TracheaThe windpipe. Rings of cartilage in its wall keep it open. It divides into two bronchi, one to each lung.
LungsOne on each side of the heart. In them the blood gives up carbon dioxide and takes up oxygen. The right lung is divided into more lobes than the left.
HeartIt lies between the lungs. It pumps blood to them and then to the rest of the body.
DiaphragmA dome-shaped sheet of muscle that separates the chest from the abdomen.
LiverThe large organ just behind the diaphragm. It is deeply cleft into lobes, and in the rat it has no gallbladder.
StomachIt is shaped like half a doughnut. It lies on the rat's left side, against the back of the liver.
SpleenA long, flat organ along the outer curve of the stomach.
Small intestineA long coiled tube in three parts: duodenum, jejunum and ileum. Its coils fill most of the abdomen.
CecumA large blind sac, the first part of the large intestine. Nearly all rodents have a large one.
ColonThe large intestine after the cecum. It ends in the rectum, which opens at the anus.
IncisorsA pair of long, curved, chisel-like teeth in each jaw. They never stop growing, and gnawing keeps them sharp. A rat has no canine teeth.
Vibrissae (whiskers)The long stiff hairs on the snout. They work as feelers.
Submaxillary glandsA pair of large salivary glands on the underside of the neck. The two touch along the midline.
Liver, stomach and kidneys 11
EsophagusThe tube that carries food to the stomach. It passes through the diaphragm and enters the stomach near the middle of its inner curve.
Cardiac partThe left part of the stomach. A thin-walled sac with a tough, smooth lining. It is thought to hold chewed food until it can be digested.
Pyloric partThe right part of the stomach. Its wall is thicker, and its folded lining holds the glands that make gastric juice. It narrows to the pylorus.
DuodenumThe first part of the small intestine. It is a U-shaped loop on the rat's right side.
PancreasNot one solid organ in the rat. It is a gland scattered in small lobes through the sheet of tissue that holds the duodenum.
Bile ductCarries bile from the lobes of the liver straight to the duodenum. A rat has no gallbladder to store the bile on the way.
Median lobeThe lobe in the middle, in front of the others. It lies against the diaphragm. A cleft partly divides it in two.
Left lobeA large lobe on the rat's left, behind the median lobe. Its back rests against the stomach.
Right lobeThe lobe on the rat's right. It is partly divided into a front part and a rear part. The right kidney fits against it.
Caudate lobeA small lobe in two parts that fits round the esophagus. It lies against the inner curve of the stomach. It is also called the Spigelian lobe.
KidneysBean-shaped organs on the back wall of the abdomen. The right kidney lies farther forward than the left.
How this list was compiled: Every name checked on 2026-09-30 in two sources on the rat. H. R. Hunt, A Laboratory Manual of the Anatomy of the Rat (1924, public domain): whiskers, incisors, salivary glands, chest organs, the lobes of the liver, the missing gallbladder, the two regions of the stomach, the intestines and the kidneys, https://archive.org/details/laboratorymanual00hunt. H. N. Martin and W. A. Moale, Handbook of Vertebrate Dissection, part 3, How to Dissect a Rodent (1884, public domain): the same organs in the brown rat, https://archive.org/details/ahandbookverteb01moalgoog. E. C. Greene, Anatomy of the Rat (1935), searched inside on the Internet Archive, for the liver lobes, the missing gallbladder, the diffuse pancreas and the parts of the stomach, https://archive.org/details/anatomyofrat0000euni. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
A rat dissection diagram, unlabeled, as two drawings on one sheet: the whole rat on its back with its head to the left, and the front of its abdomen enlarged with the lobes of the liver spread apart. Twenty-four parts wait for a name.
Read the full guide
Thirteen names on the whole rat
From the snout back: vibrissae, incisors, submaxillary glands, trachea, heart, lungs, diaphragm, liver, stomach, spleen, small intestine, cecum and colon. The stomach and the spleen lie on the rat's left, which is toward the top of the sheet.
Eleven names on the enlarged drawing
Esophagus, cardiac part, pyloric part, duodenum, pancreas, bile duct, kidneys and the four lobes of the liver. The left lobe is the large one at the top, the right lobe the large one at the bottom, the median lobe lies between them, and the caudate lobe is the small one beside the esophagus.
The intestines are taken away on the enlarged drawing, so the two kidneys show at its right.
The pancreas is the cluster of small lobes inside the U of the duodenum, not one solid shape.
Seven parts have no line: the heart, the liver, the cardiac part and the four lobes take their names on the organ itself.
Questions and answers
Which part of a rat's stomach is the cardiac part?
The left part, a thin-walled sac that the esophagus opens into. On the enlarged drawing it is the upper half of the stomach. The pyloric part is the lower half, with a thicker wall, and it leads to the duodenum.
Where is the spleen on a rat diagram?
Along the outer curve of the stomach, on the rat's left. On the whole rat it is the narrow curved strip at the edge of the stomach, near the top of the sheet.
What is left off this unlabeled rat diagram?
The reproductive organs, the adrenal glands, ureters and bladder, the thymus and thyroid, and the chambers of the heart. There is no gallbladder to look for: a rat has none.
Does the rat diagram unlabeled come with an answer key?
Yes. The key is the same sheet with every name written in. It prints left lobe and right lobe where some lab manuals say left lateral and right lateral lobe, and it shortens three names: Small int., Submaxillary and Caudate.