Structure of the Human Gas - Exchange System Flashcards
Why do mammals need a constant supply of oxygen?
Oxygen is required for aerobic respiration, which releases ATP for energy
Why must carbon dioxide be removed from the body?
A buildup of carbon dioxide can be harmful, as it can lower pH and affect enzyme activity
Why do mammals require large volumes of oxygen? (two reasons - size + temp)
1/ Mammals are large organisms with a high number of living cells
2/ They maintain a high body temperature, which increases metabolic and respiratory rates
What specialised surface have mammals evolved for gas exchange?
Lungs, which allow efficient gas exchange between the air and the blood
Where does gas exchange occur in mammals?
In the lungs, which are specialised for efficient gas exchange
Why are the lungs located inside the body? (two reasons - air + water)
1/ Air is not dense enough to support and protect the delicate lung structures
2/ To prevent excessive water loss and the body drying out
What structure protects and support the lungs?
The rib cage, a bony structure that encloses the lungs
How is air constantly replenished in the lungs?
The lungs are ventilated by a tidal stream of air, maintaining a fresh supply of oxygen and removing carbon dioxide
What are the lungs made up of?
A pair of lobed structures containing highly branched bronchioles that end in alveoli
What is the function of the trachea, and how is it structured?
The trachea is a flexible airway supported by cartilage rings to prevent collapse when air pressure drops
Its walls contain muscle, ciliated epithelium and goblet cells to trap and remove dirt
What are the bronchi, and how do they function?
The bronchi are two divisions of the trachea, each leading to a lung.
They have mucus - producing goblet cells and cilia to move mucus to the throat.
Large bronchi are supported by cartilage, but smaller ones have less cartilage
What are bronchioles, and how do they help control airflow?
Bronchioles are branching subdivisions of the bronchi.
Their walls contain muscle and epithelial cells, allowing them to constrict and regulate airflow to the alveoli
What are alveoli, and how do they aid gas exchange?
Alveoli are tiny sacs lined with epithelium
They contain collagen and elastic fibres, allowing them to stretch during inhalation and recoil during exhalation, expelling carbon dioxide - rich air
What is the gas exchange surface in the lungs?
The alveolar membrane serves as the gas - exchange surface
