6.6 - Human Gas Exchange System Flashcards
An introduction to the gas exchange system The structure and function of the ciliated epithelium The structure and adaptations of the trachea, bronchi and bronchioles The structure and adaptations of the alveoli (21 cards)
What does the human gas exchange system consist of?
VEEEERY simply (like basics)
Lungs and air passages
What is the function of the gas exchange system?
Allows:
- oxygen to enter
- carbon dioxide to leave
- ( the blood )
Where are the lungs located?
Thoracic cavity
Why is the gas exchange system located inside the body?
Air is not dense enough
What is the pathway of air through the respiratory system? Check
Trachea
What tissue is located throughout most of the airways?
Ciliated epithelium
What cells does the ciliated epithelium contain?
Goblet cells and ciliated epithelial cells
What do goblet cells do?
Produce mucus
What do cilia on epithelial cells do?
Waft mucus upward
What are the adaptations of the trachea? Check
Cartilage rings
What are the adaptations of the bronchi?
Name 2
- Reinforced with cartilage to keep the airway open.
- Smooth muscle can contract or relax to constrict or dilate the airway and change airflow.
- Elastic tissue contains elastic fibres with elastin that allows stretching and recoiling.
- Lined with ciliated epithelial cells and goblet cells.
What are the adaptations of the bronchioles?
Name 1
- No cartilage, can change shape.
- Smooth muscle can contract or relax to constrict or dilate the airway and change airflow.
- Elastic tissue contains elastic fibres with elastin that allows stretching and recoiling.
- Simple squamous epithelium (only larger bronchioles have a ciliated epithelium).
What are alveoli?
Tiny air sacs at the end of bronchioles
What surrounds alveoli?
Capillaries
How does gas exchange occur in alveoli?
Oxygen diffuses into blood and Carbon Dioxide into the alveoli
What are the adaptations of alveoli for gas exchange?
Name 3
Wall consists of one layer of squamous epithelial cells - This allows rapid diffusion.
Large surface area - This increases rate of gas exchange.
Partially permeable - This means that only certain gases can move across the wall.
Surrounded by dense network of capillaries - These bring blood close to air for gas exchange.
Ventilation of air - This maintains steep diffusion gradient.
Elastic fibres - These allow stretching and recoiling.
Collagen fibres - These contain strong collagen that prevents alveoli from bursting and limits overstretching.
* Moist inner surface - This allows gases to dissolve, and lung surfactant helps alveoli remain inflated.
What are the pulmonary blood vessels?
Pulmonary artery
Pulmonary vein
What does the pulmonary artery do?
Delivers deoxygenated blood to capillaries
What does the pulmonary vein do?
Delivers oxygenated blood to heart
What do pulmonary capillaries do?
Gas exchange
What are the adaptations of pulmonary capillaries for gas exchange?
name 2
Thin walls (one endothelial cell thick) - This maintains a short diffusion distance.
Red blood cells pressed against capillary walls - This reduces diffusion distance.
Large surface area - This increases diffusion speed.
Movement of blood - This maintains steep diffusion gradient.
Slow blood movement - This allows more time for diffusion.
