OrganisationKey Facts
Key Facts: Heart and Circulation
Part of The Heart and Circulation — GCSE Biology
This key facts covers Key Facts: Heart and Circulation within The Heart and Circulation for GCSE Biology. Heart structure, cardiac cycle, blood vessels, double circulation, heart rate control, and cardiovascular health It is section 10 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 10 of 15
Practice
20 questions
Recall
25 flashcards
Key Facts: Heart and Circulation
Heart Structure:
- 4 chambers: 2 atria (top), 2 ventricles (bottom)
- 4 valves prevent backflow of blood
- Made of cardiac muscle - never tires
- Has its own blood supply (coronary arteries)
Blood Vessels:
- Arteries: Carry blood away from heart (thick walls, high pressure)
- Veins: Carry blood to heart (thin walls, low pressure, valves)
- Capillaries: Microscopic vessels for exchange (one cell thick)
Double Circulation:
- Pulmonary: Heart → Lungs → Heart (oxygenation)
- Systemic: Heart → Body → Heart (delivery)
- Prevents mixing of oxygenated and deoxygenated blood
- Maintains high pressure to body organs
Cardiac Cycle:
- Systole: Heart contracts, blood pumped out
- Diastole: Heart relaxes, chambers fill
- Complete cycle takes ~0.8 seconds at rest
- Heart sounds: "lub-dub" from valve closure