human lungs and gas exchange Flashcards
Respiration is used several different ways:
Cellular respiration is the aerobic breakdown of glucose in the
mitochondria to make ATP.
Respiratory systems are the organs in animals that exchange
gases with the environment.
“Respiration” is an everyday term that is often used to mean
“Breathing.”
Main function of the respiratory system
Respiratory systems allow organisms to move oxygen (needed for cellular
respiration) into body tissues, and remove carbon dioxide (waste product of
cellular respiration) from cells
Gas exchange by diffusion
this is about those fishes
Some animals simply allow gases
to diffuse through their skins.
Structures specialised for gas
exchange include:
* gills (aquatic animals)
* spiracles (terrestrial insects)
* lungs (most terrestrial vertebrates)
Chat about Countercurrent Exchange
In a concurrent system,
exchange is inefficient.
Equilibrium is reached at one
end.
In a countercurrent system,
equilibrium is not reached, so
gas exchange continues,
increasing efficiency.
What is the site of gas
exchange in mammals
Alveoli
Chat ab fish gills
Fish increase gas exchange
efficiency using countercurrent
exchange.
Running blood through the system in
the opposite direction to water keeps
a diffusion gradient throughout the
entire exchange
What are the parts of the respiratory system
Trachea
* Bronchi
* Bronchioles
* Alveoli
Chat ab air flow in humans
During inspiration (inhalation), the diaphragm and intercostal muscles contract.
During exhalation, these muscles relax. The diaphragm domes upwards.
Alveoli
The alveoli are moist, thin-walled pockets which are the site of gas exchange.
A slightly oily surfactant prevents the alveolar walls from collapsing and sticking together.
Circulation and gas exchange
Gas exchange at the lungs and in the cells moves oxygen into cells and carbon dioxide out
The alveolus
The respiratory surface is made up of the alveoli and capillary walls
Gas exchange
Air entering the lungs contains
more oxygen and less carbon
dioxide than the blood in the
pulmonary capillaries
Oxygen transport
Haemoglobin binds to
oxygen that diffuses into
the blood stream.
Haemoglobin Increases
blood oxygen capacity by
70x compared to dissolved
oxygen. Maintains
concentration gradient
between blood and alveoli.
carbon dio transport
Carbon dioxide can dissolve in
plasma, and about 70% forms
bicarbonate ions.
Some carbon dioxide can bind to
haemoglobin for transport.
At the cells: Oxygen
Oxygen
Cells use oxygen during respiration, lowering its concentration inside. This creates a steep diffusion gradient, allowing oxygen to move efficiently from the blood into cells.
