Gas exchange in humans Flashcards
Where is the gas exchange system located?
Thorax
When we breathe in, where does air pass down?
Trachea
What is the trachea surrounded by?
C shaped rings of cartilage
What does the cartilage do?
Keep the trachea open and make swallowing easier
What does the trachea split to form?
The two bronchi
What are the bronchi surrounded by?
Cartilage rings
What do the bronchi divide into?
Smaller tubes called bronchioles
What is at the end of each bronchiole?
Microscopic air sacs called alveoli
What are alveoli the site of?
Gas exchange
What are the lungs surrounded by?
The pleural membrane
What is there in between the membranes?
Pleural fluid
What do the pleural fluid and the pleural membrane do?
Form an air tight seal and prevent the lungs from sticking to the thorax
What do the ribs protect?
The organs in the thorax
What do intercostal muscles do?
Connect the bones and help in moving air into and out of the lungs
What is the diaphragm?
A dome sheet of muscle which is important in moving air into and out of the lungs
Where does gas exchange occur?
In the alveoli
How is the alveoli specialised for efficient gas exchange?
It has a large surface area due to enormous number of them
They are surrounded by a network of capillaries
What do the network of capillaries around alveoli do?
Constantly carry deoxygenated blood to the alveolus and move oxygenated blood away which maintains a high concentration gradient and so speeds up diffusion
How thick are the walls of the alveoli?
Only one cell thick
How thick are the capillary walls next to the alveoli?
Only one cell thick
What are the benefits of the alveoli and capillary walls being only one cell thick?
Gases only need to move a very small distance speeding up diffusion
Where does oxygen diffuse into and from?
The red blood cells from the air
What does oxygen bind with for transport?
Haemoglobin
What is carbon dioxide carried in in the blood?
Plasma
How much less oxygen and carbon dioxide does the air leaving the lungs contain compared to the air entering the lungs?
4% less oxygen and 4% more carbon dioxide
What does our breathing rate do during exercise?
Increase
Why does breathing rate remain high after exercise if we respire anaerobically?
To supply the extra oxygen needed to oxidise lactic acid
How do you measure breathing rate?
Count the number of breaths per minute
How do you measure breathing depth?
Use a spirometer (measure volume of air inhaled and exhaled)
How many harmful chemicals do cigarettes contain?
Over 4000
What is nicotine?
A highly addictive drug
How many carcinogens are there in tobacco smoke?
17 including tar
What potential damage can chemicals in tobacco smoke cause?
Altered DNA and increased risk of cancer
Carbon monoxide binds to haemoglobin reducing amount of oxygen transported
Cilia are destroyed
Mucus production will increase and cannot be removed due to damaged cilia causing bronchitis
Damage to alveoli decreasing surface area for gas exchange leading to emphysema
