In the context of erythrocytes, what is crenation of red blood cells?

• A. Shrinking of red blood cells due to water loss, producing a spiky or scalloped membrane (often in a hypertonic solution)
• B. Sickle-shaped deformation of red blood cells caused by polymerization of abnormal hemoglobin
• C. Swelling and rupture of red blood cells due to water gain in a hypotonic solution (hemolysis)
• D. Formation of rouleaux, where red blood cells stack like coins due to increased plasma proteins

Answer: (A)

Verified step by step guidance

1. Understand that crenation refers to a specific change in the shape of red blood cells (erythrocytes) caused by water movement across the cell membrane.
2. Recall that red blood cells placed in a hypertonic solution lose water by osmosis, causing the cells to shrink.
3. Recognize that as the cells shrink, their membranes develop spiky or scalloped edges, which is characteristic of crenation.
4. Differentiate crenation from other red blood cell changes: sickling (due to abnormal hemoglobin), hemolysis (swelling and rupture in hypotonic solutions), and rouleaux formation (stacking due to plasma proteins).
5. Conclude that crenation specifically describes the shrinking and spiky membrane appearance of red blood cells caused by water loss in a hypertonic environment.