[The anatomy of the Isthmus pharyngis (author's transl)]

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, and electrolytes from food and drink also occurs in the intestine. The intestines can be divided into two structurally distinct organs—the small and large intestines.
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the small...

The pharynx, a tubular structure framed by skeletal muscle and lined with mucous membrane, extends continuously from the nasal cavities. It is segmented into three major areas: the nasopharynx, oropharynx, and laryngopharynx.
Nasopharynx
The nasopharynx, bordered by the conchae of the nasal cavity, serves exclusively as an air conduit. In its superior region, the pharyngeal tonsils or adenoids are located. These tonsils are clusters of lymphoid reticular tissue akin to a lymph node. The precise...

The esophagus, a muscular conduit linking the pharynx and stomach, measures roughly 10 inches (25.4 cm) and sits behind the trachea. It remains collapsed when not swallowing. The esophagus follows a predominantly straight path through the thoracic mediastinum and enters the abdominal cavity through a diaphragmatic opening known as the esophageal hiatus.
The movement of edibles from the pharynx into the esophagus is facilitated by the upper esophageal sphincter, which is formed primarily by the...

The human stomach is a vital part of the digestive system, performing multiple functions. It is located within the peritoneum, a serous membrane that lines the abdominal cavity. The stomach plays a central role in processing food substances and interacts with other digestive organs through coordinated digestive processes. The stomach has a characteristic J-shape and is divided into four main regions. The cardia is the first section where the esophagus connects to the stomach and is the entry...

The upper respiratory tract plays a vital role in the respiratory system, comprising several structures that facilitate air intake and prepare air for the lungs. It also serves as the first line of defense against pathogens and particles. This tract includes the nose and nasal cavity, the oral cavity, the paranasal sinuses, and the pharynx, each with specific functions and features.
Nose and nasal cavity
The nose and nasal cavity represent the main external openings of the respiratory tract.

A hiatal hernia is the abnormal protrusion of the stomach or other abdominal organs through the esophageal hiatus of the diaphragm into the thoracic cavity.Normally, the gastroesophageal junction (GEJ) lies below the diaphragm and is supported by the phrenoesophageal membrane, the diaphragmatic crura, and connective tissues. Weakening of these structures—due to aging, congenital defects like a short esophagus, or increased intra-abdominal pressure from coughing, obesity, pregnancy, or heavy...