Question

What is crenation?
A) Abnormal notching around the edge of erythrocytes due to shrinkage.
B) Abnormal invagination around the edge of erythrocytes due to shrinkage.
C) Normal notching around the edge of erythrocytes due to shrinkage.
D) None of the above

Answer 1

Hint: When the RBCs or erythrocytes are placed in the hypertonic solution then RBCs will shrink. Because of this, the hypertonic solution has less potential for water.

Complete Answer:
- Crenation is defined as the formation of abnormally notched surfaces due to water loss by the help of osmosis.
- Inside the body, cells are in the isotonic solution which means that there is the same concentration of solute and water inside and outside the cell. Then, the equilibrium helps in maintaining the same osmotic pressure across semi-permeable membranes.
- But when the equilibrium gets disturbed due to the presence of higher solute concentration in the solution and this creates hypertonic solution. This causes water to diffuse out and the cell starts to shrink and form abnormal notches on the membrane. This process is known as crenation.
- Erythrocytes or RBCs undergo crenation by disturbing the ability of the cell to maintain an isotonic state. Erythrocytes are also called echinocytes and they are uniformly distributed. In the hypertonic solution, erythrocytes will shrink and develop abnormal notches.

Thus, the correct answer is option A. i.e., Abnormal notching around the edge of erythrocytes due to shrinkage.

Note: In the erythrocytes the crenation is reversible which is caused due to the iconic imbalances like presence of high pH, high calcium etc. Food pickling is one of the examples of the crenation process. Vegetables like cucumbers when placed in acidic solution which cause water to diffuse out and shrinkage takes place.