Welcome to the first week of the course. Have you ever wondered what lies inside your abdomen? Do you know where the spleen or appendix is situated? Would you like to know how the physician looks at it and get the basics of a physical examination of the abdomen? Do you want to understand how all these structures can be seen on scans or X-rays? During this week you will get a better understanding of these things. We also lay the foundation for the following weeks of the course, like basic things to know about vascularization, the nervous system, embryology, and the wonderful membrane holding all these structures together: the peritoneum.

After the first introduction of the abdomen with all its organs, this week we will focus at some microscopy and the first stages of gut development in the embryo. The gut starts as a simple straight tube which differentiates further into a internalized tract with specialized sections, each with its own function. You will learn how the esophagus transports your food, while its lower sphincter prevents food from returning - even if you're upside down! Then you will focus on how the stomach drenches all food in an extremely acid pool, attacking ingested bacteria and starting the digestion. That same acid would also damage the duodenum, so protective action is required. You will follow the digestion further down the tract, with its extensive folds and specialized cells and end up with more and more solid bowel contents when water is extracted in the colon. In order to demonstrate some functions further, we also have to dive into the world of microscopy. Join us on this trip into the gut with all its ingenious structural specializations along the way!

We discussed some microscopy before and the embryonic origin of the initial gut tube and how it differentiates into specialized sections for digestion. We will now focus on the question why the bowels are not arranged symmetrically left and right, like in the rest of our body, but are closely encircling and crossing over each other. With a unique 3D animation you will learn about the rotation of the gut during development. This key concept will help you to understand the anatomical relationships of the gut with its suppliers and purchasers. The gut cannot do it alone; it needs additional organs which supply digestive chemicals such as enzymes and bile and organs that process the absorbed food further. Both the gut and these organs also need a blood supply. You will learn where their blood vessels are situated. Also, the less prominent, but very important 'sewage' system, the lymphatics, will be dealt with. In the gut area, the lymphatics are specialized in transporting fats that are absorbed from the food! Lymphatic vessels also keep an eye on pathological invaders. Unfortunately they may also spread tumor cells. In short, this week's module is for everyone who is interested in the collaboration between the abdominal organs and the gut.

You have already learned that the bowels are not arranged symmetrically left and right. The rotation processes of the gut and its suppliers have important consequences for the peritoneal coverings of the gut and the abdominal wall. It determines why some structures lie easily accessible in the abdomen and others are more hidden away. In this week you will get a grip on difficult concepts as 'intraperitoneal' and 'retroperitoneal'. It is also a starter week about abdominal surgery. You will also learn a secret: The best way to mobilize the abdominal and pelvic organs is to separate what got adhered when the patient was just an embryo! Please feel free to dive into these embryonic matters and enjoy all the twists and turns!