Osmotic Pressure 1

Is that so, huh?

On the other hand, if you can understand osmotic pressure, physiology will undoubtedly become enjoyable.

Alright then, let's begin today's lecture! Listen attentively!

First of all, do you know what diffusion is referring to?

I see. Osmosis refers to the method of water movement within cells.

Yes.

You can roughly interpret it as the method cells use to regulate their water content for survival.

And as a result of cells regulating water through osmosis, the pressure that arises is called osmotic pressure.

How about it? Do you understand a little now?

I see. I will explain step by step.

Now, let's explain osmosis specifically.

First, take a look at this diagram.

The container has water on both sides, right?

The dashed line represents a semipermeable membrane.

Look back at the previous lecture. For now, just understand that it's a partition with holes.

Let's continue the lecture.

Let's imagine that we have put a large amount of salt only on the left side of this container.

I see. And let's assume that water can freely pass through the holes of the partition, but salt cannot.

Now, I have a question for Cell-kun.

If we leave this container alone for a while, what do you think will happen to the water and the salt?

Correct!

That's right, water moving is the correct answer.

Now, between the side with salt and the side without, which way do you think water will move?

Close, but not quite! The correct answer is that water will move to the side with salt.

You're on fire today! That's absolutely correct!

As Cell-kun mentioned,

when you divide a container filled with water using a partition with holes, water moves from the side with a higher concentration to the side with a lower concentration.

This phenomenon is called osmosis. By the way, in the case of cells, the partition is the cell membrane.

That's the spirit! And as a result of osmosis moving the water, do you think the side without salt would have less water now?

The pressure difference that arises from this movement is called osmotic pressure.

In the scope of Cell-kun's physiology class, there's no need to explain in such detail.

In reality, the terms "osmosis" and "osmotic pressure" are often used interchangeably in physiology classes.

So, understanding that osmosis refers to the movement of water from a concentrated area to a diluted area should be sufficient.

Lastly, remember that osmosis is a form of passive transport that does not require energy.

Now, let's conclude today's lecture here.

Osmotic pressure is an essential concept in the study of physiology, and it includes explanations about hypertonic, isotonic, and hypotonic conditions that cannot be avoided.

Since the lecture would become lengthy, we decided to split it into two parts.

To better understand the upcoming discussion about hypertonic, isotonic, and hypotonic conditions, it's important to solve problems and review thoroughly.