Gas exchange Flashcards
How does the stomata open and close?
- To close the stomata, the guard cells lose water and return to a limp state
- the guard cells can open the stomata by taking up lots of water, causing them to swell
What colour does hydrogencarbonate turn with high and low levels of Co2?
- high=yellow
- low-purple
How are the trachea and bronchi adapted for breathing?
-contain rings of cartilage, which gives support to keep them open but is also flexible to allow movement for breathing
How do we inhale?
- INSPIRATION
- The diaphragm contracts and becomes flattened.
- The internal intercostal muscles relax and the external intercostal muscles contract, moving the ribcage up and out.
- The thorax volume increases, forcing air into the lungs because of decreased internal pressure
How do we exhale?
- EXPIRATION
- The diaphragm relaxes and becomes dome-shaped.
- The internal intercostal muscles contract and the external intercostal muscles relax, moving the ribcage downwards and in.
- The thorax volume decreases, increasing internal pressure.
- Air is forced out of the lungs
What is the pulmonary artery?
-transports deoxygenated blood to the lungs
What is the pulmonary vein?
-transports oxygenated blood throughout the body
What is the pleural membrane?
-a thin moist membrane that lines the inside of the ribcage
What surrounds alveoli?
- a network of capillaries, allowing for oxygen and carbon dioxide to be exchanged between the blood in the capillaries and the air in the lungs
How are exchange surfaces such as alveoli adapted for their role?
- large surface area allows more of a substance to diffuse at the same time
- high blood supply to maintain a high concentration gradient by bringing in new blood as diffusion starts to even out the concentrations
- ventilation to maintain a high concentration gradient and increase the rate of exchange
- thin membrane increases rate of diffusion, alveoli are 1 cell thick
- they have goblet + cilia cells which produce sticky mucus that traps particles and cilia cells waft the mucus up and out of the airway (kept clear)
How do the alveoli work?
- Deoxygenated blood arrives into the alveolus.
- In the alveolus, oxygen and carbon dioxide are exchanged between the blood in the capillaries and the air in the lungs.
- Oxygenated blood leaves the alveolus
What does lime water turn when CO2 is present?
-cloudy
How does the body respond to exercise?
- the increased rate of respiration in cells creates a higher concentration of carbon dioxide in the blood.
- The brain detects this and causes breathing to become deeper and faster.
- This means more carbon dioxide can be breathed out at a quicker rate (and more oxygen is also breathed in)
How can we investigate breathing?
-using a piece of equipment called a spirometer
-The closer together the waves shown by the spirometer, the faster the breathing rate.
The higher the waves, the deeper the breaths
What harmful substances do cigarettes contain?
-nicotine, carbon monoxide and carcinogens (cancer-causing chemicals).
