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

Determine some food sources for copper, Determine some Food Sources for Cop...

Determine some Food Sources for Copper? Foods containing more than 1 mg copper per 1000 kilocalories are considered high in copper and include green leafy vegetables, nuts, leg

Why the vast majority of segregation errors in human patient, Which of the ...

Which of the following defines why the vast majority of segregation errors in human patients include the two sex chromosomes (XXY, XO, XYY) or chromosome 21 (triple 21)? A. Th

Explain aortic valvuloplasty, Q. Explain Aortic Valvuloplasty? Valvar a...

Q. Explain Aortic Valvuloplasty? Valvar aortic stenosis accounts for 4-6 per cent of CHD. LV Outflow Tract obstruction eventually leads to LV dysfunction and congestive heart f

Biochemestry, what are peptides and poly peptides hormones

what are peptides and poly peptides hormones

Determine the term anapsid , Determine the term Anapsid ? The type of s...

Determine the term Anapsid ? The type of skull found in reptiles and seen today only in turtles. Behind the opening of the orbits the skull is solid and lacks temporal openings

Define reaction of glucose & fructose with fehlings reagent, Define Reactio...

Define Reaction of glucose and fructose with Fehlings reagent? Lactose is a milk sugar. It is a reducing disaccharide having a free sugar group and can reduce Fehling's reagent

Venting of the heart in myocardial protection, Venting of the Heart :  It ...

Venting of the Heart :  It is important that heart does not distend during cardio pulmonary bypass. This is prevented by venting of the left side of the heart by inserting a cannu

Mitosis, What is the role of mitosis in growth?

What is the role of mitosis in growth?

Which are the germ layers present in cnidarians, Q. Which are the germ laye...

Q. Which are the germ layers present in cnidarians? Which tissues of the animal do they originate? These beings present endoderm and ectoderm, two germ layers. Animals only wit

Steroid and thyroid hormones, Steroid and Thyroid Hormones Cytoplasmic...

Steroid and Thyroid Hormones Cytoplasmic receptors for steroids are proteins with two subunits that bind to the steroid molecules. When both receptor sites are occupied by the

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