Skip to main content

What is the process involved in the gaseous exchange between the alveoli and the body cells?

Respiration occurs when there is an exchange of gases between a living thing and its environment. In the case of humans, the structure for gas exchange is called an alveolus. The oxygen gas which is inhaled is exchanged for carbon dioxide gas-- a waste product that will be excreted when it is exhaled.


The respiratory system is composed of the nose, pharynx, larynx, trachea, bronchi, and lungs. It is within the lungs that the millions of alveoli take part in gas exchange.


Air moves from the nose to the pharynx, which is the tube in the throat. From there, it enters the trachea which is held open by cartilaginous rings. This airway divides into two tubes called bronchi. Each bronchus leads to each lung. Bronchi subdivide into bronchioles which get progressively smaller. Eventually, at the end of the bronchioles are the millions of alveoli which are surrounded by tiny capillaries-- blood vessels from the circulatory system. Because capillaries and alveoli are thin-walled, gas exchange can occur between them by the process of diffusion.


Oxygen can diffuse from high concentration in the alveoli to lower concentration in the blood stream by passing through the thin capillary walls. As long as a gradient is present, passive transport will occur. With carbon dioxide in higher concentration in the bloodstream relative to the amount in the alveoli, it will pass from the bloodstream to the alveoli also by diffusion. 


When the muscle called the diaphragm located between the chest and abdominal cavity contracts, the chest cavity expands. This creates a difference in air pressure--it is greater outside the body relative to the inside. This causes the lungs to fill with air and inhalation occurs. When the diaphragm muscle relaxes, the size of the chest cavity decreases. There will be greater air pressure inside the body relative to the outside. This allows air to be pushed out of the lungs and exhalation occurs. 


Breathing is regulated by the medulla oblongata in the brain. As carbon dioxide levels rise, nerve signals are sent to the diaphragm to increase its contractions which regulates breathing rate.


I have included a link of a cross section of an alveolus that shows its relation to the blood capillary and gas exchange.

Comments

Post a Comment

Popular posts from this blog

Is there a word/phrase for "unperformant"?

As a software engineer, I need to sometimes describe a piece of code as something that lacks performance or was not written with performance in mind. Example: This kind of coding style leads to unmaintainable and unperformant code. Based on my Google searches, this isn't a real word. What is the correct way to describe this? EDIT My usage of "performance" here is in regard to speed and efficiency. For example, the better the performance of code the faster the application runs. My question and example target the negative definition, which is in reference to preventing inefficient coding practices. Answer This kind of coding style leads to unmaintainable and unperformant code. In my opinion, reads more easily as: This coding style leads to unmaintainable and poorly performing code. The key to well-written documentation and reports lies in ease of understanding. Adding poorly understood words such as performant decreases that ease. In addressing the use of such a poorly ...
Post a Comment
Read more

A man has a garden measuring 84 meters by 56 meters. He divides it into the minimum number of square plots. What is the length of the square plots?

We wish to divide this man's garden into the minimum number of square plots possible. A square has all four sides with the same length.Our garden is a rectangle, so the answer is clearly not 1 square plot. If we choose the wrong length for our squares, we may end up with missing holes or we may not be able to fit our squares inside the garden. So we have 84 meters in one direction and 56 meters in the other direction. When we start dividing the garden in square plots, we are "filling" those lengths in their respective directions. At each direction, there must be an integer number of squares (otherwise, we get holes or we leave the garden), so that all the square plots fill up the garden nicely. Thus, our job here is to find the greatest common divisor of 84 and 56. For this, we prime factor both of them: `56 = 2*2*2*7` `84 = 2*2*3*7` We can see that the prime factors and multiplicities in common are `2*2*7 = 28` . This is the desired length of the square plots. If you wi...
Post a Comment
Read more

What warning does Chuchundra issue to Rikki?

Chuchundra, the sniveling, fearful muskrat who creeps around walls because he is too terrified to go into the center of a room, meets Rikki in the middle of the night. He insults Rikki by begging him not to kill him. He then insults him by suggesting that Nag might mistake Chuchundra for Rikki. He says, "Those who kill snakes get killed by snakes."  He issues this warning to Rikki not to help keep Rikki safe but as a way of explaining why Rikki's presence gives him, Chuchundra, more reason to fear.  Chuchundra starts to tell Rikki what Chua the rat told him--but breaks it off when he realizes he might be overheard by Nag. He says, "Nag is everywhere, Rikki-Tikki." Rikki threatens to bite Chuchundra to get him to talk. Even then, Chuchundra won't overtly reveal any information. But he does say, "Can't you hear, Rikki-Tikki?" This is enough of a clue for the clever mongoose. He listens carefully and can just make out the "faintest scratch-s...
Post a Comment
Read more