Counting Sheep

The Biology Behind the Sheep

Sheep may appear to be woolly pillows on four legs, but on the inside they are complicated and intriguing creatures.

Digestive System

Sheep are ruminant animals, meaning they digest their food using bacteria in the front component of the stomach, the rumen and like all ruminants, they have a four chambered stomach. Humans, horses and wolves are three examples of non-ruminant species who digest their food with the use of enzymes.

For the this herbivore, there are several steps to break down and digest their food. To begin this cycle, the sheep eats for several hours a day, only stopping to chew and relax. This broken down food travels down the esophagus and into the rumen. The rumen behaves like a shed for storing food, which is then regurgitated and re-chewed. Once the food has been regurgitated and rechewed, the food tours down to the other three segments of the stomach, the reticulum, omasum and abomasum. In the reticulum, a honey comb like section which mixes with food in the rumen. Little occurs in the omasum, or the many piles, known as this because of the fact that it is made up of many layers of tissue. The abomasm is rather like one of a non-ruminant's such as a human, digesting nutrients via enzymes and acid.

Basic Respiratory System

The respiratory system allows animals to retrieve oxygen and then use the oxygen to stamp out carbon dioxide in the body. It is made up of the basic nostrils, mouth and the pleura, naval cavities, pharynx, larynx, trachea and bronchi. The respiratory system of a sheep is very much like that of a humans.

The sheep mainly breaths through the nose though rarely through the mouth. When one breathes, the diaphragm and surrounding muscles tighten, enabling the lungs to expand for the duration of the breath. Once the lungs have expanded, the nose (which wets and warms the air for the larynx, trachea and the bronchial tubes in the lungs) or possibly mouth takes in air, which travels down the trachea, or windpipe and then into the bronchi. From the bronchi, it moves into the lungs. There the red blood cells pick it up and deliver the oxygen to other needing cells all over the body. Whilst doing this they pick up the carbon dioxide and take it to the lungs to be exhaled.

The Sheep Brain & Those Surrounding

While mammal brains are pretty similar, or have some similarities at least, their are several differences that define a sheep and human brain, our two main subjects in this chapter, for comparison. Both humans and sheep have the same basic structure, made up of the usual cerebrum, cerebellum, brain stem e.t.c.

For starters, the sheep brain is smaller in both size and shape and has less ridges and contours than the human brain. Increased contours and ridges increase the area and space inside the brain, allowing more intelligence. Other noticeable differences involve the brain stem, skull and spine. Humans have the ability to rotate their necks 90 degrees due to the fact that we carry our weight upright, where as sheep are four legged, with horizontal spines and do not. Additionally, the human brain weighs 1300-1400 grams, the sheep, roughly 140 grams. The average size of the frontal lobe, number of ridges and contours are connected to the intelligence of the species. Sheep do not have as many ridges, contours and their frontal lobe is not as large or heavy as the humans, but it doesn't mean they're dumb. Though when you observe the sheep, you probably don't see anything special, but the sheep can perform some advanced tasks, like remembering the faces of humans and sheep for 2 years plus.

Frontal Lobe

The frontal lobe, is, hence the name located in the front of the brain and only distributes around a few percent of the overall weight and volume, in contrast the human's frontal lobe gives around twenty five percent of the overall weight and volume. The frontal lobe accounts for behavior, analysis and the similar.

Olfactory Bulb

Humans, compared to other mammals have a rather bad sense of smell. Like a lot of mammals, the sheep has a better sense of smell than your general human, meaning a more developed olfactory bulb, two or three times bigger than a humans. This fact shows that smell is a important function for the sheep, allowing the sheep to recognize their mothers and other important sheep. You will find the olfactory bulb underlying the frontal lobe in the brain. As is obvious, the olfactory bulbs plays a role in smell.

Optic Chiasm

Hence its name, the optic chiasm supports the eyes, located down the bottom of the brain, near the optic nerve fibers from each eye cross over to reach the other side of the brain, as the right eye's messages go to the left side of the brain and the left eye's is vise versa. Again, the sheep's optic chiasm is more developed than the humans due to the fact that their eyes are on either side of their head, rather than on the front.

Photo Caption: Made by Ashley, comparison of the human and sheep digestive system (venn diagram)

Reference:

http://www.answers.com/Q/Examples_of_non-ruminant_animals -Around 5/6/15

http://www.ctsanimals.ca/va2040/resources/toKnow/pdfSH_2040_1-1.pdf

Around 5/6/15

http://en.wikipedia.org/wiki/Sheep#Diet Around 6/6/15

http://www.sheep101.info/cud.html Around 6/6/15 and 12/06/15

https://answers.yahoo.com/question/index?qid=20071128203543AAJhYkM Around 6/6/15

http://tinypic.com/?t=postupload 12/06/15 & 10/6/15

https://uk.answers.yahoo.com/question/index?qid=20081005143459AA9aZxA 12/06/15

http://www.nhlbi.nih.gov/health/health-topics/topics/hlw/whathappens 12/6/15

http://hes.ucfsd.org/gclaypo/repiratorysys.html 12/6/15

http://www.differencebetween.net/science/difference-between-human-and-sheep-brain 15/06/15

Gas By Fannylight, yahoo user, answered somethinghonest in 2011 on https://answers.yahoo.com/question/index?qid=20110222235735AAXCBXE We visited the answer on 16/06/15

16/06/15

http://www.dummies.com/how-to/content/examining-the-brains-four-lobes-frontal-parietal-t.html 16/06/15

http://www.ehow.com/facts_5976187_differences-between-human-sheep-brain.html 17/06/15