Once you cut up into the throat with scissors and remove the two flaps to expose what is under, the larynx is easily identifiable due its width compared to the small ringed trachea and light pinkish color. Be careful not to remove the lobes of the thyroid gland, which are located on either side of the trachea just posterior to the larynx or voice box. Find the esophagus and locate where it pierces the diaphragm to join the stomach. Observe the eyes of the pig, carefully remove the eyelid so that you can view the eye underneath. Tibialis anterior: This is the most ventral muscle of the shank and lies upon the tibia.
Observe the pancreas, a lobulated glandular structure lighter in color than the neighboring intestines. The penis can be located by cutting away the skin on the flap near the umbilical cord. The pyloric sphincter at the posterior end regulates the release of partially digested food chyme into the duodenum. You can easily locate the right and left atria and ventricle by looking at the heart. Use your pig and also a pig of the opposite sex to identify the structures in the photographs below. The arteries have been filled with red latex and the veins with blue. Neck region: locate the esophagus which transports food and fluids from the pharynx to the stomach in the abdominal cavity.
Do not confuse these glands with lymph nodes which are also located in this region and are smaller, rounded structures superficial to the salivary glands. Large Intestine: the large intestine is joined at the bottom of the small intestine. Stomach Sack-like structure near the liver and intestines where the second phase of digestion breaks down food using acids. Then continue the incision anteriorly toward the thoracic region. Does it seem well developed? Insert one blade of scissors through the body wall on one side of the umbilical cord and cut posteriorly to the base of the leg as shown in figure 6. Clean up your materials and work area.
Small Intestine Tubular organ that is long and small in diameter large surface area where much of digestion occurs. Follow the esophagus and locate the soft, sac-like stomach beneath the liver. It begins at the base of the right ventricle then branches into two pulmonary arteries left and right , which deliver de-oxygenated blood to the corresponding lung. Looking at the respiratory and circulatory system requires you to cut open the thoracic cavity of the pig. The right side of the heart pumps blood to the lungs, while the left side of the heart pumps blood to all other parts of the body. Thymus gland immune system Long pinkish glands on either side of the trachea that provide immunity to fetus and protect against disease.
To find the salivary glands, you must turn the fetal pig on its side first to get a better view of its cheeks. Male Structures Female Structures If working with live rats, see appendix A on small mammal surgery. Trachea outlined in green can be distinguished from the esophagus, because the trachea is bigger and has cartilage rings. Soleus: This muscle lies deep in the gastronemius. Count and record the number of toes and the type of hoof the pig has.
The fetal pig that you will dissect has been injected with a colored latex rubber compound. Above the epiglottis, find the round opening of the nasopharynx. What does the letter N refer to in the figure of the internal anatomy of the fetal pig? A very small lobe, the caudate lobe, may be seen when the intestinal coils are moved to the left. In the figure of the internal anatomy of the fetal pig, what letter refers to the liver? Continue separating the tissue with a probe until the trachea and esophagus are exposed. Wrap the pig in damp paper towels and put it in a zip-lock plastic bag.
This is where you will make incision 2. Lift the stomach and identify this light-colored organ. Label these on your hand-in. The diaphragm in adult pigs moves up and down changing air pressure in the chest cavity causing air to move into and out of the lungs. If a structure is anterior to another, then it is closer to the head. Be sure to follow all directions.
Also, remember to cut away from yourself. Thymus: The thymus is a pinkish-gray color, soft, and lobulated on its surfaces. It lies ventral to the pinna external ear and is recognized by its triangular shape and lobular texture. Anterior to the heart, you can locate a large vein that enters the right atrium. Rugae Ridge-like structures foldings in stomach lining inside the stomach that aid in digestion of enzymes Pyloric Sphincter Connects the stomach and small intestine, prevents flowback of food from stomach.