Lungs - respiration, Biology

Assignment Help:

Lungs - Respiration

Lungs can be simple, characterised by air exchange with surrounding environment by diffusion only. These are called the diffusion lungs and are present in small animals such as pulmonate snails, small scorpions, sane spiders and some isopods. The other type - ventilation lungs are typical of vertebrates.

2440_Lungs - Respiration.png

Figure: Breathing Cycle in Frogs

The air passes through a tube into inflatable lungs where gas exchange takes place and oxygen poor, carbon dioxide rich air is then forced out usually through the same tube. This is known as tidal flow of air. Ventilation of the lungs can take place in two different ways:

1) By using a pressure pump as in amphibians. Figure shows the process of ventilation in frog. The inflation of lungs depends on positive pressure bucco pharengeal pump. The nares remain open while glottis is closed (the air does not enters the lungs). The floor of the buccal cavity is raised and lowered periodically. At irregular intervals the glottis is open and nares are closed. The floor of the buccal cavity is raised forcing air into the lungs. As a result the frog can take in air several times without exhaling and blow itself up to considerable size. The glottis can close and while the air remains inside the lungs the cycle is replated in the buccal cavity.

2) By using a suction pump. Exhalation can be passive and inhalation is aided by muscle contraction or as in mammals, by contraction of muscular dome shaped diaphragm and external intercostal muscles lifting the ribcage. This decreases the pressure in the pleural space so causing the lungs to expand and air flows in.

 


Related Discussions:- Lungs - respiration

Illustrate the diabetic contract of the eye, Illustrate the diabetic contra...

Illustrate the diabetic contract of the eye? Diabetic Cataract: 1) Sorbitol Aldose Pathway: In patients with diabetes, there is increase in sugar alcohol which results in

Filaments of a sarcomere in a skeletal muscle is decreasing, When the overl...

When the overlap between the thin and thick filaments of a sarcomere in a skeletal muscle is decreasing, the A. total length of the I band minus the length of the H zone is dec

Trinomial system, who proposed trinomial system of classification? in ALLEN...

who proposed trinomial system of classification? in ALLEN modules ans is Huxley & Stricklandt but in AAKASH its given Lamarck so what is correct?

Describe two differences among green algae and plants, Describe two differe...

Describe two differences among green algae and plants. Algae lack tissue differentiation and have no true roots, leaves and stems. The gametangia of algae are single-celled; th

Explain the feeding process for preschoolers, Explain the Feeding process f...

Explain the Feeding process for Preschoolers? The word preschool children, you may be aware, is used for children less than six years of age. After the first year, there is a s

Genetics, what about cytoplasmic sex determination

what about cytoplasmic sex determination

What is meant by the expression infant mortality, What is meant by the expr...

What is meant by the expression 'infant mortality'? Infant mortality refers to the number of babies in a population who die at the age of 1 year or less. It is usually express

Explain noncompetitive inhibition, Noncompetitive inhibition In  this ...

Noncompetitive inhibition In  this  type  of  inhibition, the inhibitor binds at  a site  on  the  enzyme  other  than catalytic site. As there is no competition between the s

Intron, The introns are the portions of genomic DNA which are transcribed (...

The introns are the portions of genomic DNA which are transcribed (and hence present in the primary transcript) but are then spliced out later. They therefore are not present in 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