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

What are non-threshold approaches, Non-threshold  approaches For  gene...

Non-threshold  approaches For  genetic carcinogenes, the  "NOEL-safety factor"  approach  is generally  not considered a suitable method for setting the acceptable intake level

The deficiency in hepatic glucose 6 phosphatase, Under fasting conditions, ...

Under fasting conditions, individuals with a deficiency in hepatic glucose 6 phosphatase cannot dephosphorylate glucose 6 phosphate generated from liver glycogenolysis. As a result

Explain the sources of microorganisms, Explain the Sources of Microorganism...

Explain the Sources of Microorganisms? Microorganisms are virtually present everywhere in nature including air, water and soil. The microbial flora is also associated with the

PHYLUM MOLLUSCA, How we attempt a question of phylum mollusca?

How we attempt a question of phylum mollusca?

Define the sphingolipid metabolism - vitamin k, Define the Sphingolipid Met...

Define the Sphingolipid Metabolism - Vitamin K? Sphingolipids, as you would recall from your Biochemistry Course, are a class of membrane lipids that are composed of one molecu

Meiosis, Meiosis is the special type of cell division in which the numbers ...

Meiosis is the special type of cell division in which the numbers of chromosomes in daughter cell are reduced to half, as compared to parent cell. Occurrence: It takes place

Beta decay, Beta decay  is the type of radioactive decay in which the radio...

Beta decay  is the type of radioactive decay in which the radioisotope emits a little negatively-charged and fast-moving particle from its nucleus. A beta particle is almost simila

Divisions and representing species of the gymnosperms, Q. What are the majo...

Q. What are the major divisions and representing species of the gymnosperms? This group of plants can be separated into conifers (pine, sequoia, cypress), that have flowers cal

Explain the character of pulse, Explain the Character of Pulse ? A norm...

Explain the Character of Pulse ? A normal pulse wave has an upstroke and down stroke. Dicrotic notch present on direct arterial traces is impalpable. Figure: Arterial

Intermediate products of anaerobic respiration, (a) What are the intermedia...

(a) What are the intermediate products of anaerobic respiration in an active muscle? (b) Which of them is associated with oxygen debt? (c) In what way is th

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