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

Can you explain the process of branchiae, Q. What are branchiae? What are e...

Q. What are branchiae? What are examples of animals that "breath" through branchiae? Branchiae also known as gills are small portions of richly vascularized tissues external or

Sharps-hazards in biology laboratory, SHARPS : Cuts due to careless handli...

SHARPS : Cuts due to careless handling of sharps such as sectioning razors, microtome blades etc. are probably the most common cause of injury in the biology lab. The only real re

Alfieri repair-technique of operation, Alfieri Repair: This is advised ...

Alfieri Repair: This is advised for ischaenlic mitral regurgitation. In the area of prolapse, the anterior and posterior leaflet edges are approximated with one or two mattress

Amoeboid movement, Normal 0 false false false EN-IN X...

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

Transportation of gases in tracheophytes vascular tissues, Is the transport...

Is the transportation of gases in tracheophytes made through the vascular tissues? The Carbon dioxide and The Oxygen are not transported through the xylem or phloem. These gase

Ant-nutritional factors limiting their optimum use, Ant-Nutritional Factors...

Ant-Nutritional Factors Limiting their Optimum Use The anti-nutritional factors (ANFs) are non-fibrous natural substances which occur as natural constituents of plants and anim

Bioprosthetic valves, Bioprosthetic Valves :  The risk of thromoboembolism...

Bioprosthetic Valves :  The risk of thromoboembolism is limited to the first three months, until the sewing ring gets endothelialised. The recommendation is to have less intense r

Regulation of cholesterol biosynthesis, Cholesterol can be gained either fr...

Cholesterol can be gained either from the diet or it can be synthesized de novo, mainly in the liver. Cholesterol is transported round the body in lipoprotein particles. The rate

How bone density affect osseointegration, How Bone density affect Osseointe...

How Bone density affect Osseointegration The most important bone property is density which is influenced by factors such as patient age and genetics. Higher density bones have

Explain procedure for temporary mounts of fungal culture, Explain Procedure...

Explain Procedure for Temporary Mounts of Fungal Culture? (1) Observe mould culture for the colonial appearance and colour. Also observe the underside. (2) Label the clean,

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