Respiratory system Flashcards
What is breathing??
The exchange of gases through taking air into and out of the lungs.
Where are your lungs?
In the upper part of your chest.
What separates the lungs from the digestive organs?
The diaphragm.
What gasses are inhaled?
Carbon dioxide, nitrogen, oxygen and argon.
What gasses are exhaled?
Carbon dioxide, nitrogen, oxygen and argon.
How much of each gas do you breathe in and out?
- Breath in less carbon dioxide.
- The same amount of nitrogen is inhaled and exhaled.
- Breath in more oxygen.
- The same amount of argon is inhaled and exhaled.
What happens to lung volume during inhalation?
It increases.
What happens to lung volume during exhalation?
It decreases.
What happens to lung pressure during inhalation?
It decreases.
What happens to lung pressure during exhalation??
It increases.
What happens to the intercostal muscles during inhalation?
They contract.
What happens to the intercostal muscles during exhalation?
They relax.
What happens to the ribs during inhalation?
They move up and out.
What happens to the ribs during exhalation?
They relax.
What happens to the diaphragm during inhalation?
It contracts downwards, flattening.
What happens to the diaphragm during exhalation?
It relaxes.
How is the trachea strengthened?
It has rings of c-shaped cartilage.
What connects one rib to the next?
The intercostal muscles.
Where does gas exchange take place?
The alveoli.
What is breathing also known as?
Ventilation.
What adaptions does the alveoli have for gas exchange?
• The wall of an alveolus is a single layer of epithelial cells. The wall of a capillary is a single layer of endothelial cells. This means that there is a short diffusion distance for oxygen from the air in the alveoli to the red blood cells in the capillary. Therefore, making it easier for oxygen to get into the red blood cells.
• The many alveoli mean there is a large surface for gas exchange. About 75m (squared) in an adult.
• Ventilation of the lungs maintains a high concentration of oxygen and low concentration of carbon dioxide in the air in the alveoli.
• A good blood supply ensures that carbon dioxide is continually brought to the lungs and oxygen is carried away, which also helps maintain the high concentration gradient.
How do the respiratory and circulatory systems work together?
The red blood cells in the capillaries can pick up oxygen that was inhaled to deliver it throughout the body and bring Co2 to the lungs to get exhaled.
How does gas exchange happen?
- Oxygen and carbon dioxide are constantly being supplied and removed via breathing.
- Oxygen can diffuse across the membrane of the cells that line the alveoli, to the outside of the cell. The same applies for the lining of the capillaries, until oxygen eventually diffuses into the red blood cells, where it can bind with haemoglobin to make oxyhemoglobin.
- Carbon dioxide can also diffuse across these membranes and enter the alveoli sacks to then exit the body via the alveolar duct.
- While oxygen is being supplied, it’s also being taken away due to blood flow. This means we’re constantly maintaining a concentration gradient which allows gas exchange to continue.
Define gas exchange.
Taking in oxygen and releasing carbon dioxide.
Explain the structure of the respiratory system.
• The two lungs fill the thorax.
• The mouth and nose lead to the trachea.
• The trachea splits into two bronchi, one leading to each lung.
• Bronchi divide into many bronchioles.
• Bronchioles lead to alveoli.
What keeps the trachea open?
C-shaped rings of cartilage.
What are the alveoli?
Small air filled sacs that have a wall consisting of a single layer of thin epithelial cells.
They are the site of gas exchange.
What do the walls of the bronchioles and alveoli contain?
Elastic tissue to allow for the expansion of the lungs during breathing.
What are the lungs surrounded by?
Pleural membranes, which contain the lungs and allow for expansion when breathing.
What encloses the chest cavity?
The ribs.
What connects the ribs to eachother?
They are connected to eachother by intercostal muscles.
What is the diaphragm?
A sheet of muscle that forms the floor of the chest cavity.
It separates the chest cavity from the abdominal cavity.
What does the process of ventilation involve?
Inspiration and expiration.
What does ventilation ensure?
That fresh air high in oxygen is brought into the alveoli when we breath in and carbon dioxide is removed when we breath out.
What 2 muscles does the process of inspiration involve?
• The diaphragm contracts causing it to move down.
• The external intercostal muscles contract causing the rib cage to move up and outwards.
How does elastic tissue assist in expiration?
It recoils, increasing the pressure in the lungs, helping to force air out.
What muscles are involved in forced expiration?
The internal intercostal muscles contract causing the rib cage to be pulled in and down more forcefully, expelling air more rapidly from the lungs.
What 2 muscles are involved in expiration?
• The rib cage relaxes causing it to move in and down.
• The diaphragm relaxes causing it to move up.
Define recoil.
The process where elastic tissues return to their original length after having been stretched/expanded.
Elastic tissue only recoils, it does not contract.
What are two other factors that help maximise the rate of diffusion?
• Alveoli walls are coated in a film of moisture. Oxygen dissolves in the water before diffusing across the epithelium of the alveoli. Pulmonary surfactant, produced by some cells in the wall of the alveoli, coats the epithelial cells and reduces the surface tension of water. This makes it easier for the lungs to inflate and stops the surfaces of the alveoli sticking together.
• Rate of diffusion increases with temperature, so body temperature helps to ensure maximum rate of diffusion.
