AQA As Biology 5.1 The structure of the heart
- Created by: maddie
- Created on: 24-11-12 16:18
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- The structure of the heart
- Two pumps each with two chambers
- atrium
- Thin-walled, elastic, stretches when filled with blood
- Thin muscular wall - only pumps blood to ventricle - short distance.
- Ventricle
- Thich muscular wall - pump blood to lungs or body - larger distance
- Left and right vernticle. Left - thick musclular wall = produce enough pressure to punmp blood to body. Right = thin, pump blood to luings needs little pressure
- Left pump - oxgenated blood from lungs, right deoxgenated blood from body
- Why two pumps?
- Blood has to pass through thin capillaries in lungs to give large surface area for gas exchange so pressure drops.
- Low pressure= flow to body slow so blood returnerd to heart to increase pressure
- Blood has to pass through thin capillaries in lungs to give large surface area for gas exchange so pressure drops.
- Valves between atrium and ventricle to prevent backflow
- left atrioventricular (biscupid) valves - formed of 2 cup-shaped flaps of left side of heatrt
- right atrioventricular (triscupid) valve: 3 cup-shaped flaps on right side
- atrium
- chambers served by blood vessel.Ventricle: blood away, arteries: blood towards. Atria recieve blood from veins
- vessels connecting heart - lungs: Pulmonary vessels. Vessels connected to chambers:
- Vena Cava
- Two pumps each with two chambers
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