Dissection Exercise 3
1. How do the locations of the endocrine organs in the fetal pig compare with those in the human? They are similar except for the pancreas and the adrenal glands. In the fetal pig, the adrenal glands are medial to each kidney and inferior to the pancreas rather than atop to kidneys and superior to the pancreas as in humans. 2. Name two endocrine organs located in the throat region? Thymus gland and thyroid gland. 3. Name three Endocrine organs located in the abdominal cavity. Adrenal glands, pancreas, and gonads. 4. Given the assumption that human beings have more stress than adult pigs, which endocrine organs would expect to be relatively larger in humans? The adrenal glands. 5. Explain why the thymus gland in the fetal pig is so large, relatively speaking. It is so large because it is still a fetus and it will shrink as the big matures.
Dissection Exercise 4
1. Is the fetal pig’s lymphatic drainage pattern basically similar or dissimilar to that of humans? Similar. 2. What is the role of the following? a. Thoracic duct: Receives lymph and drains lymph from everywhere except for what the right lymphatic duct covers. b. Right lymphatic duct: Drains lymph from the right upper extremity, head, and thorax delivered by the jugular, subclavian, and bronchomediastinal trunks. 3. What differences did you observe between the origin of the common carotid arteries in the pig and in the human? In the pig, the left common carotid artery originates from the brachiocephalic trunk while in humans the left common carotid artery originates from the aortic arch.
4. How do the relative sizes of the external and internal jugular veins differ in the human and the pig? In the fetal pig, both internal and external jugular veins were about the same size in diameter. In humans, the internal jugular vein has a larger diameter than the external jugular vein. 5. How do the brachial veins in the pig differ from those of human? The brachial veins in the pig follow the same path along with the brachial arteries. 6. What difference did you note between the origin of the hepatic portal vein in the pig and in humans? They are similar except that the fetal pig has a gastrosplenic vein and a gastroduodenal vein instead of a splenic vein and left gastric vein as in humans. 7. Define the following terms.
Ascending aorta: The ascending part of the aorta as it emerges from the left ventricle. Aortic arch: The part of the aorta that arches and turns downward. Descending thoracic aorta: The descending part of the aorta that branches into the thoracic and abdominal aortae. Descending abdominal aorta: The distal part of the descending aorta, below the diaphragm; it is continuous with the thoracic aorta.
Dissection Exercise 5
1. Are the cartilaginous rings in the pig trachea complete or incomplete? Incomplete 2. How does the number of lung lobes in the pig compare with the number in humans? Pigs have 4 lobes in the right lung and 2 lobes in the left lung. Humans have 3 lobes in the right lung and 2 lobes in the left lung. 3. Describe the appearance of lung tissue under the dissection microscope. Dense since the lungs haven’t been inflated yet. 4. Why did the segment of lung tissue, cut from the fetal pig’s lung, sink when placed in water? The fetal pig has not yet used the lungs to breathe so they are dense and deflated.
Dissection Exercise 6
1. Several differences between pig and human digestive anatomy should have become apparent during the dissection. Note the pertinent differences between the human and the pig relative to the following structures. Structure| Pig| Human|
Dissection Exercise 7
1. How do the structure and connectivity of the urinary bladder of the fetal pig differ from those of the urinary bladder of the human (or adult pig for that matter)? The fetal pig’s urinary bladder is collapsed elongated sac that lies between the umbilical arteries. This is due to the fetal use of the allantois. 2. What differences in fetal elimination of nitrogenous wastes account for the structural differences described above? The fetus gets rid of wastes via the allantois. 3. How does the site of urethral emptying in the female pig differ from the termination point in the human female? In the female fetal pig, urine is emptied into the urogenital sinus while in a human female urine is emptied through the external urethral orifice which is separate from the vagina.
Dissection Exercise 8
1. The female pig has a Y-shaped (bipartite) uterus; that of the human female is pear-shaped (one-part). Explain the difference in structure of these two uterine types. 2. What reproductive advantage is conferred by the pig’s uterine type? The ability to produce litters. 3. Cite differences noted between the pig and human relative to the following structures: A. Uterine tubes or Oviducts: In the fetal pig, the uterine tubes are tiny and relatively much shorter than in a human. B. Urethral and vaginal openings in the female: In the female fetal pig, the urethra and vagina meet to create the urogenital sinus. The urethra and vagina in a female human never meet and are separate from one another.