Bonus question: Can anyone explain how the shape of red blood cells differs in people with sickle cell anemia? What complications does this cause?

Sure, I'd be happy to explain.

1. Normal Red Blood Cells: Typically, red blood cells are round and flexible with a donut-like shape, minus the hole in the center. This shape allows them to move easily through the blood vessels, including the smallest capillaries.

2. Sickle Cell Anemia: In people with sickle cell anemia, the red blood cells become rigid and sticky. They are shaped like sickles or crescent moons. This abnormal shape is due to a mutation in the gene that produces hemoglobin, the protein in red blood cells that carries oxygen.

3. Complications: The sickle-shaped cells can get stuck in small blood vessels, which can slow or block blood flow and oxygen to parts of the body. This can cause pain and tissue damage. In addition, because sickle cells don't last as long as normal red blood cells, they can cause anemia, a condition in which there aren't enough red blood cells to carry adequate oxygen to the body's tissues. Other complications can include infections, delayed growth, and vision problems.