Respiratory System

Captions are on! Take a deep breath. And let it out. Isn’t  it remarkable? The human respiratory system,   I mean. The system that lets us  do that – an exchange of gases.   Now don’t confuse the respiratory system with  cellular respiration. If you watched our cellular   respiration video, you learned about why our cells  need oxygen. Your cells need oxygen to make ATP,   an energy currency, and the gas byproduct  produced is carbon dioxide which the body   must remove. This is part of the equation in  aerobic cellular respiration done by your cells. But your respiratory system which takes in the  oxygen and expels the carbon dioxide – working   closely with the circulatory system and other  systems to do so – is how we get that oxygen   into human body in the first place. And that  oxygen will be needed for cellular respiration. So you inhale. Air passes through your  nasal cavity. The air is warmed, humidified,   and filtered. This involves mucus and hairs. Nasal  hairs that you can see and then microscopic cilia   which are similar to hair-like structures. Now,  we come to the pharynx. A junction if you will   of both food and air. From the pharynx, we go  through the larynx (often called the voice box).   Then the trachea. By the way, food should be  traveling down the esophagus not the trachea.   We mention in our digestive system video that an  epiglottis keeps food from going down the trachea.   The trachea is a pretty fascinating cylinder tube  with rings of cartilage. That cartilage helps   support the trachea and keep it open for that air  to travel through. The trachea goes down, down,   down to the primary bronchi. One on each side  as this branches to the lungs. Just to mention   a bit about the lungs. There are two. Each  lung has sections called lobes. Three lobes   on the right and two on the left. There’s a  cardiac notch on the left lung side where it's   a little indention to give the heart some room.  The left lung is generally smaller than the right.   Now our main focus is going to be what’s happening  inside the lungs so let’s continue to go through   the primary bronchi. Primary bronchi divide into  secondary bronchi then tertiary bronchi and then   smaller bronchioles. And, you know, it kind of  looks like an upside down tree. I like trees. So a general recap of where we’ve gone: nasal  cavity -> pharynx -> larynx  trachea  primary   bronchi  secondary bronchi   tertiary bronchi  bronchioles. Diameter is getting smaller as you  go through these different areas.   Beyond the terminal bronchioles, there will  be branching into respiratory bronchioles   and then on to alveolar ducts. Each alveolar  duct is surrounded by alveolar sacs. Alveolar   sacs look a lot like…a bunch of grapes. I’m  not the only one to think that. Each of these   alveolar sacs contain alveoli and this is  where the gas exchange will actually occur.   That’s because these alveoli are made of thin  walled cells, have a lot of surface area, and they   have direct contact with capillaries. We mentioned  that other body systems work closely together:   the circulatory system works closely with the  respiratory system here. Red blood cells in   the capillaries can pick up the oxygen that was  inhaled to deliver it throughout the body and   also bring carbon dioxide -a waste gas that  needs to be removed- so that it can be exhaled. Besides the circulatory system, there are other  body systems working with this respiratory system.   The skeletal system includes the ribs that  protect the lungs like a cage around them.   But muscles of the muscular system are involved  too. Muscles involved in respiration includes   muscles between your ribs called intercostal  muscles. It includes a major muscle under   your lungs called the diaphragm. It includes  abdominal wall muscles. All of these are part of   the muscular system – and they are involved with  helping to expand or contract the thoracic cavity. While you can take voluntary  control of your breathing,   you’ll notice that most of the  time your breathing is involuntary:   that is, you aren’t consciously controlling it.  The nervous system regulates this, and here’s   something pretty cool: it uses pH to do so. The  pH scale is based on hydrogen ion concentration   (H+). Acidic substances – shown here as lower  numbers on this pH scale - have a higher   H+ concentration compared to bases - which have a  lower H+ concentration. Ultimately, the increase   of carbon dioxide concentration in the blood  increases the concentration of H+. If you want   to learn more about how that happens – fascinating  chemistry- check out our further reading links. So as the carbon dioxide concentration  increases in the blood, the blood pH falls   slightly lower on the pH scale – it is becoming  more acidic. The increasing acidity is detected   and sent as signals to the brain. The brain  can then control the intercostal muscles,   diaphragm, and abdominal muscles in order to  increase the rate and depth of breathing. This can   restore the blood to a normal blood pH and keep  the blood pH stable. Around 7.4. Great example of   keeping homeostasis. Just think about when you’re  exercising and how amazing it is to have such a   fine-tuned system so your breathing rate and depth  can increase as needed. And while we’re really   trying to give general examples to emphasize  that body systems don’t work in isolation,   keep in mind that there are other systems  involved with the respiratory system to explore. Before we go, there are 2 final notes I want  to mention. First, we want to remind you we   focused on humans. But obviously it’s  not just humans that have gas exchange.   Earthworms actually have gas exchange through  their skin. Fish can use gills for gases to   diffuse, insects can have a tracheal system  which means they can have little openings on   their body- called spiracles – that connect  to little tubes inside. It’s fascinating to   learn about all these different systems for  getting oxygen in and carbon dioxide out. Second, understanding how the respiratory  system works can help us understand   treatments for respiratory illnesses  or respiratory problems that may arise.   There are many careers that focus specifically  on the respiratory system – two examples include   pulmonologists and respiratory therapists. They  may be involved in the treatment of respiratory   conditions like asthma or emphysema, and, an  example I’d like to end with: they might be   involved in the treatment for premature babies  that might not have fully developed lungs. So to expand on this: remember we were talking  about the alveoli – we mentioned alveoli have a   large surface area? Ideal for gases to diffuse.  But without something called surfactant inside   them, alveoli can be prone to collapse due to  the surface tension of water inside the alveoli.   Surface tension being a great thing to review in  our properties of water video. So, type 2 alveolar   cells makes surfactant, a substance that includes  phospholipids and proteins. Surfactant interferes   with the bonding of water which contributes to  lowering the surface tension, making it easier   for alveoli to inflate. But sometimes, babies that  are premature may not yet have enough surfactant   in their lungs. This can make it difficult  for the alveoli to inflate properly; it can   cause collapse. This can result in respiratory  distress syndrome (RDS). But now…due to better   understanding of this, artificial surfactants  can be used to treat premature infants and it’s   saved the lives of many. Well, that’s it for the  Amoeba Sisters, and we remind you to stay curious.

Channel: Amoeba Sisters

Views: 1,665,322

Keywords: respiratory, lungs, body systems, anatomy, science, biology, TEKS, amoeba sisters, ameba sisters, amoba sisters, ameeba sisters, overview, review, basics, introduction, tutorial, animation, cartoon, blood pH, alveoli, trachea, surfactant, breathing, gas exchange, hydrogen ion concentration, bronchi, homeostasis, human respiratory, educational, AP biology, school, standards

Id: v_j-LD2YEqg

Length: 7min 34sec (454 seconds)

Published: Tue Mar 01 2022