SPO1003 Respiratory System

Aims To understand The structure and function of the respiratory tract The process of ventilation and respiration Gaseous Laws

Ventilation & Respiration Introduction: http://www.youtube.com/watch?v=hc1YtXc_84A

Respiratory Function Three major functions: Get Oxygen (O2) Remove Carbon dioxide (CO2) Maintain Acid / Base balance (regulate acidity)

Respiratory Function Inspired air Expired air CO2 - 0.03% Expired air O2 - 16% CO2 - 4% Expired values change dictated by level of activity

Boyle’s Law: Inverse relationship As the volume of a gas ↑ pressure ↓ https://www.youtube.com/watch?v=q6-oyxnkZC0

Dalton's Law: The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases in the mixture

Atmospheric pressure at sea level = 101.3 kPa (Kilopascal) In practice……. Atmospheric pressure at sea level = 101.3 kPa (Kilopascal) N2 + O2 + H2O + Ar + CO2 78.1 + 20.9 + 1.28 + 0.97 + 0.5 = 101.3 https://www.youtube.com/watch?v=tTGehRESHmA

Henry's Law: Gases dissolve in liquids in proportion to their partial pressures, depending on their solubility in the specific fluids and depending on the temperature https://www.youtube.com/watch?v=dd9xPEePX9w

Ventilation & Respiration Pulmonary ventilation Inspiration and Expiration Respiration Exchange of oxygen and carbon dioxide between the lungs (i.e. the air) and the blood (external) Exchange of oxygen and carbon dioxide in musculature (internal)

Ventilatory Anatomy

Ventilation Muscles of Ventilation Intercostal muscles Diaphragm Between ribs Internal and External intercostal muscles Work in opposing directions External raise rib cage internal lower it Diaphragm Sits in thorax underneath the lungs During contraction moves away from lungs During relaxation moves towards lungs

Ventilation At rest pressure in lungs = air pressure Inspiration Diaphragm contracts Moves downwards increasing thoracic volume Lungs attached to rib cage and diaphragm Thus increase chest volume - increase lung volume

Ventilation Expiration So the opposite occurs In order to breath out pressure in lungs must increase above atmospheric pressure So the opposite occurs Diaphragm relaxes & moves upwards - volume decreases

If air pressure within the lungs is greater than atmospheric pressure, air will move out of the lungs (expiration). If intrapulmonic pressure is less than atmospheric pressure, air will move into the lungs (inspiration)

Boyle’s Law

Respiration External: process of inhaling the air into the lungs and expelling the air that contains more CO2 from the lungs to the outer environment. Internal: a metabolic process during which oxygen is released to tissues and carbon dioxide is absorbed by the blood. Once inside the cell the oxygen is utilized for production of energy in the form of ATP Gas exchange occurs via diffusion

External Respiration Diffusion of O2 & CO2 across membrane

Dalton’s Law Pressure of a mixture of gases equals the sum of the partial pressures: Inspired air has a high PO2 and low PCO2 Blood has lower PO2 and higher PCO2 Diffusion occurs by movement of gasses from high pressures to low pressures Thus the high O2 in the alveoli diffuses into the blood and the high CO2 in the blood diffuses into the air

Partial Pressure of O2 & CO2 https://www.youtube.com/watch?v=kY79-Q9t-0s

Partial Pressure of O2 & CO2 Total 100.00 760 760 760 0 O2 20.93 159 100 40 60 CO2 0.03 0.2 40 46 6 Partial pressure (mmHg) % in Dry Alveolar Venous Diffusion Gas dry air air air blood gradient

Gaseous Laws Boyle’s Law: Dalton's Law: Henry's Law: As the volume of a gas increases, pressure decreases, and as the volume decreases, pressure increases Dalton's Law: The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases in the mixture Henry's Law: Gases dissolve in liquids in proportion to their partial pressures, depending on their solubility in the specific fluids and depending on the temperature

Important Points Ensure you understand the following: Ventilatory structures Respiratory mechanisms Gaseous laws and their importance to ventilation and respiration

QUESTIONS