Tuesday, January 24, 2012

Comparative Vertebrate Post

The immune system is a complex network of cells and organs, designed to defend the body against bacteria’s, viruses, toxins, parasites and other foreign material.

The Human Immune System:
The organs of the immune system are found all throughout the body, they're called lymphoid organs because they are the place where the growth of the lymphocytes happens. White blood cells are the key operators of the immune system. Other important components of the immune system are in the blood, thymus, lymph nodes, bone marrow, spleen, lungs, liver, and intestines.
The immune system organs are connected by lymphatic vessels (kind of like blood vessels). The immune cells proteins are carried through the vessels in the lymph, which is a clear fluid that bathes the body tissues. All immune system components are connected by the circulatory system.
Major components explanation:
Lymph nodes: Bean shaped structures lying along the lymphatic vessels in specific sites. Like the neck, armpit, and groin. They filter and trap antigens.
-Cells of the lymphocyte portion of the immune system, these are divided into T-cells and B-cells. T-cells or T-lymphocytes initially are processed by the thymus gland; they are responsible for cellular immunity (the recruitment of white blood combat cells). The B-lymphocytes make antibodies, proteins that are used to fight infections. Both cells are all over the body.
-The spleen: Is an organ, in the upper left abdomen, it filters and traps antigens directly from blood stream.
-Bone marrow: consists of connective tissues, where cells form a "delicate mesh work" in a marrow cavity (inside of bones). It is a site of production for many white blood cells.
-The thymus: In front of your heart, it is largest when immune system is still developing and produces T-lymphocytes, which attack foreign materials.
-Leukocytes/white blood cells: They each have a special function in the immune system. Some are designed to react only to bacteria and inflammation, where as some react to parasites and foreign materials, and some produce antibodies.
-Antibodies: They are specialized serum proteins made by B-lymphocytes, in response to antigens. They are also called immunoglobulins.
*The Rat's Immune System is very similar because they are both mammals. Each species creates immune cells and molecules that function in basically the same way, but have variations here and there that make them different from one another. Immune Systems in any vertebrate or invertebrate are trying to accomplish the same thing, health.





Digestion is the process by which food substances are chemically altered into forms of energy where they can be absorbed through cell membranes.

The Digestive System of a Human:
The digestive system is made up of the digestive tract, which is a series of hollow organs joined in a long, twisting tube from the mouth to the anus, as well as other organs that help the body break down and absorb food.
The organs that make up the digestive tract are the: mouth, esophagus, stomach, small intestine, large intestine(colon), rectum, and anus. Inside these organs is a lining called mucosa. In the mouth, stomach, and small intestine, the mucosa has tiny glands that make juices to contribute to the digestion of food. The digestive tract also has a layer of smooth muscle making the walls move, that helps break down food and move it along the tract. The movement of organ walls propels food and liquid through the system and helping mix the contents inside each organ.
Two digestive organs, in particular, the liver and the pancreas, make digestive juices that go to the intestine through small tubes called ducts. The gallbladder keeps the liver's digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive system.



Similarities: The location and function of the humans and the rats digestive systems have many similarities, both are mammals, and possess the three main areas of the digestive system: salivary glands, the oral cavity, and the abdominal cavity. Each of these are divided into specific organs.
Because a rat's digestive tract is so similar to that of a human, it is fair to say that they function in similar ways.
Because a rat's digestive tract is so similar to that of a human, it is fair to say that they function in 
similar ways.
An rats diet is observed by its "dentition pattern", referring to the types of teeth the animal has, the number of teeth, and how they are arranged. There are three main types of dentition patterns: herbivorous, carnivorous, and omnivorous. Rats and humans are both omnivores, so they eat meat and vegetation. Rats, though need to chew more rough food, like tree bark. This is because their front incisor teeth would, if left to grow with nothing to wear them down, would grow through their jaw. This couldn't happen with humans because our teeth stop growing after a certain point.

Differences: A major difference between the rat and human digestive tract, is the fact humans have gall bladders, rats do not. Instead of a gall bladder, rats have a bile duct which is formed from several tubes from the liver. The various lobes of the liver come together to form the bile duct and this helps the transportation of bile into the duodenum.
Also, because rats do not have gall bladders, they are more likely to graze throughout the day, because they do not have a gene to make them feel full, rats could literally eat themselves to death.


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