Mechanism of Respiration//BREATHING MECHANISM//Gaseous exchange//INSPIRATION and EXPIRATION

Mechanism of Respiration involves breathing mechanism and exchange of gases (Oxygen and Carbon Dioxide). Breathing mechanism will be continued with Inspiration (Inhalation) and Expiration (Exhalation) .

1. Represented by WASIM AKRAM BSc Nursing ADWIKA INSTITUTE OF NURSING Mechanism of Respiration

2. Contents Introduction Definition Mechanism of Respiration Mechanism of Breathing Exchange of gases Pressure differences

3. Introduction Respiration is the movement of oxygen from the Outside environment to the cells Within Tissues , And the removal of carbon dioxide In the opposite direction That’s to The environment . the mechanism of Respiration involves breathing mechanism and exchange of gases .

4. Respiration Respiration is defined as the process of inhaling of oxygen and Exhaling of carbon dioxide by the lungs . The process by which cell use oxygen to break Down sugar and obtain energy . The normal Respiratory rate is 16 – 24 breaths/min .

5. Mechanism of Respiration the mechanism of Respiration involves two PROCESS : A. Breathing mechanism B. Exchange of gases

6. A. Breathing mechanism THE AIR WHICH WE BREATHE IN AND OUT OF THE LUNGS VARIES IN ITS PRESSURE . SO basically when there is a fall in air pressure the alveolar spaces falls & the air enters the lungs ( inspiration ) and as the pressure of the alveolar within exceeds the atmospheric pressure, the air is blown from the lungs ( expiration ) . The flow rate of air is in proportion to the magnitude of the pressure difference . The breathing mechanism involves two processes : INSPIRATION EXPIRATION

7. 1.Mechanism of Inspiration THE PROCESS OF INTAKE OF ATMOSPHERIC AIR IS KNOWN AS INSPIRATION . IT IS AN ACTIVE PROCESS . WHEN THE VOLUME OF THE THORACIC CAVITY INCREASES AND THE AIR PRESSURE DECREASES , INSPIRATION TAKES PLACE . CONTRACTION OF EXTERNAL INTERCOSTAL MUSCLES INCREASES THE VOLUME OF THE THORACIC CAVITY . CONTRACTION OF THE DIAPHRAGM Further increases the size of the thoracic cavity . Simultaneously, the lungs expand . With the expansion of the lungs , the air pressure inside the lungs DECREASES . The pressure equalizes and the atmospheric air rushes inside the lungs.

8. 2. Mechanism of expiration THE EXPIRATION PROCESS IS CONSIDERED ONCE AFTER THE GASEOUS EXCHANGE OCCURS IN THE LUNGS AND THE AIR IS expelled OUT . THE PROCESS OF EXHALING CARBON DIOXIDE IS CALLED Expiration . It is a passive process . It occurs when the size of the thoracic cavity DECREASES and the air pressure increases . Now the external INTERCOSTAL muscles relaxed and the INTERNAL INTERCOSTAL muscles contracts . As a result, the ribs are pulled inwards and the size of the thoracic cavity reduced . The diaphragm is relaxed and the lungs get compressed . Consequently , the pressure increases and the air is forced outside .

9. B. Exchange of gases The exchange of gases takes place in the alveoli in the following manner : Transport of oxygen : Oxygen in the blood is carried to the tissues in two forms – OXYHEMOGLOBIN in RBC (97%) - chemical composition of oxygen & hemoglobin . SOLUTION OF OXYGEN IN THE BLOOD PLASMA (3%) . The oxygen in the blood combines with hemoglobin when concentration of oxygen is high in the blood . Oxyhemoglobin , being unstable , dissociates to Release oxygen . Low oxygen, low pH and high temperatures stimulate the dissociation process .

10. Exchange of gases Internal Respiration : The gaseous exchange taking place in the tissues is called internal Respiration . Here , the oxygen is carried in the form of OXYHEMOGLOBIN gets dissociated to release oxygen . This oxygen helps in break down of glucose to release carbon dioxide , water and energy . The energy is utilized by the body , while the carbon dioxide is diffused out from the tissues and mixed with blood .

11. Exchange of gases Transport of carbon dioxide : Carbon dioxide is transported from tissues to the lungs by three mechanisms : Some carbon dioxide dissolved in water of the blood plasma to form carbonic acid . => 7% . Carbonic acid ionizes to form bicarbonate ions . The hydrogen ions are catalyzed by the enzyme carbonic anhydrase . Bicarbonate ions combine with sodium and potassium to form sodium bicarbonate and potassium bicarbonate . => 70% . Some carbon dioxide combines with hemoglobin for the formation of Carbaminohaemoglobin . => 20 – 25% . These three forms are finally carried to the lungs ( alveoli – site of GASEOUS EXCHANGE ) and released out of the body through expiration .

12. -: PRESSURE DIFFERENCES :- ATMOSPHERIC – Partial pressure of Oxygen : 159 mm-hg Partial pressure of carbon dioxide : 0.3 mm-hg Alveoli – Partial pressure of oxygen : 104 mm-hg Partial pressure of carbon dioxide : 40 mm-hg Oxygenated blood – Partial pressure of oxygen : 95 mm –hg Partial pressure of carbon dioxide : 40 mm-hg Tissue – Partial pressure of oxygen : 40 Mm-hg Partial pressure of carbon dioxide : 45 mm-hg Deoxygenated blood – Partial pressure of oxygen : 40 Mm-hg Partial pressure of carbon dioxide : 45 mm-hg

13. Conclusion Respiration is the process of breathing and exchange of gases (oxygen and carbon dioxide ) . The breathing mechanism involves Inspiration ( taking oxygen inside the lungs ) and expiration ( removing carbon dioxide from the lungs to the environment ) . The gaseous exchange takes place in the alveolar wall . In the alveolar surrounding capillaries , the oxygenation of blood ( purification of blood ) takes place .

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