Physiology and Hygiene for Secondary Schools

by Francis M. Walters

1. Cut through the abdominal wall in the center of the triangular space where the ribs converge. From here cut a slit downward to the lower portion of the abdomen, and sideward as far as convenient. Tack the loosened abdominal walls to the board, and proceed to study the exposed parts. Observe the muscles in the abdominal walls, and the fold of the peritoneum which forms an apron-like covering over the intestines.

2. Observe the position of the stomach, liver, spleen, and intestines, and then, by pushing the intestines to one side, find the kidneys and the bladder.

3. Study the liver with reference to its location, size, shape, and color. On the under side, find the gall bladder, from which a small tube leads to the small intestine. Observe the portal vein as it passes into [pg 170] the liver. As the liver is filled with blood, neither it nor its connecting blood vessels should be cut at this time.

4. Trace out the continuity of the canal. Find the esophagus where it penetrates the diaphragm and joins the stomach. Find next the union of the stomach with the small intestine. Then, by carefully following the coils of the small intestine, discover its union with the large intestine.

5. Within the first coil of the small intestine, as it leaves the stomach, find the pancreas. Note its color, size, and branches. Find its connection with the small intestine.

6. Beginning at the cut portion of the abdominal wall, lift the thin lining of the peritoneum and carefully follow it toward the back and central portion of the abdomen. Observe whether it extends back of or in front of the kidneys, the aorta, and the inferior vena cava. Find where it leaves the wall as a double membrane, the mesentery, which surrounds and holds in place the large and small intestines. Sketch a coil of the intestine, showing the mesentery.

7. Find in the center of the coils of small intestine a long, slender body having the appearance of a gland. This is the beginning of the thoracic duct and is called the receptacle of the chyle. From this the thoracic duct rapidly narrows until it forms a tiny tube difficult to trace in a small animal.

8. Cut away about two inches of the small intestine from the remainder, having first tied the tube on the two sides of the section removed. Split it open for a part of its length, and wash out its contents. Observe its coats. Place it in a shallow vessel containing water, and examine the mucous membrane with a lens to find the villi. Make a drawing of this section, showing the coats.

9. Study the connection of the small intestine with the large. Split them open at the place of union, wash out the contents, and examine the ileo-cæcal valve.

10. Observe the size, shape, and position of the kidneys. Do they lie in front of or back of the peritoneum? Do they lie exactly opposite each other? Note the connection of each kidney with the aorta and the inferior vena cava by the renal artery and the renal vein. Find a slender tube, the ureter, running from each kidney to the bladder. Do the ureters connect with the top or with the base of the bladder? Show by a sketch the connection of the kidneys with the large blood vessels and the bladder.