1. The Respiratory System
The respiratory system functions to bring oxygen into the body & remove carbon dioxide

2. Composition of Air GAS N2 O2 Ar CO2 INHALED EXHALED 78 % 21 % ~ 1 %
0.03 %
~ 1 %
5 %
78 %
16 %

3. RESPIRATORY SYSTEM A J B K L C M D N E O F G P H Q I

4. 1. Breathing
Inhalation
Diaphragm contracts (it flattens and moves downwards)
Intercostal muscles contract to move rib cage up and out
Thoracic cavity enlarges
pressure in lungs decreases
air is sucked into lungs by the air pressure difference

5. Pathway for air inhaled
Nasal cavity or mouth
Pharynx
Larynx and vocal cords
Trachea
Bronchi
Bronchioles
Alveoli

6. Exhalation diaphragm relaxes and moves upwards
intercostal muscles relax to move rib cage down and in
volume of thoracic cavity decreases
pressure in lungs increases
air is pushed out

7. Pathway for air exhaled
Nasal cavity or mouth
Pharynx
Larynx and vocal cords
Trachea
Bronchi
Bronchioles
Alveoli

8. 2. Air Processing
Blood Vessels
Air is warmed to body temperature

9. Cilia small hairs lining nasal cavity and airways
‘sweep’ debris & dirty mucous up trachea for disposal by coughing, swallowing, or spitting

10. Mucous Coats cilia & lung tissue Traps dust and bacteria
allows gases to dissolve so they can diffuse through membranes

11. 3. Gas Exchange External Respiration
oxygen diffuses from alveoli into blood
oxygen binds to hemoglobin and is carried by red blood cells
carbon dioxide diffuses from blood into alveoli

12. Internal Respiration
oxygen diffuses out of blood into extra-cellular fluid, then into cells
carbon dioxide diffuses out of cells, into extra-cellular fluid, then into blood
carbon dioxide is carried in blood plasma as a dissolved gas

13. 4. Cellular Respiration occurs in the mitochondria
breakdown of glucose to produce ATP
requires large amounts of oxygen
produces carbon dioxide

14. 5. Regulation of Breathing
[CO2] in
blood rises
blood pH
falls
carotid artery sensors
detect low pH
medulla oblongata
signals diaphragm and
intercostal muscles
to relax
production of
CO2 by cells
[CO2] in
blood falls
CO2 expelled

15. ACIDITY OF THE RESPIRATORY SYSTEM
CO2 + H2O
 H2CO3
 H+ + HCO3-
carbonic acid
hydrogen ion and bicarbonate ion

16. Math of breathing
Purpose: To calculate how much O2 is used by an organism in a given amount of time.
Comparisons: In order to compare animals of different sizes, the calculations must be done on a per kilogram basis

17. Formula: O2 inhaled per hour per kilogram = breathes per hour
X volume per breathe
X percent of air that is oxygen
_________________________________________________________
mass in kilograms

18. Example:
How much oxygen does a 72 kg person inhale per hour if they have a tidal volume of 0.82 L and breathe 17 times per minute?
[17 br/min X 60 min/h]
X L/br
X 21% O2
________________________________________
O2 inhaled =
72 kg
1020 br/h X L/br X O2 72 kg
O2 inhaled =
O2 inhaled =
L/h/kg
The man inhales 2.43 LO2/h/kg

19. Another Example:
A 53 kg woman breathes times per day and has a tidal volume of 0.67 L. What is her volume of oxygen inhaled per hour on a per kilogram basis?
[ br/day / 24h/day]
X 0.67L/br
X 21% O2
_______________________________________
O2 inhaled =
53 kg
br/h X L/br X O2 53 kg
O2 inhaled =
O2 inhaled =
L/h/kg
The woman inhaled 2.08 LO2/h/kg

20. IRV, TV, RV, ERV, VC, IC, FRV, TLC
Respiration Chart
TERMS
IRV, TV, RV, ERV, VC, IC, FRV, TLC

21. Voice Production
Voice production occurs by forcing air through connective
tissue at the point of the larynx during exhalation

23. Assignment
pg 23 Procedure 1- 5
Questions 1 - 4