does yawning relate to alveolar function?

Yawning helps to re-inflate collapsed smaller alveoli.

What is Surfactant?

A substance that reduces surface tension in the alveoli, allowing them to maintain structure and function.

How does surfactant affect surface tension during inhalation?

During inhalation, surfactant concentration is low, resulting in high surface tension.

What is the role of surfactant during exhalation?

Surfactant molecules are forced closer together, increasing their concentration and reducing surface tension.

What happens if an RBC is placed in a hypotonic solution?

Water diffuses into the cell, causing it to swell and burst (lysis).

What does crenation refer to in red blood cells?

Crenation occurs when RBCs lose water in a hypertonic solution, causing them to shrivel and lose function.

What is the impact of aspirated saltwater in terms of osmosis?

Aspirated saltwater is hypertonic, causing water to leave the bloodstream into the lungs, which can lead to secondary drowning.

What occurs when fresh water is aspirated into the lungs?

Fresh water is hypotonic, leading to water moving from the lungs into the bloodstream, lowering haematocrit and stressing the heart.

How does surface tension contribute to expiration?

Surface tension contributes about half of the force required for expiration.

What are the implications of treatment for near-drowning incidents?

Treatment depends on the type of water inhaled, as aspirated saltwater vs. fresh water has significantly different effects.

What is a major complication of pneumonia with respect to osmosis?

Water in the lungs dilutes surfactant, making respiration difficult.

What is the primary function of surfactant in the alveoli?

To reduce surface tension and prevent collapse of alveoli.

How does the concentration of surfactant molecules change during breathing?

It varies with inhalation and exhalation, affecting the surface tension of alveolar fluid.

What happens to surfactant concentration during exhalation?

It increases, which helps to reduce surface tension.

What is the role of lipo-proteins in alveoli?

They act as surfactants, reducing surface tension and allowing alveoli to expand.

What is the result of high internal osmotic pressure in cells?

It can cause cells to burst if they are in a hypotonic environment.

How quickly do changes in gas partial pressures occur during respiration?

Changes occur rapidly, within approximately 0.75 seconds.

What defines a semi-permeable membrane?

It allows solvent ions to pass but restricts larger solute ions.

How does surfactant affect pressure in alveoli of different sizes?

Surfactant equalizes pressure, allowing smaller alveoli to inflate more easily.

What occurs during osmosis across a semi-permeable membrane?

Solvent moves from areas of lower solute concentration to areas of higher solute concentration until equilibrium is reached.

What factor determines the end of osmotic transfer?

It ends when osmotic pressure equals the gauge pressure of the solution on the other side.

What happens when osmosis leads to fluid accumulation in the lungs?

It can cause serious complications such as secondary drowning.

What happens to lung function if water is introduced to it?

Lung function is impaired due to diluting surfactant and increasing surface tension.

What happens to the concentration of dissolved gases in the blood?

It varies with changes in partial pressures during respiration.

What is the significance of elastic collisions between gas molecules?

They prevent the loss of velocity and maintain the distinct gas properties.

Why is osmosis crucial in medical treatment?

It informs the administration of isotonic IV fluids to prevent cellular damage.

What is the danger posed by near-drowning incidents?

They can introduce water into the lungs, leading to complications based on water salinity.

What does secondary drowning imply physiologically?

Accumulation of fluid in the lungs due to aspirated hypertonic solutions.

Why is rapid establishment of equilibrium important in gas exchange?

It ensures efficient gas exchange to meet metabolic needs.

What role does the diaphragm play in respiration?

It contracts and relaxes to facilitate inhalation and exhalation.

How does breathing in fresh air help with alveolar gas exchange?

It creates a high O2 concentration that drives diffusion into blood.

What can happen if ventilation is impaired?

It can lead to inadequate oxygenation and retention of carbon dioxide.