Physiological change with aging on lung volume &

capacity

Done by;; saja . H.S

Physiological change with ageing on lung volume &

capacity

• In order for us to understand the lung volumes & capacity changes with age we have to revise them in brief so we can get the idea..

• Lets GOOOOOOOOOOO

Lung volumes1 -Tidal volume (VT) is the volume of air

inspired or expired in each respiratory cycle during normal quiet breathing i.e. under resting conditions. It is normally around 1.2L at age 25 and gradually increases with age due to loss of lung elasticity. Less elastic lungs are more distensible and also have reduced recoil during expiration. This results in 'air trapping'. A typical 70-year-old's RV will have increased to around 1.8L

2- Inspiratory reserve volume (IRV) is the volume of air which can be inspired by maximal inspiration after a normal inspiration.

Cont..

3 -Expiratory reserve volume (ERV) is the volume of air which can be expired by maximal expiration after a normal expiration .

4 -Residual volume (RV) is the volume of air remaining in the lungs after maximal expiration .

Lung capacities

Any volume that is a combination of other volumes

is called a “capacity”

1 -Inspiratory capacity (IC) is the volume of air taken

by maximal inspiration after a normal expiration

2 -Functional residual capacity (FRC) is the volume

of air remaining in the lung after a normal

expiration.

3 -Vital capacity (VC) is the maximal volume of air

exhaled from the point of maximal inhalation or the maximal

volume of air inhaled from a point of maximal exhalation.

In an average male aged 25 this is around 5L, declining to around 3.9L at

age 65. A similar decline is seen in females, from an average of

around 3.5L at 25 to around 2.8L at 65 . These reductions in VC are

primarily due to the gradual increase in chest wall rigidity and loss of

respiratory muscle strength described above.

4 -Total lung capacity (TLC) is the volume of air contained in the

lungs at the end of maximal inspiration.

Cont..• 4-Total lung capacity (TLC) is the total

volume of air within the lungs following a full inspiration. In an average male it is around 6L and in an average female around 4.2L. The TLC does not change significantly throughout life. It has been hypothesised that this is because the reduction in lung elasticity is counterbalanced by the increased rigidity of the chest wall.

• CHANGE IN Tidal volume through age :

• in the absence of pathology, does not change significantly with age. But, because of increased chest wall rigidity and reduction in lung elasticity, it is estimated a 60-year-old will expend 20% more energy during normal breathing than a 20-year-old

Finished with the adults common changes now we will move on to the change in neonatal population ..

HANG ON

Numbers of alveoli..• A full term infant, at delivery

has approximately 50 million alveoli.

• The number will increase SIX fold by the age of 8 approximately up to 300 million alveoli.

• relationship between the FRC and body length of a considerable number of neonates, infants and toddlers. Let us start with the neonate and first The FRC in a healthy neonate who measures 50 cm from crown to heel is on average 80 mL. That is the contents of about ½ a coffee cup.

Lung elasticity, thorax and age• The lung and thorax become stiffer

(more elastic) from birth to adolescence.

• These changes are accompanied by an absolute and relative increase in FRC.

• From adolescence to old age the lung becomes more flaccid.

• As the lung loses elasticity its relaxed volume increases; this also holds for the FRC.

• The graph discloses that the FRC increases linearly with body height. In a 6-year old with a standing height of 120 cm the FRC has increased to about 900 mL.

•THANQ