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

How to identify the metal out of which the wire is made, A wire 50.0 m long...

A wire 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 33.7 A. Assume a temperature of 20°C and,

Advice on follow up for cardiac patients, Advice on Follow up The pa...

Advice on Follow up The patient should adhere to the follow-up schedule strictly. Generally, one week after discharge, then one month and then 3 to 6 months interval, the

Acute myocardial infarction, Acute Myocardial Infarction :  Patients with ...

Acute Myocardial Infarction :  Patients with acute non-Q myocardial infarction may need urgent intervention as indicated for cases of unstable angina.

Into which classes are mollusc divided, Into which classes are mollusc divi...

Into which classes are mollusc divided? What are some representing beings of each class? The phylum Mollusca is separated into five major classes: pelecypods, or bivalves (Pele

Uses of plural embryos, Uses of Plural Embryos Although the basic tha...

Uses of Plural Embryos Although the basic that trigger causes polyembryony are not fully understood, there has been no dearth of interest in exploiting supernumerary embryos.

Define the role of riboflavin in drug and lipid metabolism, Define the role...

Define the role of riboflavin in Drug and lipid metabolism? Flavoproteins catalyze dehydrogenation reactions, as well as, hydroxylations, oxidative decarobxylations, deoxygenat

Calculate the amount of nacl, A saline drip is to be prepared for a lab exp...

A saline drip is to be prepared for a lab experiment that is looking at hydration in lab rats. Calculate the amount of NaCl need to make 4 liters of a 0.9% solution.

Explain the objective of cardiac rehabilitation, Explain the OBJECTIVE of C...

Explain the OBJECTIVE of Cardiac Rehabilitation ? After going through this unit, you should be able to: 1 identifies the eligible candidate for cardiac rehabilitation and be

What is the formula for calculation of bone distortion, What is the formula...

What is the formula for calculation of bone distortion The following formula can be used to calculate for distortion: Effective Bone available = Reference sphere diameter ×

Acid rain, The Phenomenon of acid rain was first introduced by Rober Angus ...

The Phenomenon of acid rain was first introduced by Rober Angus smith in 1852. Is means presence of excessive acids in rain water? Acid rain is a form of precipitation (rain, sn

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