Gaseous Exchange
Why is GE necessary
- GE supplies the body with the oxygen it needs for oxidation of food to release energy during CR
- Energy is used to perform work done to keep cells and organisms alive
- Allows body to excrete CO2 from CR otherwise it’ll form carbonic acid that’ll lower the pH of body fluids
- This’ll affect the functioning of enzymes and they will denature if not at ideal pH
Difference between CR, GE & Breathing
1. Cellular Respiration
- The oxidation (breakdown) of organic compounds in cells to release energy for metabolic activities
- Oxygen is used & water and CO2 are released as waste
- Occurs in mitochondria
- Glucose + oxygen ---> carbon dioxide + water + energy
2. Gas Exchange
- O2 diffuses across respiratory surface in one direction and CO2 in the other
- “An exchange of gases across respiratory surface”
3. Breathing (ventilation)
- Mechanical process that moves air into and out of respiratory organs
- O2 enters CO2 leaves
Requirements of efficient GE organs
- A respiratory surface is made up of thin, moist epithelial cells and for GE to happen easily to must be:
- Large for maximum surface area
- Thin & permeable for quick and easy diffusion
- Moist for gases to dissolve and form a solution to diffuse through membrane
- Well-ventilated to bring fresh air for maintaining a diffusion gradient
- Well-protected to prevent drying out and mechanical injury
- Some animals have an efficient transport system close to the respiratory surface to carry gases to and from the cells
, Human Gaseous Exchange
Ventilation (Breathing) System
1. Air Passages
- Air passages are lined with mucous membrane with ciliated columnar epithelium
- The goblet cells in the epithelium secrete mucus that covers it
Nasal cavity
- Through nostrils into nasal cavity where it is filtered, moistened & warmed to body temp
- Then it passes through the pharynx through the glottis into the trachea
- The epiglottis closes to prevent breathing and swallowing at the same time and is a reflex action when bolus touches soft
plate
Why is GE necessary
- GE supplies the body with the oxygen it needs for oxidation of food to release energy during CR
- Energy is used to perform work done to keep cells and organisms alive
- Allows body to excrete CO2 from CR otherwise it’ll form carbonic acid that’ll lower the pH of body fluids
- This’ll affect the functioning of enzymes and they will denature if not at ideal pH
Difference between CR, GE & Breathing
1. Cellular Respiration
- The oxidation (breakdown) of organic compounds in cells to release energy for metabolic activities
- Oxygen is used & water and CO2 are released as waste
- Occurs in mitochondria
- Glucose + oxygen ---> carbon dioxide + water + energy
2. Gas Exchange
- O2 diffuses across respiratory surface in one direction and CO2 in the other
- “An exchange of gases across respiratory surface”
3. Breathing (ventilation)
- Mechanical process that moves air into and out of respiratory organs
- O2 enters CO2 leaves
Requirements of efficient GE organs
- A respiratory surface is made up of thin, moist epithelial cells and for GE to happen easily to must be:
- Large for maximum surface area
- Thin & permeable for quick and easy diffusion
- Moist for gases to dissolve and form a solution to diffuse through membrane
- Well-ventilated to bring fresh air for maintaining a diffusion gradient
- Well-protected to prevent drying out and mechanical injury
- Some animals have an efficient transport system close to the respiratory surface to carry gases to and from the cells
, Human Gaseous Exchange
Ventilation (Breathing) System
1. Air Passages
- Air passages are lined with mucous membrane with ciliated columnar epithelium
- The goblet cells in the epithelium secrete mucus that covers it
Nasal cavity
- Through nostrils into nasal cavity where it is filtered, moistened & warmed to body temp
- Then it passes through the pharynx through the glottis into the trachea
- The epiglottis closes to prevent breathing and swallowing at the same time and is a reflex action when bolus touches soft
plate
