2. Organisation (the lungs and the heart)

Question 1

Where are the lungs?

Answer 1

In the thorax

Question 2

What is the thorax?

Answer 2

The upper part of the body separated by the diaphragm

Question 3

What is alveoli and what is it the site for?

Answer 3

• tiny air sacs in the lungs
• the site for gas exchange

Question 4

What exchange of gases takes place at the alveoli?

Answer 4

• Diffusion of oxygen in the blood, diffusion of carbon dioxide out of the blood

Question 5

What is the equation for rate of diffusion?

Answer 5

surface area x concentration gradient
———————————————————-length of diffusion pathway

Question 6

What are the adaptations of the lungs for surface area?

Answer 6

• lots of alveloi, which means there is a large surface area, so there is a faster rate of diffusion
• lots of capillaries, which means there is a large surface area, so faster rate of diffusion

Question 7

What is the adaptation of the lungs for concentration gradient?

Answer 7

• lots of capillaries, so lots of circulation
• high concentration gradient is always maintained
• because the oxygen concentration in the blood is always going to be lower than in the alveoli
• so faster rate of diffusion

Question 8

What is an adaptation of the alveloi?

Answer 8

They have moist walls meaning that gases can dissolve and move around easily

Question 9

Describe the process of gas exchange?

Answer 9

• The air moves down the trachea into the bronchi and then the bronchioles
• The air then moves into the alveoli
• This is where the air diffuses into the blood vessels around it
• the oxygen diffuses into the bloodstream and binds to the haemoglobin in red blood cells to be transported

Question 10

What happens to the carbon dioxide made during respiration?

Answer 10

It is dissolved into the plasma of the blood, where it diffuses into the lungs and is exhaled

Question 11

What is an adaptation of the capillaries?

Answer 11

• the capillaries are one cell thick
• so length of diffusion pathway is smaller
• so there is a faster rate of diffusion

Question 12

Where do veins take the blood?

Answer 12

They take blood into the heart

Question 13

Where do arteries take blood?

Answer 13

Away from the heart

Question 14

What does the word ‘pulmonary’ have something to do with?

Answer 14

The lungs

Question 15

What does the Pulmonary artery do?

Answer 15

It carries deoxygenated blood away from the heart to the lungs

Question 16

What does the Vena carva do?

Answer 16

It brings deoxygenated blood from the rest of the body to the right atrium

Question 17

What does the Aorta do?

Answer 17

It takes oxygenated blood from the left ventricle to the rest of the body

Question 18

What does the Pulmonary vein do?

Answer 18

It carries oxygenated blood from the lungs into the left atrium

Question 19

What does the right side of the heart deal with?

Answer 19

Deoxygenated blood

Question 20

What does the left side of the heart deal with?

Answer 20

Oxygenated blood

Question 21

What does the Coronary artery do?

Answer 21

Supplies oxygen rich blood to the hearts muscles

Question 22

What do the pacemaker cells do?

Answer 22

They control the natural resting heart rate

Question 23

Where are the pacemaker cells located?

Answer 23

In the right atrium

Question 24

Why is the left side of the heart thicker than the right side?

Answer 24

• The left side is thicker
• This is because it needs to pump blood a further distance than the right side
• It needs to pump blood to the rest of the body whereas the right side needs to pump blood to the lungs
• which is right above the heart
• so the left side is thicker as more force is needed to pump the blood to the rest of the body

Question 25

What are the 8 steps of how the right side of the heart gets blood to the lungs?

Answer 25

1. Veins take deoxygenated blood through the vena carva into the right atrium
2. the right atrium begins to fill up with deoxygenated blood, so in the same volume, there is more blood, so pressure increases
3. The pressure behind the valve is greater than the pressure in front, so the valve opens
4. This allows blood to travel from the right atrium to the right ventricle
5. As the right ventricle begins to fill up, the pressure in the right ventricle starts to increase
6. So the pressure at the front of the valve becomes greater than the pressure behind the valve, so the valve closes.
7. So valves prevent the back-flow of blood
8. The right ventricle contracts and pushes the blood up through the pulmonary arteries to be taken to the lungs to be oxygenated

Question 26

What are the 5 steps of how the left side of the heart gets oxygenated blood to the rest of the body?

Answer 26

1. Oxygenated blood enters the pulmonary vein from the lungs
2. Then it enters the left atrium and fills up
3. The pressure behind the valves, between the left atrium and ventricle, will be greater than in the front, so the valve opens
4. Blood flows down into the left ventricle and the valves will close
5. The ventricle contracts, then blood leaves through the aorta to provide oxygen to the rest of the body.

Question 27

What do the valves do?

Answer 27

Prevent the back-flow of blood

Question 28

What circulatory system is the heart?

Answer 28

A double circulatory system

Question 29

How is the heart a double circulatory system?

Answer 29

• Because it has 2 cycles
• 1 for oxygenated blood, and the second one for deoxygenated blood

Question 30

Why may someone have an artificial pacemaker inserted?

Answer 30

In some diseases, contraction may be difficult, so artificial pacemakers may be inserted