Gas exchange in humans Flashcards
state the features of gas exchange surfaces
in humans
large surface area
thin surface
good blood supply
good ventilation with air
Why does the gas exchange surface in humans have a large surface area?
to allow faster diffusion of gases across the surface
Why does the gas exchange surface in humans have a thin surface?
to ensure that diffusion distances remain short
Why does the gas exchange surface in humans have a good blood supply?
to maintain a high concentration gradient so diffusion occurs faster
Why does the gas exchange surface in humans have good ventilation with air?
this is so diffusion gradients can be maintained
State the function of cartilage in the trachea
Cartilage is a connective tissue that is found in many parts of the body, including the trachea.
In the trachea, cartilage plays several important functions, including:
Providing structural support: The rings of cartilage in the trachea help to keep the airway open and prevent it from collapsing or becoming obstructed. This is important for maintaining a clear airway and allowing air to flow freely in and out of the lungs.
Allowing flexibility: Although the rings of cartilage provide support, they are also flexible enough to allow the trachea to move and stretch as needed. This allows the trachea to adjust to changes in the body, such as during breathing or swallowing.
Preventing compression: The rings of cartilage in the trachea are shaped like a “C” with the open part facing towards the back of the body. This shape helps to prevent compression of the trachea by surrounding structures, such as the oesophagus, which lies directly behind it.
Overall, the cartilage in the trachea plays a vital role in maintaining a clear and open airway, allowing air to flow freely in and out of the body.
Explain the role of the ribs
bone structure that protects internal organs like the lungs
Explain the role of the internal and external intercostal muscles
Muscles between the ribs which control their movement causing inhalation and exhalation
Explain the role of the diaphragm
sheet of connective tissue and muscles at the bottom of the thorax that helps change the volume of the thorax to to allow inhalation and exhalation
Describe the differences in composition between
inspired and expired air, limited to: oxygen,
carbon dioxide and water vapour
Inspired and expired air differ in their composition with respect to their levels of oxygen, carbon dioxide, and water vapor. Here are differences between the two:
Oxygen (O2): Inspired air contains about 21% oxygen, while expired air contains about 16% oxygen. During inhalation, oxygen is taken up by the body for use in cellular respiration, which produces energy in the form of ATP. As a result, the concentration of oxygen in expired air is lower than that in inspired air.
Carbon dioxide (CO2): Inspired air contains only about 0.04% carbon dioxide, while expired air contains about 4% carbon dioxide. During cellular respiration, carbon dioxide is produced as a waste product and is expelled from the body during exhalation. This results in the higher concentration of carbon dioxide in expired air.
Water vapor: Inspired air is relatively dry, with a low water vapor content. However, during respiration, water vapor is added to the air as it passes through the moist surfaces of the respiratory tract. This results in the higher water vapor content in expired air.
Overall, the main differences in composition between inspired and expired air are due to the processes of gas exchange and water vapor addition that occur during respiration. Inspired air contains a higher concentration of oxygen and a lower concentration of carbon dioxide and water vapor, while expired air contains a lower concentration of oxygen and a higher concentration of carbon dioxide and water vapor.
Explain the differences in composition between
inspired and expired air
Inspired and expired air differ in their composition due to the processes that occur during respiration. Here are some of the main differences in the composition of inspired and expired air:
Oxygen (O2) and Carbon Dioxide (CO2) levels: Inspired air contains a higher concentration of oxygen (about 21%) than expired air (about 16%). During respiration, oxygen is taken up by the body and converted to carbon dioxide, which is then exhaled. Therefore, expired air contains a higher concentration of carbon dioxide (about 4%) than inspired air (about 0.04%).
Water vapor content: The air we breathe in is generally dry, with a low water vapor content. However, during respiration, water vapor is added to the air as it passes through the moist surfaces of the respiratory tract. As a result, expired air has a higher water vapor content than inspired air.
Nitrogen (N2) levels: Nitrogen is the most abundant gas in the atmosphere, making up about 78% of the air we breathe in. During respiration, nitrogen is not used or produced, and its concentration remains the same in both inspired and expired air.
Other gases: There are trace amounts of other gases in the air, such as argon, helium, neon, and methane. These gases make up only a very small percentage of the air we breathe and their concentrations remain relatively constant in both inspired and expired air.
