The Mechanism of Breathing

1
The Mechanism of Breathing

• L.O to describe the steps in inspiration and
  expiration
• to define and calculate pulmonary ventilation
• Starter Recall knowledge from last lesson and
  answer this exam q worth 5 marks

2
How do we breathe?

• http//www.bbc.co.uk/learningzone/clips/how-do-we-
  breathe/10646.html

3
Mechanism of Breathing
Inspiration Expiration
External intercostal muscles
Internal intercostal muscles
Ribs
Diaphragm
Volume of thorax
4
Mechanism of Breathing
Inspiration Expiration
External intercostal muscles Contract
Internal intercostal muscles Relax
Ribcage Up and out
Diaphragm Contract
Volume of thorax Increases
5
Mechanism of Breathing
Inspiration Expiration
External intercostal muscles Contract Relax
Internal intercostal muscles Relax Contract
Ribcage Up and out Down and in
Diaphragm Contract Relax
Volume of thorax Increases Decreases
6
Under Pressure

• http//www.bbc.co.uk/learningzone/clips/under-pres
  sure/10861.html

7
Under Pressure
http//www.youtube.com/watch?vaw9PTVmPJAY
8
Pulmonary Ventilation

• Pulmonary Tidal x Ventilation
• Ventilation Volume Rate

Total volume of air moved into the lungs in one
minute
Number of breaths in one minute
Volume of air in each breath
dm3 min -1 dm3 min-1
9
Past Exam Question
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
Now leave your work from today on my desk please.
Thank you ?