lungs volume & capacity, neuromuscular activity of respration

2. 1. TIDAL VOLUME
• It is the volume of air which is normally inhaled
& exhaled in normal resting position.
• Volume:- 500 ml
• Out of 500 ml 350 reaches alveoli which is called
alveolar volume
• 150 remain in the anatomical dead space.
• Physiological dead space:- these are non
functional alveoli where gracious exchange not
takes place

4. 2. INSPIRATORY RESERVED VOLUME
• Volume of air which can be forcefully inhale
after normal inhalation.
• Volume:- 2000 ml-3000ml (2 lit-3 lit)
3. INSPIRATORY CAPACITY:-(IC)
That means tidal volume + inspiratory reserve
volume(IRV)
TV+IRV= 500+2000-3000 ml= 2500 to 3500 ml

5. 4. EXPIRATORY RESERVE VOLUME (ERV)
• It means after normal expiration if we can exhale
some more it is called expiratory reserve volume.
• It is the air which is normally present in our lungs
before inhalation
• Range:- 1000-1500 ml( 1100 ml average)
5. VITAL CAPACITY (VC):-
It is the or forceful exhalation after the forceful
inhalation
It means :-
normal breathing(TV)= 500ml+
Inspiratory reserve volume( IRV)=2000-3000 ml+
Expiratory reserve volume(ERV)= 500+2000-
3000+1100ml= 3500ml-4500 ml ( vital capacity)

6. 6. RESUDUAL VOLUME
• Volume of air that remain in the lungs after
forceful exhale
• (It means even after forceful exhalation some air
remain in the lungs that is known as reserve volume )
• Volume:- 1500 ml

7. 7.FUNCTIONAL RESIDUAL VOLUME
• It means in general condition how much air
which is always their in lungs during gascious
exchange.
• RV+ERV=1100+1500ML=2500ML

8. 10. TOTAL LUNGS CAPACITY
• It means how much of air can be there in total
• TLC=VC+RV=3500-4500+1500=5000-6000ML

9. 9. MINUTE RESPIRATORY VOLUME
• It means how much of air goes through the lungs
in a minute.
• 500 ml in every normal breath* 12 times
approximately in a minute=500*12=6000ml or 6 lit
10. ALVEOLAR VENTILATION:-
• Out of 500 ml of air that taken in the normal
respiration 350 reaches the alveoli & 150 ml
remain in the dead space
• 350 ml *12 time respiration=4200 ml
• So alveolar ventilation in one minute is 4200 ml.

10. Air which always
remain in lungs
TV,IRV,ERV
Forceful
inspiration
VC+RV=6000

11. CONTROL OF RESPIRATION
• Effective control of respiration enables the
body to regulate blood gas level over a wide
range of physiological environmental &
pathological condition.
• Voluntary control is exerted during activities
such as speaking & singing but is overridden if
blood co2 raise.

12. The respiratory centre
• Respiratory centre present in medulla which control
rate & depth of breathing.
• Regular discharge of inspiratory neurones within this
centre set the rate & depth of breathing
• Activity of the respiratory rhythmicity centre is
adjusted by nerve in the Pons ( the pneumotaxic
centre & apneustic centre ) in response to input
from other parts of the brain.
• Motor impulses leaving the respiratory centre pass
in Phrenic & intercostal nerves to the diaphragm &
intercostal muscle to stimulate respiration

15. chemoreceptor's
• These are receptors that respond to changes in
the partial pressure of oxygen & Carbon dioxide
in the blood & CSF.
• Central chemoreceptor's:- located on the surface
of medulla oblongata & are bathed in CSF.
• When arterial PCO2 rise (hypercapnia) the
central chemoreceptor by stimulating the
respiratory centre which increase the ventilation
to reduce the PCO2

16. Cont..
• Peripheral chemoreceptor's:- these are situated
in the arch of aorta & in the carotid bodies.
• They respond to change in the blood co2 & o2
level.
• It is more sensitivity to CO2 then O2.
• Change in the co2 & o2 level activate these
receptors trigger the nerve impulse to the
respiratory centre via the glossopharyngeal &
vagus nerve.
• This stimulation raise the rate & depth of the
respiration