Exchange and Transport Flashcards
Name one type of epithelial tissue found in the lungs.(1)
squamous / ciliated;
Explain why the lungs can be considered to be an organ. (2)
(organ is) a collection of tissues / named tissues;(working together) to enable gas exchange / AW;
Outline the mechanism of inspiration. (3)
diaphragm / intercostal muscles, contract:
diaphragm moves down / ribs move upwards and outwards;
volume of thorax increased;
pressure inside thorax falls;
to below atmospheric pressure (so air enters lungs);
A person breathes through the mouthpiece of a spirometer. State what happens to the air chamber during inspiration. (1)
it falls/ goes down;
Suggest a chemical that could be used in a spirometer to absorb carbon dioxide. (1)
soda lime/ sodium hydroxide / potassium hydroxide /
calcium hydroxide;
Explain why a person using the spirometer to measure their vital capacity should wear a nose clip. (2)
to ensure all air breathed comes from chamber
OR
to prevent, escape of air / entry of air, through nose;
make results invalid;
State three precautions that should be taken when using a spirometer to measure vital capacity.
- wear nose clip
- use (medical grade) oxygen / fresh air;
- disinfect mouthpiece;
- ref. to health of subject;
e.g. asthmatics - ref to correct functioning of equipment;
e.g. maintain constant temperature (so that volume of gases is not affected)
ensure, valve / hinge, is working
level of water correct
no leaks / airtight / lips sealed around mouthpiece
what are the four things in common in all effective gas exchange surfaces?
- increased SA
- thin layers
- good blood supply
- good ventilation
why is it important to maintain a good blood supply in an exchange surface?
in order to maintain a steep concentration gradient for diffusion of substances
what is the journey that air takes through the mammalian gaseous exchange system?
nasal cavity trachea bronchus bronchioles alveoli
features of the nasal cavity
- large SA with good blood supply
- –> warms the air to body temp
- hairy lining
- –> secretes mucus to drap dust and bateria, protecting delicate lung tissue
- moist surfaces
- –> increase humidity of incoming air, reducing evaporation from exchange surfaces
structure of mammalian trachea
- wide tube supported by incomplete rings of strong, flexible cartilage —- stops the trachea from collapsing,
- ciliated epithelium
- goblet cells
why are the cartilage rings of trachea incomplete?
so as not to break the oesophagus when food moves down
what does mucus do in the trachea?
beats rhythmically and moves the mucus (along with trapped dust and pathogens) away from the lungs towards the mouth where it is swallowed and digested
structure of bronchus
- cartilage rings
- smaller than trachea
structure of bronchioles
- no cartilage
- smooth muscle —-> allows bronchioles to constrict when it contracts and dilate when it relaxes, so controls the amount of air reaching the lungs
- flattened epithelium
structure of alveoli
- thin, flattened epithelial cells
- a little collagen and elastic fibres —–> allow alveoli to stretch as air is drawn in and squeeze air out as they return to their resting size ELASTIC RECOIL
- lined with lung surfactant —–> ensures alveoli remain inflated by coating
adaptations of alveoli for effective gaseous exchange
- large SA
- thin layers
- good blood supply (capillaries)
- good ventilation