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

Pathophysiology of endocrine system, What is the relation between posterior...

What is the relation between posterior pituitary gland and diabetes insipidus?

Can it be influenced by environmental factors, Variation exhibited in share...

Variation exhibited in shared traits present in a population is due to alleles of the shared genes. can be influenced by interactions of alleles of multiple genes. Can be influence

Long-term responses - behaviour of plants, Long-term responses - Behaviour ...

Long-term responses - Behaviour of Plants Plants alter their course of development to suit the prevailing environmental conditions. For example, leaf maturation and fall, onse

Explain counseling strategies, Counseling Strategies The counseling str...

Counseling Strategies The counseling strategies which may serve  lo be useful are described herewith. Individual Counseling: Individual counseling is personal counseling.  T

Change in structure of a protein, Q. Is it expected that a change in the pr...

Q. Is it expected that a change in the primary, in the secondary or in the tertiary structure of a protein will produce furthermore functional consequences? Any change of the p

What are some prophylactic measures for tapeworm infections, Q. What are so...

Q. What are some prophylactic measures for tapeworm infections? The major prophylactic measures against the taeniasis and the cysticercosis are not to ingest raw or badly cooke

Type of bacterial food poisoning, Type of bacterial food poisoning In...

Type of bacterial food poisoning Infection type: The infection type results from the release of toxin in the bowel by microorganisms taken in foods, e.g., Salmonella or Vibr

What is a species, What is a species? A species is a set of living bei...

What is a species? A species is a set of living beings able to cross between themselves generating fertile offspring. This method though does not apply to individuals of ex

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