Basic Power Points on Anatomy and Physiology.pptx

Human Anatomy & Physiology

1. Anatomy and Physiology of Stomach Prepared by Mah Rukh Asif BSN(semester one) Submitted to Miss Faheema Al- Razi Institude

2. Key Points Discovery Introduction J-shaped Parts of stomach Direction of stomach Anatomy of stomach Physiology of stomach Gastric Secretions Function

3. Parts of Stomach Fundus Serosa Muscularis Submucosa Pyloric antrum Cardia Antrum Muscosa Antrum Greater & Lesser Curvature Pylorus

4. Main Part of Stomach Cardia Fundus Body Pylorus

5. Discovery of Stomach William Beaumont (the first person to observe & study human digestion as it occurs in the stomach) First American surgeon scientist and father of gastric physiology His Groundbreaking research, made possible by his care of a patient with a unique stomach wound , laid the foundation for modern gastroenterology h

6. Introduction of Stomach The stomach is an important organ and the most dilated portion of the digestive system The esophagus precedes it, and the small intestine follows. It is a large, muscular, and hollow organ allowing for a capacity to hold food.

7. J-Shaped The stomach is the J-shaped Organ in the upper belly (abdomen). Its parts of the digestive system . Its between the end of the food pipe (esophagus) and the start of the first part of the small bowel

8. Direction The stomach is located in the upper –left part of the abdomen , below the ribcage and under the diaphragm

9. Anatomy of Stomach Greater curvature The greater curvature of the stomach is significant anatomically & functionally. Anatomically, it refers to the outer, longer curve of the stomach, opposite to the lesser curvature. Functionally, it plays a role in the expension of the stomach to accommodate food a long the digestive tract during digestion. Smaller curvature The smaller curvature of the stomach refer to the inner, shorter curve of the stomach. It is also know as the lesser curvature . This curvature is important in the anatomy of the stomach Plays a role in the arrangement of blood vessels.

10. Layers of Stomach Mucosa The innermost layer that secretes mucus, enzymes, and acids for digestion. Submucosa A layer of connective tissue that contains blood vessels, nerves, and glands. Muscularis Serosa Consists of The outermost smooth muscle layer that tissue responsible provide for mixing & protection moving food & support through the to the stomach stomach

11. Internal features The stomach has internal features such as gastric pits, gastric glands, rugae, and a sphincter at both ends (cardiac and pyloric sphincters) These features help in digestion, secretion of digestive enzymes, and movement of food

12. Physiology of stomach

13. Regulation of digestion Neural Regulation Hormonal Regulation Paracrine Regulation Feedback Mechanism

14. Secretion Neural regulation The vagus nerve plays a crucial role in stimulating gastric secretion . It releases acetylocholine , which binds to receptors on stomach cells, leading to increased secretion of gastric acid and enzymes. Hormonal regulation Gastrin: Released by a cells in response to food, gastrin stimulates gastric acid secretions. Histamine : Released in response to gastrin, histamine further enchances gastric acid production . Somatostatin : produced by D cells somatostatin inhibits gastrin release, moderating gastric acid secretion

15. Secretion Local Factors Acetylcholine : Released locally, Acetylcholine stimulates gastric acid and enzyme secretion. Prostaglandins : Certain prostaglandins protect the stomach lining by reducing acid secretion and promoting mucus production Feedback Mechanisms Feedback mechanisms help regulate gastric secretion based on the contents of the stomach. For example :As the stomach fills with food, stretch receptors in the stomach wall send signals to decrease gastric secretion until the food can be adequately processed. These regulatory mechanisms work together to ensure that gastric secretion is appropriately controlled to facilitate digestion without causing harm to the stomach lining

16. Protection mechanism Mucus layer The stomach lining secretes a thick layer of mucus that coats the stomach inner surface , protecting it from the corrosive effects of gastric acid and digestive enzymes Bicarbonate secretion Cells in the stomach lining produce bicarbonate , which neutralizes any acid that comes into contact with the stomach lining Epithelial cell Renewal The stomach lining rapidly regenerates, replacing damaged cells with new ones to maintain the integrity of the stomach wall

17. Protection Mechanism Tight Junctions: The epithelial cells of the stomach lining are tightly joined together, preventing acid from seeping between them and damaging deeper tissues. Prostaglandins: These compounds promote mucus and bicarbonate production and help blood flow to the stomach lining, Ensuring that it receive adequate nutrients and oxygen. Acid and Enzyme : The stomach regulates the secretion of acid and digestive enzymes, releasing them only when food is present to minimize potential damaged These mechanism work together to protect the stomach from its own harsh digestive environment while allowing it to perform its function in breaking down food

18. Digestion Mechanism Ingestion and Mechanical Bolus Formation: When food is chewed and mixed with saliva , it forms a bolus that is swallowed and travel down the esophagus to the stomach. Churning: The stomach muscular walls contract to mix and break down the bolus into smaller pieces, a process called Mechanical digestion Chemical Digestion Gastric Juices: The stomach secretes gastric juices , which contain hydrochloric acid (HCL) and digestive enzymes like pepsin. Hydrochloric acid :HCL lowers the PH of the acidic environment that help breakdown food and activates pepsinogen into pepsin . Pepsin: This enzyme begins the digestion of proteins by breaking them down into smaller peptides . Formation of Chyme : As mechanical and chemical digestion progress , the bolus is converted into a semi-liquid mixture called chyme.

19. Digestion Mechanism Regulation of Gastric Secretions: Cephalic Phase: The sight, smell, taste, or thought at food triggers the brain to stimulate gastric juice production. Gastric Phase: When food reaches the stomach, walls and activates gastrin release, further stimulating gastric juice secretion. Intestinal Phase: As Chyme enters the small intestine, it triggers the small intestine, it triggers the release of hormones that inhibit gastric secretion and slow gastric emptying to ensure proper digestion and absorption in the intestine

20. 5. Controlled Release to the small intestine Pyloric sphincter: The pyloric sphincter regulates the passage of chyme from the stomach to the duodenum (the first part of the small intestine) allowing small amounts to enter at a time for further digestion and absorption.

21. Thank you