Final answer:
When blood is centrifuged, it forms three layers: the plasma, the buffy coat, and the erythrocytes. Plasma is the uppermost layer, carrying vital substances. The buffy coat contains leukocytes and platelets for immune response and clotting, and erythrocytes settle at the bottom, responsible for oxygen transport.
Step-by-step explanation:
When blood is centrifuged, it separates into distinct layers based on the density of its components. The upper layer is the plasma, which is a straw-colored liquid making up about 55% of the blood volume. Plasma contains 90 percent water and is essential for carrying various substances needed by the body, including antibodies and coagulation factors.
Below the plasma is the buffy coat, which is a thin, pale layer comprising leukocytes (white blood cells) and platelets. This layer is responsible for the immune response and blood clotting and constitutes less than 1% of the blood volume. Lastly, at the bottom layer, we find the erythrocytes (red blood cells), which are the heaviest elements and make up about 45% of the blood. They are critical for transporting oxygen throughout the body.
The percentage of the total blood sample made up of erythrocytes is known as the hematocrit. A hematocrit test, which involves spinning a blood sample at high speeds, is used to measure this percentage. An abnormal hematocrit level can indicate various health issues.