AeroLab Reading room

Biology / IGCSE

Transport in animals

The mammalian heart pumps blood through pulmonary and systemic circuits.

Learning objectives

The big idea

The mammalian heart pumps blood through pulmonary and systemic circuits. Valves maintain directional flow, and cardiac muscle creates pressure differences rather than pulling oxygen into the blood.

Arteries carry blood away from the heart and veins return it; oxygen content depends on the circuit. Capillaries support exchange. Red cells transport oxygen, plasma carries dissolved substances, platelets support clotting and white cells contribute to defence.

Worked example

A heart beats 72 times in one minute. Find beats in five minutes at that unchanged rate.

Follow the solution

Multiply the assumed constant rate by time: 72×5=360 beats.

Investigate and explain

Using the worked example as supplied data, predict the effect of changing one condition. Draw a labelled model, record your reasoning and identify a variable that would need controlling. No human, animal or microbial experiment is required.

No exact PhET model is claimed for this topic. Use diagrams and supplied-data reasoning instead.

Open the interactive investigation

Check your understanding

1. What defines an artery?

  1. It always contains oxygenated blood
  2. It carries blood away from the heart
  3. It has valves along its entire length
Check the answer and reasoning

It carries blood away from the heart

Direction relative to the heart defines the vessel, not oxygen content.

2. A heart beats 72 times in one minute. Find beats in five minutes at that unchanged rate.

  1. 77
  2. 14.4
  3. 360
Check the answer and reasoning

360

Multiply the assumed constant rate by time: 72×5=360 beats.

3. Is blood in the pulmonary artery usually oxygen-rich?

  1. No
  2. Yes
  3. Only because it is an artery
Check the answer and reasoning

No

It travels from the right ventricle to the lungs before pulmonary oxygen uptake.