22 Questions
Which of the following cells is responsible for producing lysozyme in the intestinal mucosa?
Paneth cells
What is the primary function of the Brunner's glands in the duodenum?
Neutralization of acid from chyme
Which layer of the small intestine is responsible for the absorption of nutrients?
Mucosa
What is the primary function of the enteroendocrine cells in the intestinal mucosa?
Production of hormones that regulate digestion
Which of the following structures is responsible for increasing the surface area of the intestinal mucosa?
Kelenjar kriptus Lieberkuhn
What is the primary function of the urogastrone produced by the Brunner's glands in the duodenum?
Inhibition of gastric acid secretion
What is the primary function of the mucosa in the gastrointestinal tract?
Protection against mechanical stress
Which of the following layers is responsible for the movement of food through the gastrointestinal tract?
Muskularis
What is the main function of the submucosa in the gastrointestinal tract?
Attachment of the mucosa to the muskularis
Which of the following plexus is responsible for the control of secretion in the gastrointestinal tract?
Submucosal plexus
What is the main difference between the esophagus and the rest of the gastrointestinal tract?
The absence of serosa
Which of the following nervous systems stimulates the enteric nervous system to increase secretion and activity?
Parasympathetic nervous system
What is the function of the mucosa in the esophagus?
Protection against mechanical stress
Which of the following layers is composed of smooth muscle and is responsible for peristaltic contractions?
Muskularis externa
What is the main function of the fundus region in the stomach?
To secrete pepsinogen
Which of the following layers is responsible for muscle contractions in the stomach?
Muscularis propria
What is the main function of the duodenum in the small intestine?
To mix food with bile and pancreatic enzymes
What is the name of the finger-like projections of the mucosa in the small intestine?
Villi
Which of the following cells in the gastric mucosa produces pepsinogen?
Chief cells
What is the name of the layer of the stomach that contains a network of nerve fibers?
Myenteric plexus
What is the main function of the small intestine?
To absorb nutrients
Which of the following is NOT a function of the stomach?
To absorb nutrients
Study Notes
Layers of Intestinal Wall
- The intestinal wall consists of four layers: mucosa, submukosa, muscularis, and serosa.
- Each layer has a specific function and structure.
Mucosa
- The mucosa is the innermost layer of the intestinal wall.
- It consists of absorptive cells, goblet cells, intestinal glands, and enteroendocrine cells.
- The mucosa is rich in MALT (mucosa-associated lymphoid tissue).
- It is responsible for absorption, digestion, and secretion.
Submukosa
- The submukosa is the layer beneath the mucosa.
- It contains Duodenal glands that secrete alkaline mucus.
- It is composed of loose connective tissue, lymphatic vessels, and blood vessels.
Muscularis
- The muscularis is the layer of smooth muscle that surrounds the intestinal wall.
- It is responsible for peristaltic movements that propel food through the digestive system.
- It has two layers: an inner circular layer and an outer longitudinal layer.
Serosa
- The serosa is the outermost layer of the intestinal wall.
- It is a thin layer of connective tissue that surrounds the intestine.
- It is also known as the visceral peritoneum.
- It is continuous with the peritoneum of the abdominopelvic cavity.
Inervation of Intestine
- The intestine has two types of innervation: enteric nervous system (ENS) and autonomic nervous system (ANS).
- The ENS is the intrinsic nervous system of the gut and consists of two plexuses: myenteric plexus and submucosal plexus.
- The ANS is the extrinsic nervous system that controls the intestine and consists of parasympathetic and sympathetic nerves.
Esophagus
- The esophagus is a muscular tube that propels food into the stomach.
- It has a mucosa, submukosa, and muscularis layers.
- The mucosa is lined with stratified epithelium and has a lamina propria with blood vessels and lymphatic nodules.
- The muscularis is composed of skeletal muscle in the upper third and smooth muscle in the lower two-thirds.
Stomach
- The stomach is a sac-like organ that secretes digestive enzymes and acid.
- It has a mucosa, submukosa, and muscularis layers.
- The mucosa has rugae, gastric pits, and glands that produce pepsinogen, renin, and lipase.
- The stomach has a capacity of around 1500 ml and produces chyme.
Small Intestine
- The small intestine is the longest part of the intestine and is responsible for digestion and absorption.
- It has a mucosa, submukosa, and muscularis layers.
- The mucosa has villi and microvilli that increase the surface area for absorption.
- The small intestine has three regions: duodenum, jejunum, and ileum.
Explore the structure and function of the four layers of the intestinal wall: mucosa, submucosa, muscularis, and serosa.
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