1. AS level PE
Respiratory system

2. Discus mechanics of breathing Inspiration Expiration
Air is distributed to the lungs by way of the
Trachea
Primary bronchi (Also secondary/tertiary)
Bronchioles
alveoli

3. Respiratory system – 3 main processes
Pulmonary respiration
The breathing of air into and out of the lungs
External respiration
Exchange of O2 and CO2 between the lungs and the blood
Internal respiration
Exchange of O2 and CO2 between the blood and muscle tissues

4. RESPIRATORY VOLUMES AT REST
Tidal volume
Amount of air inhaled and exhaled with each breath (approx 500ml)
Frequency (f)
Rate of breathing
Minute Ventilation
VE = TV X f
Residual volume
Volume of air remaining in the lungs (1200ml)

5. RESPIRATORY VOLUMES AT REST (Cont’d)
Inspiratory reserve vol
Expiratory reserve volume

6. LUNG CAPACITIES Inspiratory capacity = IRV + TV
Expiratory capacity = ERV + TV
Vital capacity
Maximal vol of air that can be expired after maximal inspiration
Total lung capacity
Maximal volume of air contained in the lungs after a maximal inspiration
TLC = TV + IRV + ERV + RV

7. ALVEOLI

8. Gaseous Exchange
Gaseous exchange refers to the exchange of gases, namely O2 and CO2 and relies on a process called diffusion
What is Diffusion??
PP – partial pressure of a gas is the pressure it exerts within a mixture of gases
Gases always move from an area of high pressure to an area of low pressure

9. Inspired air – PO2 -159 , PCO2 -0.3 Trachea – PO2 – 149, PCO2 – 0.3
Pulmonary veins – PO2-100, PCO2 -40
Heart
Body tissues – PO2 – 40, PCO2 - 46

10. MYOGLOBIN – RED PIGMENT IN MUSCLES THAT STORES O2 AND TRANSPORTS O2 TO THE MITOCHONDRIA
02 – muscle cells (hb – myoglobin)
-- by product – CO2
CO2 travels in blood as carbonic acid (70%),
Carbaminohaemoglobin(20%) & 7% plasma

11. TASK
IN GROUPS OF 3-4 YOU HAVE 5-10MINS TO DISCUSS AND PRESENT THE MECHANICS OF RESPIRATION DURING EXERCISE
MECHANICS
LUNG VOLUME CHANGES DURING EXERCISE
SKIPPING ROPES
CONES & PAPER

12. MECHANICS OF RESPIRATION DURING EXERCISE
What muscles are involved?
Inspiration – SCOM(sternocleidomastoid), scalenes & pec minor
Expiration – internal intercostals & rectus abdominals / obliques
See p.96
Discuss the ventilatory response to light, moderate and heavy exercise

13. LUNG VOLUME & EXERCISE Tidal volume – 500ml 3-4litres
Frequency – 40-60
VE – 6-7.5l  l
IRV – 3100ml  decreases
ERV – 1200ml  slightly decreases
Vital capacity – 4800ml  slight decrease
Residual volume – 1200ml  slight increase
Total lung capacity – 6000ml  slight decrease

14. EXERCISE CHANGES TO GASEOUS EXCHANGE
BOTH EXTERNAL & INTERNAL RESPIRATION INCREASE DURING EXERCISE IN ORDER TO INCREASE THE SUPPLY OF O2 TO THE WORKING MUSCLES

15. OXYGEN-HAEMOGLOBIN DISSOCIATION CURVE