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

Which of the substances is chromatin made, Q. Which Of the substances is ch...

Q. Which Of the substances is chromatin made? Chromatin is made of the DNA molecules associated to proteins known as histones.

Concept of reproductive isolation and the concept of species, What is the r...

What is the relationship between the concept of reproductive isolation and the concept of species? The Reproductive isolation is an important concept because it defines the con

Foot-rot, Foot-rot Foot-rot is a term applied to the condition of feet ...

Foot-rot Foot-rot is a term applied to the condition of feet of cattle, sheep, goats and sometimes pigs. It is characterized by inflammation, necrosis and ulceration of underly

What chromosome condition is created, Following fertilization by a normal s...

Following fertilization by a normal sperm, what chromosome condition is created?

Swine influenza, Swine influenza Swine influenza, a highly contagious ...

Swine influenza Swine influenza, a highly contagious disease affecting the respiratory tract of pigs, is c a use d  b y a  vir us b e lo nging t o the ge nus I nflu e nz a vir

Identify by mean of biochemical tests, The human blood group, related to th...

The human blood group, related to the MN system is controlled by two alleles, S and s. Three distinct phenotypes can be identified by mean of biochemical tests. Among 1000 Britishe

Define reflection - endodontic surgery, Define Reflection - Endodontic Surg...

Define Reflection - Endodontic Surgery -  Marginal gingival is very delicate and easily injured, therefore you should begin reflection of the vertical incision in the attached

Descibe the lymphatic system, Q. What is the lymphatic system? The lymp...

Q. What is the lymphatic system? The lymphatic system is a network of specialized valved vessels that drain interstitial fluid (lymph), the lymphatic system is as well responsi

Define historical example of ecosystems science, Define Historical example ...

Define Historical example of Ecosystems Science? Mathematical and statistical tools are central to enhancing our understanding of large-scale systems and contain, for instance,

What is the most likely source of error in the study, In a cohort study tha...

In a cohort study that found an association between alcohol consumption and bladder cancer, 20,000 middle-aged men were asked about their drinking habits and then tracked for five

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