Digestive Systems in Cows and Humans

Digestive Systems in Cows and Humans By Troy Clacy

Small Intestine

Large Intestine

cow

human

cow

human

The large intestine is made up of many different structures including the cecum, colon, rectum and anus. The main roles of these structures is to absorb water from the remaining food that couldn't be digested and excrete the unwanted waste material from the body. Cows and humans both have large intestines present and they play the same role in the two digestive systems. As the same as rest of the organs it is much bigger in cows as they have a larger body mass and their diet of grass is harder to breakdown. In cows it is also longer with no real shape to it placed at the rear end of the cow, on the other hand it forms an upside U shape forming around the rest of the digestive sytem.

The small intestine is found after the stomach and before the large intestine in both human and cow's digestive systems. The small intestine is where 90% of the absorption that occurs in our digestive system takes place of nutrients such as: fatty acids, sugars, and amino acids. These nutrients are enzymatically broken down in order for them to be absorbed and dispersed to the rest of the body. These nutrients are absorbed by villi which are finger like projections found in the intestinal wall to increase the surface area to aid the rate of absorption. An average human small intestine is about 6.1m, however, a cow's small intestine is on average a whopping 46m. Cow's small intestines are much larger because their diet of grass is much harder to breakdown and absorb the nutrients of cellulose compared to a human diet which contains a lot of protein which is easier to absorb.

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human

Similarities

Cow and human digestive systems are actually really similar in the process and organs used for their digestion of food. Both cows and humans have a mouth, esophagus, main stomach, a large and small intestine, a colon and a cecum. All these organs are in both but are much bigger in a cow as a cow is bigger and eats grass which is harder to breakdown. Even though the cow has an abnormal stomach a human still has a gastric chamber and pyloric chamber in common with the cow's stomach.

Pancreas

Salivary Glands

Differences

Digestive Systems

The pancreas is a long, flat gland that lies in the abdomen area just after the stomach. It's main job is to produce enzymes which get released into the small intestine to help with the breakdown of the food and further digestion. The pancreas also contains little lots of cells called islets. These cells produce insulin and glucagon to help control the level of glucose in the blood. Cows and humans both have a pancreas for the same function and in both species the pancreas can elevate the pH level to between 7 and 8 to further break down the food in the small intestine.

Cows and humans are both heterotrophs as they cannot gain their energy from the sun they need to eat a substance and absorb the nutrients and energy from it in order to create their own energy. However, their two digestive systems are both very different based on their diet and nutritional needs. Cows are found in the foregut fermenters as they have a vastly expanded stomach compared to humans. Humans fit in to the carnivore digestion category as we eat a lot of meat and have kanine teeth to break down the meat. Humans and cows have majority the same organs in the digestive system nevertheless cows eat grass not meat so there are a few differences between the two.

There are a few differences between the digestive systems of cows and humans and they are mainly as a result of their dietary needs. Obviously, cows eat grass and grass requires different or modified organs to digest and extract the nutrients and energy from it compared to what is needed for the food humans eat. In saying this the main differences are the teeth, mouth, stomach, gut and enzymes.

looks same in both

The salivary glands are apart of the digestive system and they are found in both cows and humans to help with the chemical breakdown of food. The function of the salivary glands is to produce saliva, which is needed to keep the mouth and other parts of the digestive system moist. The salivary glands also help break down carbohydrates and lubricates the food and the esophagus to get it down to the rest of the digestive system. Between cows and humans the salivary glands perform the same function but are much larger in cows to help digest the grass. In humans the amount of saliva secreted by the salivary glands is usually about 1–1.5 litres in 24 hours as the meat and food we eat only requires a small amount of saliva in their digestion. Cows however, produce about 65 litres of saliva a day to help with the digestion of the grass they've eaten, if this much saliva was not produced the cow would be unable to swallow the dry grass.

Teeth

Cecum

The teeth are apart of the digestive system as a mechanical system breaking down the food by crushing them and increasing the surface are preparing them for swallowing and then digestion. Cows and humans have different teeth, and this is a result of their different diets. Cows are herbivores and eat only eat grass meaning they only have a bottom row of teeth with 8 incisors and 6 molars and a hard leathery pad at the top instead of a top row of teeth. They grind the grass on to the pad with their teeth and tongue and break it down to make it easier to digest. canines are not present in cows as they are not needed to eat grass, however, humans have four canines which are required for the mechanical breakdown of meat. An average human has 32 teeth with 16 on the top and bottom rows unlike the cow which only has the bottom row and the rough pad on the top.

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cow

Esophagus

human

Colon

The cecum is a pouch-like organ found between the small and large intestines in humans and many animals including cows. and the appendix, essentially right in the center of the digestive tract. Its chief role in most animals is to provide bacteria that can help the body break down plant-based foods, The cecum accepts and stores processed material from the small intestine and moves it towards the colon. As the processed food approaches the end of the small intestine, a valve separating the small and large intestines opens, the cecum expands and the material enters. After being stored in the cecum the digested food then enters the large intestine to continue the process of digestion and absorption.

Stomach

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cow

The esophagus is a muscular tube connecting the stomach to the mouth and really only has one function. This function is to transport food, liquids, and saliva from the mouth to the stomach ready for the rest of the process of digestion, and the absorption of nutrients has not begun yet. The food isn't moved down the tube by gravity, contractions of the muscles in the esophageal wall move the food down the esophageal tube and through the sphincter. The esophagus is found in both cows and humans and the function is identical between the two with nearly no difference besides the length.

Summed up

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human

Liver and Gall Bladder

Cows and humans both have stomachs but this is the main part of the digestive system where the two are most different. In a human stomach the food enters the stomach and the muscles in the stomach wall mix and mash the food whilst acidic juices made by glands are secreted into stomach help breakdown the food. After the food has spent 3 hours breaking down it becomes a liquid and is moved into the small intestine, where the process of digestion is continued. Cows on the other hand are ruminants which have one stomach but several different compartments. They graze and chew grass which is then swallowed for the first time, and is passed into the rumen the first compartment of the stomach. Fermentation begins in this chamber by bacteria beginning to breakdown the cellulose in the grass and then moving the now "cud" to the next part of the stomach, the reticulum preparing it to be regurgitated. Parts of the cud is then moved back up to the mouth where it is chewed for a second time creating a paste out of it. This paste is then swallowed again and passes through the first two compartments of the stomach aging before eventually getting to the omasum where water and salts are absorbed from the food. From the omasum it is taken to the abomasum which is the last compartment of the stomach and is equivalent to the human stomach where the juices are secreted into it to finish off the breaking down of the food.

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human

cow

Rectum and Anus

Bibliography

• https://books.google.com.au/books?id=Aw1fBwAAQBAJ&pg=PT920&lpg=PT920&dq=colon+length+in+cow&source=bl&ots=YoDrfMu8W3&sig=k8SXHc-gfeh_K-2Iy4gx9l6KEsU&hl=en&sa=X&ei=2QdbVY-RAYmI8QXf6oDwAg&ved=0CDgQ6AEwBA#v=onepage&q=colon%20length%20in%20cow&f=false
• http://www.fda.gov/AnimalVeterinary/ResourcesforYou/AnimalHealthLiteracy/ucm255500.htm
• http://www.dairyvietnam.com/en/Structure-of-the-digestive-system/How-does-cow-digestive-system-work.html
• http://www2.kenyon.edu/projects/farmschool/food/milkbio.htm
• http://animalcorner.co.uk/cow-anatomy/
• http://www.enchantedlearning.com/subjects/anatomy/digestive/
• http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Digestive_system
• http://www.webmd.com/digestive-disorders/picture-of-the-intestines
• Biology book

Cow and human digestive systems are extremely alike but do have some very clear differences in their digestive systems. The main differences are the mechanical breakdown in the mouth, the stomach and the size and length of each organ compared to each other. Most other organs have the same function in both cows and humans except for most of the time when the cow organ is much larger based on their diet and habitat.

In both cows and humans there are is a liver and gall bladder which are found just after the stomach and before the small intestine and they both play a small role in the digestive system. Bile is produced by the liver which is a greenish-brown alkaline fluid which aids digestion. This bile is stored in the gall bladder and is secreted into the small intestine as the food doesn't enter these two organs which the bile is then used to help break down dietary fats. A human liver weighs on average of about 1.5kg and a cow liver can reach much larger weights.

The colon takes up most of the room in the large intestine where it reabsorbs fluids and process waste in the body and prepares the left over to be excreted via the other structures of the large intestine. In both cows and humans the colon consists of four different parts: descending colon, ascending colon, transverse colon, and sigmoid colon. All these different parts of the colon play their own role in completing the process of digestion and absorption before it gets to the elimination stage. All up the colon is about 5-6 metres in a human and 11 metres in a cow, quite obviously the large intestine is much shorter than the small intestine but is quite larger in diameter.

The rectum and anus are both apart of the excretion process of cows and humans. The rectum is a temporary storage place for feces before they are excreted via the anus.This defecate occurs by the rectal walls expanding due to the feces stacking up, then the stretch receptors in the rectal walls stimulate an urge to defecate and it occurs. The flow of feces through the anus is controlled by the anal sphincter muscle, the internal and external sphincter muscles relax, allowing the feces to pass through to the outside world. The anus is the end of the digestive system for both cows and humans and all the nutrients have been absorbed throughout the whole system to be used all around the body.