The Lungs & The Circulatory System (p.45 revision guide)

Question 1

Name the tubes that branch of the the trachea

Answer 1

Bronchus

Question 2

Explain the role that alveoli play in gas exchange

Answer 2

►blood next to alveoli containing carbon dioxide and little oxygen has just returned to lungs
►oxygen diffuses out of out of alveoli(high conc.)into blood(low conc.)
►CO2 diffuses out of blood into alveolus to be breathed out.
►when blood reaches body cells, oxygen released from RBC’s and diffuses in to body cells
►at the same time, CO2 diffuses out of body cells into blood.
► it is then carried back to the lungs.

Question 3

Explain why thew circulatory system is described as the ‘double circulatory system’

Answer 3

Because it is two circuits joined together made up of the heart, blood vessels and blood

Question 4

Why does the heart have valves?

Answer 4

The heart has valves to ensure that the blood flows in the right direction. - Prevents back flow of blood.

Question 5

Name the four chambers of the heart

Answer 5

►Left atrium - top left
►Right atrium - top right
►Left ventricle - bottom left
►Right ventricle - bottom right

Question 6

How is the resting heart rate controlled in a healthy heart?

Answer 6

They are controlled by a group of cells in the right atrium wall that acts as a pacemaker.

Question 7

How are arteries adapted t carry blood away from the heart?

Answer 7

►Walls are strong and elastic
►Walls are thick compared to lumen
►Contain thick layer of muscles to make them strong
►contain elastic fibres to allow them to stretch and spring back

Question 8

Why do red blood cells not have a nucleus?

Answer 8

Red blood cells don’t have a nucleus so that there is more space for oxygen to be carried.