BIOL 121 Lecture Notes - Lecture 2: Muscular Layer, Pylorus, Gastric Glands
Document Summary
Layer of stomach wall that faces the inside. Glue of cell walls hold mucosa to next layer. Bigger blood vessels but mostly just connective tissue: smooth muscle (muscularis externa): Circular muscles contract- diameter smaller, relax- diameter bigger. Mechanical digestion also occurs in the stomach to turn the bolus into chyme, a more digestible liquid. Gentle mixing waves are generated every 15-25 seconds to mix the food with the secretions of the gastric glands. More vigorous mixing occurs as digestion proceeds, beginning at the body of the stomach and intensifying towards the pylorus. Pyloric sphincter is slightly open, so a small amount of the chyme empties into the beginning of the small intestine (duodenum) Most of the chyme is pushed back into the body of the stomach where more mixing can occur. The acidic gastric juices inactivate the salivary amylase and activate the lingual lipase.
