Interesting Absorption

Cow intestines, (photo credit,www2.ca.uky.edu/)

Cow Intestines.

I’m back!  And none the worse for wear.  Today I’m here to talk about a very interesting subject, cow intestines.  A cow’s intestines are made up of three different organs.  The small intestine, the cecum, and the Large intestine.  The small intestine measures about 20 times the length of the animal. It is composed of three sections: the duodenum, jejunum, and ileum. The small intestine also receives the secretions of the pancreas and the gallbladder, which aids digestion. Most of the digestive process is completed here, and many nutrients are absorbed through the villi (small finger-like projections) and into the blood and lymphatic systems.  The cecum is a large area located at the junction of the small and large intestine where some previously undigested fiber may be broken down. Although the complete function of the cecum has not been established.  And the large intestine is the last segment of the tract through which undigested feed passes. Some bacterial digestion of undigested feed occurs, but absorption of water is the primary digestive activity occurring in the large intestine.  Isn’t it interesting how long the intestines are?  Though I imagine that it takes a lot of work to break down and get nutrients from what a cow eats.

To see more cow intestine, click here to watch my video.

Surviving Seeds

Chicken stomach (photo credit nutrenaworld.com)

Chicken Stomachs

This week we’ll look at the chicken stomach.  Bird stomachs are different from mammal stomachs in many ways.  Today we will be looking at the Crop, the Proventriculus, and the Gizzard.  The crop is an out-pocketing of the esophagus and is located just outside the body cavity in the neck region.  Any swallowed food and water is stored in the crop until it is time to pass it on to the rest of the digestive tract. When the crop is empty, or nearly empty, it sends hunger signals to the brain so that the chicken will eat more. Although salivary glands of the mouth secrete the digestive enzyme amylase, very little digestion actually takes place in the crop, it is simply a temporary storage pouch.  The proventriculus (also known as the ‘true stomach’) is the glandular stomach where digestion begins. As with human stomachs, hydrochloric acid and digestive enzymes (like pepsin) are added to the food here. At this point however, the food has not yet been ground up. The term ‘proventriculus’ is used since it comes before the ‘ventriculus’ or gizzard, with ‘pro’ being the Latin term meaning before.  And finally, the gizzard.  The gizzard, or ventriculus, is a part of the digestive tract unique to birds. It is often referred to as the ‘mechanical stomach’. It is made up of two sets of strong muscles which act as the bird’s teeth. Consumed food and the digestive juices from the salivary glands and the proventriculus pass into the gizzard for grinding, mixing, and mashing, which is aided by the small stones or grit the bird consumes. These stones remain in the gizzard until they become ground into pieces small enough to pass through to the rest of the digestive tract. The stones/grit are weakened by the acidic environment created in the proventriculus and then are ground into tiny pieces by the strong muscles of the gizzard.  This is how chickens can eat a lot of hard seeds and not get digestive issues like humans.  Ultimately, Chicken stomachs are designed to ingest the bugs and seeds which chickens need to survive.  If any part of the stomach did not work correctly, the chicken might die.  Which just goes to show how intricate the whole system is.

To see more chicken anatomy, click here to watch my video.

Explaining Ingestion Of Excrement

Dog Stomachs

Dog stomach (Photo credit Hill’s Pet Nutrition)

Now, no talk of stomachs can be complete without finding out how dogs can eat carrion and excrement.  A dog’s stomach is like an accordion in that it folds to almost a thin intestine-like organ when it is empty, and when filled, it expands to full size, unfolding all the wrinkles.  While a human stomach is simply a bag, not folding at all.  The stomach has some very strong muscle in its lining, and it will constantly massage the food, thus making sure the digestive juices get into close contact with all the food.  Accordingly, the dog’s stomach will take up some 70-75% of the total volume of the entire gastrointestinal system. It is huge. The human stomach will be only a small fraction of the system, taking up only about 20% of its total volume.  In general, all this is geared towards the stomach handling big portions of food at a time -and being given the opportunity to finish a meal before being filled again. It is like a washing machine running through its program and then waiting for the next load.  This is a huge difference compared to the human system that is much more like a septic tank where the food seeps through all the time.  Another important aspect that is often ignored is that a dog’s stomach is not supposed to be working constantly. It is meant to do a lot of hard work for some time – and then rest for a long period of time. It makes sense that it needs rest, considering how much harder it has to work, compared to a human stomach. Yet, a human stomach generally gets some serious rest every night. Our meals typically take no more than about 3-4 hours for the stomach to finish and hand over to the intestine, so even if we get a “good night snack” just before bedtime, there will still be 4-6 hours rest available for the stomach before breakfast. For the dog, digestion of a full meal can easily take more than 24 hours.  Conclusively, the dog’s stomach is a depot organ – the human stomach is merely a transit station.  This is why a dog can ingest excrement.  And as said before, humans cannot ingest excrement without painful consequences.  So I would advise against eating anything rotten, or something that has already been digested, and anyway, who would want to?

To see what the inside of a dog stomach looks like and where it is in a dog’s body, click Here to watch the video

Prosperous And Carnivorous

Concerning Cat Stomachs.

Cat stomach (photo credit, Drs. Foster & Smith)

Now it is time to focus on a carnivore’s stomach.  Namely, the cat stomach.  Obviously, a carnivore’s stomach is different then say, a goat or horse stomach.  The esophagus transports food to the stomach where it enters a valve-like structure titled the cardiac sphincter.  From there, it enters the stomach.  A cat’s stomach is a sac-like structure designed to store large amounts of food and continue the digestive process.  Cats usually swallow large lumps of food, rarely chewing for very long.  So meat and bones make their way to the stomach and are ground up there.  The interior of the stomach is made up of a series of folds called “gastric folds”.  Their function is to grind the food into small pieces and digest it.  The inner stomach lining also secretes acids and enzymes to break down food.  Once the initial stomach digestive process is complete, the partially digested food exits the stomach through the pyloric sphincter area and then enters the duodenum. Once eaten, most food leaves the stomach within twelve hours after entering.  The cat stomach was designed very well for what it is meant to do, although, modern cats that are fed cat food out of containers may need some supplementing.   What is better for my cat?  You may ask, wet food or dry food?  Well, this is sort of a trick question because truthfully, (depending on the quality) the most ideal diet is a mixture of both.  You see, wet food is usually more nutritious, although if a cat never chews anything other than soft food their teeth can get weak.  Hearts and brains are the best things you can supplement into your cat’s diet.  As they contain the taurine cats need to thwart health problems and death.  Egg yolks are also a good idea as they are nutritious and good for your cat’s fur.  Conclusively, cats are carnivores and need lots of protein and saturated fats as well as access to greenery such as cat grass or catnip for other nutrients.  Assuredly, if you give your cat this diet, it will live long and prosper.

To see what the cat stomach looks like and some more anatomy, watch my video at http://youtu.be/y9-M99e4l0I

Chyme Time

Horse Stomachs

Horse stomach (photo credit, succeed-equine.com)

Now we are going to move on to another kind of stomach, the horse stomach.  Interestingly, horse’s stomachs (like their hearts) are relatively small for the size of the animal, this limits the intake and storage of food.   An average horse weighs 800 to 1,200 pounds.  But their stomach capacity is only about four gallons, and works best when it contains two gallons.  Also, their stomachs empty when they are about 2/3 full.  Whether or not the stomach enzymes have completed their processing of the food.  This inhibits full digestion and proper utilization of food. Continuous foraging or several small feedings per day are preferable to one or two large feedings.  

The horse stomach consists of a non-glandular proximal region (saccus cecus), divided by a distinct border, the margo plicatus, from the glandular distal stomach.  In the stomach, assorted acids and the enzyme pepsin break down food. Pepsin allows for the further breakdown of proteins into amino acid chains.  Other enzymes include resin and lipase. Additionally, the stomach absorbs some water, as well as ions and lipid soluble compounds. The end product is food broken down into chyme.  It then leaves the stomach through the pyloric valve, which controls the flow of food out of the stomach.  Although not as complex as a cow stomach, horses stomachs serve them well.  They do not weigh the horse down or hinder their agility, such as the cow stomach does.  Although if a horse eats too much, it can get bloated like a cow.  Ultimately, make sure your horse doesn’t eat too much too fast, and remember, if an animal’s gut is not healthy, the animal is not healthy.

To see a horse stomach compared to a cow stomach and what the horse stomach looks like, watch my video at http://youtu.be/n1jUkgmUAts

Honeycombs and Hardware

Cow Stomachs.

Abomasum (Photo credit: Wikipedia)

It is widely known that cattle have four stomachs, enabling them to consume grass and vegetation.  But, this statement is a little misleading and not quite accurate.  You see, cattle do not have “four stomachs” per se, instead they have one stomach with four compartments, the rumen, the reticulum, the omasum, and the abomasum.  The rumen is the largest compartment and forms specialized microorganisms that assist in digesting recosumed cud.  Cud is the product of otherwise undigestible foods that are regurgitated, rechewed, and reswallowed.  The microbes in the rumen also synthesize amino acids from non protein nitrogenous sources, such as urea and ammonia.  As these microbes reproduce in the rumen, older generations die and their cells continue on through the digestive tract. These cells are then partially digested by the cattle, allowing them to gain a high-quality protein source. These features allow cattle to thrive on grasses and other vegetation unlike dogs, cats, and humans, who are forced to find their protein sources elsewhere.  While the omasum’s main function is to absorb water and nutrients from the digestible food, and the abomasum functions like the human stomach; this is why it is known as the “true stomach”.  The reticulum, the smallest compartment, is known as the “honeycomb”. Cattle sometimes consume metal objects which are deposited in the reticulum, and irritation from the metal objects causes hardware disease. So in conclusion, cattle have a very sophisticated and convenient way to ingest and digest grasses and vegetation and still get all the nutrients that they need to survive and thrive.  

To see some more cow anatomy and a few different breeds of cattle, watch the video at http://youtu.be/Ce7kjmLcPPg