Hi. In this video, we'll be talking about digestion and the digestive system, the organ system responsible for bringing in food, extracting nutrients from it, and getting rid of the waste. Now food is any substance that has nutrients needed by an organism to live. We consider food to be things like pasta, which is chock full of carbohydrates, meat, which has proteins, or fats, which can be found in things like dairy products. Now, those are all well and good. However, we also need what are known as essential nutrients. These are nutrients that we can't synthesize, and they have to be obtained in the diet. So while we can, for example, make a bunch of amino acids, we can't make all 20 that are used to build proteins. In fact, there are actually 8 amino acids that we can't synthesize, and we call these essential amino acids. And in case you're curious, and don't worry about memorizing this, these include isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine, and tryptophan. Methionine is actually significant in there, since that is going to be the amino acid coded for by the start codon. Now, it should also be noted, you know, case you're curious about these things, that infants also can't produce histidine. This can lead to certain infantile diseases that, you know, maybe you'll learn about if you go to medical school or something. Now vitamins are organic compounds that are required in small amounts, and are used for a variety of different things, including as coenzymes, which are going to be important parts of enzymes. In fact, usually the essential part to carry out whatever reaction it's responsible for. We also need minerals, which are inorganic substances, required again in just small amounts. However, they're going to be incorporated into proteins and, you know, the active sites of enzymes for example, where the reactions take place, and they also can be important components in hormones. Now minerals also include what we refer to as electrolytes, that are going to be, mineral ions that are super important for maintaining osmotic balance in the body, because remember, water follows solutes. And these will also be super important for nerve signals, and, we'll learn more about that in the section on the nervous system. However, just know that the electrical signals sent through nerves are actually being conducted by the movement of these electrolytes or ions. Lastly, there's also essential fatty acids, and it should be noted that, most animals can produce, you know, all the fatty acids that they need. However, there are certain double bonds that we, as humans can't produce, and those are commonly referred to as omega 3 and omega 6 fatty acids due to the double bond at the omega 3 position and omega 6 position. This just has to do with the chemical naming, so you know don't worry about trying to memorize any of this. It's just a convention in terms of counting the carbon tail from the end, as opposed to the beginning. Anyways, omega threes are found in, you know, things like tree nuts for example. These are often thought of as plant fats. Omega sixes are commonly, referred to as animal fats, and interestingly, it's been theorized that issues with obesity can actually be in part due to the ratio of omega 3 and omega 6s you have in your diet, and Americans tend to have too many omega 6s, not enough omega 3s. So our balance is a little out of whack, and you know, as you know America suffers from obesity quite a bit. Now if I jump out of the way here, I also want to point out how these vitamins can be used. This is a vitamin called riboflavin, because it's got all the flavor. And riboflavin is an essential component of FAD, which you can hopefully see riboflavin's structure in this portion of the molecule. FAD is, of course, the essential electron carrier that it plays a critical role in the electron transport gene, and of course, cellular respiration, production of ATP. So these essential nutrients are truly essential. We need them to build components that aren't just there for, you know, a little added advantage. These build components that are essential to living organisms. Now there are different techniques when it comes to obtaining food. You know, I've always admired, whales that have this stuff called baleen, which you can see here. It almost looks like a comb. It's these bristled, bristled structures that surround their jaws. And you can actually see the baleen in a whale's mouth right there, that's a sperm whale. And what it's doing is it's basically, you know, taking a big bite of ocean water, rich in these tiny little organisms called krill, and then it's going to filter those krill through its baleen, and basically strain its food out of the water. This tactic is known as suspension feeding. Technically it's a type of filter feeding, which is like a, filter feeding is like a type of suspension feeding. And, you know, this is just one of the many ways that organisms can obtain their food. There's also, deposit feeding where, for example, a sea cucumber will kind of eat the I mean, it's kind of yucky, but the sediment deposited material around it. There is substrate feeding, which is basically when an organism lives on its food source, kind of like a caterpillar on a leaf. There's also fluid feeding, like insects sucking your blood, or in a way less creepy and gross example, a nice little hummingbird that eats nectar. Right? Now, we have the dubious title of being mass feeders. Sometimes this is called bulk feeding. Basically, we eat large chunks of food, sometimes whole organisms. Basically, we eat big pieces of other things' bodies, and that is considered like a mass and we feed on it, and it's kind of why I like to think of animals as a very crude form of life. You know, we have to just take in this matter from the outside, and like stick it in our bodies, and then process it, and waste all this stuff that just comes out of us anyways. And, you know, when you compare that to, for example, a plant which you know absorbs sunlight, produces its own sugars, much more elegant way of living. Anyways, that's just my little 2¢ on that. And let's flip the page.
Table of contents
- 1. Introduction to Biology2h 40m
- 2. Chemistry3h 40m
- 3. Water1h 26m
- 4. Biomolecules2h 23m
- 5. Cell Components2h 26m
- 6. The Membrane2h 31m
- 7. Energy and Metabolism2h 0m
- 8. Respiration2h 40m
- 9. Photosynthesis2h 49m
- 10. Cell Signaling59m
- 11. Cell Division2h 47m
- 12. Meiosis2h 0m
- 13. Mendelian Genetics4h 41m
- Introduction to Mendel's Experiments7m
- Genotype vs. Phenotype17m
- Punnett Squares13m
- Mendel's Experiments26m
- Mendel's Laws18m
- Monohybrid Crosses16m
- Test Crosses14m
- Dihybrid Crosses20m
- Punnett Square Probability26m
- Incomplete Dominance vs. Codominance20m
- Epistasis7m
- Non-Mendelian Genetics12m
- Pedigrees6m
- Autosomal Inheritance21m
- Sex-Linked Inheritance43m
- X-Inactivation9m
- 14. DNA Synthesis2h 27m
- 15. Gene Expression3h 20m
- 16. Regulation of Expression3h 31m
- Introduction to Regulation of Gene Expression13m
- Prokaryotic Gene Regulation via Operons27m
- The Lac Operon21m
- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Eukaryotic Post-Translational Regulation13m
- 17. Viruses37m
- 18. Biotechnology2h 58m
- 19. Genomics17m
- 20. Development1h 5m
- 21. Evolution3h 1m
- 22. Evolution of Populations3h 52m
- 23. Speciation1h 37m
- 24. History of Life on Earth2h 6m
- 25. Phylogeny2h 31m
- 26. Prokaryotes4h 59m
- 27. Protists1h 12m
- 28. Plants1h 22m
- 29. Fungi36m
- 30. Overview of Animals34m
- 31. Invertebrates1h 2m
- 32. Vertebrates50m
- 33. Plant Anatomy1h 3m
- 34. Vascular Plant Transport2m
- 35. Soil37m
- 36. Plant Reproduction47m
- 37. Plant Sensation and Response1h 9m
- 38. Animal Form and Function1h 19m
- 39. Digestive System10m
- 40. Circulatory System1h 57m
- 41. Immune System1h 12m
- 42. Osmoregulation and Excretion50m
- 43. Endocrine System4m
- 44. Animal Reproduction2m
- 45. Nervous System55m
- 46. Sensory Systems46m
- 47. Muscle Systems23m
- 48. Ecology3h 11m
- Introduction to Ecology20m
- Biogeography14m
- Earth's Climate Patterns50m
- Introduction to Terrestrial Biomes10m
- Terrestrial Biomes: Near Equator13m
- Terrestrial Biomes: Temperate Regions10m
- Terrestrial Biomes: Northern Regions15m
- Introduction to Aquatic Biomes27m
- Freshwater Aquatic Biomes14m
- Marine Aquatic Biomes13m
- 49. Animal Behavior28m
- 50. Population Ecology3h 41m
- Introduction to Population Ecology28m
- Population Sampling Methods23m
- Life History12m
- Population Demography17m
- Factors Limiting Population Growth14m
- Introduction to Population Growth Models22m
- Linear Population Growth6m
- Exponential Population Growth29m
- Logistic Population Growth32m
- r/K Selection10m
- The Human Population22m
- 51. Community Ecology2h 46m
- Introduction to Community Ecology2m
- Introduction to Community Interactions9m
- Community Interactions: Competition (-/-)38m
- Community Interactions: Exploitation (+/-)23m
- Community Interactions: Mutualism (+/+) & Commensalism (+/0)9m
- Community Structure35m
- Community Dynamics26m
- Geographic Impact on Communities21m
- 52. Ecosystems2h 36m
- 53. Conservation Biology24m
39. Digestive System
Digestion
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