User:Jut254/sandbox

Wilbur (pronouced Will-Burr) was a genius pig used in the fetal pig dissection in Ms. Carol Lehman's Honors Anatomy and Physiology class during the week of May 20,2013.

Background
Many people have compared the story of Wilbur's life to the story of Frankenstein. In the beginning, Wilbur was created to be a super genius pig and redefine Sus scrofa domesticus evolution. In the laboratory where she was created (location classified), scientists used genetic engineering and DNA from a special breed of pigs to create a "superpig". At first, the creation seemed to go very well, with Wilbur displaying extraordinary characteristics from conception. When scientists realized that this pig could redefine biology, they secretly isolated Wilbur and her mother in a remote part of the world. Word got out, however, and the hunt was on for Wilbur and her scientists. Eventually, a group of soldiers (country unknown) found their hideout and completely wiped out the entire group, leaving Wilbur to be born eventually die. Little did they know that they should have taken the pig, because when Wilbur was born she immediately started acting like no other pig had ever acted before. Wilbur knew that she had very little time to live due to the lack of food and water, so she decided to design this page so her legacy would live on forever. Nobody will ever know how she was able to dissect herself and put herself back together before donating herself to Ms. Carol Lehman's Honors Anatomy and Physiology class, but Wilbur's memory will never be forgotten.

Describe the anatomical position of the fetal pig? Why is this positioning so important in the study of anatomy and physiology?
The anatomical position of the fetal pig is with the pig laying on its back, with the forelegs in a lateral position. This is important because the organs are closest to their natural position and it gives you an open view to dissect it.

Toward the head?
Anterior means toward the head.

Toward the side?
Lateral means toward the side.

Toward the backbone?
Dorsal means toward the backbone.

What structure on the abdominal surface connect the fetus to the placenta? What is the importance of this structure?
The structure that connects the fetus to the placenta is the umbilical cord. This is important because it carries nutrients and wastes to and from the placenta of the mother.

The pig walks on the tip of his toenails, a method of locomotion known as “unguligrade”. How does this differ from the human method of walking?
Humans walk on their heels, while pigs walk on the tip of their toenails.

Gender
Gender: Female

Wilbur is a female because she has a second open just ventral to the anus, known as the urogential opening. This indicates she is a female because males don't have these openings. In our picture, you can see the second opening very clearly, indicating it's a female.

Which ventricle has the greatest muscle mass?
The right ventricle is responsible for pumping blood to the lungs, while the left ventricle is responsible for pumping blood through the aorta and throughout the entire body. Because of this, the left ventricle needs more muscle mass to pump the blood further throughout the entire body.

Is the blood flowing in the arteries under high or low pressure?
Blood flows in the arteries under high pressure. Cardiac muscle contraction creates high blood pressure in the ventricles, which the blood is then pumped to the arteries. The arteries then weave throughout the entire body delivering oxygenated blood. As you get further from the heart, the arterioles decrease in diameter, encountering resistance for the blood to pass through, making it a necessity for arteries to have high blood pressure.

Name three mechanisms that help veins force blood back to the heart
Muscular pumps are necessary for blood to return to the heart, but skeletal muscles contracting, pushing on adjacent veins propelling the blood upward to the heart. Venous valves are folds in the tunica interna that prevent blood from flowing backwards. Also, the respiratory pump aids as the diaphragm contracts, it moves downward decreasing the volume of the abdominal cavity, which results in an increase in pressure which causes a squeezing of local veins which forces blood towards the heart.

Trace the flow of blood from the right atrium to the aorta
Right Atrium…….Tricuspid AV Valve…….Right Ventricle…….Pulmonary Semilunar Valve…….Pulmonary Trunk…….Right/Left Pulmonary Arteries…….Lungs (gas exchange)…….4 Pulmonary Veins…….Left Atrium…….Bicuspid AV Valve…….Left Ventricle…….Aortic Semilunar Valve….Aorta

Why are the lungs by-passed before birth?
The lungs are by-passed before birth because the pulmonary artery is joined with the other artery by a connection called the ductus arteriosus. Much of the blood bypasses the lungs to move directly into the aorta in the fetus. After birth, this short vessel should close, allowing the lungs to become the major factor in circulating gas exchange.

What is the main vessel to which the pulmonary artery joins in the fetal pig?
The main vessel to which the pulmonary artery joins in the fetal pig is the ductus arteriosus. Because the fetal pig doesn’t have fully developed lungs, it would be wasteful to send large amounts of oxygen to the lungs, so the ductus arteriosus takes blood from the pulmonary artery and it directs it to the aorta.

What major artery in your own body carries blood poor in oxygen?
The Pulmonary Artery is the only major artery that carries oxygen poor blood.

Does the blood always flow in the same general direction?
Yes, because the blood must keep its cycle to efficiently carry oxygen throughout the body. The heart must pump de-oxygenated blood to the lungs through the Pulmonary Artery so that it can become oxygenated blood. Then the blood is carried through the Pulmonary veins back to the heart so that it can be pumped to the rest of the body. This cycle cannot be interrupted or have any backflow. We can see this cycle is present in the Fetal Pig with the colored veins and arteries that lead to and from the heart just like a human’s veins and arteries would.

Is the blood flowing in all the capillaries or only in some?
The blood only flows to capillaries when an organ near the capillaries is in need of oxygen or nutrients. For example, when you eat a meal, blood is diverted from other parts of the body and directed to the GI tract to aid digestion.

Why are lymph valves important?
The lymph capillaries are what line the walls of capillaries and helps propel blood throughout the body through propulsion. The lymph valves are one-way flap like structures in blood vessels that prevent blood backflow.

Does the umbilical vein carry blood rich or poor in oxygen? Why does the umbilical vein carry much of the blood from the placenta directly to the liver?
The umbilical vein carries oxygenated blood to the fetal pig’s liver where it continues towards the transverse fissure of the liver, where it splits into two. One of these branches joins with the hepatic portal vein, which carries blood into the liver. The second branch (known as the ductus venosus) allows the majority of the incoming blood to bypass the liver and flow via the left hepatic vein into the inferior vena cava, which carries blood towards the heart.

How do nutrients enter the fetal circulation?
Mainly, nutrients enter the fetal circulation via the umbilical vein. Other ways nutrients are spread throughout the fetal pig is its underdeveloped foramen ovale (separation of the atriums). A fetal Pig’s foramen ovale is open which allows oxygen rich and oxygen poor blood to mix a little bit.