Alright, folks. As we dive into the physiology of the respiratory system, we're going to be talking a lot about two things: ventilation and respiration. So we're going to break these things up here. Now remember, our real goal here is to get oxygen to the tissues of our body and to get carbon dioxide out of those tissues and back into the air. So that's sort of what our respiratory system is doing. And when we think of that process, altogether sort of breathing, we can take that and break it up into two components. The first is going to be ventilation, and ventilation is the moving of the air in and out of our lungs, getting the air in and out of our body. And the second one is going to be respiration. And respiration is getting that oxygen, that oxygen, O2, and CO2, the carbon dioxide, getting that in and out of the blood. Alright. So let's break these things down separately. Let's go through ventilation first. So we said that is the movement of air in and out of the lungs. Well, there are two basic processes to that. We have inspiration. And inspiration, that's your normal inhale. That's your breathing in, and this moves air into the lungs. Now inspiration, we're going to say here, uses muscular force. And our major muscle of breathing here, our diaphragm, we have this illustrated. So we have our anatomical model. We can see the respiratory system. And importantly, we see the diaphragm pulling downwards. It contracts, pulls downwards, makes more space in that thoracic cavity, which pulls air into the lungs. So that uses force. The muscles of the diaphragm are using energy to pull downwards in that case. Now in contrast, we have expiration. Expiration, well, that's our breathing out. That's our exhale, we'll say, and this moves air out of our lungs. And this is a little counterintuitive to some people, a lot of times. This normally just involves muscular relaxation. So we use force to bring air into our lungs, but then to breathe out, that diaphragm is going to go back up. But it's just everything sort of recoiling to its natural space. So sort of your natural tendency, if you just relax, you're going to expire, you're going to exhale. Alright. Now what I've just described is what happens in what we call quiet breathing. And quiet breathing, there's a vocab word for that. We call it eupnea. So eupnea or quiet breathing, that's just that normal quiet breaths, restful breathing, the type of breathing that you do when you just don't think about breathing and you're not doing anything too strenuous. This is what we're going to use for most physiological measures. So as we go through this chapter, when you see volumes, numbers, unless stated otherwise, we're talking about that quiet, restful breathing. Now, obviously, we can breathe harder than that. And when we do that, we call it forced breathing. Forced breathing is deeper, harder breathing, either because you're doing something very strenuous or you're deliberately taking big breaths, something like that. Now in forced breathing, we are going to use muscles for inspiration just like in quiet breathing, but we're going to recruit more muscles to help us breathe in deeper. But we're also going to use muscles for expiration. So in forced breathing, we force air into our lungs, and we use muscular force to force the air out again. Alright. So now let's talk about respiration. So respiration, we've gotten the air into our lungs. Well, now how do we get it to the tissues? Well, there's going to be two steps to this. First, we have external respiration. This is going to be that exchange of oxygen and carbon dioxide between the air and the blood, and that happens in the alveoli. So we have this image of the alveoli drawn there. Now, some people sometimes get a little confused. External respiration, this is happening in my alveoli. My alveoli are in my chest. That seems kind of in my body. Why is it external? The way I think of it, it's the exchange between the blood and the external air. You bring this external air in through ventilation, and this exchange of gases happens in the alveoli, external respiration. Alright. Where we really want to get those gases to and from though is the tissues, and that is internal respiration. So the blood leaves the alveoli, takes it to the tissues, and then we have this exchange between the blood and tissues. And to illustrate this, we have this drawing of, sort of, simple columnar epithelium here. So that's where that oxygen is going to pop out of the blood, go into the tissues, excess carbon dioxide waste is going to come out of the tissues in the blood, so it can be carried back to the alveoli for external respiration. Alright. Just a quick note, that word respiration, sometimes people get a little confused. We also have cellular respiration. Cellular respiration is breaking down molecules like sugar to make ATP. We use oxygen for that, and that produces carbon dioxide. That is something different. Now, obviously, it's related. That's where this oxygen is going. That's where this carbon dioxide is coming from. But respiration in the respiratory system is something very different than cellular respiration; the using and production of these molecules in the making ATP from molecules like sugar. Alright. The final note that we just have here, in respiration, we have hemoglobin. Hemoglobin, you've learned about when you've learned about the blood, is this incredibly important molecule because when we exchange these gases we actually need a ton of oxygen. And it increases the amount of oxygen especially, but also CO2 to a lesser extent, importantly oxygen though, that can be carried in the blood. Alright. So again, we want to get these molecules to and from the tissues, but there are two steps to do that. We need to get the air in and out of our lungs. That's ventilation. We need to get the molecules in and out of the blood. That's respiration. Alright. We're going to have a lot more on this going forward. It's going to be a grand old time. See you there.
Table of contents
- 1. Introduction to Anatomy & Physiology5h 40m
- What is Anatomy & Physiology?20m
- Levels of Organization13m
- Variation in Anatomy & Physiology12m
- Introduction to Organ Systems27m
- Homeostasis9m
- Feedback Loops11m
- Feedback Loops: Negative Feedback19m
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- Anatomical Position7m
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- Review- Using Anatomical Terms and Directions12m
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- Organization of the Body: Serous Membranes14m
- Organization of the Body: Serous Membrane Locations8m
- Organization of the Body: Thoracic Cavity8m
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- 4. Tissues & Histology10h 3m
- Introduction to Tissues & Histology16m
- Introduction to Epithelial Tissue24m
- Characteristics of Epithelial Tissue37m
- Structural Naming of Epithelial Tissue19m
- Simple Epithelial Tissues1h 2m
- Stratified Epithelial Tissues55m
- Identifying Types of Epithelial Tissue32m
- Glandular Epithelial Tissue26m
- Introduction to Connective Tissue36m
- Classes of Connective Tissue8m
- Introduction to Connective Tissue Proper40m
- Connective Tissue Proper: Loose Connective Tissue56m
- Connective Tissue Proper: Dense Connective Tissue49m
- Specialized Connective Tissue: Cartilage44m
- Specialized Connective Tissue: Bone12m
- Specialized Connective Tissue: Blood9m
- Introduction to Muscle Tissue7m
- Types of Muscle Tissue45m
- Introduction to Nervous Tissue8m
- Nervous Tissue: The Neuron8m
- 5. Integumentary System2h 20m
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- An Introduction to Bone and Skeletal Tissue18m
- Gross Anatomy of Bone: Compact and Spongy Bone7m
- Gross Anatomy of Bone: Periosteum and Endosteum11m
- Gross Anatomy of Bone: Bone Marrow8m
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- Gross Anatomy of Bones - Structure of a Long Bone23m
- Microscopic Anatomy of Bones - Bone Matrix9m
- Microscopic Anatomy of Bones - Bone Cells25m
- Microscopic Anatomy of Bones - The Osteon17m
- Microscopic Anatomy of Bones - Trabeculae9m
- 7. The Skeletal System2h 35m
- 8. Joints2h 17m
- 9. Muscle Tissue2h 33m
- 10. Muscles1h 11m
- 11. Nervous Tissue and Nervous System1h 35m
- 12. The Central Nervous System1h 6m
- 13. The Peripheral Nervous System1h 26m
- Introduction to the Peripheral Nervous System5m
- Organization of Sensory Pathways16m
- Introduction to Sensory Receptors5m
- Sensory Receptor Classification by Modality6m
- Sensory Receptor Classification by Location8m
- Proprioceptors7m
- Adaptation of Sensory Receptors8m
- Introduction to Reflex Arcs13m
- Reflex Arcs15m
- 14. The Autonomic Nervous System1h 38m
- 15. The Special Senses2h 41m
- 16. The Endocrine System2h 48m
- 17. The Blood1h 22m
- 18. The Heart1h 42m
- 19. The Blood Vessels3h 35m
- 20. The Lymphatic System3h 16m
- 21. The Immune System14h 37m
- Introduction to the Immune System10m
- Introduction to Innate Immunity17m
- Introduction to First-Line Defenses5m
- Physical Barriers in First-Line Defenses: Skin13m
- Physical Barriers in First-Line Defenses: Mucous Membrane9m
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- First-Line Defenses: Normal Microbiota7m
- Introduction to Cells of the Immune System15m
- Cells of the Immune System: Granulocytes28m
- Cells of the Immune System: Agranulocytes26m
- Introduction to Cell Communication5m
- Cell Communication: Surface Receptors & Adhesion Molecules16m
- Cell Communication: Cytokines27m
- Pattern Recognition Receptors (PRRs)48m
- Introduction to the Complement System24m
- Activation Pathways of the Complement System23m
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- Review of the Complement System13m
- Phagocytosis17m
- Introduction to Inflammation18m
- Steps of the Inflammatory Response28m
- Fever8m
- Interferon Response25m
- Review Map of Innate Immunity
- Introduction to Adaptive Immunity32m
- Antigens12m
- Introduction to T Lymphocytes38m
- Major Histocompatibility Complex Molecules20m
- Activation of T Lymphocytes21m
- Functions of T Lymphocytes25m
- Review of Cytotoxic vs Helper T Cells13m
- Introduction to B Lymphocytes27m
- Antibodies14m
- Classes of Antibodies35m
- Outcomes of Antibody Binding to Antigen15m
- T Dependent & T Independent Antigens21m
- Clonal Selection20m
- Antibody Class Switching17m
- Affinity Maturation14m
- Primary and Secondary Response of Adaptive Immunity21m
- Immune Tolerance28m
- Regulatory T Cells10m
- Natural Killer Cells16m
- Review of Adaptive Immunity25m
- 22. The Respiratory System3h 20m
- 23. The Digestive System2h 5m
- 24. Metabolism and Nutrition4h 0m
- Essential Amino Acids5m
- Lipid Vitamins19m
- Cellular Respiration: Redox Reactions15m
- Introduction to Cellular Respiration22m
- Cellular Respiration: Types of Phosphorylation14m
- Cellular Respiration: Glycolysis19m
- Cellular Respiration: Pyruvate Oxidation8m
- Cellular Respiration: Krebs Cycle16m
- Cellular Respiration: Electron Transport Chain14m
- Cellular Respiration: Chemiosmosis7m
- Review of Aerobic Cellular Respiration18m
- Fermentation & Anaerobic Respiration23m
- Gluconeogenesis16m
- Fatty Acid Oxidation20m
- Amino Acid Oxidation17m
- 25. The Urinary System2h 39m
- 26. Fluid and Electrolyte Balance, Acid Base Balance Coming soon
- 27. The Reproductive System2h 5m
- 28. Human Development1h 21m
- 29. Heredity Coming soon
22. The Respiratory System
Introduction to Lung Physiology
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