What blood carries
A small cut on your knee stops bleeding after a while. Something in blood plugs it.
- Blood is a liquid with cells floating in it.
- The liquid part is plasma. It carries dissolved things.
- Red cells carry oxygen.
- Platelets are tiny pieces of cells. They help blood clot at a cut.
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Count the red cells. Then count the platelets.
The rule
Plasma is the liquid part of blood. It carries food, wastes and much of the carbon dioxide. Red cells carry oxygen with haemoglobin. Platelets help blood clot at a cut.
Platelets are tiny pieces of cells. To clot is to form a plug that seals the cut.
Haemoglobin is a red colouring inside red cells. It picks up oxygen in the lungs. It releases the oxygen in the body.
With too little haemoglobin, less oxygen reaches the cells. Cells need oxygen to release energy. A person can feel tired and weak.
In a blood sample, red cells are the big round ones. Platelets are the tiny dots. Plasma is the liquid around them.