Intro to the Respiratory System Flashcards
Describe the differences between pulmonary circulation and systematic circulation
Pulmonary circulation is the opposite in function to systematic circulation.
Pulmonary circulation delivers CO2 to the lungs and picks up oxygen to bring to the heart.
Funtion of the respiratory system
- Gas exchange – Oxygen added to the blood from the air, carbon dioxide removed from the blood into the air.
- Acid base balance – regulation of body pH (see renal lectures)
- Protection from infection – first line of defence
- Communication via speech – controlling the vocal chords in the larenx
How can the airway diameter, and therefore resistance to air flow be altered by activity of bronchial smooth muscle?
Contraction decreases diameter = increases resistance
Relaxation increases diameter = decreases resistance
What are the 3 exchanges in external respiration?
Exchange I - between the atmosphere and lungs
Exchange II - between lungs and blood
Exchange III - between blood and cells
What are the average volumes of gas exchanged per minutes?
250 ml oxygen exchanged (consumed)
200 ml carbon dioxide exchanged (produced)
What are the structural differences between the right and left bronchi?
R splits 3 times and is a more straight angle therefore aspirated foreign bodies lodge in the R bronchi
L splits 2 times and is in an acute angle.
What is anatomical dead space?
Air in the upper airways that cannot participate in gas exchange.
What is the average breathing rate?
Breathing rate is 10-20 breaths/min at rest, 40 - 45 at maximum exercise in adults
What is the function of the elastic fibres in the alveoli?
The elastic fibres allow the alveoli to stretch as they are filled with air during inhalation. They then spring back during exhalation in order to expel the carbon dioxide-rich air.
Why does gas exchange in the lungs with blood only occur at the alveoli?
They have thin walls, the walls of the upper airways are too thick to allow gas to cross and there function is purely conduction of air too and from the alveoli. The huge surface area of the alveoli futher enhances their gas exchange function.
Why is gas exchange important?
We need oxygen to produce energy and to keep our brain cells active, maintain the heart cells and give them energy = to keep our cells alive
Why is most resistance to airflow in the larger tubes such as the trachea and bronchi?
As the diameter of these airways does not increase in proportionate to the air molecules trying to flow through them.
Why is the net volume of gas exchanged in the lungs per unit time is equal to the net volume exchanged in the tissues.
This prevents gas build up in the circulation which would hamper gas exchange.
Helps to ensure supply = demand
