Lesson 2 - The respiratory system and the mechanism of breathing Flashcards
What does the respiratory system consist of?
The respiratory system consists of a number of tubes that take in air from our surroundings and carry it to small air sacs (alveoli) where it can diffuse into the blood.
Where are the lungs located?
The lungs are in the upper part of the body (the thorax) and are protected by the rib cage.
What separates the lungs from the abdomen?
The lungs are separated from the lower part of the body (the abdomen) by the muscular diaphragm.
What is the pathway of air starting from the trachea?
Air passes into the trachea, which then branches into 2 bronchi, with 1 bronchus going into each lung.
What are bronchioles?
Bronchioles are smaller tubes that branch off the bronchi.
What is the function of mucus in the respiratory system?
The walls of the trachea and bronchi are covered in mucus to catch any microbes or dust that may be in the air we inhale.
How is mucus moved in the respiratory system?
Mucus is moved to the back of the throat by small hair-like structures called cilia.
What happens to the mucus after it is swallowed?
After swallowing, the acid in the stomach kills off any bacteria in the mucus.
Label diagram
What is the mechanism of breathing divided into?
Breathing is divided into two parts: ventilation and gas exchange.
What is ventilation?
Ventilation is getting the air into and out of the lungs.
What is gas exchange?
Gas exchange is getting the gases to move into or out of the blood, involving the removal of waste gases and absorption of oxygen.
How does ventilation work in humans?
Ventilation in humans is the movement of air through the nose or mouth, down the trachea, through the bronchi and bronchioles, and into the alveoli of the lungs.
What are the two components of ventilation?
Ventilation consists of inhaling (breathing in) and exhaling (breathing out).
What happens during inhalation?
During inhalation, the diaphragm contracts and flattens, intercostal muscles contract, ribs move up and out, chest cavity volume increases, and air pressure inside the chest cavity decreases below atmospheric pressure.
What occurs as a result of decreased air pressure in the lungs during inhalation?
Air rushes in from the higher pressure outside the mouth into the area of lower pressure in the lungs.
What happens to the diaphragm when you exhale?
The diaphragm relaxes and domes up.
What happens to the intercostal muscles during exhalation?
The intercostal muscles relax.
How does the rib cage move when you exhale?
The rib cage moves down and in.
What happens to the volume of the chest cavity during exhalation?
The volume of the chest cavity is decreased.
What happens to the air pressure inside the chest cavity when you exhale?
The air pressure inside the chest cavity is increased above atmospheric air pressure.
What is the result of the changes during exhalation?
Air is forced out.
Label model lung
