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

Xerarch - ecology, Xerarch - Ecology Successions initiated on bare roc...

Xerarch - Ecology Successions initiated on bare rock, wind-blown sand, rocky talus slopes, or other situations where there is an extreme deficiency of water are termed xerarch

Why is it dangerous to talk while eating, Q. Why is it dangerous to talk wh...

Q. Why is it dangerous to talk while eating? If a person talks when eating, food may be inhaled into the lungs. Generally after food is swallowed, it passes into pharynx and th

Excretory organs in different animals, EXCRETOR Y ORGANS In protozo...

EXCRETOR Y ORGANS In protozoa through plasmalemma by diffusion. Contractile vacuole present for osmoregulation (absent in parasitic and marine protozoa). In porifera and

Homestasis, why does an organism internal environment change

why does an organism internal environment change

What is the objectives of evaluation of patient clinical, What is the OBJEC...

What is the OBJECTIVES of evaluation of patient clinical examination ? After going through this unit, you should be able to: 1. Carried out the general physics-examination; 2.

Explain nutritional support management - cancer patient, Explain about the ...

Explain about the Nutritional Support Management? Tube feeding is usually started. If tube feeding is not possible, parenteral nutrition through peripheral vein or through the

Describe circulatory system, Circulatory system:  One of the eleven major b...

Circulatory system:  One of the eleven major body organ systems in animals; carbon dioxide, nutrients, transports oxygen, and waste products between the cells and the respiratory s

Explain risk factors and their role in cad, Explain risk factors and their ...

Explain risk factors and their role in cad ? The concept of risk factors constitutes a major advance for developing strategies to prevent CVD. The Framingham Heat Study played

Infectious coryza, I nfectious coryza A highly infectious bacterial di...

I nfectious coryza A highly infectious bacterial disease of chickens caused by Hemop hilus paragallinarum, is characterized by catarrhal inflammation of the upper respirator

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