AQA GCSE FOUNDATION Biology: Blood Composition and Function

AQA GCSE Foundation Biology: Blood Composition and Function

Blood: The Body's Transport System

Blood is a vital fluid that circulates throughout our bodies, delivering essential substances and removing waste products. It's like a complex delivery system, ensuring every cell gets what it needs to function.

Components of Blood

Blood is composed of several key components:

• Plasma: This is the liquid part of blood, making up around 55% of its volume. It's a pale yellow fluid that contains dissolved substances like:
  • Nutrients: Glucose (sugar) for energy, amino acids for building cells, and fatty acids for cell membranes.
  • Waste products: Carbon dioxide (CO2) from respiration, urea from protein breakdown.
  • Hormones: Chemical messengers that regulate various bodily processes.
  • Proteins: Including antibodies to fight infections and clotting factors to stop bleeding.
• Red Blood Cells: These are the most numerous blood cells, responsible for transporting oxygen from the lungs to the body's tissues. They contain the protein haemoglobin, which binds to oxygen and gives blood its red color.
• White Blood Cells: These cells are part of the body's immune system, defending against infections and diseases. They can engulf and destroy pathogens (disease-causing organisms) and produce antibodies.
• Platelets: These tiny cell fragments play a crucial role in blood clotting. When a blood vessel is damaged, platelets clump together, forming a plug to stop bleeding.

Roles of Blood Components

• Plasma:
  • Transport: Delivers nutrients, hormones, and waste products throughout the body.
  • Regulation: Maintains body temperature, pH levels, and water balance.
• Red Blood Cells:
  • Oxygen Transport: Carry oxygen from the lungs to the body's cells, where it is used for respiration.
• White Blood Cells:
  • Immune Defense: Fight infections by destroying pathogens and producing antibodies.
• Platelets:
  • Blood Clotting: Form a plug at the site of a wound to stop bleeding.

Understanding the Importance of Blood

Each component of blood plays a vital role in maintaining our health and survival. Understanding the function of each component helps us appreciate the complexity and importance of this essential fluid.