The document discusses respiratory volumes and capacities. It defines various lung volumes including tidal volume, inspiratory reserve volume, inspiratory capacity, functional residual capacity, expiratory reserve volume, residual volume, vital capacity, and alveolar ventilation rate. It explains that tidal volume is around 500ml per breath and vital capacity is the total lung volume and is around 4800ml. The document also discusses factors that influence respiratory rate and depth such as carbon dioxide levels, oxygen levels, temperature, exercise and emotions.

1. Respiratory Volumes and Capacities
Prepared by
Mr. Abhay Rajpoot
HOD (Dep. of Medical Surgical)
abhayrajpoot5591@gmail.com

2. The word respiration means a complete cycle i.e. one inspiration and
one expiration. Normal breathing average rate is 15 complete
respiratory cycles per minute, During respiration 6 liters of air moves
in and out. The apparatus used to measure the volume of air
exchanged is called spirometer or respirometer.
About 500ml of air is exchanged during an inspiration and expiration
cycle.
Respiratory Volumes and Capacities

3. Respiratory Volumes and Capacities
Tidal volume (TV): This is the volume of the air passing into and out of
the lungs during one breath. It is about 500ml.
Inspiratory reserve volume (IRV): This is the amount of air, which can be
inhaled into the lungs, after forceful inspiration. It is about 3100ml.
Inspiratory capacity (IC): It is the inspiratory ability of the lungs. It is the
sum of inspiratory reserve volume (3100ml) and tidal volume (500ml)
and total is 3600ml.

4. Functional residual capacity (FRC): This is the amount of air that remains inside the air
passage and alveoli at the end of expiration. The composition of the alveolar air
changes because the tidal air mixes with this air. It is the sum of residual volume and
expiratory reserve volume (2400 ml). The functional residual volume also prevents
collapse of the alveoli on expiration.
Expiratory reserve volume (ERV): This is the amount of air which can be exhaled from
the lungs, during maximal expiration. It is about 1200 ml.
Residual volume (RV): It is the amount of air which remains inside the lungs after
forceful expiration. This cannot be measured by a spirometer. It is about 1200 ml.
Respiratory Volumes and Capacities

5. Respiratory Volumes and Capacities
Vital capacity (VC): It is the sum of the inspiratory reserve volume, tidal volume and expiratory
reserve volume (4800 ml)
VC = Tidal volume +IRV + ERV
Alveolar ventilation rate (AVR): It is the volume of air chat moves into and out of alveoli per
minute. It is equal to the total volume minus the anatomical dead space, multiplied by respiratory
rate.
Anatomical dead space:
Alveolar ventilation = (TV anatomical dead space x respiratory rate)
= (500-150) mlx.15 per min.
= 5.25 liters per minute

6. Respiratory Capacities

7.  Sounds are monitored with a
stethoscope
 Bronchial sounds – produced by
air rushing through trachea and
bronchi
 Vesicular breathing sounds – soft
sounds of air filling alveoli
Respiratory Sounds

8.  Oxygen movement into the blood
The alveoli always has more oxygen
than the blood
Oxygen moves by diffusion towards the
area of lower concentration
Pulmonary capillary blood gains oxygen
External Respiration

9.  Carbon dioxide movement out of the blood
 Blood returning from tissues has higher concentrations of
carbon dioxide than air in the alveoli
 Pulmonary capillary blood gives up carbon dioxide
 Blood leaving the lungs is oxygen-rich and carbon
dioxide-poor
External Respiration

10.  Oxygen transport in the blood
Inside red blood cells attached to
hemoglobin (oxyhemoglobin
[HbO2])
A small amount is carried dissolved
in the plasma
Gas Transport in the Blood

11.  Carbon dioxide transport in the blood
Most is transported in the plasma as
bicarbonate ion (HCO3
–)
A small amount is carried inside red blood
cells on hemoglobin, but at different
binding sites than those of oxygen
Gas Transport in the Blood

12.  Exchange of gases between blood and body cells
 An opposite reaction to what occurs in the lungs
Carbon dioxide diffuses out of tissue to blood
Oxygen diffuses from blood into tissue
Internal Respiration

13. Internal Respiration

14. A Summary of External
Respiration, Gas
Transport, and Internal
Respiration

15.  Activity of respiratory muscles is transmitted to the brain by the
phrenic and intercostal nerves
 Neural centers that control rate and depth are located in the medulla
 The pons appears to smooth out respiratory rate
 Normal respiratory rate (eupnea) is 12–15 respirations per minute
 Hypernia is increased respiratory rate often due to extra oxygen
needs
Neural Regulation of Respiration

16. Neural
Regulation of
Respiration

17.  Physical factors
 Increased body temperature
 Exercise
 Talking
 Coughing
 Volition (conscious control)
 Emotional factors
Factors Influencing Respiratory Rate and Depth

18.  Chemical factors
Carbon dioxide levels
 Level of carbon dioxide in the blood is the main regulatory
chemical for respiration
 Increased carbon dioxide increases respiration
 Changes in carbon dioxide act directly on the medulla
oblongata
Factors Influencing Respiratory Rate and Depth

19.  Chemical factors (continued)
Oxygen levels
 Changes in oxygen concentration in the blood are
detected by chemoreceptors in the aorta and carotid artery
 Information is sent to the medulla oblongata
Factors Influencing Respiratory Rate and Depth

20. Respiratory Diseases

21.  Exemplified by chronic bronchitis and emphysema
 Major causes of death and disability in the United States
Chronic Obstructive Pulmonary Disease (COPD)

22.  Features of these diseases
Patients almost always have a history of smoking
Labored breathing (dyspnea) becomes progressively
more severe
Coughing and frequent pulmonary infections are
common
Chronic Obstructive Pulmonary Disease (COPD)

23.  Features of these diseases
(continued)
Most victims retain carbon
dioxide, are hypoxic and
have respiratory acidosis
Those infected will ultimately
develop respiratory failure
Chronic Obstructive Pulmonary Disease (COPD)

24.  Alveoli enlarge as adjacent chambers break
through
 Chronic inflammation promotes lung fibrosis
 Airways collapse during expiration
 Patients use a large amount of energy to
exhale
 Over inflation of the lungs leads to a
permanently expanded barrel chest
 Cyanosis appears late in the disease
Emphysema

25.  Mucosa of the lower respiratory
passages becomes severely inflamed
 Mucus production increases
 Pooled mucus impairs ventilation and
gas exchange
 Risk of lung infection increases
 Pneumonia is common
 Hypoxia and cyanosis occur early
Chronic Bronchitis

26. Hypoxia

27.  Chronic inflamed
hypersensitive
bronchiole passages
 Response to irritants
with dyspnea,
coughing, and
wheezing
Asthma

28.  Newborns – 40 to 80 respirations per minute
 Infants – 30 respirations per minute
 Age 5 – 25 respirations per minute
 Adults – 12 to 18 respirations per minute
 Rate often increases somewhat with old age
Respiratory Rate Changes Throughout Life

29. THANK YOU