Med-Surg Respiratory System, part 1: Introduction, Function, Components

by Cathy Parkes August 18, 2021 Updated: August 30, 2021

In this article, we give an overview of the topics in the respiratory system that you will need to know about for your Med-Surg and Critical Care classes. We also give you a refresher on how the respiratory system works, the main components, and the difference between ventilation, diffusion, and perfusion. These topics are covered in our Medical-Surgical Flashcards (Respiratory system), and the video series follows along with the cards!

Med-Surg respiratory system topics

These are the topics that we will cover in the respiratory system playlist for Med-Surg. These are the topics in the respiratory system that you should know for your exams! If you'd like to study and remember the key points on these topics, check out our Medical-Surgical Nursing Flashcards.

  1. Introduction, Function, Components (this article!)
  2. Diagnostic Tests
  3. Oxygen Delivery Devices, Hypoxemia/Hypoxia, Sleep Apnea
  4. Asthma
  5. COPD
  6. Cystic Fibrosis
  7. Interstitial Lung Disease, Pulmonary Hypertension
  8. Upper Respiratory Tract Disorders, Influenza, Pneumonia
  9. Tuberculosis
  10. Pulmonary Embolism
  11. Pleural Disorders, Chest Tubes, Tension Pneumothorax
  12. ARDS and ARF
  13. Mechanical Ventilation

The respiratory system

The key function of the respiratory system is gas exchange. The respiratory system provides oxygen to the body's cells and removes carbon dioxide from the body.

Respiratory system components

The respiratory system comprises an upper airway and lower airway.

Upper airway

The upper airway of the respiratory system is made up of the nose, mouth, pharynx, larynx, and trachea. The upper airway's function is to warm, humidify, and filter the air we breathe.

Lower airway

The lower airway of the respiratory system includes the bronchi, bronchioles, alveolar ducts, and alveoli. The key function of the lower airway is gas exchange, and alveoli are the functional units for gas exchange.

Pleura

We have pleura that surround and cushion each of the lungs. The space between the two layers of the pleura is known as the pleural cavity. When we cover disorders of the respiratory system later in this series, you will notice that some disorders cause a buildup of air, blood, or fluid in that pleural cavity, which compresses the lungs and puts the lungs at risk for collapse.

Blood flow in the lungs

  1. Deoxygenated blood from the body goes to the right atrium, then the right ventricle, then to the lungs.
  2. In the lungs, the alveoli absorb carbon dioxide FROM the capillaries, which allows us to breathe out carbon dioxide.
  3. Alveoli diffuse oxygen (that we've breathed in) INTO the capillaries, which oxygenates our blood.
  4. The oxygenated blood returns to the left atrium.

Ventilation

Ventilation is the flow of air in and out of the alveoli. If a patient were to have a condition like asthma, that results in bronchoconstriction, which would impair their ventilation.

Diffusion

Diffusion is the exchange of oxygen and carbon dioxide between the alveoli and the red blood cells in the bloodstream.

If a patient were to have a condition like pulmonary fibrosis, which causes scarring and thickening of the lung tissue, that makes diffusion less effective.

Perfusion

Perfusion is the exchange of oxygen and carbon dioxide between red blood cells and the body's tissues.

If a patient had a condition such as peripheral arterial disease, which results in impaired blood flow to extremities, it affects perfusion to the cells in the lower extremities. Peripheral arterial disease is covered in the cardiovascular section of our Medical-Surgical Nursing Flashcards.


Full Transcript

Hi, I'm Cathy with Level Up RN. This is the first video in our Respiratory System video playlist. In this video playlist, I will go over the key concepts and facts you need to know to be successful on the NCLEX and for your nursing school exams. I will be following along with my flashcards, our Medical-Surgical Nursing Flashcards, edition 2. You don't need these flashcards in order to get value out of this video series. However, repetition really helps the information to sink in, and flashcards are perfect for learning through repetition. So both practical nurse students as well as registered nurse students will benefit from this playlist and from our flashcard deck. If you do have our deck, be sure to pay close attention to the bolded red text that you'll find throughout the deck because those concepts are going to be particularly important for you to know. One thing I'll be doing differently with this playlist is at the end of each video I'm going to give you guys a quiz, just a simple, straightforward quiz to test your understanding of the information that I'll be covering in each of the videos.

Let's kick things off by talking about the key function and components of the respiratory system.

The key function of the respiratory system is gas exchange. So it will provide oxygen to the body cells and remove carbon dioxide from the body.

In terms of the components of the respiratory system, we have these upper airway components, which include the nose, mouth, pharynx, larynx, and trachea.

And their function is to warm, humidify, and filter the air that we breathe.

Then we have our lower airway components, which include the bronchi, bronchioles, alveolar ducts, and alveoli.

The key function down there is gas exchange. So alveoli are the functional units for gas exchange.

I also want to mention that we have pleura that surround and cushion each of the lungs, and the space between the two layers of the pleura is called the pleural cavity. And when we get into disorders of the respiratory system, there will be some disorders that cause a buildup of air, blood, or fluid in that pleural cavity, which compresses the lungs and really makes the lungs at risk for collapse.

Now, let's do a quick review of blood flow in and out of the lungs. So deoxygenated blood from the body goes to the right atrium and then to the right ventricle and then to the lungs, where it becomes oxygenated and then is returned to the left atrium.

So you can see the blood coming here from the right ventricle and it is passing along the alveoli, and this is where diffusion takes place.

So oxygen is diffused from the alveoli into the capillaries, and then carbon dioxide moves the opposite direction into the alveoli, where we can in turn breathe out that carbon dioxide. And then the oxygenated blood returns to the left atrium.

The last thing I want to cover in this video is the difference between ventilation, diffusion, and perfusion.

So ventilation is the flow of air in and out of the alveoli. So if a patient were to have a condition such as asthma, that would result in bronchoconstriction, which in turn impairs that ventilation.

Then we have diffusion, which is the exchange of oxygen and carbon dioxide between the alveoli and the red blood cells in the bloodstream.

So if the patient were to have a condition such as pulmonary fibrosis, which causes scarring and thickening of the lung tissue, that would make diffusion less effective.

And then finally, we have perfusion, which is the exchange of oxygen and carbon dioxide between those red blood cells and the body's tissues.

So if the patient had a condition such as peripheral arterial disease, which results in impaired blood flow to those extremities, that in turn would affect perfusion to those cells in the lower extremities.

All right. Are you guys ready for a quick quiz? Question number one. What is the functional unit for gas exchange in the body? The answer is the alveoli.

Question number two. What do you call the structure that surrounds and cushions the lungs? The answer is the pleura.

Question number three. The exchange of oxygen and carbon dioxide between the alveoli and the red blood cells is called what? The answer is diffusion.

So I hope you did well on that quiz. I hope this video was helpful as well. Be sure to leave us a comment and like this video if you found it of value. Thank you so much for watching.


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