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

Define the term price mechanism and its working, Define the term price mech...

Define the term price mechanism and how it works. The price mechanism and its working: The above demonstrated diagram assumes the market is into equilibrium, whereby deman

Air pollution - environmental pollution, Air Pollution - Environmental Poll...

Air Pollution - Environmental Pollution The threat due to air pollution became apparent only when some severe episodes caused human casualty in USA, Britain (London) and Japan

Conduction of impulse, CONDUCTIO N OF IMPULSE - IN NON-MYELINATED AXO...

CONDUCTIO N OF IMPULSE - IN NON-MYELINATED AXONS - The impulse moves along the axon as local effect by altering the permeability of neighbouring Na +  channels and af

Hardy - weinberg law, HARD Y - WEINBERG LAW - Proposed by G.H. Hard...

HARD Y - WEINBERG LAW - Proposed by G.H. Hardy and W. Weinberg in 1908 independently. The law states "the frequency of genes or alleles in a population remains constant

Introduction to population dynamics , Introduction: the term, population i...

Introduction: the term, population is derived from lation word' populus' meaning 'people'. Population is a group organism of same in a particular is at a definite time period.

Give a detailed account on central nervous system of frog, Question 1 Iden...

Question 1 Identify the specimen, class to which it belongs and write the salient features of that class.                                               Question 2 Write

Explain about the herbal of valerius cordus, Explain about the Herbal of Va...

Explain about the Herbal of Valerius Cordus? The Herbal of Valerius Cordus published posthumously in 1561; contained not only medicinal plants found in Germany and Italy, but

Observation of hemichordata, Q. Observation of Hemichordata ? • identif...

Q. Observation of Hemichordata ? • identify Balanoglossus as a hemicliordate and give its scientific and common name. • classify Balanogiossus LIP to the level of order.

Explain advantages of having internal gills, 1. Explain the challenges and ...

1. Explain the challenges and advantages of having internal gills over external gills for gas exchange? 2. Explain how increased stress levels can affect hormones which ultimate

What is motor neuropathy, What is Motor Neuropathy It leads to muscular...

What is Motor Neuropathy It leads to muscular weakness and wasting.  Muscle wasting leads to various foot deformities and abnormal pressure points develop due to loss of even p

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