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

Why the vitamin niacin is a necessary component of nad, The vitamin niacin ...

The vitamin niacin is a necessary component of NAD. Niacin can be consumed in food or manufactured in the body from tryptophan, an amino acid. How would a person's ability to break

What are the male and the female gonads in humans, Q. What are gonads? What...

Q. What are gonads? What are the male and the female gonads in humans? Gonads are the organs that produce gametes they contain the germ cells that undergo division and generate

Explain oxidation-reduction potential, Oxidation-reduction  Potential (ORP)...

Oxidation-reduction  Potential (ORP) ORP is related to the concentration of oxidizers or reducers in a solution, and their activity or strength. It provides an indication of th

Define the carbohydrate and fat required for elderly, Define the Carbohydra...

Define the Carbohydrate and Fat required for elderly? Carbohydrate: It is usually recommended that approximately 55en% (percent of  energy) be provided from carbohydrate food

Assessment of aplastic anaemia, Assessment   The patient will present w...

Assessment   The patient will present with striking pallor, irritability and lethargy due to anaemia, bledding or bruising and petechiae due to thrombocytopenia, fever and infe

How do ascaris obtain food, Q. How do ascaris obtain food? An ascaris l...

Q. How do ascaris obtain food? An ascaris live within the human gut and feed from the food ingested by the infected person.

Explain the process of nuclear reorganization, Process of nuclear reorganiz...

Process of nuclear reorganization in protozoa in which nucleus divides, each half undergoes a maturation, and two persisting functional nuclei reunite is termed as: a) Autogamy

Chronic mitral regurgitation-indications for surgery, Chronic Mitral Regurg...

Chronic Mitral Regurgitation :  In chronic mitral regurgitation, the asymptomatic phase is much longer than in mitral stenosis. Onset of symptoms may also mean the onset of l

Discuss about dengue and aids, Why is it difficult to produce efficient vac...

Why is it difficult to produce efficient vaccines against a viral infection like dengue and AIDS? It is complex to make vaccines against dengue because there are four dissimila

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