what is crystalloid & what are the differences between colloid & crystalloid?

Crystalloid is defined as a substance when dissolved forms a true solution rather than a colloid and is able to pass through a semi permeable membrane.

On the basis of the diffusion rate of liquid and solution through the animal membrane, they can be of two types. Crystalloid and Colloids. 

• The main difference between crystalloid and colloids is their ability to diffuse through the membrane. 
• Crystalloids pass through filter paper as well as through animal membrane while colloids cannot pass through animal and vegetable membranes due to large particle size. 
• Since colloidal particles are large enough to pass the diffusion barrier, they are infused in to the vascular space and show a great tendency to stay in intra vascular space to enhance the plasma volume compared to any crystalloid.
• Colloids contain much larger molecules than crystalloids do.
• Crystalloid solutions can be stored in room temperature, but colloidal solutions cannot be stored in room temperature. They need to be stored in the refrigerator, and there is a limited time period for it too.
• Crystalloids are much cheaper than colloids, and they are readily available.