What Is The Gallbladder?

Questions
Circulatory
Compare and contrast veins and arteries in blood traveling to or from the heart and containing oxygenated or deoxygenated blood (and the exception).
The arteries job is to take oxygenated blood and transport if to the other organs and cells of the body, away from the heart. Then the veins carry deoxygenated blood back to the heart from the organs. The two exceptions to this is the pulmonary arteries and veins. The pulmonary arteries take deoxygenated blood and delivers it to the the lungs. While the pulmonary veins take deoxygenated blood from the lungs and then transport it throughout the body.
Compare and contrast veins and arteries in terms of the following: Thickness of muscle layer
Both veins and arteries have the
Why doesn’t a rat have one?
The purpose of the gallbladder is to hold the bile when it is not being used. Rats don’t need a gallbladder because they don’t consume that many fatty foods that require a lot of bile. Instead, rats consume mostly plants. Bile is a liquid that breaks down fatty acids. The rats make muricholic acid which is a type of bile that is directly released into the small intestines from the liver, instead of stored in the gallbladder.
What does a caecum contain and for what purpose? Why does a rat have a large caecum? What do we have instead and why?
The caecum contains symbiotic bacteria. Symbiotic bacteria breaks down cellulose from plants. Rats have a large caesum because they are herbivorous and mainly eat plants so they have to have lots of room to digestive the cellulose. Humans have an appendix that used to help them digest plants. This is because over the years while humans evolved the function of the appendix was no longer needed. So, appendix does not have an important function, and if it is removed it wouldn’t do any
Having so many alveoli is an advantage because it gives a larger surface area in order for gas exchanges (oxygen and carbon dioxides) to happen successfully. The alveoli is better for the lungs than having a smooth flat lining because they create a larger surface area, like I said above. The blood vessels that surround the alveoli are capillaries. The capillaries go around the alveoli like a net. The capillaries around the alveoli is where oxygen will enter the alveoli. The capillaries are the blood vessels because they are known as the exchange vessels. These vessels are the thickness of one cell and they are also where oxygen and other substances are taken out of the bloodstream and transported to other parts of the body.
What are the ridges on the trachea? What is their purpose?
The ridges on the trachea are called C-shaped cartilage rings. The cartilage being firm helps the trachea from not collapsing, then the cartilage being movable lets the trachea be able to move to move freely while breathing. The opening of the C-shaped of the cartilage is on the back of the trachea. The ridges on the trachea don’t go completely around the trachea because if they would the ridges would push against the esophagus it would make it hard to