7 EXCHANGE - humans Flashcards
What is pulmonary ventilation?
volume of air taken in to the lungs in one minute (tidal volume x ventilation rate)
What is the tidal volume?
The volume of air in each breath
What is a spirometer?
Machine used to measure the volume of air breathed in and out
Pathway of air (IN)
Trachea, bronchus, bronchioles, alveoli
Adaptations of the lungs
- large surface area
- good consistent blood supply
- short diffusion pathway
- concentration gradient
Inspiration.
- Diaphragm contracts and flattens
- Intercostal muscle contracts and pushes ribcage upwards and outwards
- Pressure in lungs decreased and volume increased
- air is drawn in to the lungs
- active process
Expiration
- Diaphragm relaxes and flattens
- Intercostal muscles relax and move ribcage inwards and downwards
- pressure in the lungs is increased and the volume is decreased
- air is forced out the lungs
- passive process
Alveoli
Oxygen enters the alveoli and diffuses across the epithelium and then across the epithelium of the capilliaries down the concentration gradient
Adaptations:
- good blood supply: wrapped in lots of capilliaries, maintains a constant concentration gradient for o2 to diffuse down
- short diffusion pathway, alveoli walls are one cell thick and the epithelium of the capilliaries are one cell thick
- large SA:volume ratio, lots of o2 able to be transported unto the bloodstream
Trachea
Lining is made up of ciliated epithelial cells
Bronchus
Lobed structures which are highly branched
Bronchiole
Muscle lined walls: contrist to aid movement of air in and out of the lungs
Lung diseases
- tuberculosis
- asthsma
- emphysema
- fibrosis
Tuberculosis
- bacterial, lives in the lungs, communicable by droplets in the air
- prevents contraction of the lungs, affects the large surface area to volume ratio as the volume is decreased
Fibrosis
- Scar tissue in the lungs: affects large surface area to volume ratio as lungs do not contract and expand properly, decreasing the volume
- thickened alveoli: affects short diffusion pathway
Emphysema
- caused by smoking
- reduces the surface area of alveoli
Asthsma
- narrowing of the airways
- affects the concentration gradient
