Body Fluids and Circulation: common misconceptions

If your child says… “Platelets carry oxygen.”

Ask together

Which cells in the diagram contain haemoglobin?

What’s true

Haemoglobin belongs in red cells, while platelets help blood clot.

If your child says… “Rh-negative blood already has anti-Rh.”

Ask together

Without earlier exposure, what would have triggered anti-Rh production?

What’s true

Rh-negative people make anti-Rh only after exposure; preventive anti-Rh treatment helps prevent their own antibody production.

If your child says… “Fibrinogen makes thrombin.”

Ask together

Which must form before fibrinogen can become fibrin?

What’s true

Thrombokinase helps convert prothrombin into thrombin, which then converts fibrinogen into fibrin.

If your child says… “Every vertebrate has four heart chambers.”

Ask together

How many chambers does the fish outline contain?

What’s true

Fish have two chambers, amphibians and most reptiles three, and crocodiles, birds and mammals four.

If your child says… “The AV node starts each beat.”

Ask together

Which node comes first along the route you traced?

What’s true

The SA node initiates the beat, and the AV node passes its signal onwards.

If your child says… “An ECG records lub and dub.”

Ask together

Would a recording of electrical changes be a recording of valve sounds?

What’s true

P marks atrial excitation, QRS ventricular excitation, and T ventricular recovery.

If your child says… “Every artery carries oxygen-rich blood.”

Ask together

Which direction defines an artery on this route?

What’s true

The pulmonary artery carries oxygen-poor blood towards the lungs.

If your child says… “Heart failure, arrest and attack all mean the heartbeat stops.”

Ask together

If a heart still beats but pumps too little, which condition fits?

What’s true

Failure means inadequate pumping, arrest means stopped beating, and attacks damage heart muscle through inadequate blood supply.