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 taenias and diseases caused by them, Q. What are taenias? What are...

Q. What are taenias? What are the diseases caused by them? The Taenias, as well know as tapeworms, are platyhelminth animals (flatworms). The major diseases caused by taenias a

Explain the history of plant classification, Explain the History of Plant C...

Explain the History of Plant Classification? Before Darwin's theory of evolution and publication of his epoch making work 'Origin of Species' in 1959 no outstanding basis for

What are the valves of the venous system, What are the valves of the venous...

What are the valves of the venous system? What is their function? The valves of the venous system are structures within the veins that permit blood to flow only in the normal w

Osmoregulation in freshwater metazoans, Osmoregulation in Freshwater Metazo...

Osmoregulation in Freshwater Metazoans Freshwater and brackish water animals that are live in hypoosmotic(of lower osmotic pressure) environment and keep a hyperosmotic (of h

Heliozoans - protozoan, Heliozoans - Protozoan Heliozoans are spherica...

Heliozoans - Protozoan Heliozoans are spherical protozoan that occur in the sea or in still bodies of fresh water. They are mainly located in the bottom debris. Fine needle li

Iodine - mineral elements, IODINE The element is available is drinking ...

IODINE The element is available is drinking water, vegetables and fish. Table salts are also compulsorily iodized to provide iodine in the diet. All sea foods are rich in

Normal pigmentation, The female I-1 and her mate, male I-2, had four childr...

The female I-1 and her mate, male I-2, had four children, one of whom has albinism. What is the probability that they could have had a total of four children with any other outcome

Zoology, #question.characteristics of coelenterata?.

#question.characteristics of coelenterata?.

What concerns should alek''s healthcare team, Nine-year-old Alek is admitte...

Nine-year-old Alek is admitted to the emergency room with a closed fracture of the right femur. Radiography revels that the fracture crosses the distal epiphyseal plate. What conce

What are primary consumers, What are primary consumers? Can a food chain pr...

What are primary consumers? Can a food chain present quaternary consumers without having secondary or tertiary consumers? Can a tertiary consumer of one chain be a primary or secon

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