- Define of diffusion ?
Ans: the process by which the particles move from a region of higher concentration to a lower concentration to spread uniformly.
Define diffusion co-efficient ?
Ans: it is the mass of solute diffusing across 1 cm square area in 1 second down a concentration gradient of unity.
state the clinical importance of diffusion?
- the alveolar surface area per unit body weight is larger in children than in adult humans. so the resting uptake of oxygen per unit body weight by its diffusion across the alveolar surface is higher in children than in adults.
- diffusion of respiratory gases across the erythrocytes membrane is much faster in larger erythrocytes of mammals than in larger erythrocytes owing to higher surface: volume ratios in the smaller cells.
- the enzyme lysozyme is polar and water soluble. since it is insoluble in the outer lipoprotein layer of gram negative bacterial cell wall it cannot diffuse through that layer to penetrate into the cell wall for digesting the latter. thus, gram negative bacterial cells are unaffected by lysozyme.
- the diffusion of oxygen and carbon dioxide between the capillary blood and the tissues is facilitated due to the thinness of capillary walls. the alveolar membrane is also thin which helps in the diffusion of respiratory gases across it. but this membrane is thickened in pneumonia resulting in the decreased diffusion of oxygen showing decline in the oxygenation of blood.
- many small alveoli fuse to form fewer and larger alveoli due to chronic smoking. as a result, the total alveolar surface is a result, the total alveolar surface is reduced and the diffusion of gases between the alveolar air and the blood is decreased leading to asphyxiating effects.
- diffusion is involved in the intestinal absorption of pentose, some water soluble vitamins and the renal reabsorption of urea.
Ans: it is a mixture of weak acids with their salts of strong bases and resist sudden change in hydrogen ion concentration even after the addition of hydrogen or hydroxyl ion.
