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 - leuconoid sponge, Determine the term - Leuconoid spong...

Determine the term - Leuconoid sponge. The most complex of the three different sponge architectures. Choanocytes are found in chambers, and there is not any spongocoel. Water e

In how many categories nutrients are divided, In how many categories nutrie...

In how many categories nutrients are divided? The nutrients are grouped into three categories: 1) Energy Yielding: Carbohydrates and fats produce energy in the body. 2) B

Bud dormancy - plant growth substances, Bud Dormancy - Plant Growth Substan...

Bud Dormancy - Plant Growth Substances Environmental Factors The most important factor inducing dormancy appears to be photoperiod. Short days induce dormancy in many w

#green algae, #what characteristics of green algae that led to biologists c...

#what characteristics of green algae that led to biologists considered it as a plant?

Sastry, he heartbeat begins with the depolarization of the

he heartbeat begins with the depolarization of the

Define recommended dietary allowances for vitamin d, Define Recommended Die...

Define Recommended Dietary Allowances for Vitamin D? The recommendations of vitamin D are expressed as IU. 1 IU is defined as the activity contained in 0.025 mcg of cholecalci

Diabetes mellitus, 1. How often should she have Glycated hemoglobin (HgbA1C...

1. How often should she have Glycated hemoglobin (HgbA1C) drawn?  What percentage is desired? 2. How often should she see an ophthalmologist or optometrist? 3. What should be

Evolution of the cell, EVOLUTION OF THE CELL All the living organisms a...

EVOLUTION OF THE CELL All the living organisms are made up of cells. A living cell may be defined as a compartment enclosed by a membrane that consists of several chemical cons

Blood flow, if i start in the superior mesenteric vain where do i have to g...

if i start in the superior mesenteric vain where do i have to go through to get to the left anterior circumflex humeral artery. by the way of the hepatic portal vein and the heart

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