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

What are infructescences fruits and pseudofruits, What are infructescences,...

What are infructescences, pseudofruits and parthenocarpic fruits? Infructescences are aggregated fruits created from inflorescences, aggregated flowers. Grape clusters are inst

Engler and prantls system of classification, Q. Engler and Prantl's System ...

Q. Engler and Prantl's System of Classification? Adolf Engler, Professor of Botany, University of Berlin, Germany, proposed a phylogenetic system of classification in a book en

Companion cells, Companion cells  are the specialized cells in the phloem w...

Companion cells  are the specialized cells in the phloem which load sugars into the sieve elements and help to maintain a functional plasma membrane in the sieve elements.

What are fibroids, Fibroids, also called as leiomyomas, are benign smooth m...

Fibroids, also called as leiomyomas, are benign smooth muscle tumors that happen in the uterus. They grow under the influence of estrogen and progesterone, and are therefore seen i

Its possible to obtain probability of emergence of genotype?, How is it pos...

How is it possible to obtain the probability of emergence of a given genotype formed of more than one pair of different alleles with independent segregation from the knowledge of t

Explain the working of conical flasks, Explain the working of Conical Flask...

Explain the working of Conical Flasks? Conical flasks of different volumes can be used for media preparation and also for culturing large amount of microorganisms in liquid med

Zoology, Write briefly on neural mechanism of learning?

Write briefly on neural mechanism of learning?

Define aerobic exercise or aerobic energy system, Define Aerobic Exercise o...

Define Aerobic Exercise or Aerobic Energy System? To produce necessary energy, the body uses an aerobic pathway and an anaerobic pathway. Exercise that relies heavily on oxygen

How does temperature affect the action of enzymes, How does temperature aff...

How does temperature affect the action of enzymes upon their substrates? There are explained temperature ranges under which enzymes operate and there is a specific temperature

Bioinformatics is important, Why do you think that bioinformatics is import...

Why do you think that bioinformatics is important?         Ans) Today, we can use computers to access much more biological data than still before. You can learn a lot by analysi

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