Week 7 - Respiration during Exercise Flashcards
What is the primary purpose of the respiratory system?
to maintain arterial blood-gas homeostasis
How does the respiratory system maintain arterial blood-gas homeostasis? (4-step process)
- Pulmonary ventilation
- Alveolar gas exchange
- Gas transport
- Systemic gas exchange
Oxygen rich air breathed in from the atmosphere whilst CO2 rich air is expired (pulmonary ventilation).
Oxygen the moves into the blood from the alveoli (alveolar gas exchange).
Blood containing 02 is then transported around the body (gas transport) where oxygen moves into systemic cells, such as muscles (systemic gas exchange).
How can we separate the structural organization of the respiratory system?
The upper and the lower respiratory tract separated by the epiglottis.
What does the upper respiratory tract include?
Nose, nasal cavity and the pharynx
What does the lower respiratory tract include?
airways - larynx, trachea, bronchus, bronchioles, terminal bronchioles
How is the functional organization of the respiratory system divided?
Conduction zone and respiratory zone
What is the role of the Conduction zone?
conducts air in and out the lungs - includes nose to the terminal bronchioles
Where do we define the end of the conducting zone?
16th airway generation which is the terminal bronchioles
What is the difference between the conduction zone and the respiratory zone of the respiratory system functional organization?
The respiratory zone contains alveoli which is where gas exchange takes place.
What is the role of the respiratory zone?
its where the transport and diffusion of gases along the pulmonary (lung) capillary takes place with 02 moving into arterial blood and C02 moving out.
Match the key term to the description.
Key terms: parietal pleura, visceral pleura, pleural cavity.
a) outside of the pleural cavity
b) deepest layer which covers the lungs directly
c) area that contains small amounts of fluid which prevents friction when the lungs move and expand
a) visceral pleura
b) pleural cavity
c) parietal pleura
Intrapleural pressure < atmospheric pressure, what does this prevent?
the alveoli from collapsing
What are the lungs enclosed within?
membranes called pleura
How many airway generations are there?
23
Where does gas exchange occur?
in the respiratory zone (Z17-23)
In terms of airways, where does the conducting zone start and extend to?
starts at the main bronchi (Z1) and extends to the terminal bronchioles (Z16)
- large conductors
- resistance higher
How many alveoli does the human lung contain?
300-500 million - each 1/3mm in diameter
Where does pulmonary gas exchange take place across?
the pulmonary capillary
- very thin and vast surface area which makes it ideal for gas exchange/diffusion
How does oxygen and carbon dioxide move between air (alveoli) and blood?
by simple diffusion (from high to low partial pressure)
- Oxygen moves from alveoli to pulmonary artery
- Carbon dioxide moves from venous blood to alveolus (to then expire).
Explain the two types of alveolar cell (pneumocytes).
Type 1 cells cover 95% of the internal surface of the alveolus and are critical for gas exchange.
Type II cells release surfactant - a molecule that lowers the surface tension (like soap) and prevents the alveoli collapsing.
What is the volume of gas passing through a sheet dependent upon?
- Surface area (A)
- Thickness (T)
- Diffusion coefficient (D)
- Pressure gradient (alveolar to arterial)
What is Fick’s law of diffusion?
Rate of diffusion is proportional to SA/thickness x diffusion coefficient x pressure gradient
What are the 5 layers of the pulmonary capillary that gas has to diffuse across (from alveolus) in order to enter the erythrocyte?
- Surfactant
- Alveolar epithelium
- Interstitium
- Capillary endothelium
- Plasma
What are the mechanisms of breathing concerned with?
the movement of air into and out of the lungs by changes in pressure (contraction force), flow (contraction velocity), and volume (contraction length)
