Here’s the story.
Function of alveoli
The function of the alveoli is to get oxygen into the blood stream for transport to the tissues, and to remove carbon dioxide from the blood stream.
Structure of alveoli
In the lungs, air is diverted into smaller and smaller microscopic branches called respiratory bronchioles, which connect to the alveolar ducts.
(from mrsbioblog.blogspot.com)
At the end of each duct are approximately 100 alveolar sacs, each containing 20 to 30 alveoli that are 200 to 300 µm in diameter.
Each alveolar membrane is one cell thick and is in direct contact with capillaries that are also one cell thick.
There are about 600 million alveoli in the lungs, with a total surface area of about ##”75 m”^2##.
(from www.enotes.com)
The large alveolar surface area, combined with the thin membranes, allows gases to diffuse easily across the alveolar walls.
The diameter of the capillaries surrounding the alveoli is so small that only one red blood cell can pass through at a time.
This slows down the blood cells, so that gases have more time to diffuse through the capillaries.
It also forces the red blood cells close to the walls of the capillaries, decreasing the diffusion distance.
The mechanism of gas exchange
Oxygen from the inhaled air diffuses through the walls of the alveoli and the capillaries into the red blood cells, which carry it through the blood to the body tissues.
Carbon dioxide produced by the body’s tissues returns to the alveoli via the blood.
It then diffuses across the capillary and respiratory membranes into the air space to be removed by expiration.
Our website has a team of professional writers who can help you write any of your homework. They will write your papers from scratch. We also have a team of editors just to make sure all papers are of HIGH QUALITY & PLAGIARISM FREE. To make an Order you only need to click Ask A Question and we will direct you to our Order Page at WriteDemy. Then fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Fill in all the assignment paper details that are required in the order form with the standard information being the page count, deadline, academic level and type of paper. It is advisable to have this information at hand so that you can quickly fill in the necessary information needed in the form for the essay writer to be immediately assigned to your writing project. Make payment for the custom essay order to enable us to assign a suitable writer to your order. Payments are made through Paypal on a secured billing page. Finally, sit back and relax.
About Writedemy
We are a professional paper writing website. If you have searched a question and bumped into our website just know you are in the right place to get help in your coursework. We offer HIGH QUALITY & PLAGIARISM FREE Papers.
How It Works
To make an Order you only need to click on “Place Order” and we will direct you to our Order Page. Fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Are there Discounts?
All new clients are eligible for 20% off in their first Order. Our payment method is safe and secure.