Please enable JavaScript.

Coggle requires JavaScript to display documents.

An elderly male patient with stomach cancer has recently had a feeding…

- - - - Mucus cells: produce and secrete mucus, which serves to protect the stomach lining from the acidic environment and the digestive enzymes. Mucus also lubricates the food as it moves through the digestive tract. While mucus itself is not an enzyme or hormone, it facilitates digestion and helps in protecting the stomach lining.
      - Chief cells: Responsible for producing and releasing pepsinogen, an inactive precursor to the enzyme pepsin. Pepsinogen is activated by the acidic environment in the stomach, particularly by hydrochloric acid secreted by parietal cells. Once activated, pepsin breaks down proteins into smaller peptides, aiding in protein digestion.
      - parietal cells: secrete hydrochloric acid and intrinsic factor. Hydrochloric acid creates an acidic environment in the stomach, which is essential for the activation of pepsinogen to pepsin and for the breakdown of food molecules. Intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine.
      - G cells: found in the stomach and secrete gastrin, a hormone that stimulates the secretion of gastric acid (HCl) by the parietal cells and promotes gastric motility. Gastrin release is triggered by the presence of food in the stomach, particularly protein-rich foods, and it helps in the regulation of gastric function.
    - - Stomach: muscular sac located between the esophagus and the small intestine. Makes juices with acid and enzymes that help break down food, while also moving and mixing it to form a thick liquid called chyme.
      - Small Intestine: long, coiled tube located between the stomach and the large intestine. Bile and pancreatic juices help digest fats, carbs, and proteins, while enzymes on the intestine's surface break down nutrients, and the intestine's movements mix and push the food for digestion and absorption.
      - Esophagus: The esophagus is a muscular tube connecting the throat with the stomach.Does not contribute to chemical digestion or nutrient absorption. Its function is solely mechanical, facilitating the movement of food through the gastrointestinal tract.
      - Large Intestine: wider tube extending from the small intestine to the anus. The colon absorbs water, electrolytes, and vitamins from gut bacteria and pushes waste toward the rectum for elimination through peristaltic contractions.
      - Pancreas: an endocrine and exocrine gland located behind the stomach. Releases pancreatic juice with enzymes like amylase, lipase, and proteases to help break down carbs, fats, and proteins, and it also sends bicarbonate to neutralize stomach acid in the duodenum.
      - Gall Bladder: small sac located beneath the liver. When cholecystokinin (CCK) triggers it, the gallbladder squeezes out bile into the duodenum, where bile helps break down fats for easier digestion and absorption.
  - - - CCK: produced by cells in the duodenum and jejunum of the small intestine. Stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.
      - Mucus: produced by mucus cells lining the stomach and gastrointestinal tract. Acts as a protective barrier for the stomach lining and lubricates the food bolus, aiding in swallowing and movement through the digestive tract.
      - Pepsinogen: produced by chief cells in the gastric glands of the stomach. precursor of pepsin, An enzyme that breaks down proteins into smaller peptides.
      - HCI: secreted by parietal cells in the gastric glands of the stomach. Creates an acidic environment in the stomach, which helps in activating pepsinogen to pepsin and in breaking down food molecules.
      - Gastrin: produced by G cells in the gastric glands of the stomach. Stimulates the secretion of gastric acid and promotes gastric motility.
      - Bile: synthesized by hepatocytes in the liver and stored in the gallbladder. Emulsifies fats, breaking them down into smaller droplets to increase their surface area for digestion by lipases.
      - Pancreatic Juice: produced by the exocrine pancreas. Contains digestive enzymes such as amylase (for carbohydrate digestion), lipase (for fat digestion), and various proteases (for protein digestion).
    - - Submucosa:
        
        Function: Provides support, vascular supply, and contains submucosal plexus (Meissner's plexus) for regulating glandular secretions.
        
        Connective tissue: Contains blood vessels, lymphatic vessels, and nerves.
        
        Submucosal glands: Present in some organs (e.g., esophagus, duodenum) for mucous secretion.
        
        Submucosal plexus: Part of the enteric nervous system, regulating secretions and blood flow in the mucosa.
      - Muscularis Externa:
        
        Function: Responsible for movement and peristalsis of the digestive tract.
        
        Inner circular muscle layer: Contracts to constrict the lumen.
        
        Outer longitudinal muscle layer: Contracts to shorten the tube.
        
        Myenteric plexus (Auerbach's plexus): Located between the circular and longitudinal muscle layers, controlling muscle contractions for peristalsis.
      - Mucosa:
        
        unction: The innermost layer lining the lumen of the digestive tract, responsible for absorption and secretion.
        
        Epithelium: Varied depending on location, can be simple columnar, stratified squamous, or specialized for specific functions like absorption (e.g., microvilli in small intestine).
        
        Lamina propria: Contains blood vessels, lymphatic vessels, and mucosa-associated lymphoid tissue (MALT) for immune defense.
        
        Muscularis mucosae: Thin layer of smooth muscle that enhances movements of the mucosa for absorption and secretion.
      - Serosa/Adventitia
        
        Function: Provides protection and support to the digestive tract.
        
        Serosa: Present in organs within the peritoneal cavity, consists of a layer of simple squamous epithelium (mesothelium) and underlying connective tissue.
        
        Adventitia: Found in organs outside the peritoneal cavity, composed of connective tissue.
    - - Stomach:
        
        Divided into regions: cardia, fundus, body, and pylorus.
        
        Contains gastric glands that secrete gastric juices (HCl, pepsinogen, mucus) for digestion.
        
        Site of mechanical digestion (churning) and initial protein digestion.
      - Small Intestine:
        
        Divided into three parts: duodenum, jejunum, and ileum.
        
        Receives bile from the liver and gallbladder, as well as pancreatic juices from the pancreas.
        
        Main site of nutrient absorption (carbohydrates, proteins, fats) and chemical digestion
      - Oral Cavity: Includes the lips, tongue, teeth, salivary glands, and palate. Functions in mechanical digestion (chewing) and chemical digestion (saliva contains enzymes like amylase).
      - Colon:
        
        Comprises the cecum, colon (ascending, transverse, descending, sigmoid), and rectum.
        
        Absorbs water and electrolytes from undigested food, forming feces.
        
        Contains gut microbiota responsible for fermentation and production of vitamins.