4.5 Breathing And Gas Exchange Flashcards
Describe how air is moved in and out of the lungs.
Air is moved in and out of the lungs by the contraction and relaxation of the intercostal muscles and the diaphragm, changing pressure inside the chest cavity
What is meant by the term “gaseous exchange”?
The exchange of oxygen and carbon dioxide between the air in the lungs and the bloodstream.
Why is ventilation important for your body?
Ventilation supplies oxygen to the body and removes waste carbon dioxide from the blood.
What is the difference in the composition of gases when you breathe in compared to when you breathe out?
When breathing in, the air contains approximately 80% nitrogen, 16% oxygen, and 4% carbon dioxide
Why is there less oxygen in exhaled air compared to inhaled air?
Oxygen is absorbed by the bloodstream from the lungs during gas exchange, leaving less oxygen in the exhaled air
Describe the adaptations of the alveoli and explain how they make gas exchange efficient.
- The alveoli provide a large surface area
- Have thin walls (only one cell thick)
- surrounded by capillaries with rich blood supply
- these adaptations create a steep concentration gradient and allow rapid diffusion of gases
Describe the passage of air to the lungs
Nose —> trachea —> bronchi —> bronchioles —> alveoli —> blood
How does the diaphragm contribute to ventilation?
The diaphragm contracts and flattens to increase the volume of the chest cavity during inhalation and relaxes to decrease the volume during exhalation, causing air to flow in and out of the lungs
What happens to the pressure inside the chest cavity when you inhale?
The pressure decreases as the chest cavity expands, allowing air to flow into the lungs
How does oxygen move from the alveoli into the blood?
Oxygen diffuses across the thin walls of the alveoli into the blood, where it binds to the haemoglobin in red blood cells
How is carbon dioxide removed from the bloodstream?
Carbon dioxide diffuses from the blood into the alveoli and is expelled from the lungs during exhalation
What role do the intercostal muscles play in ventilation?
The intercostal muscles contract to raise the ribs and expand the chest cavity during inhalation and relax to lower the rubs during exhalation
What is the purpose of maintaining a steep concentration gradient in the lungs?
A steep concentration gradient ensures efficient diffusion of oxygen into the blood and carbon dioxide out of the blood
What gases are exchanged in the alveoli during breathing?
Oxygen is absorbed into the blood, and carbon dioxide is released from the blood into the air from the lungs
