Basic Colon Anatomy

This is an educational illustration of the human colon, part of the larger digestive system. On the left, there’s a faded full-body human silhouette with the digestive system highlighted, showing the location of the colon within the body. The main image zooms in on the colon and surrounding structures, with labels identifying each part.

Starting from the bottom, the ‘Anus’ is labeled as the terminal part of the digestive tract. Moving up, the ‘Rectum’ is the final straight section where feces are stored before they are expelled through the anus. Just above this is the ‘Sigmoid colon’ or ‘Colon Sigmoidum,’ which is an S-shaped segment that connects the rectum to the descending colon.

The ‘Descending colon’ or ‘Colon descendens’ runs vertically downward on the left side of the abdomen and transitions into the ‘Transverse colon’ or ‘Colon transversum,’ which crosses the abdomen from left to right. The ‘Ascending colon’ or ‘Colon ascendens’ travels up the right side of the abdomen and leads into the ‘Cecum,’ a pouch that connects the colon to the small intestine and is considered the beginning of the large intestine. Attached to the cecum is the ‘Appendix,’ a narrow tube-shaped pouch.

The ‘Small intestine’ or ‘Intestinum tenue’ is illustrated at the top, looping around the colon. It’s where most of the nutrients from ingested food are absorbed before the remaining waste moves into the colon.

The anatomical relationships shown here indicate how waste moves through the large intestine: beginning at the cecum, ascending on the right side, crossing the abdomen transversely, and then descending on the left to eventually be expelled.  

Digestive System Anatomy

This image provides an overview of the human digestive system, featuring a transparent human figure with the primary digestive organs highlighted in red. Each organ is labeled, indicating its position and role within the system.

At the top inside the head, we see the ‘Esophagus,’ a muscular tube that delivers food from the mouth to the stomach. Below the esophagus and slightly to the left is the ‘Stomach,’ where food is mixed with digestive juices.

To the right of the stomach, the ‘Liver’ is indicated, which is a large organ that processes nutrients and detoxifies harmful substances. Below the liver, the small, pear-shaped ‘Gallbladder’ is tucked away, responsible for storing bile produced by the liver.

The winding structures represent the ‘Small intestine,’ a long, convoluted tube where most digestion and nutrient absorption occurs. Encircling the small intestine is the ‘Large intestine,’ which compacts waste into feces. The ‘Appendix,’ a small pouch-like structure, is shown extending from the large intestine.

The ‘Rectum’ is at the bottom of the large intestine, where waste material is stored before it is expelled from the body through the anus, not labeled but implied to be at the end of the digestive tract.

The illustration emphasizes the sequential nature of digestion: from ingestion to the esophagus, then to the stomach, through the liver and gallbladder’s processing, absorption in the small intestine, waste compaction in the large intestine, and finally, excretion through the rectum. 

Intestinal Lining Anatomy

Depicted here is a detailed representation of the intestinal villi, which are tiny, finger-like projections found in the lining of the small intestine. Each villus is covered in epithelial cells, which are labeled at the top and the side of the image. These cells are crucial for absorbing nutrients from digested food into the bloodstream.

The illustration also shows the vascular structure associated with the villi. Each villus contains a network of blood vessels, including a small artery and a small vein, which transport nutrients absorbed by the epithelial cells to the rest of the body. The presence of these vessels in each villus allows for efficient absorption due to the close proximity of the circulatory system to the digested nutrients.

Additionally, lymphatic vessels, also known as lacteals, are depicted in green. These vessels are part of the lymphatic system and are responsible for absorbing and transporting fats and fat-soluble vitamins from the digestive tract into the bloodstream.

At the base of the villi are the intestinal crypts, which are invaginations of the intestinal lining that host a variety of cells, including those responsible for secreting intestinal juices and new epithelial cells for the continuous renewal of the intestinal lining.

Overall, the image captures the complex and highly specialized structure of the intestinal villi, which are essential for the digestive process. Their structure maximizes surface area to optimize the absorption of nutrients and fluids. 

Cross-Section of Abdomen

This image presents a cross-sectional view of the human abdomen at the level of the lumbar spine, illustrating various anatomical structures and their spatial relationships.

Central in the image is the ‘Aorta,’ the body’s main artery, which carries oxygenated blood from the heart to the rest of the body. Running parallel to it is the ‘Inferior vena cava,’ the large vein that carries deoxygenated blood from the lower body to the heart.

Surrounding these vessels are sections of the digestive tract. The ‘Small intestine’ is illustrated in a simplified manner, looped around the central area. Attached to it is the ‘Mesentery,’ a fold of tissue that supports and anchors the small intestines to the posterior abdominal wall.

The ‘Rectus’ muscles are shown on either side of the central structures, known as the muscles that make up the “six-pack” in well-developed abdomens.

The ‘Descending colon’ and ‘Ascending colon’ are parts of the large intestine, shown on the left and right sides of the image, respectively. These are involved in the process of absorbing water from waste material and moving it toward the rectum.

At the bottom of the image are the ‘Psoas major’ muscles, which are important for flexing the hip joint and stabilizing the lower spine.

This cross-section is an informative representation emphasizing the abdominal cavity’s organization, highlighting the relationship between major circulatory vessels, digestive organs, and musculature. 

Sagittal Section of Peritoneal Cavity

This diagram is a sagittal section of the human body, illustrating the anatomical divisions and contents of the peritoneal cavity, which houses many abdominal organs.

At the top of the image, the ‘Subphrenic space’ is indicated, which is the area below the diaphragm. The ‘Peritoneal cavity’ is the primary focus, divided into ‘Supracolic’ and ‘Infracolic’ compartments. The ‘Supracolic’ compartment is the upper part, above the transverse colon, containing the stomach and the liver (not labeled but implied by the location). The ‘Infracolic’ compartment is the lower part, below the transverse colon, leading into the pelvic cavity. The pelvic area is marked at the bottom of the image.

Within the peritoneal cavity, several organs are visible and labeled. The ‘Stomach’ is shown on the left, with the ‘Transverse colon’ arching across the middle. Below it is the ‘Third part of the duodenum,’ which is the latter portion of the duodenum following its initial C-shaped curve around the pancreas (not shown but would be located behind the stomach area).

The ‘Superior mesenteric artery’ is illustrated branching from the aorta and spreading out to supply blood to the small intestine and portions of the large intestine. The shaded area labeled ‘Lesser sac’ represents a division of the peritoneal cavity, which is a space behind the stomach.

The ‘Greater omentum’ is a significant structure hanging down from the greater curvature of the stomach, covering the transverse colon and the small intestine. It is a large fold of visceral peritoneum that stores fat and contains immune cells that help fight infection.

This diagram is used to give medical students and professionals a clear view of the spatial arrangement of the organs within the peritoneal cavity, as well as the divisions within the cavity itself. It also helps to understand the complex anatomy of the blood supply and the protective and immune roles of the omental structures.

Anatomical Terms and Definitions

Subphrenic spaceThe area of the peritoneal cavity that lies directly below the diaphragm.
Peritoneal cavityA potential space between the parietal and visceral peritoneum, housing many abdominal organs.
Supracolic compartmentThe part of the peritoneal cavity above the transverse colon, containing the stomach and liver.
Infracolic compartmentThe part of the peritoneal cavity below the transverse colon, extending into the pelvis.
PelvisThe lower part of the torso, forming the basin of the spine and housing parts of the digestive and urogenital systems.
StomachA digestive organ that processes food by secreting acid and enzymes.
Transverse colonThe middle section of the large intestine, passing from right to left across the abdomen.
Third part of the duodenumThe horizontal section of the duodenum, the first part of the small intestine.
Superior mesenteric arteryA major artery that supplies blood to the small intestine and parts of the large intestine.
Lesser sacThe division of the peritoneal cavity behind the stomach.
Greater omentumA large fatty structure attached to the stomach, draping over the intestines, with immunological functions.
DiaphragmA large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity and plays a major role in breathing.
LiverA vital organ involved in metabolism, detoxification, protein synthesis, and other essential bodily functions.
AortaThe largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen where it branches off.
Visceral peritoneumThe inner layer of the peritoneum that surrounds the abdominal organs.
Parietal peritoneumThe outer layer of the peritoneum that lines the abdominal and pelvic cavities.
MesenteryA fold of the peritoneal cavity that attaches the stomach, small intestine, pancreas, spleen, and other organs to the posterior wall of the abdomen.
Small intestineA part of the gastrointestinal tract following the stomach and preceding the large intestine, where most of the end absorption of nutrients occurs.
Large intestineThe last part of the gastrointestinal tract, responsible for water absorption and feces formation.

What's Next...