Related Concept Videos

Overview of Secretory Vesicles01:33

Overview of Secretory Vesicles

Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Pathophysiology of Peptic Ulcer Disease: Injurious Factors01:22

Pathophysiology of Peptic Ulcer Disease: Injurious Factors

Peptic ulcers are sores on the stomach's inner lining and the upper small intestine, which are the result of disruptions in the mucosal layer that houses parietal cells which produce gastric acid, and chief cells which secrete pepsinogen.
In the antrum region, G cells secrete the gastrin hormone that binds to gastrin-cholecystokinin-B (CCK2) receptors on parietal and enterochromaffin-like (ECL) cells in the fundic glands. Simultaneously, the vagus nerve releases acetylcholine, which binds to M3...
Gross Anatomy of the Stomach01:16

Gross Anatomy of the Stomach

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...
Intestinal Phase of Digestion01:29

Intestinal Phase of Digestion

The intestinal phase of digestion is the third and final stage of the digestive process, occurring after the cephalic and gastric phases. It begins when chyme, a partially digested mixture of food and digestive enzymes, enters the small intestine from the stomach. This phase is crucial for nutrient absorption and involves complex hormonal and enzymatic interactions.
The arrival of the chyme in the small intestine distends the duodenum, which triggers the enterogastric reflex. This distension...
Mucosal Barrier of the Stomach01:25

Mucosal Barrier of the Stomach

The gastric glands contain parietal cells that secrete hydrochloric acid (HCl) for digestion. The cells secrete HCl because it is highly corrosive and essential for breaking down food. To achieve this, they secrete hydrogen and chloride ions into the lumen of the gastric glands, which combine to form HCl.
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...
Gastric Motility01:16

Gastric Motility

Gastric motility is the coordinated contraction and relaxation of stomach muscles that convert ingested food into chyme, a semi-liquid substance ready for further digestion in the intestines. The process begins with the vagus nerve inducing the relaxation of the smooth muscles in the fundus and body of the stomach, allowing these regions to expand and accommodate up to approximately 1.5 liters of food and liquid.
Peristaltic Waves and Chyme Formation
Upon food entry, the stomach initiates...