GI system 2

A J-shaped muscular organ in the digestive system that stores ingested food, mixes it with gastric juice, and initiates digestion of proteins and fats.

The ability of the stomach to expand and hold a significant amount of food. It allows for a gradual digestion and release of food into the small intestine.

A mixture of hydrochloric acid, enzymes, and mucus secreted by the stomach to break down food.

A process where food in the stomach gets churned and mixed with gastric juice, breaking down large particles into smaller pieces.

A process where the semi-digested food in the stomach (chyme) is slowly released into the small intestine for further digestion and absorption.

The substance that results after the stomach has partially digested food. It's a thick, semi-liquid mixture that travels to the small intestine for further digestion.

The enzyme found in gastric juice, primarily active in the stomach. It helps break down proteins into smaller peptides.

The salivary enzyme that begins carbohydrate digestion in the mouth. It continues to work in the stomach but its activity is partially inhibited by the stomach's acidity.

Parietal cells in the stomach produce hydrochloric acid (HCl), which is essential for digestion and protection. HCl breaks down food, activates pepsinogen, and kills bacteria.

Chief cells in the stomach secrete pepsinogen, an inactive precursor of the enzyme pepsin. Pepsinogen is activated by HCl in the stomach and breaks down proteins.

Intrinsic factor, produced by parietal cells, is a protein crucial for vitamin B12 absorption in the small intestine. B12 is essential for red blood cell production.

Surface mucous cells secrete mucus and bicarbonate, which form a protective barrier against HCl and pepsin. This prevents damage to the stomach lining.

Gastrin, secreted by G cells, is a hormone that stimulates the release of HCl and pepsinogen. It plays a role in regulating gastric function.

Somatostatin, produced by D cells, acts as a 'brake' on gastric secretion. It inhibits the release of gastrin and other agents that stimulate HCl production.

The activation of pepsinogen to pepsin occurs in the acidic environment of the stomach. HCl provides the optimal pH for pepsin to function.

A specialized cell in the stomach lining responsible for producing hydrochloric acid (HCl), a key component of gastric juice.

A protein pump located in the parietal cell membrane that actively transports hydrogen ions (H+) from the cytoplasm into the gastric lumen, generating the highly acidic environment of the stomach.

The activation of the proton pump in parietal cells is triggered by the binding of signaling molecules like gastrin and histamine to their respective receptors on the cell surface. This binding initiates a cascade of events leading to the activation of the pump and subsequent HCl secretion.

The cephalic phase is triggered by external stimuli like seeing, smelling, or even thinking about food. This phase stimulates the release of gastrin and acetylcholine, which in turn activate parietal cells and increase HCl secretion.

The gastric phase is stimulated by the presence of food in the stomach. The distension of the stomach wall and the presence of peptides and amino acids trigger the release of gastrin and histamine, further activating parietal cells and increasing HCl secretion.

The intestinal phase is initiated as food leaves the stomach and enters the duodenum. The presence of chyme in the duodenum triggers the release of hormones like cholecystokinin (CCK) and secretin, which act to decrease gastric acid secretion and promote the release of pancreatic enzymes and bile. This phase ensures a balanced pH in the small intestine for optimal digestion and absorption.

This phase is characterized by the release of hormones like gastrin and acetylcholine, which stimulate parietal cells and increase HCl secretion. This is a crucial step in the digestion process as it increases the acidity in the stomach, aiding in the breakdown of food.

The intestinal phase is the inhibitory phase of gastric secretion, where the release of hormones like CCK and secretin reduces the acidity. This helps prevent the duodenum from becoming overly acidic and protects the delicate intestinal lining from damage.

The gastric mucosal barrier is a protective layer that prevents damage to the stomach lining from the highly acidic environment.

The gastric mucosal cells lining the stomach are impermeable to HCl, meaning the acid cannot pass through their membranes.

Tight junctions between gastric mucosal cells form a barrier that prevents HCl from leaking into the underlying tissues.

HCO3- rich mucus coats and protects the stomach lining.

The stomach lining is constantly replaced, with entirely new cells every 3 days.

Prostaglandins, a type of hormone, help regulate the stomach's acid secretion and mucus production, contributing to protection.

The small intestine is the primary site for digestion and absorption of nutrients.

The small intestine secretes fluid, including salt and mucus, to help lubricate and protect the lining.

The small intestine uses muscle contractions, called segmentation and peristalsis, to mix and move food efficiently.

Digestion in the small intestine is facilitated by enzymes from the pancreas and bile from the liver, along with enzymes produced by the intestinal cells themselves.

Gastric juice is a mix of hydrochloric acid, enzymes, and mucus secreted by the stomach. It breaks down food, kills bacteria, and activates digestive enzymes.

The stomach's lining is constantly renewed with new cells, creating a protective barrier against the harsh digestive environment.

Chyme is the semi-digested food mixture that moves from the stomach to the small intestine.

The stomach mixes chyme with gastric juice, breaks down food into smaller particles, and propels it towards the small intestine.

Parietal cells are responsible for producing hydrochloric acid (HCl), which is essential for digesting food and killing bacteria in the stomach.

Pepsinogen is produced by chief cells in the stomach and gets activated by HCl to become pepsin, which aids in breaking down proteins into smaller peptides.

Intrinsic factor, produced by parietal cells, is crucial for the absorption of vitamin B12 in the small intestine. B12 is essential for red blood cell production.

Surface mucous cells secrete mucus and bicarbonate, which form a protective barrier against HCl and pepsin in the stomach, preventing damage to the lining.

Gastrin, secreted by G cells, stimulates the release of HCl and pepsinogen, playing a key role in regulating gastric function.

Somatostatin, produced by D cells, acts as a 'brake' on gastric secretion, inhibiting the release of gastrin and other agents that stimulate HCl production.

Pepsinogen is activated in the acidic environment of the stomach by HCl, converting it into pepsin, which then breaks down proteins.

Gastric HCl secretion is regulated by a complex process involving parietal cells, proton pumps, and signaling molecules like gastrin and histamine.

The phenomenon where the stomach's muscular contractions, called peristalsis, push partially digested food (chyme) into the small intestine.

A group of cells that releases a hormone called gastrin, which directly stimulates the production of stomach acid (HCl).

The acidic environment of the stomach partially inhibits salivary amylase, which is the enzyme that starts carbohydrate digestion in the mouth.

The breakdown of proteins begins in the stomach, specifically in the antrum, where the enzyme pepsin plays a crucial role.

Parietal cells in the stomach release hydrochloric acid (HCl) which is crucial for digestion. The proton pump is a protein pump that actively transports hydrogen ions (H+) into the stomach lumen, generating the highly acidic environment necessary for digestion. This process occurs due to the binding of signaling molecules like gastrin and histamine to their respective receptors on the parietal cell surface, initiating a cascade of events that activate the protein pump.

The cephalic phase is triggered by external stimuli like seeing, smelling, or even thinking about food. This phase stimulates the release of gastrin and acetylcholine, which in turn activate parietal cells and increase HCl secretion.

The gastric phase is stimulated by the presence of food in the stomach. The distension of the stomach wall and the presence of peptides and amino acids trigger the release of gastrin and histamine, further activating parietal cells and increasing HCl secretion.

The intestinal phase is initiated as food leaves the stomach and enters the duodenum. The presence of chyme in the duodenum triggers the release of hormones like cholecystokinin (CCK) and secretin, which act to decrease gastric acid secretion and promote the release of pancreatic enzymes and bile. This phase ensures a balanced pH in the small intestine for optimal digestion and absorption.

The excitatory cephalic and gastric phases are characterized by the release of hormones like gastrin and acetylcholine, which stimulate parietal cells and increase HCl secretion. This is a crucial step in the digestion process as it increases the acidity in the stomach aiding in the breakdown of food.

The inhibitory intestinal phase is a critical phase in which hormones like CCK and secretin reduce acidity in the stomach. This phase is crucial for protecting the duodenum from excessive acidity and ensuring optimal digestion in the small intestine.