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

Describe the complete transposition of great arteries, Describe the Complet...

Describe the Complete transposition of great arteries ? Lethal, relatively frequent malformation. Without treatment, it results in 30 per cent mortality within the first week o

Headache associated with neurological diseases, Headache Associated with Ne...

Headache Associated with Neurological Diseases Headache is a symptom of many nervous system disorders, usually resulting from the distortion of pain sensitive structures. Commo

Admission to the hospital - nursing, Admission to  the Hospital The ...

Admission to  the Hospital The  philosophy of  childcare, whether in the home, hospital, or  other community agency, should be consistently one of concern and support for the

Explain human leucocyte antigen complex, a) Explain the polygonum type of e...

a) Explain the polygonum type of embryo sac. Why is it generally referred to as monosporic ? b) Explain human leucocyte antigen complex? Describe its role in organ transplantati

Sds page, describe sds page for the proteins

describe sds page for the proteins

Explain two capacities and volumes of respiratory, Given four respiratory c...

Given four respiratory capacities (a - d) and four jumbled respiratory volumes of a normal human adult: Respiratory Respiratory capacities volumes. 1.            Residual vol

What is the meaning of trocophore, What is the meaning of Trocophore? T...

What is the meaning of Trocophore? This free-swimming ciliated larval stage is found in numerous animal phyla including Mollusca and Annelida. Larvae has a unique circle of pre

What is dyslipidaemia, What is Dyslipidaemia ? The results of epidemiol...

What is Dyslipidaemia ? The results of epidemiological studies, as well as trials with angiographic or clinical endpoints, confirm the importance of various lipid fractions in

Corpus luteum in human females.., what is the fate of corpus luteum if egg...

what is the fate of corpus luteum if egg gets fertilised ?

Cleft palate, Cleft Palate   Well you have now learnt about the cleft l...

Cleft Palate   Well you have now learnt about the cleft lip and now let us discuss and understand what is cleft palate. Cleft palate (CP) is midline fissure of  the palate that

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