Respiratory 2 - BIO10004 Week 9.2 PDF

Respiratory 2 Dr Greg Davis Martini Chapter 23 Copyright notice  Summary 1. Define and compare the process of external and internal respiration 2. Summarise the physical principles controlling air movement in and out of lungs and muscles responsible 3. Su...

Respiratory 2 Dr Greg Davis Martini Chapter 23 Copyright notice  Summary 1. Define and compare the process of external and internal respiration 2. Summarise the physical principles controlling air movement in and out of lungs and muscles responsible 3. Summarise the physical principles of gas diffusion in and out of blood and body tissues 4. Summarise the function of haemoglobin and transport of oxygen and carbon dioxide in the blood 5. Describe age-related changes in the respiratory system Sections: 23-6...23-9, 23-11, 23-12 Figures: 23-11... 23-16, 23-18, 23-19, 23-24, 23-27 Questions: 5, 8, 10 Function of the respiratory system Provide large area for gas exchange Move air to and from lungs Protect respiratory surfaces Produce sounds: speaking, singing, communication Detection of odours in superior section  Gas transfer and respiration There are 2 types of respiration – Occurring in the lungs – external – Occurring in the cells – internal – Opposite process in each case with respect to blood Respiration (both types) Chest and lungs 1  Muscles and actions Series of muscles involved in respiration Inhalation – Diaphragm Voluntary skeletal muscle (requires nervous drive) Major driver of inspiration – External intercostals assist – Other muscles assist when required Exhalation – Elastic recoil of chest and diaphragm – Internal intercostals assist – Other muscles assist when required Chest and lungs 2  Pressures in the chest Pressure inside the chest decreases – intrapleural Air is pulled right down into the lungs – Intrapulmonary Close but not quite identical pressures Pressures  Volumes Most important volume measurements are: Tidal volume VT – Amount of air moved in quiet breathing – Typically 500 mL Vital capacity Vc – Largest possible breath – full inspiration to full expiration – Typically 4.5 L Residual volume – The air that remains trapped in airways (full expiration) Volumes  Properties of gases Gas volume and pressure are inversely related – Larger the volume, lower the pressure Gas volume and temperature are directly related – Higher the temperature, larger the volume Gas temperature and pressure are directly related – Higher the temperature, the higher the pressure Much movement of gas is down pressure gradient Dissolved gases Special properties of haemoglobin Gases can dissolve directly in blood – Oxygen, carbon dioxide, (nitrogen) Carrying capacity is higher if bound in structure – Oxyhaemoglobin – Carbaminohaemoglobin – Carbonic acid Haemoglobin function  Control of respiration Breathing rate is determined by tissue requirements Receptors for carbon dioxide and oxygen CO2 receptors are more sensitive – Hypercapnia (elevated CO2) – Hypocapnia (depressed CO2) CO2 increase CO2 decrease  Summary 1. Define and compare the process of external and internal respiration 2. Summarise the physical principles controlling air movement in and out of lungs and muscles responsible 3. Summarise the physical principles of gas diffusion in and out of blood and body tissues 4. Summarise the function of haemoglobin and transport of oxygen and carbon dioxide in the blood 5. Describe age-related changes in the respiratory system