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

State in detail about the thylakoid membrane, State in detail about the thy...

State in detail about the thylakoid membrane The thylakoid membrane contains all the factors associated with the photosynthetic electron transport leading to the generation of

Define significance of plants and animals on human life, Define Significanc...

Define Significance and Impact of Plants and Animals on Human Life? Plants and animals both have a great significance and unparalleled impact on human life. Most of our needs a

Determine the atp-sensitive potassium channel, ATP-sensitive potassium chan...

ATP-sensitive potassium channel A. The channel is a spanning protein with a receptor site for ATP located on an intracellular region of the protein. B. When blood plasma lev

Define synthesis of hormones - vitamin c, Define Synthesis of Hormones - Vi...

Define Synthesis of Hormones - Vitamin C? Ascorbate is involved in the amidation, thereby conferring stability to hormones such as thyrotropin releasing hormone, adrenocorticot

Describe primitive anaerobic eukaryotic cells, Q. How can the hypothesis th...

Q. How can the hypothesis that asserts that chloroplasts as well as mitochondria were primitive prokaryotes that related in mutualism with primitive anaerobic eukaryotic cells be c

Show the embryological evidence, Q. Show the Embryological Evidence? Em...

Q. Show the Embryological Evidence? Embryology is the study of the successive stages of sporogencsis , gametogenesis and the growth and development of the embryo. The number o

Reproductive mechanisms, Normal 0 false false false EN-...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is the chemical nature of carbohydrates, What is the chemical nature o...

What is the chemical nature of carbohydrates? The name carbohydrate owes its origin to the fact that most substances of this class have empirical formulae suggesting that they

External factor - factor controlling metamorphosis in insect, External fact...

External factors - Factors Controlling Metamorphosis in Insects In few cases an external factor may be accountable for initiating moulting, as for instance in the blood su

Explain healthy nutrition, Explain Healthy nutrition There is no doubt...

Explain Healthy nutrition There is no doubt that adoption of Healthy nutrition lifestyle and the practice of good nutrition habits would help eliminate many health problems ca

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