Pulmonary ventilation, Biology

Assignment Help:

Pulmonary Ventilation:
Pulmonary ventilation is the process by which gasses flow between the atmosphere and lung alveoli. Air moves into the  lungs when air pressure  inside the lungs is less than  the  air pressure in the atmosphere and out of  the lungs when  the pressure inside the lungs is greater than the atmosphere pressure. Breathing  in  is called inhalation or inspiration. Just before each inhalation air pressure inside the  alveoli is equal to the atmospheric pressures, 760 rnmHg,  and the intrapleural pressure is 756 mmHg. With  inspiration, the cavity of the thorax is enlarged as external intercostals muscles  and the diaphragm contract causing a decrease in  the  intrapleural pressure to about 754 mmHg. The parietal pleura lining the cavity is pulled outward in all direction and the visceral pleura and lungs are pulled along with  it. As  the  lung volume increases in this way  the pressure inside the lungs i.e.  760 mmHg drops to 758 mmHg. Thus a pressure difference  is established between the atmosphere and alveoli and air flows into the  lungs from the atmosphere. Breathing out or exhalation (expiration) starts when the  inspiratory muscles and diaphragm relaxes,  the dome of the diaphragm moves up, the ribs are depressed leading  to decrease in the  lung volume and increase in  the lung pressure (763 rnm Hg). Air flows out form the area of higher pressure to the area of lower pressure  in  the atmosphere. The elastic recoil  of the chest wall and the lungs is due to  the recoil of elastic fibers and the inward pull of surface tension due to  the alveolar fluid. A thin  layer of alveolar fluid coats the  surface of the alveoli and exerts a  force known as surface tension. Exhalation is a passive process while inhalation or  inspiration  is an active process.

 


Related Discussions:- Pulmonary ventilation

Classification and features of echinodermata, Classification with its Justi...

Classification with its Justification Kingdom Animalia Animals, multi-cellular organisms with cells that lack a cell wall, many capable of movement or movement of some o

Similarities in body parts often indicate shared ancestry, Similarities in ...

Similarities in body parts often indicate shared ancestry. Which of the following is true? Structures used for different purposes in different groups can be controlled by the same

Genotype for each individual, The allele that causes albinism (p) is recess...

The allele that causes albinism (p) is recessive to the allele for normal pigmentation (P). A normal woman whose father is an albino marries an albino man whose parents are both no

Diarrhoea, Diarrhoea   Diarrhoea refers to frequent passage of loose wa...

Diarrhoea   Diarrhoea refers to frequent passage of loose watery stools. Acute diarrhoea often called as acute gastroenteritis  is particularly a leading cause of mortality in

Define requirements of sodium during pregnancy period, Define requirements ...

Define requirements of Sodium during pregnancy period? As you know, sodium plays a role in fluid balance. Sodium metabolism is altered during pregnancy under the stimulus of a

Explain the importance of cellulose, Importance of cellulose About one ...

Importance of cellulose About one third of the world's production of  purified cellulose is  used as the base material for a number of water-soluble derivatives with predesigne

What is meant by the substrates of enzymatic reactions, Q. What is meant by...

Q. What is meant by the substrates of enzymatic reactions? The Substrates are reagent molecules upon which enzymes act. The enzyme has spatial binding sites for the attachmen

Explain animal fats, Animal Fats This group consists of depot fats from...

Animal Fats This group consists of depot fats from domestic land animals (e.g., lard and tallow), all containing large amounts of C16 and C18 fatty acids, medium amounts of uns

Chuck darwin knew blending theory, Chuck Darwin knew BLENDING THEORY, but h...

Chuck Darwin knew BLENDING THEORY, but he also knew that if it was true his NOT work because

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd