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

Determine the term - origin of life on earth, Based on your reading of the ...

Based on your reading of the article "Origin of Life on Earth" which of the following is a false statement regarding how life developed? A. As proteins are needed for the repli

Smoking, SMOKIN G - It means to draw tobacco smoke into the mouth o...

SMOKIN G - It means to draw tobacco smoke into the mouth or lungs & exhale it via mouth, nostrils or both. Tobacco is obtained from Nicotiana tobacum & Nicotiana r

Define regents for determination of inorganic phosphorus, Define Regents fo...

Define Regents for Determination of Inorganic Phosphorus? 1. Trichloroacetic acid (10%) - Dissolve 100 g of high grade crystalline acid in distilled water and dilute to 1 Litre

What the henderson-hasselbalch equation expresses, The Henderson-Hasselbalc...

The Henderson-Hasselbalch equation expresses the pH of a solution as: Select one: a. The equilibrium constant of the acid and the dissociated form of the weak acid. b. The

What is the usual morphological feature of nematodes, Q. What is the usual ...

Q. What is the usual morphological feature of nematodes that differentiates them from platyhelminthes? Nematodes are also called as roundworms. As the name indicates they are n

Explain resistance to infection in nutritional care, Explain Resistance to ...

Explain Resistance to Infection in Nutritional Care? Amino acids help to build the body's defence mechanisms like antibodies, blood cells, hormones and enzymes so as to prevent

Explain about the iron - micro minerals, Explain about the Iron - Micro Min...

Explain about the Iron - Micro Minerals? Iron was a familiar metal even in the ancient civilization. In India, iron implements made their appearance in between 1300-1000 BC and

What food items include in full liquid diet, What food items  include in f...

What food items  include in full liquid diet -  Soups and broths -  Cereal porridges (refined cereals) -  Milk and milk beverages, yoghurt - Coffee, tea, fruit  juices

Define the bioavailability of vitamins, Define the Bioavailability of Vitam...

Define the Bioavailability of Vitamins? The term bio availability refers to the overall efficiency of utilization, including physiological and biochemical processes involved in

What is ridge morphology, What is Ridge morphology The implant-supporte...

What is Ridge morphology The implant-supported prosthesis is affected by the ridge morphology especially implant-supported overdentures which gain dual support from implants an

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