2.2: Adaptations for gas exchange in humans Flashcards
The alveolus are covered by?
an extensive capillary network.
How does the human respiratory system maintain a high concentration gradient?
Oxygenated blood is carried away whilst carbonated blood is taken to.
What is the first step of breathing in?
Intercostal muscles contract, ribs move up and out.
What is the second step of breathing in?
Diaphragm contacts and flattens.
What is the third step of breathing in?
Volume of chest cavity increases, pressure is lowered.
What is the fourth step of breathing in?
Air is drawn in.
What is the first step of breathing out?
Intercostal muscles relax, ribs move down and in.
What is the second step of breathing out?
The diaphragm relaxes and expands.
What is the third step of breathing out?
Volume of chest cavity decreases and pressure is raised.
What is the fourth step of breathing out?
Air is pushed out.
What substance covers alveoli?
A surfactant.
What is the purpose of the substance that covers the alveoli?
Prevents the alveoli from collapsing when breathing out.
Premature babies are given ___? Why?
Surfactant to prevent the alveoli within their immature lungs sticking together.
