Section of GIT
This specimen shows the abdominal cavity with all the viscera insitu. The structures that can be identified in this specimen are the diaphragm, the liver, the stomach, the small intestine and the urinary bladder.
The diaphragm is a musculo-aponeurotic partition between the thorax and the abdomen. It is a dome-shaped structure which is made up of the muscle fibres at the periphery and a central tendon in the centre. It has major and minor openings, which allow passage of the structures from the thorax to the abdomen and vice-versa. The diaphragm is a chief muscle of respiration. Any developmental anomaly of the diaphragm can lead to congenital diaphragmatic hernia, in which, the structures from the abdomen would herniate into the thorax, thereby reducing the size of the lungs.
The liver is the largest gland of the body, that is located in the right upper part of the abdominal cavity. It is mainly concerned with the secretion of bile necessary for the digestion of fats and also detoxifies the blood. It is divided into two large lobes, namely, the right and the left lobes. It is held in position by the peritoneal folds, known as, the ligaments. The porta hepatis, along its inferior surface, allows the passage of structures to and from the liver. Excessive alcohol consumption can cause fibrosis of the liver cells (hepatocytes). This condition is clinically termed as cirrhosis of the liver.
The stomach is located in the upper left part of the abdominal cavity. It is the widest part of the gastrointestinal tract. It has two orifices (cardiac orifice and pyloric orifice), two curvatures (greater curvature and lesser curvature) and two surfaces (anterosuperior surface and posteroinferior surface). It is divisible into three parts, namely, the fundus, the body and the pylorus. In the contrast radiograph, the area of the fundus appears dark due to gas present within it. The interior of the stomach shows numerous temporary mucosal folds known as rugae. It gastric cells secrete Hydrochloric acid and Pepsinogen. Excessive secretion of Hydrochloric acid leads to gastric ulcers.
The small intestine is six meters long and highly coiled. It fills most of the abdominal cavity. It consists of three parts, namely, the Duodenum, the Jejunum and the Ileum. The duodenum consists of four parts, namely, 1st part, 2nd part, 3rd part and 4th part. In contrast radiographs, the first part normally appears to be triangular, known as the duodenal cap. The interior of the 2nd part shows two elevations, known as the major duodenal papilla and the minor duodenal papilla. The major duodenal papilla receives the opening of the bile duct and the main pancreatic duct, whereas the minor duodenal papilla receives the opening of the minor pancreatic duct. The jejunum and the ileum are enclosed within peritoneal folds known as mesentery.
The urinary bladder lies in the anterior part of the pelvis. An empty urinary bladder is tetrahedral in shape. The ureters open into the posterior aspect of the urinary bladder. The neck of the urinary bladder is directed downwards and becomes continuous with the urethra at the internal urethral orifice. In males, the prostate gland is situated onto the urethra and the neck of the urinary bladder. In case of benign prostatic hypertrophy, the median lobe of prostate enlarges producing an elevation within the urinary bladder known as uvula vesicae. This uvula vesicae obliterates the internal urethral orifice, thereby making the passage of urine more difficult.