all right so chapter 41 is all about animal nutrition the idea of an electrician is accounting for taking in food breaking it down getting it absorbed throughout that particular animals body systems and then removal of any unused parts of that food item we have three different types of animals typically that we are going to be talking about we have herbivores carnivores and omnivores animals can be different ways and we'll talk about some of those ways I think in section two so we need to make sure animals diet has everything that they need to be able to survive they need to provide it needs to provide energy which can be converted to ATP it needs to have all the building blocks so it can build all the different macromolecules and it needs to have different nutrients which will help to provide enzymes or assists in some of those chemical reactions taking place they could be essential amino acids the essential fatty acids your vitamins and your minerals there are 20 different amino acids we talked about them earlier they can make about half of them from molecules that they have ingested the rest the essential amino acids have to be obtained from their food directly they cannot make those meat eggs and cheese will all provide those they're considered to be complete proteins if you do not eat those items you only eat plant proteins you're going to have to make sure that you take care with what you eat to get the right amounts of what you combinations of those plants to get the essential amino acids that you need to be able to build your proteins fatty acids animals from those part can synthesize fatty acids that they need they have to get them from their diet they need to have some that are unsaturated fatty acids this is not typically an area that we run into difficulties vitamins organic molecules that are needed to help with the chemical reactions we touch with us previously I'm going to show you a list of them there's 13 vitamins they can either be fast soluble which can be stored a little bit longer in the human body or they can be water soluble so those are ones that you're probably pretty familiar with minerals these are trace metals that you wouldn't think you'd normally ingest usually in just the most part of compounds they're very small amounts and they do help to convert your food into energy they help with the hydration and they help with function of the heart skeletal muscular nervous systems and if you take in too many of these you can cause some problems with homeostasis okay Mel nourishment is when you are missing something this can result in deformities it could result in disease or even death under nutrition is when you are not getting enough chemical energy from your diet it will cause you to use up stored fat or carbohydrates break down your own proteins reduce your muscle mass can cause protein deficiencies for your brain and it can cause long term or long term damage or death we can look at nutritional needs to get an idea if there are genetic issues at play so one example hemochromatosis will cause iron to build up even if you're not taking in a lot of iron how we've been able to examine these is through epidemiology it's a really cool field you're hearing a lot about it right now and one more practical example of where this has kind of come up is folic acid and if you are an expecting mother typically they will have you take tablets with folic acid or have you eat food items that contain folic acid because that will help to prevent neural tube defects so four main stages that are going to be involved with food processing are the actual ingestion digestion which is where we're going to spend a good chunk overtime absorptions another big one and then finally elimination ingestion is taking in your food suspension feeders an example that would be like whales where they take in water under and the ocean and then they use their baleen to push the water back out but to keep any of the small fish or other organisms that are present in the ocean water that they would then be able to ingest so substrate feeders would be like caterpillars they live on or in their food source fluid feeders would be like mosquitoes taking out our blood and then bulk feeders the picture on the next page is truly amazing I feel like that is a I knew I was gonna forget it I believe it's a rock python and it is ingesting I mean one second it's ingesting that ghazal which I just think is freaking amazing anyone so moving on digestion is breaking things down small enough that our cells are going to be able to absorb it so mechanical digestion helps to make the surface area or food more manageable for the rest of the organs in our alimentary canal chemical digestion is using enzymes to help to split the food down into even smaller pieces so we can get it into the cells and they can make it into what they needed so this is chemical digestion process of enzymatic hydrolysis we check for the slowly will basically slit bonds and molecules by adding water so this is gone back all to that dehydration synthesis stuff we took the water out now we're adding the water back in okay absorption is taking up the nutrients and elimination is getting rid of any of the undigested material so digestive compartments most of our animals are going to process their food in specialized compartments this helps us to not digest our own cells only Anja and digest the materials that have been taking in intracellular that's when the food particles are broken down via phagocytosis we talked about that a while back with cells extracellular is breaking down the food outside of the cells this is pretty much what we do so it's in compartments that are continuous with the external part of the animal's body if you have a simple body plan you're trying to have a gastrovascular cavity we see that with a Hydra that takes care of both the digestion and the distribution okay and then you can have more complex animals that will have that complete digestive tract that has both the mouth and the anus as part of their digestive tube we also call that an elementary canal and it will have regions that kind of take things step by step to allow these both the digestion and the absorption processes to occur so those are just some examples other than humans so the mammalian digestive system has the alimentary canal we just talked about that and also has some accessory glands that help to get the enzymes and other juices and the pH levels that we need to be able to digest our food these accessory glands include the salivary glands the pancreas the liver and the gallbladder okay food is moved along the elementary canal by peristalsis those are the smooth muscles we talked about back in chapter 40 rhythmic contractions that help to kind of move things along and then there are valves that are sphincters that basically did are like our stop lights and they determine whether something can enter and whether something can exit okay so the picture on the left is one that you definitely have seen before I would suspect the one on the right I thought was kind of different but it's showing you have where those accessory glands come into play and just how the elementary canal if you just wanted to draw it not necessarily how we see it in the human body but just going from one place to another going down that particular chain you can see the different steps that would take place okay so the first place where digestion takes place is in the oral cavity that's mechanical so that's your mouth solidary glands are able to lubricate the flute food by delivering saliva to it and our teeth helped break it down using the salivary amylase so that's going to break down your sugars your carbohydrates the sly ball also has mucus which is gonna have some other stuff in there but the big one is the mucin that helps to protect your mouth and also helps to lubricate the food again we're increasing our surface area we're turning our food into bolus and then the tongue is able to help to make that and to help you swallow it the far niché's is basically the connection to our respiratory system and to the rest of our digestive system is able to throat is able to open to both the esophagus which is where we're going to be going next or to the trachea the windpipe and we want to make sure that food doesn't go down our windpipe so we have this nice little piece of our phonics called the epiglottis which basically will block the trachea so that food goes straight down the esophagus rather than going down the trachea if for some reason that does not work correctly you might call because you might have food inadvertently going through the windpipe which our lungs cannot tolerate okay so we can kind of see where everything is connecting here and again we've got the peristalsis helping to bring those Bullas of food down into the stomach from our esophagus so the bonuses are able to enter the stomach when the cardiac sphincter that's the connection between the esophagus and stomach says okay can enter it turns green in that stomach the food stays there well as it's starting to get digested by the gastric juice which is a mixture of hydrochloric acid and pepsin and enzyme which helps to start break down proteins so we talked about how in the oral cavity we're starting to break down carbohydrates in the stomach we're starting to break down our proteins and then you also know the gastric juice is really acidic so that helps to break down any bacteria that might have inadvertently come in and to break the nature of those proteins so they're more able to be broken apart we don't want that time to stay acidic sorry I'm getting ahead of myself so how we get those the gastric juices the parietal cells are able to provide us with a hydrogen and chlorine hydrogen chloride ions that come into the lumen of the stomach gastrin which is present in the mucus is able to help to encourage their production and stimulates their secretion chief cells and I'll show you a picture with all these in them what are able to secrete the inactive form a pepsin pepsinogen and then in the presence of that acidic environment it's able to become activated and then work its magic on the polypeptides and we talked about how the mucus contains gastrin it also kind of helps protect and stomach lining from the acidic gastric juice and then the food when it's ready is now chyme it's not completely digested but it will be leaving the stomach through the pyloric sphincter and if for some reason you have a gastric ulcer lesion in your stomach lining this often occurs because of that particular bacterium Helicobacter pylori all right so there are your cells you can see how you've got your parietal cells and the prata cells are the source of the hydrogen and chloride ions the chief cells are gonna give you the enzyme pepsin via pepsinogen which is going to help to break down your polypeptides and you've got lots of folds going on there to help to increase the surface area so your stomach is constantly moving it's coordinating those contraction relaxations to help to kind of like a washer help to mix things up to help to break down your food we don't want that acidic time to go back up and to your Vegas and we want to make sure that it doesn't go into the small intestine until it has been somewhat digested so again those speakers sphincters excuse me are acting as your stop and then go entryways between the esophagus obviously we want it not to come in and we don't want to go back into the esophagus and we don't want it to go into the small intestine until we're ready for it so the small intestine is the biggest section or sorry the longest section of our elementary canal at least in humans and this is where the vast majority of digestion of digestion and absorption takes place the major part that we're going to talk about the small intestine is a dragon duodenum yes sorry where the chyme is gonna mix with all of those accessory glands we talked about the different juices that are gonna come from that the different enzymes pancreas liver gallbladder are other chemicals and then actually a small intestine is generating some as well that's actually where the first place we get them from and again I said most of the digestion is gonna occur here the pancreas is able to provide all sorts of enzymes that can break down peptides nucleic acids carbohydrates and lipids and to that we're gonna that it mentions here trypsin chymotrypsin they are released from the pancreas but they are not activated until they are in the lumen of that duodenum remember that we the kind that came in was acidic so that needs to be neutralized and the juices that are being released they are able to neutralize that acidic chyme because the solution that's present there is alkaline so it's basic acid plus base is going to make it have a neutral pH or definitely closer to neutral there's also file that is released that helps to break down fats that's the only one that will be able to do that it's actually made in the liver but it's stored in your gallbladder and it's also used to help break red blood cells that aren't working anymore and then we so in our small intestine we can break down all four types of macromolecules and this continues to take place peristalsis continues to move things along and when it is ready to leave the small intestine it actually is gonna go through some other filters before it goes out but what we can see here this is just kind of showing you step by step you've got your carbs breaking down in your oral cavity and in your small intestine both from enzymes within the small intestine and then sounds coming from the pancreas the proteins are digested in the stomach again and there's enzymes from both the pancreas and the small intestines epithelium that help to break down the proteins the nucleic acids do not get broken down until they get to the small intestine and they can there are enzymes from both places there that help to break those down while fats are only going to be broken down via the enzymes that are generated from the pancreas the jejunum and the ileum are also able to play a role with a small intestine they absorb nutrients and they absorb water we've got a lot of nutrients again we're just constantly breaking down this food so we need to have a place for all these nutrients to go there is a lot of surface area available through the small intestine that basically is acting like a brush and it's able to help give lots of places for those nutrients to be absorbed there's definitely a lot more you would get into if you were taking a physiology class but we're going to stop it here for this intro biology class a little bit more so the nutrients actually do not go straight out into the body they're going to go to the liver the liver is able to make sure those nutrients go where they need to go it's able to help it's the storage place for glucose at least initially they can convert other organic molecules like glucose can be converted to glycogen and they also can break down like drugs and things like that our other organic molecules that you're probably wouldn't be able to get rid of otherwise it's actually in the small intestine where the epithelial cells absorb the lipid components that have been broken apart the fatty acids and monoglycerides and they reform them into triglycerides they coat those now fat units with phospholipids and cholesterol and proteins to form these chylomicrons that will move into lacteals and I'll show you a picture where all this is going and so so the fats are kind of separate from the proteins and the carbohydrates however if you have a lot of fats I do think some of those can go into your liver and that's where you get the fatty liver issues lymphatic vessels are able to take the chylomicron containing lymph that's that extracellular fluid to veins that then return the blood to the heart which is where we can get fatty buildup in our cardiac muscles okay so picture on the left is showing you the villi of the small intestine and then is taking that and breaking it down a little bit further you can see the veins traveling to the liver from the small intestine excuse me and then you've got all the individual little villi and you've got your capillaries your epithelial cells and so again that's where you're going to have the source of the fatty acids reform into triglycerides and then they travel through the lacteal which is able to go straight into the lymph vessel once they have formed they're kymo forgetting the name of it sorry the color microns and then they would go straight up into the vessels that would lead up to your heart okay so they're show another picture of it breaking down the large intestine is where we're gonna be absorbing a lot of the remaining water that's present it's connected via the ileocecal valve 1.5 meters is its approximate length the large intestine consists of the cecum the ascending colon the transverse colon the descending colon the sigmoid column and the rectum so I talked about how it's gonna take up water it's also gonna help to take up salts from any solid waste before you're eliminated before they were eliminated sorry you're not eliminated the cecum helps to get rid of we haven't really talked about what happens with roughage like lettuce spinach things like that the cecum helps to ferment that plant material and it's the connection point between the small and the large intestines it contains a little extension called the appendix which can have some roles with immunity and there is the colon Isis houses bacteria that can live on unabsorbed organic material so that would be like this plant material and sometimes can produce vitamins so there are the different components of your large intestine and there you can see the cecum wares connecting to your small intestine and that little appendix thing coming off of it okay to get rid of our waste materials that's in the form of feces undigested material bacteria because more solid is initially that colon and where water is removed that's the order in the rectum until it's eliminated and then there are speakers that between the rectum and the anus to help to control those bowel movements all right so evolutionary adaptations that have kind of come along with diet so vertebrates tend to have a pretty basic plan but there are some variations depending on what types of food sources they eat that would be dental they're variations also within their stomach and intestinal and then we're also going to talk about some mutualistic adaptations so dentition would be the first one what types of teeth and the amount of teeth that we tend to see and that will play a role based on your diet so carnivores are gonna have molars and canines and incisors herbivores are gonna have more the broadridge surfaces like your molars and then omnivores would have both so there you can see examples it's not that you won't have all of them but you're going to have more the ones that you need and they're going to be more useful in the form that you need them so carnivores have larger expandable stomachs herbivores and omnivores are gonna have bigger elementary cow nails our sorry longer elementary canals because remember they've got the undigested stuff they've got the the grass and the plants that have to be fermented to be broken down as opposed to carbohydrates or lipids or probably peptides so remember we said how the cecum is where you're gonna have your undigested plant material kind of fermented you can see in the carnivore we don't have too much of a space for that because that's not our primary source of food we can see over with more of herbivore you need to have a much larger cecum to be able to handle digesting all that I started fermenting all that undigested plant material ok mutualistic adaptations so we talked about the fermentation chambers so what's gonna happen here with these animals called ruminants aka counts is that you need to have microorganisms be involved to help to break down some of this undigested plant material so a mutualistic relationship develops the cow takes in grass or plant material and it enters into the rumen it is partially broken down in the rumen and then it actually comes back out the cow spits chews it back up and helps to break it down a little bit more so that then and through the so that happens in the reticulum and then once it comes back in it moves into the Amasa which helps to break it down even further and then finally it's able to go into the abomasum and move through the rest of the digestive system feedback circuits we're going to talk about some different examples of feedback circuits that influence digestion and energy storage as well as appetite what type of food and what type of nutrients you need depend on or will vary based on what's available to you and what an animal has chosen to eat the digestive system does not work together all at once it works as it's needed based on what's in it and so the nervous system and the endocrine system will be involved in regulating that digestion process the endocrine system does it with hormones okay so if we take a look at this particular picture we see that what's the stomach as it takes in food and starts to enlarge will promote the release of gastrin which will help to get the gastric juices ready to go within the stomach with our second example here we have that as time has entered in to our small intestine secretin and another enzyme CCK will be released the CC the CC k is helping to release some of the enzymes that need to go into the small intestine help to break down the food the secretin is producing the buffer the alkaline solution that will help to neutralize the acidic chyme we also see that CCK will play a role if you have a pretty sorry and C CK will also help to encourage the release of bile to help to break down fats if you have a lot of secretin and a lot of CCK that are released they actually help to slow down the digestion process because you've had a pretty fatty meal and so they make it so that it's moving a little bit slower to help to give it more time to digest the fats that were a part of that particular food meal energy storage energy molecules that are not needed initially will get stored in the liver through or in muscle cells through the form glycogen and if there is energy above and beyond that is stored in adipose tissue and we talked about the cellular respiration how we can oxidize our glucose to give us ATP to be able to do what we need to and there are two hormones insulin and glucagon which help to break down the glycogen into glucose liver is where this homeostasis process takes place when you have a hefty carbohydrate mill your insulin levels go up and that causes quite a jen to be formed from the glucose and if your blood sugar drops glucagon will start to break down the glycogen is another enzyme there's another hormone excuse me that will break down the glycogen and cause glucose to form so here's that feedback loop homeostasis is what we would expose that are considered normal for glucose and you're on your blood stream so we see that it goes up after you eat the pancreas releases the insulin or secretes the insulin which allows the glucose to be converted into glycogen and then when your blood glucose levels drop your pancreas rather than secreting insulin skree sleek akan which will help to break down the glycogen into glucose and cause your blood glucose blood levels to raise if you have taken in too much nourishment you can become obese and that excess energy would be stored as fat and houses or is thought to contribute to a lot of pretty serious medical situation such as diabetes colon breast cancer heart attacks strokes some mechanisms researchers have been able to identify to help to regulate the body weight will are based in part on hormones that affect both long term and short term appetite and one study they've seen is with leptin that it's made by adipose tissue and so if you had lose weight if you have leptin present that helps to reduce your appetite but as you lose weight and you're not making as much left and that can actually cause an increase in appetite so it kind of acts as a vicious cycle jerilyn is the is known the hormone that prevents sorry does not prevent and that triggers hunger feelings insulin was we've talked about is what's gonna help to break down the sugar but insulin also plays a role in suppressing your appetite pyy is secreted by the small intestine it's that happens after your meals that also helps to suppress your appetite by countering geralyn's impact and then we talked about what leptin will do so how does a beastie play a role with evolution there's a species of birds that called pay trolls that become a beast as chicks so they have to observe consume enough protein from their food to take in more calories and what they're going to use up what this idea of maintaining weight comes from is again survival of the fittest by having nutrients stored in your body you're more likely to survive famines and so that would have been kind of what are the issues with maintaining weight