When is osmosis used in the body

It was diffusion of molecules from the kitchen to the front door of the house that allowed you to detect the odors. Diffusion is defined as the net movement of molecules from an area of greater concentration to an area of lesser concentration.

The molecules in a gas, a liquid or a solid are in constant motion due to their kinetic energy. Molecules are in constant movement and collide with each other. These collisions cause the molecules to move in random directions. Over time, however, more molecules will be propelled into the less concentrated area. Thus, the net movement of molecules is always from more tightly packed areas to less tightly packed areas.

Many things can diffuse. Odors diffuse through the air, salt diffuses through water and nutrients diffuse from the blood to the body tissues. This spread of particles through random motion from an area of high concentration to an area of lower concentration is known as diffusion. This unequal distribution of molecules is called a concentration gradient.

Once the molecules become uniformly distributed, dynamic equilibrium exists. The equilibrium is said to be dynamic because molecules continue to move, but despite this change, there is no net change in concentration over time. Both living and nonliving systems experience the process of diffusion. In living systems, diffusion is responsible for the movement of a large number of substances, such as gases and small uncharged molecules, into and out of cells.

Osmosis is a specific type of diffusion; it is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration. Semi-permeable membranes are very thin layers of material which allow some things to pass through them, but prevent other things from passing through. Roots have hair, which increases surface area and hence the water intake by the plants.

We drink water, but also our cells absorb it by osmosis in the same way that plant roots do. Even the primary nutrients and minerals get transferred through osmosis into the cells. Also, our intestine absorbs nutrients and minerals through osmosis.

Water travels from high concentration to low concentration and keeps moving by osmosis until the equilibrium is reached, that is when the concentration of both solutions is the same.

When we sit in the bathtub or submerge our fingers in water for a while they got wrinkly. And that is too because of osmosis. The skin of our fingers absorb water and get expanded or bloated; leading to the pruned or wrinkled fingers.

You must have heard about the killing of slugs or snails by putting salt on it. The liquid inside them comes out and try to dilute the salt concentration and maintain the mucus layer, and hence, they end up shedding water.

Too much salt and slugs or snails will dry up and die! We usually feel thirsty after eating salty food; because salt is a solute and after consuming lots of salt, our cells become concentrated with salt, which triggers the process of thirst. So, our cells absorb water and we feel thirsty, and hence, we start drinking water. In case you have a sore throat, cells and tissues surrounding the throat are swollen because of the excess of water. The salt water which we use for gargles has a lower concentration of water than the cells of the throat.

So, water molecules move from the swollen cells of the throat to the salt water; reducing pain and swelling. The reason why we can enjoy pickles and jams for a longer period of time without any fear of their spoilage is osmosis.

Pickles and Jams have been used over decades as quick spreads and ready to eat food for kids as well as adults. In active transport a special transport protein in the cell membrane picks up the useful particle on one side of the membrane. The transport protein then rotates through the membrane and releases the particle on the other side of the membrane.

This uses energy from cellular respiration. Active transport is used to move substances into cells and out of cells. Cells which carry out a lot of active transport often have lots of mitochondria to give them the energy they need. Active transport is important in the kidney for hanging on to the substances needed by the body such as glucose and some sodium ions. Diffusion, osmosis and active transport. Show animation full screen in new window.