Question

Normal value of blood colloid osmotic pressure is about
A) 75mmHg
B) 30mmHg
C) 20mmHg
D) 10mmHg

Answer 1

Hint:Osmotic pressure is defined as the pressure which when applied to a particular solution prevents its flow across a semipermeable membrane.

Complete answer:
Blood colloid osmotic pressure is also known as oncotic pressure where the term oncotic stands for colloids in solution. The blood colloid osmotic pressure develops mainly due to the colloidal proteins such as albumin present in the plasma. This causes the water molecules to move back to the circulatory system and thus creates a difference in solute concentration. The plasma proteins being large in size cannot move out of the capillary wall and thus prevents fluids from leaking out from the capillaries. The total osmotic pressure of blood is around 28 mmHg. Colloid osmotic pressure is somewhat the opposite of the hydrostatic pressure. The hydrostatic pressure increases the filtration rate at the glomerulus that pushes fluid and other solutes out of the capillary whereas colloid osmotic pressure prevents fluids from leaving the capillary. Any changes in the colloid osmotic pressure of the blood is mostly brought about by changes in the level of serum albumin.

Hence the correct answer is option (B) 30mmHg.

Note:The colloid osmotic pressure is an important factor to retain fluid inside capillaries and any increase or decrease in it can cause adverse effects. For example the decrease in colloid osmotic pressure makes the capillaries leaky causing fluid to leave whereas an increase in the colloid osmotic pressure causes fluid build up in the capillary or edema.