Gas exchange in humans Flashcards
which process takes place at the alveoli
gas exchange
Alveoli are surrounded by a….
a single layer of cells to minimise diffusion distance
What are the features of alveoli that make them an efficient exchange surface?
large total surface area
short diffusion distance
steep concentration gradient, maintained by a good blood supply and good ventilation
How is a steep concentration gradient for both oxygen and carbon dioxide maintained in the alveoli?
good ventilation supplies oxygen to the alveoli, and removes carbon dioxide from the alveoli
A good blood supply means that the blood immediately next to each alveolus is always low in oxygen and high in carbon dioxide
How does the oxygen and carbon dioxide content of inspired and expired air differ?
Inspired air contains a higher oxygen concentration than expired air
Inspired air contains a lower carbon dioxide concentration than expired air
Why is a large surface area important for gas exchange within the lungs?
it allows for faster diffusion of oxygen and carbon dioxide across the alveoli walls.
How can a student’s breathing rate at rest be calculated?
Count breaths over a minute
repeat several times to get an average - allows any anomalies to be identified and left out when calculating average
describe the alveoli
Alveoli are tiny air sacs surrounded by a network of capillaries
serving as the site of gas exchange between the air and the blood.
what is the function of the trachea/windpipe?
connects the nose and mouth to the lungs
What is the role of the bronchi?
The bronchi (singular bronchus) branch off the trachea and carry air into the right and left lungs
They contain mucus to trap dust and pathogens.
When investigating the effect of exercise on breathing rate, which variables should be kept constant?
the age and general fitness level of the students
students have all eaten similar meals at the same time prior to exercise
the type of exercise
the temperature of the room
When investigating the effect of exercise on breathing rate, how can consistency of exercise intensity be ensured for each repeat?
students should be given an exercise type where intensity can be measured
such as running at a set speed on a treadmill or cycling with a specific resistance
What is the function of cartilage in the trachea?
support the airways and keep them open during breathing
What is the role of the external intercostal muscles during ventilation?
to pull the ribcage up
This occurs when the external intercostal muscles contract during inhalation.
Define the term ventilation
movement of air into and out of the lungs during breathing.
What happens to the diaphragm during exhalation?
the diaphragm relaxes and moves upwards into its domed shape
What is the role of the internal intercostal muscles in ventilation?
pull the ribcage down
This occurs when the internal intercostal muscles contract during exhalation
