What can you remember?

1. How many chambers does the heart have?

2. What are the chambers called?

3. Which side of the heart pumps blood around the body?

4. What does pulmonary mean?

5. What do the valves do?

6. What stops the valves from operating as “double doors”?

7. Which vessel carries blood from the heart to the cells around the body?

8. Which vessels carries the deoxygenated blood back to the heart?

9. Why is the cardiac system called a double system?

Keeping the blood flowing

• All will know the three main types of blood vessels and their function

• Most will be able to describe the adaptations of each vessel

• Some will be able to evaluate the methods used to repair blocked vessels

Circulatory questions

1. What are the three elements of the circulatory system?

2. Humans have a double circulatory system. What does this mean? (draw fig 1 p.238)

3. What are the three types of blood vessels?

• What is the total length of blood vessels in the average adult human body?

• 100,000 Km

carries blood back intothe heart

carries blood away fromthe heart

blood to the heart

blood from the heart

carries blood to and from the body’s cells

veinartery

• Artery

thick outer wall

thick inner layerof muscle and elastic fibres

narrowlumen

• Vein

thin outer wall

thin inner layerof muscle and elastic fibres

widelumen

Blood travels back to the heart in veins at low pressure.

If the blood pressure is too low, what, for example, might happen to the blood in leg veins?

gravity

blood to the heart possible

backflow of blood

If low-pressure blood has to move against gravity, it mightslow down further and even flow in the wrong direction!

blood to the

heart

backflow preventedvein valve

openvein valve

closed

When blood flows along veins it pushes past

the valves, which can only open in one direction.

If blood in a vein does flow backwards,

it is trapped by closed valves.

Keeping the blood flowing

• Capillaries

Blood vessels

1. Draw the 3 blood vessels

2. Complete the card sort and record in your books

Keeping the blood flowing

What could go wrong with the heart?

• Copy the headings for the following table into your books

What is a stent?

When is a stent used?

Advantages of using a stent

Disadvantages of using a stent

Before reading

After first reading

After second reading

• Complete the first line of the table – it doesn’t matter if you don’t know!

• Now read (and only read) the information on stents.

• Complete row 2 of your table

• Now read again

• Complete row 3!

• Now write a paragraph explaining what a stent is and how a stent works for an adult who has a blocked artery. Don’t forget to include any advantages and disadvantages!