Answer
Blood is composed of both liquid and cellular components. The liquid portion of blood is called plasma, and the cellular components are collectively referred to as formed elements. The relative amounts of plasma and formed elements in the blood are approximately as follows:
1. **Plasma:** Plasma constitutes about 55% of total blood volume. It is a yellowish fluid that serves as the medium in which blood cells and various solutes are suspended. Plasma is made up of water, electrolytes (such as ions), proteins, hormones, waste products, and nutrients.
2. **Formed Elements:** Formed elements make up about 45% of total blood volume. These components include three main categories of blood cells:
a. **Red Blood Cells (Erythrocytes):** Red blood cells are the most numerous formed elements in the blood. They make up about 99% of all blood cells. Their primary function is to transport oxygen from the lungs to body tissues and carry carbon dioxide from tissues to the lungs for elimination. Red blood cells contain hemoglobin, a protein that binds to oxygen and gives blood its red color.
b. **White Blood Cells (Leukocytes):** White blood cells are involved in the body's immune response and defense against infections. They make up a smaller portion of the formed elements, accounting for around 1% of total blood volume. There are several types of white blood cells, each with specific functions in immune surveillance, pathogen destruction, and immune memory.
c. **Platelets (Thrombocytes):** Platelets are cell fragments rather than complete cells. They play a crucial role in blood clotting (hemostasis) by forming blood clots to prevent excessive bleeding from damaged blood vessels. Platelets account for a small fraction of the formed elements, making up less than 1% of total blood volume.
In summary, the relative amounts of plasma and formed elements in the blood are approximately 55% plasma and 45% formed elements. The formed elements consist of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). These components work together to fulfill the blood's various functions, including oxygen transport, immune response, and clotting.
Work Step by Step
Blood is composed of both liquid and cellular components. The liquid portion of blood is called plasma, and the cellular components are collectively referred to as formed elements. The relative amounts of plasma and formed elements in the blood are approximately as follows:
1. **Plasma:** Plasma constitutes about 55% of total blood volume. It is a yellowish fluid that serves as the medium in which blood cells and various solutes are suspended. Plasma is made up of water, electrolytes (such as ions), proteins, hormones, waste products, and nutrients.
2. **Formed Elements:** Formed elements make up about 45% of total blood volume. These components include three main categories of blood cells:
a. **Red Blood Cells (Erythrocytes):** Red blood cells are the most numerous formed elements in the blood. They make up about 99% of all blood cells. Their primary function is to transport oxygen from the lungs to body tissues and carry carbon dioxide from tissues to the lungs for elimination. Red blood cells contain hemoglobin, a protein that binds to oxygen and gives blood its red color.
b. **White Blood Cells (Leukocytes):** White blood cells are involved in the body's immune response and defense against infections. They make up a smaller portion of the formed elements, accounting for around 1% of total blood volume. There are several types of white blood cells, each with specific functions in immune surveillance, pathogen destruction, and immune memory.
c. **Platelets (Thrombocytes):** Platelets are cell fragments rather than complete cells. They play a crucial role in blood clotting (hemostasis) by forming blood clots to prevent excessive bleeding from damaged blood vessels. Platelets account for a small fraction of the formed elements, making up less than 1% of total blood volume.
In summary, the relative amounts of plasma and formed elements in the blood are approximately 55% plasma and 45% formed elements. The formed elements consist of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). These components work together to fulfill the blood's various functions, including oxygen transport, immune response, and clotting.
