THE FUNCTION OF RESPIRATION
THE FUNCTION OF RESPIRATION
Almost every organism requires oxygen for cellular respiration:
C6H12O6 + O2 → H2O + CO2 + ATP (energy)
The job of our respiratory system is to get oxygen into our bodies, where it can then be supplied to each and every cell for cellular respiration
THE FUNCTION OF RESPIRATION
There are two parts to this process:
1. Breathing: inhalation/inspiration and exhalation/expiration
2. Gas Exchange: exchanging oxygen for carbon dioxide
a) External Respiration: exchange of oxygen and carbon dioxide between the inspired air inside the lungs and blood
b) Internal respiration: exchange of oxygen and carbon dioxide between the blood and body’s tissue cells
3. Cellular Respiration: energy releasing chemical reactions in cells
THE FUNCTION OF RESPIRATION
2. Gas Exchange
GAS EXHANGE: the two way movement of gases (oxygen, O2 and carbon dioxide, CO2) between internal (inside the organism) and external (outside the organism) environments.
OXYGEN: required to release the energy in glucose during cellular respiration
CARBON DIOXIDE: given off as a waste product
THE FUNCTION OF RESPIRATION
2. Gas Exchange
The gases can only be exchanged when they are dissolved in water because that is the only way they can diffuse through tissues
Every cell in an organism requires oxygen and needs to get rid of carbon dioxide
THE FUNCTION OF RESPIRATION
A good gas exchange system requires the following qualities:
1. Large Respiratory Surface Area
- large area for diffusion to occur
2. Moist Surface
- dissolves oxygen in the air
3. Close to Transport/Circulatory System
- delivers oxygen to circulatory system so that it can be transported throughout the body
THE FUNCTION OF RESPIRATION
Where and how do the following organisms exchange gases?
Amoeba – body surface, diffusion
Worm – body surface, diffusion
Fish – gills, diffusion
Frog – lungs, gulping and swallowing; moist outer skin, diffusion
Human – lungs, breathing
THE FUNCTION OF RESPIRATION
GAS EXCHANGE IN AQUATIC ENVIRONMENTS
Oxygen is found as a dissolved gas
Oxygen can be taken in through gills
GILLS: respiratory organ found in many aquatic animals that extracts dissolved oxygen from water, and excretes carbon dioxide
- Oxygen diffuses into the blood and circulates through surrounding capillaries
- Carbon dioxide diffuses from the blood, across the gill tissue, into the water
GAS EXCHANGE IN AQUATIC ENVIRONMENTS
GAS EXCHANGE ON LAND
Air breathing vertebrates (Ex. Reptiles, birds and mammals) rely on lungs for gas exchange
GAS EXCHANGE ON LAND
ANATOMY OF RESPIRATORY SYSTEM REQUIRED FOR BREATHING
GAS EXCHANGE ON LAND
The DIAPHRAGM and INTERCOSTALS MUSCLES work together to bring air into and out of the lungs
GAS EXCHANGE ON LAND
EXPIRATION INSPIRATION
Exhaling: air out of lungs Inhaling: air into lungs
Air pressure in lungs is GREATER than air pressure outside
Air pressure in lungs is LOWER than air pressure outside
Diaphragm relaxes Diaphragm contracts
Diaphragm moves upwards Diaphragm moves downwards
Intercostals relax Intercostals contract
Rib cage moves in and down Rib cage moves up and out
LOWER volume, HIGHER air pressure HIGHER volume, LOWER air pressure
GAS EXCHANGE ON LAND
THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL
Alveoli: thin, moist, high surface area ratio
- bathed by 4-6 L of blood every minute
Blood returning to the heart from the body is relatively low in O2 (PO2 = 40) and high in CO2 (PCO2 = 46)
This blood is pumped by the right ventricle to the lungs
In the alveoli of the lungs, gases are exchanged: O2 diffuses into capillaries and is carried by hemoglobin in
RBCs CO2 diffuses out into the alveoli and is carried as carbonic
acid
GAS EXCHANGE ON LAND
THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL
STRUCTURE GAS PRESSURE
Alveoli Oxygen 105
Capillary Oxygen 40
Alveoli Carbon dioxide 40
Capillary Carbon dioxide 46
GAS EXCHANGE ON LAND
THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL
RESPIRATORY VOLUMES
RESPIRATORY VOLUMES
Tidal Volume: Amount of air inhaled and exhaled with each normal breath
Inspiratory Reserve Volume: Maximum amount of gas that can be forcefully inhaled after a normal inhalation
Expiratory Reserve Volume: Maximum amount of gas that can be forcefully exhaled after a normal exhalation
RESPIRATORY VOLUMES
Vital Capacity: The volume of gas that can be expelled from the lungs after a full inspiration
Inspiratory Capacity + Expiratory Reserve Volume
Residual Volume: Amount of gas left in the lungs after a maximum (forced) exhalation
Total Lung Volume: The volume of gas contained in the lung at the end of maximal inspiration
Vital Capacity + Residual Volume
RESPIRATORY VOLUMES