4.2 The blood vessels Flashcards
Describe how the heart, arteries, veins and capillaries are linked together in the circulatory system? (3 points)
1 arteries carry blood away from heart to organs of the body
2 Blood returns to your heart in the veins
3 The two are linked by the capillaries
What is a circulatory system?
- One transport system carries blood from your lungs and back
- THE other transports system carries blood from your heart to other organs and back
What does your arteries do?
Carry blood AWAY from you heart (feel your pulse)
What do veins do?
Carry blood away from the organs towards your heart
- Blood low in oxygen therefore deep purple-red colour
- Veins don’t have a pulse
What are the main types of blood vessels called?
Arteries
veins
capillaries
What are the disadvantages of a single circulatory system? (4)
- Can’t maintain high blood pressure
- blood travels to organs more slowly
- low blood pressure would be insufficient for efficient kidney function in mammals
- blood can’t supply oxygen and glucose as fast =slower lifestyle
Do humans have a single or double circulatory system?
Double
What do veins do?
carry blood TO the heart
Veins are made from?
Joined up capillaries
Describe the structure of arteries? (and reason why)
- walls are strong and elastic because blood is pumped at high pressure.
- thick walls compared to the size of the hole in the middle
- thick layers of muscles to make strong
- elastic fibre = stretch and spring back
Describe the structures of veins
- Walls are thick =low pressure
- Bigger lumen (than arteries) hole in the middle to help blood flow
- Valve to keep blood flowing in the right direction
Describe the structure of capillaries?
- Very small
- permeable walls- so substance diffuse in and out
- walls only one cell thick= increase rate of diffusion
