Respiratory system and function of Lungs

So we will disscus about the lungs the respiratory system is very important because this is essentially what gives us oxygen so that we can live and during this process we also release carbon dioxide. So we inhale oxygen release carbon dioxide and it's essential for life now to learn about the respiratory system we actually have to learn about the circulatory system about the heart and how it pumps blood throughout our body.

Respiratory coincides with circulatory system:

It's important to know about the circulatory system because the respiratory system and the circulatory system coincide together. They work together so funny enough we begin learning about the respiratory system by learning about the heart . 

Here is the heart the heart consists of four chambers, blood vessels enter and leave the heart. 

Respiratory System 

The blood vessel in blue here represents deoxygenated blood which means that it contains low amounts of oxygen, typically it contains are much higher levels of carbon dioxide . This blood vessel in red represents oxygenated blood which means that it contains oxygen. 

General Process:

Now this oxygenated blood supply gets the oxygen from the lungs in this picture.  Here it represent as the lungs , now outside in the air in our atmosphere we have many types of gases including oxygen gas . 

Now we breathe in oxygen gas it comes into our lungs and as we breathe in oxygen gas we also breathe out carbon dioxide from our deoxygenated blood supply.  So carbon dioxide leaves into the atmosphere and we breathe in oxygen gas .

Now as oxygen enters our blood supply it reoxidized our blood supply so , now we have box and  oxygenated blood supply here in red they travel through our body enter our heart . The heart will then pop out the oxygen and transport it throughout two different organs to different tissues .

Production of Energy:

The different tissues will take in oxygen and use it to make energy in the forms of ATP and it's a by-product it will create carbon dioxide . So the tissues will then release carbon dioxide.  The blood vessel then transports the carbon dioxide back to the heart so then the heart can pump it up to the lungs to be exchanged for oxygen .

What happens to Carbon dioxide:

Now it is very important to understand on the side note you might ask what happens to the carbon dioxide. Well the plants actually use carbon dioxide and through photosynthesis uses  together with water and sunlight and  it makes carbon carbohydrates and also oxygen as a by-product.

As a Cycle:

So it's sort of like a cycle we breathe out carbon dioxide the plants use carbon dioxide to make oxygen and then we use the oxygen and may come in to oxide as a by product and so we can appreciate how this cycle works.

Parts of Respiratory System

Now the respiratory system or respiration can be divided into four major parts. 

Pulmonary Ventilation:

One is known as the pulmonary ventilation and this is the movement of air in and out of the lungs so the movement of oxygen into the lung and the movement of a carbon dioxide out of the  breathing lungs.

External Respiration:

External respiration is the movement of oxygen from the lungs into the blood and the movement of carbon dioxide from the blood into the lungs.

Transport of Respiratory Gases:

Number three is a transport of respiratory gases ,so how the oxygen basically gets transported to different tissues in different organs .

Internal Respiration:

Then that's we come to our last one for and this is known as internal respiration . Internal respiration is where the it is where we have the movement of oxygen from the blood to the tissues and the movement of carbon dioxide from the tissues into the blood 

Difference Between Internal and External respiration:

So hope you can understand the difference between internal and external respiration, most importantly ,now that we hopefully understood a bit of an overall picture of the respiratory system and how it interacts with the circulatory system let's look at the anatomy. 

Anatomy of lungs

Let's look at the lungs in particular in the respiratory tract. So here we have  the atmosphere again it contains many types of gases including oxygen gas. Here we have a human body I'm just going to shade some areas , here too so you can see the different parts of the respiratory tract.

Upper Respiratory Tract:

So let's start learning about the anatomy , Here we have our nasal cavity, the nose cavity , the oral cavity, the mouth cavity, the pharynx and then we have the esophagus.

Here at the back which leads towards the stomach this is part of the digestive system and then in front of it we have the larynx which actually leads to the respiratory tract. This respiratory further to the respiratory stack the lungs and so what divides the tract of the esophagus and the larynx . 

Epiglottis:

Well it's the epiglottis . The epiglottis can cover the larynx when we are eating so just to understand.

Pathway

What is happening we're breathing in oxygen gas into our nasal cavity or through oral cavity and it goes down towards our larynx and we breathe our out carbon dioxide when we breathe in oxygen gas it will proceed down here and travel to the larynx and then it will go through a cartilage area known as a trachea . 

The trachea will then divide into many types of branches the point of division is known as a Carina of the trachea.

Lungs:

And these many divisions are what make up the lungs essentially.  So here we have the right lung and here we have the left lung and below the lungs we have the diaphragm .

This is the muscle which helps in our breathing process so let's take a closer look at the and let's look closer at the anatomy of the lungs .

So here we have the lungs we breathe in oxygen gas and it comes into the lungs we also breathe out carbon dioxide and leaves the lungs ,so here we have the trachea the cartilage area full of college rings.

Trachea:

Now the trachea will divide into what's called the primary bronchus,  since there's two and then the primary bronchus will then further divided into the secondary bronchi.

Segmental Bronchi:

There are many of them and then the secondary bronchi will then divide further into the segmental bronchi and it still keeps dividing smaller and smaller. 

Now let's stop there for a second and look at this area here on the left lung as you can see that the left lung has a bit of space here this space is known as a cardiac notch and if you know what cardiac means .It means it has to relate to the heart and so this is actually where the heart is are positioned in our body.

Difference between right and left lung:

Another thing to note is that the left lung and the right lung consists of different number of lobes making up the lungs such as the right lung consists of a right superior lobe , a middle lobe and a inferior lobe. 

So the right lung has three lobes whereas the left lung only has two , it has a superior lobe and has an inferior lobe. 

Alveolus:

So that's the other difference and also going back to the trachea which the edges off to the primary bronchus then secondary bronchus then the segmental bronchus bronchi sorry what comes after this well the last point of division we have this sort of sac looking thing and this is known as alveolus .

Ducts:

The alveolar ducts so here into this  alveolar duct looking thing I look at it in a bit more detail of course to each of the of these alveoli sacs we have our blood vessels coming in and out the blue coming in and the red going out.

Bronchioles:

Now let's learn some a bit of anatomy here we have what's called the bronchial  and wrapping around the bronchioles we have smooth muscles , which are necessary in order for these to contract .

Then the bronchioles will go further to where they end known as a terminal bronchioles , churn of bronchial will essentially go into what's called the SAC consisting of many alveolus .

Conclusion

So I hope this makes sense of an important terminology is that one of these bowls these bowl looking things are known as an alveolus many of these bowls looking things are known as an alveoli .So one alveolus mini alveoli and they make up the alveolar sac or duct . 

Hope this makes sense so here we have the alveolar sac which contains many alveoli and then we have the alveolar duct which basically is the area which connects to the terminal bronchial . 

Pulmonary Vein and Artery 

Now the question is the pulmonary artery leaves the heart with deoxygenated blood and it contains mainly carbon dioxide , if you remember the pulmonary artery will enter the lungs and will basically branch into the alveolar sacs the , pulmonary artery will give CO2 to into the alveoli .

Sees the alveoli and the alveoli will give the  oxygen and so now it is re oxygenated.

Reason to be Pulmonary Vein:

It contains new oxygen and then as the as the blood vessel leaves the alveolar sac and goes back towards the heart it is now known as the pulmonary vein because vein always goes back to the heart and we'll get back to that again if you don't quite understand it .

2 Main Concepts:

But another two concepts you should understand is that the pathway from nose to the bronchioles which is there is called the shutting zone of respiration from the bronchioles to the alveolus --is the the one one meaning alveolus is known as a respiratory zone and this is where the exchange of oxygen and carbon dioxide happens .

Pulmonary Artery:

So let's go back to this pulmonary artery , pulmonary vein and look at it again so remember one one of these bowls is an alveolus.  

We have an alveolus now we have the pulmonary artery coming from the heart with deoxygenated blood with carbon dioxide and it branches into small pulmonary arterioles and then capillaries where it will give a carbon dioxide . The alveolus will give the blood vessel or the capillaries new oxygen so it will  on reaction oxygenate the blood supply .

Pulmonary Vein:

This new oxygen will then leave the alveolus as a pulmonary vein because the pulmonary vein will go back towards the heart and this pulmonary vein contains new oxygen so it's oxygenated .

Important Concept about Alveoli:

Now that's a very important concept to understand let's go back and look at the alveolar sacs the many alveolus and look at what components it has by looking at a cross sectional diagram of it so here we have a cross-section of alveoli , of course being an alveolus . 

We also have blood vessels surrounding this area consisting of red blood cells and red blood cells play an important role which we will soon see from the blood vessel  alveolus is about 0.5 micrometers which is very small . 

Why do we have macrophages?

Also around this area we have white blood cells and within the alveolus is we have macrophages . So why do we have macrophages and why white blood cells within our lungs?

Well it is important to have white blood cells such as macrophages within our lungs it's and this is because our lungs is continuously exposed to the outside so pathogens are bacteria small small things dust particles can enter our lungs and can potentially damage it and this is where the white blood cells play a role in that it basically stops this for stop subsidies invading things from damaging our body .

2 Types of cells of alveoli:

The alveolus itself consists of two main types of cells the  type 1 alveolar cell which is basically a simple squamous epithelial cell it is thin which allows for easy exchange o gas easy exchange of oxygen and carbon dioxide the second type of cell is known as the type to alveolar cell or the surfactant cell .

Surfactant:

Surfactant cells secrete surfactant and they reduce surface tension in the alveolus which means that the membranes can separate more easily allowing for easier gas exchange.

Interaction between  alveolus and blood vessel :

Now let's look at the interaction between an alveolus and a blood vessel or the capillary and see how gas exchange occurs an overall picture so here we have the type 1 alveolus  of the alveolus and then here we have the epithelial cell of the capillary.

Role of Red Blood Cell:

Now this is where red blood cells play a critical role because respiratory gases such as oxygen travel throughout the body by binding onto hemoglobin within a red blood cell carbon dioxide also requires red blood cells in order to travel around the body .

But carbon dioxides only require rare red blood cells so that the red blood cells can convert carbon dioxide into  what's called bicarbonate and carbon dioxide therefore travel throughout the body through by through a chemical known as bicarbonate .

Last Step:

So when the red blood cells reach the alveolus the red blood cells will convert the bicarbonate back to carbon dioxide and give it to the alveolus . 

The alveolus will then give oxygen gas to the red blood cell the oxygen gas will buy it onto the hemoglobin component of the red blood cell and then we'll travel around the blood the carbon dioxide will also obviously be exhaled out .