Biology Grade 7: Blood Components

What is the primary function of red blood cells?

Which component of blood is responsible for fighting infections?

What percentage of blood is made up of plasma?

Which of the following substances is NOT found in plasma?

What role do platelets play in the blood?

Which component of blood carries hormones and nutrients?

What shape are red blood cells and why is this shape important?

What is the initial step in the blood clotting process?

What is the primary function of red blood cells (RBCs)?

Which structure allows red blood cells to fit through narrow capillaries?

What do phagocytes do in the immune system?

Which component in blood is primarily responsible for clotting?

What role do lymphocytes play in the immune response?

What is the significance of the iron-rich protein found in red blood cells?

What is phagocytosis?

What happens when a cut occurs on the skin?

Blood Components

Blood is a liquid tissue consisting of four main components: plasma, red blood cells, white blood cells, and platelets.
Blood circulates within blood vessels and can clot if vessels rupture, preventing blood loss.

Plasma

Comprises about 55% of blood, appearing as a pale yellow fluid.
Contains 90-95% water with 5-10% consisting of dissolved substances.
Dissolved substances include:
- Nutrients: glucose, amino acids, vitamins, mineral ions.
- Waste products: carbon dioxide, urea.
- Clotting proteins: prothrombin and fibrinogen.
- Protective proteins: antibodies.
- Various hormones.

Red Blood Cells (RBCs)

The most numerous cells in blood, with 3-5 million RBCs per drop.
Produced in bone marrow and specialized for oxygen transport.
Features:
- Biconcave disc shape for larger surface area to absorb more oxygen.
- Lack of nucleus provides space for hemoglobin.
- Hemoglobin binds with oxygen to form oxyhemoglobin, which is transported to body cells.
- Flexible membranes allow them to navigate narrow capillaries.

White Blood Cells (WBCs)

Integral to the immune system, defending against infections caused by pathogens.
Major types include phagocytes and lymphocytes.

Phagocytes

Engulf and digest pathogens through a process called phagocytosis.
Have a lobed nucleus and irregular shape.

Lymphocytes

Produce and secrete antibodies to target and destroy pathogens.
Characterized by a large round nucleus that occupies most of the cell.

Platelets

Fragments of cells involved in blood clotting.
Activate upon skin injury to halt bleeding by forming a clot.
Release chemicals converting soluble fibrinogen into insoluble fibrin, creating a mesh to trap RBCs and form a clot.
The clot dries, forming a scab that prevents blood loss and serves as a barrier against pathogens.

Test your knowledge on blood components including red blood cells, white blood cells, platelets, and plasma. This quiz will help you identify these components under a microscope and understand their functions. Additionally, learn about the blood clotting process and its significance.