Blood Composition & Function
Start with the big picture
Blood’s composition supports several essential functions. Plasma carries water, proteins, electrolytes, nutrients, gases, wastes, and hormones; its proteins contribute to transport, immunity, and coagulation. Formed elements include erythrocytes, leukocytes, and platelets. Red blood cells carry oxygen and contribute to carbon dioxide transport and buffering, while white blood cells provide immune defense. Platelets participate in hemostasis, in which vascular responses, platelet-plug formation, and coagulation help produce a fibrin clot. The lesson also places these components in a broader physiological and clinical context, including blood groups and transfusion compatibility, buffer systems, and the complete blood count. Together, these ideas connect blood structure with its transport, protective, and regulatory functions.
What you'll learn
- Describe blood’s physical properties and distinguish plasma from formed elements.
- Explain the roles of plasma proteins and red blood cells.
- Identify major leukocyte types and summarize their defensive functions.
- Outline the stages of hemostasis and the convergence of coagulation pathways.
- Relate blood groups, buffer systems, and CBC assessment to blood function.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
