Exchange of materials: in lungs

Question 1

What exchange surface do the lungs contain?

Answer 1

breathing system

Question 2

What does the breathing system do?

Answer 2

ventilates body - so oxygen diffuses in blood and carbon dioxide diffuses out of blood

Question 3

Where are the lungs situated?

Answer 3

• thorax
• inside ribcage
• above diaphragm
• separates lungs from abdomen

Question 4

What does nose do to the air?

Answer 4

filters and warms it

Question 5

What does the trachea consist of?

Answer 5

rings of cartilage to keep air passage open

Question 6

What happens when you breathe in?

Answer 6

• diaphragm contracts- moves down
• intercostal muscles contracts - ribs move up and out
• increase in volume - decrease in pressure
• air outside at higher pressure - air moves in lungs

Question 7

What happens when you breathe out?

Answer 7

• diaphragm relaxes - moves up
• intercostal muscles relaxexs- ribs move down and in
• decrease in volume - increase in pressure
• air outside at lower pressure - air moves out lungs

Question 8

why would someone use an artificial breathing aid?

Answer 8

• damage to alveoli - surface area for gas exchange reduced
• narrowed tubes to lungs - less air to lungs
• paralysed - muscles will not work to move ribcage

Question 9

What is an iron lung - who was it used for - what does it do?

Answer 9

• large metal cylinder forming vacuum to create NEGATIVE PRESSURE (external pressure lower than internal pressure) so chest moves out and breathes in
• used for people paralysed from polio

Question 10

What other breathing aid do people use?

Answer 10

bags of air with endotracheal tubes forcing measured amounts of air down the lungs - uses POSITIVE PRESSURE (external pressure higher than internal pressure)

Question 11

Advantages of positive pressure breathing aids

Answer 11

• smaller so easier to manage
• linked to computeers for control
• rests respiratory muscles

Question 12

Disadvantages of positive pressure breathing aids

Answer 12

• damage to trachea
• pressure sores
• risk of VAP

Question 13

Advantages of negative pressure breathing aids

Answer 13

• no need for tracheal tube
• maintain speech
• effective for polio
  convenient for night ventilation patients

Question 14

Disadvantages of negative pressure breathing aids

Answer 14

• bulky - inconvenient
• irritant to skin
• lowers blood pressure
• increases risk of gastric reflux