Gas exchange in human body Flashcards
The gas exchange surface if a a mammal is what?
Alveolus
Respiration depends on the diffusion of O2 and CO2. Diffusion occurs more rapidly if:
- There is a large SA exposed to the gas.
- The diffusion distance is short.
- There is a good blood supply.
There is a big difference in the concentrations of the has at two points brought about by ventilation.
The lungs are enclosed in the what?
Thorax.
The lungs are joined to what?
Joined to the back of the mouth by the trachea.
What does the trachea divide into?
Bronchi which enters the lungs and divides into bronchioles.
What do bronchioles end in?
Microscopic air sacs called alveoli.
What does the epiglottis do?
Sit at the top of the trachea to stop food and drink from entering air passages when we swallow.
What does the larynx do?
Manipulates pitch and volume.
What is the diagram?
A sheet of tissue that separates the thorax from the abdomen.
What do the ribs do?
Form a cage to protect the lungs and heart and to move to ventilate the lungs.
Process of expiration:
- internal intercostal muscles relax and external muscles contract, pulling the ribcage upwards and outwards.
- the diaphragm contracts, pulling downwards.
- volume in thorax increases, forcing lungs to expand and air pressure inside decreases.
- air is pushed into lungs.
Process of inspiration:
- external intercostal muscles relax and the internal intercostal muscles contract, pulling the ribcage downwards and inwards.
- diaphragm relaxes, moving back upwards.
- lungs are elastic and shrink back to their relaxed volume and the air pressure inside increases.
- air is pushed out of lungs.
Gas exchange in the lungs happens in the alveoli. Name features:
- Thin walls
- Large SA
- Moist surface
- Many blood capillaries
