Human Gas Exchange and Ventilation Flashcards
What is breathing?
Movement of air into and out of the lungs
What is ventilation?
The scientific word for breathing.
What is respiration?
Chemical reaction to release energy in the form of ATP.
What is gas exchange?
The diffusion of oxygen from the air in the alveoli into the blood and of carbon dioxide from the blood to the air in the alveoli.
What does the trachea have as structural support?
Cartilage rings within it (C-shaped rings) that are tough to support the tube to keep the windpipe open.
What is the diaphragm?
Muscle under the lungs.
What do the antagonistic muscles do?
Contract or relax
Where are the external intercostal muscles?
Between the ribs.
What do the external intercostal muscles do during inspiration?
Contract pulling the ribcage up and outwards which provides a bigger volume in the thorax.
Whilst the EIM contract, what do the IIM do?
Relax
During expiration what do the internal intercostal muscles do?
Relax and pull the ribcage back in and down to decrease the volume in the thoracic cavity.
Whilst the IIM contract, what do the IIM do?
Relax
What are alveoli?
Air sacs
What are the alveoli surrounded by?
A capillary network.
How do alveoli have a short diffusion pathway?
They are made up of a single layer of cells and so is the capillary thus there is a short diffusion pathway.
How do alveoli have a large surface area?
There are many of them in the lungs.
How does oxygen move from the alveoli?
It diffuses from the alveoli, across the epithelium and into the blood.
How do the alveoli maintain their concentration gradient?
They are surrounded by a network of capillaries which maintains a constant concentration gradient and removes exchanged gases.
Explain the essential features of the alveoli that make it adapted as a surface for gas exchange.
- Flattened cells/1 cell thick - short diffusion distance.
- Folded - large surface area
- Permeable - allows diffusion of oxygen and carbon dioxide.
- Moist - gases can dissolve for diffusion.
- Good blood supply from large network of capillaries - maintains concentration gradient.
Describe how gas exchange occurs in the lungs.
- Oxygen diffuses from the alveolar air space into the blood down its concentration gradient. Across the alveolar epithelium then across capillary endothelium.
- Carbon dioxide is the opposite.
Explain the importance of ventilation.
Brings in air containing higher conc of oxygen and removes air with lower conc of oxygen. Maintaining conc gradient.
Describe inspiration.
Diaphragm muscles contract and flatten.The EIM contract and IIM relax. Ribcage is pulled up and out. Air moves into lungs down pressure gradient.
What is inspiration?
Breathing in.
Describe expiration.
Diaphragm muscles relax and move upwards. EIM relax and IIM may contract. Ribcage moves inwards and down. Volume decreases and pressure increases (above atmospheric pressure) in thoracic cavity. Air moves out of lungs down pressure gradient.
