Gas exchange in humans Details Flashcards
Features of gas exchange surfaces in humans
-Large surface area(allows for more efficient diffusion)
-Thin surface(short diffusion distance so gas exchange happens quicker)
-Good blood supply(maintains concentration gradient by carrying away substances which have diffused across already)
-Good ventilation with air
In the presence of carbon dioxide, the colour of limewater goes from…
colourless to milky
Percentage of nitrogen in inhaled air
78%
Percentage of nitrogen in exhaled air
78%
Percentage of oxygen in inhaled air
21%
Percentage of oxygen in exhaled air
16%
Percentage of carbon dioxide in inhaled air
0.04%
Percentage of carbon dioxide in exhaled air
4%
Level of water vapour in inhaled air
Lower than level of water vapour in exhaled air
Level of water vapour in exhaled air
Higher than level of water vapour in inhaled air
Effect of physical activity on the rate and depth of breathing
Rate and depth of breathing increases
Reason why physical activity increases the rate and depth of breathing
-Physical activity causes muscles to increase their rate of respiration
-Greater amount of oxygen needed for increased rate of respiration
-More carbon dioxide is also produced which diffuses into the blood, which causes the acidity of the blood to increase
-Brain detects this and signals for the rate and depth of breathing to increase
-Increased rate of breathing allows the rate of gas exchange to increase(expelling more carbon dioxide while taking in more oxygen)
Function of lungs
Contain the surfaces where gas exchange takes place(main organs of the respiratory system)
Function of intercostal muscles
External and internal intercostal muscles work antagonistically in pairs to expand and contract the rib cage during breathing
Function of ribs
Protect the lungs and heart from physical damage
Function of larnyx
Contains the vocal chords
Function of trachea
Connects the throat to the bronchi
Function of cartilage rings around the trachea
-Provide structural strength
-Keep the trachea open(so that air can pass through it)
Function of bronchi
Carry air from the trachea to the lungs(bronchioles)
Function of bronchioles
Carry air to the alveoli
Function of alveoli
Site of gas exchange(covered by capillary network; oxygen diffuses into the capillaries, while carbon dioxide diffuses out. Waste products are then breathed out)
During inhalation, the external intercostal muscles…
contract
During inhalation, the internal intercostal muscles…
relax
During inhalation, the diaphragm…
lowers/flattens(contracts)
During inhalation, the volume of the thorax…
increases
During inhalation, air…
diffuses into the lungs
(REMEMBER: IT DOES NOT GET SUCKED IN)
Why air diffuses into the lungs during inhalation
When the volume of the chest increases, there is a lower concentration of air in the lungs than outside them, so air diffuses in
During exhalation, the internal intercostal muscles…
contract
During exhalation, the external intercostal muscles…
relax
During exhalation, the volume of the thorax…
decreases
During exhalation, the diaphragm…
rises(relaxes)
Location of goblet cells
Found in the trachea and bronchi
Function of goblet cells
Produce and secrete mucus into the respiratory tract
Function of ciliated cells
Move foreign pathogens and particles(which are trapped in the mucus) towards the throat(so that the mucus can be swallowed, and the foreign pathogens and particles can be destroyed in the acidic conditions of the stomach)
Function of mucus
Trap foreign particles and pathogens(by sticking to them)
