Anatomy · Short notes

Visceral Anatomy: Short Notes & Cheat Sheet

Heart, lungs, digestive tract, liver, pancreas, spleen, kidneys and retroperitoneal organs: key anatomical facts.

Short notes

Read these before you attempt the topic's MCQs.

A single headline fact per organ answers most anatomy MCQs about the viscera.

The heart has four chambers. The tricuspid (right) and mitral (left) valves are the atrioventricular valves; the pulmonary and aortic valves are semilunar.
Coronary arteries: the left divides into the left anterior descending and circumflex arteries; the right supplies most of the right heart and usually the SA and AV nodes.
The SA node, the pacemaker, lies in the right atrium.
The right lung has three lobes and the left lung two (with a cardiac notch and lingula).
The trachea divides at the carina (about T4–T5). The right main bronchus is wider, shorter and more vertical, so inhaled objects usually enter it.
The diaphragm is supplied by the phrenic nerve (C3–C5).

The oesophagus is about 25 cm long. The stomach has a fundus, body, antrum and pylorus; parietal cells make acid and intrinsic factor, and chief cells make pepsinogen.
The small intestine (about 6 m) is the duodenum, jejunum and ileum. Iron is absorbed mainly in the duodenum; vitamin B12 and bile salts in the terminal ileum.
The large intestine (about 1.5 m) is the caecum with the appendix, the ascending, transverse, descending and sigmoid colon, and the rectum.
The common bile duct and pancreatic duct open into the duodenum at the ampulla of Vater, controlled by the sphincter of Oddi.

The liver is the largest internal organ and gland (about 1.5 kg). It gets about 75% of its blood from the portal vein and 25% from the hepatic artery.
The pancreas has exocrine acini and endocrine islets: α cells make glucagon, β cells insulin and δ cells somatostatin.
The spleen, in the left upper quadrant, is the largest lymphoid organ.
The kidneys lie behind the peritoneum at about T12–L3; the right is lower because of the liver. Each has about a million nephrons. The adrenal glands sit on top of them.

High-yield facts in one place. Cover the right-hand column and test yourself.

Organ	Fact
Right lung	3 lobes
Left lung	2 lobes, cardiac notch
Liver	Largest internal organ; 75% portal blood
Spleen	Largest lymphoid organ
Kidney	≈ 1 million nephrons; right lower
Pancreas	α glucagon, β insulin, δ somatostatin
Terminal ileum	B12 and bile salt absorption
Diaphragm	Phrenic nerve C3–C5

Organ	Note
Kidneys, ureters, adrenals	Fully retroperitoneal
Aorta, IVC	Great vessels
Duodenum (parts 2–4)	Secondarily retroperitoneal
Pancreas (except tail)	Secondarily retroperitoneal
Ascending, descending colon	Secondarily retroperitoneal
Rectum	Lower part below peritoneum

C3, 4, 5 keeps the diaphragm alive: The phrenic nerve arises from cervical roots C3–C5.
SAD PUCKER: Retroperitoneal: Suprarenals, Aorta/IVC, Duodenum, Pancreas, Ureters, Colon (ascending, descending), Kidneys, Oesophagus, Rectum.

The right main bronchus, not the left, is the usual site of inhaled foreign bodies.
Most of the liver's blood comes from the portal vein, not the hepatic artery.
Vitamin B12 is absorbed in the terminal ileum, not the duodenum.
The right kidney sits lower than the left.

Attempt the Visceral Anatomy MCQs while the notes are fresh. Anything you get wrong is saved to your incorrect list for the next revision round.