12 Questions
What is the primary function of Hydrochloric Acid secreted by the Parietal Cells in the stomach?
Dissolves proteins and acts as a bactericide
Which hormone controls the secretion of glucagon from the alpha cells in the pancreas?
Gastrin
What is the primary function of Pepsin secreted by the Chief Cells in the stomach?
Breaks down protein-forming polypeptides
What is the main role of Intrinsic Factor secreted by the Parietal Cells in the stomach?
Enhances Vitamin B12 absorption
Which of the following is NOT a stimulant for Parietal Cells to secrete acid in the stomach?
Prostaglandins
What is the function of Gastroferrin secreted by the Parietal Cells in the stomach?
Enhances iron absorption in the small intestines
What is the function of the Villi in the intestine?
Increase surface area for absorption
Which neural activity stimulates increased secretion and motility in the intestines?
Parasympathetic Nervous System (PNS)
What is the primary function of the Ileocecal Valve?
Prevent reflux into the large intestine
Which part of the peritoneum lines the surface of organs in the abdomen?
Visceral Peritoneum
What is the purpose of segmentation in digestion?
Mix chyme and promote digestion
Which reflex creates the urge to defecate by relaxing the internal anal sphincter?
Rectosphincteric reflex
Study Notes
Gastric Secretion
- Gastric juice composition depends on volume and flow rate
- High in K+, increasing the risk of potassium depletion with gastric emptying
- Secretion rate is lower in the morning and higher in the evenings
- Mucus forms a protective barrier in the stomach
- Parietal cells secrete hydrochloric acid, which:
- Dissolves food fibers
- Acts as a bactericide for swallowed organisms
- Converts pepsinogen to pepsin
- Chief cells secrete pepsinogen, which:
- Needs an acidic environment
- Breaks down protein-forming polypeptides
Regulation of Gastric Secretion
- Parietal cells are stimulated by:
- Gastrin
- Histamine
- Acetylcholine
- Parietal cells are inhibited by:
- Somatostatin
- Prostaglandins
- Secretin
- Vasoactive intestinal peptide
Hormones and Enzymes
- Gastrin is secreted by G cells and:
- Stimulates parietal cells to secrete acid
- Controls secretion of glucagon from alpha cells in the pancreas
- Intrinsic factor (IF) is secreted by parietal cells and:
- Binds with Vitamin B12 in the stomach to enhance absorption
- Deficiency leads to pernicious anemia
- Gastroferrin is secreted by parietal cells and:
- Facilitates iron absorption in the small intestine
Small Intestine
- Consists of:
- Duodenum (upper)
- Jejunum (middle)
- Ileum (lower)
- Ileocecal valve separates the small intestine from the large intestine
- Muscular layers include:
- Mucosal folds (Plica) for digestion and absorption
- Myenteric plexus for neural activity
- Villi are the functional units of the intestine, responsible for:
- Absorbing nutrients
- Increasing surface area through microvilli
Large Intestine
- Purpose: massages fecal mass, absorbs water and electrolytes
- Consists of:
- Cecum
- Appendix
- Colon (ascending, transverse, descending, sigmoid)
- Rectum/Anus
- No villi, but has mucus-secreting cells (goblet cells)
- Segmentation mixes chyme and promotes digestion
- Reflexes regulate motility:
- Ileogastric reflex
- Intestinointestinal reflex
- Gastroileal reflex
Test your knowledge on the basics of gastric secretion including which cells secrete what, composition of gastric juice, factors affecting secretion rate, and protective mechanisms of the mucosal barrier. Learn about the role of potassium, mucus, P cells, and nitric oxide in maintaining gastric health.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
