Gastric and Intestinal Histology Quiz

<p>Pernicious anemia (B)</p> Signup and view all the answers

<p>Open type enteroendocrine cells (D)</p> Signup and view all the answers

<p>Muscular layer (C)</p> Signup and view all the answers

<p>Secreting mucus and alkaline fluid (D)</p> Signup and view all the answers

<p>Paneth cells (C)</p> Signup and view all the answers

<p>Villi (A)</p> Signup and view all the answers

<p>Enteroendocrine, goblet, and stem cells (D)</p> Signup and view all the answers

<p>Stratified squamous epithelium (A)</p> Signup and view all the answers

<p>Paneth cells (C)</p> Signup and view all the answers

<p>They produce mucus. (B)</p> Signup and view all the answers

<p>Neuroendocrine cell - Pepsinogen (A)</p> Signup and view all the answers

<p>Ileum (A)</p> Signup and view all the answers

<p>Parietal cell (B)</p> Signup and view all the answers

<p>Controls defecation reflex (D)</p> Signup and view all the answers

<p>Enterocyte (D)</p> Signup and view all the answers

<p>Esophagogastric sphincter (D)</p> Signup and view all the answers

<p>Secretions of gastric mucosa (C)</p> Signup and view all the answers

<p>Myenteric (Auerbach’s) plexus (D)</p> Signup and view all the answers

<p>Hydrochloric acid and proteolytic enzymes (A)</p> Signup and view all the answers

<p>Mucous cells (C)</p> Signup and view all the answers

<p>Stratified squamous nonkeratinized epithelium (B)</p> Signup and view all the answers

<p>Muscularis externa (D)</p> Signup and view all the answers

<p>It has both skeletal and smooth muscle in the middle third. (B)</p> Signup and view all the answers

<p>Gastroesophageal junction (C)</p> Signup and view all the answers

<p>Absence of stratified epithelium (C)</p> Signup and view all the answers

<p>Small intestine (D)</p> Signup and view all the answers

<p>Smooth muscle (A)</p> Signup and view all the answers

<p>Support and transport nutrients (B)</p> Signup and view all the answers

<p>Mesothelium (B)</p> Signup and view all the answers

<p>To facilitate peristalsis (A)</p> Signup and view all the answers

<p>Auerbach’s myenteric plexus (A)</p> Signup and view all the answers

<p>Tunica submucosa (C)</p> Signup and view all the answers

<p>Participate in immune response (C)</p> Signup and view all the answers

The lower digestive tract includes the stomach, small intestine (duodenum, jejunum, ileum), and large intestine (cecum, appendix, colon, rectum).

The digestive tract has four main layers: mucosa, submucosa, muscularis externa, and serosa/adventitia.

Innermost layer of the digestive tract, consisting of epithelium, lamina propria (loose connective tissue), and muscularis mucosae(smooth muscle).

Layer beneath the mucosa, made of dense irregular connective tissue, containing blood vessels, lymph vessels, and Meissner's plexus (part of the enteric nervous system).

Layer containing smooth muscles arranged in inner circular and outer longitudinal layers responsible for peristalsis. Excluding the esophagus, generally two layers.

Outermost layer of the digestive tract, either a thin connective tissue layer (adventitia) or a serous membrane layer (serosa) containing simple squamous epithelium when intraperitoneal. This membrane is crucial for protection, support and interaction with surrounding structures.

Smooth muscles in the outer layer of the alimentary canal (except in the esophagus).

The nervous system of the digestive tract with intrinsic ganglia (Auerbach's / Meissner’s plexuses) that regulate smooth muscle movement and gastrointestinal secretions.

The esophagus is approximately 25 centimeters long, a muscular tube connecting the pharynx to the stomach.

The innermost layer of the esophagus is lined with stratified squamous nonkeratinized epithelium, which allows for passage of food without abrasion. This lining folds longitudinally to accommodate distension.

These glands are present in both the lamina propria (mucosal glands) and submucosa (esophageal glands proper) of the esophagus, secreting mucus to lubricate food passage.

The muscular layer of the esophagus is unique, containing both skeletal and smooth muscle fibers. The upper 1/3 is mainly skeletal muscle, ensuring voluntary swallowing, while the lower 1/3 is smooth muscle, controlled by the autonomic nervous system, for involuntary peristalsis.

The transition from the esophagus to the stomach is not a true anatomical sphincter, but a functional one. This is marked by the change in lining epithelium, from stratified squamous to columnar.

A muscular valve at the junction of the esophagus and stomach, preventing food reflux back into the esophagus.

A muscular valve at the junction of the stomach and small intestine, controlling the flow of chyme into the duodenum.

A valve at the junction of the ileum (small intestine) and the cecum (large intestine), preventing backflow from the large intestine into the small intestine.

A ring of involuntary smooth muscle at the anus, controlling the release of waste.

The gastric epithelium contains mucous cells responsible for mucus secretion, parietal cells that produce hydrochloric acid, chief cells that produce pepsinogen, and enteroendocrine cells that release various hormones.

The gastric mucosa is divided into three zones: superficial, neck, and deep. The superficial zone contains surface mucous cells and gland openings. The neck zone has stem cells and neck mucous cells. The deep zone contains glands with parietal and chief cells.

Parietal cells are found in the deep zone of the gastric mucosa. They are responsible for producing hydrochloric acid (HCl) and intrinsic factor, essential for vitamin B12 absorption.

Chief cells reside in the deep zone of the gastric mucosa. They synthesize and release pepsinogen, a precursor to the digestive enzyme pepsin.

Enteroendocrine cells are scattered within the gastric mucosa. They produce hormones that regulate digestion, such as gastrin, which stimulates acid production.

Enteroendocrine cells can be open or closed. Open cells release hormones directly into the lumen, while closed cells release hormones into the blood.

Brunner's glands are branched tubuloalveolar glands found in the duodenum that secrete mucus and an alkaline fluid to neutralize acidic chyme from the stomach. They also secrete the hormone urogastron.

Villi are finger-like projections of the mucosa in the small intestine that increase surface area for absorption of nutrients. These projections contain lacteals, lymphatic vessels for fat absorption.

Paneth cells are found in the crypts of Lieberkühn of the small intestine and produce antibacterial agents like lysozyme, defensin, and TNF-alpha.

Goblet cells are unicellular glands found in the epithelial layer of the small intestine that produce musinogen. Musinogen, when hydrated, becomes mucin, a component of mucus.

The myenteric plexus, also known as Auerbach's plexus, is a nerve network located between the inner circular and outer longitudinal layers of the muscularis externa in the small intestine. It regulates peristaltic movements.

The rectum is the final segment of the digestive tract, connecting the colon to the anal canal. It stores feces before elimination.

The anal canal has two sphincters: the internal anal sphincter (involuntary, smooth muscle) and the external anal sphincter (voluntary, skeletal muscle). These control the passage of feces.

The anal canal transitions from simple columnar epithelium in the rectum to stratified squamous epithelium towards the anus. This reflects the change in function, from absorption to protection against abrasion.

The internal anal sphincter is a ring of smooth muscle that involuntarily constricts to prevent the leakage of feces. It is always partially contracted.

The external anal sphincter is a ring of skeletal muscle that allows for voluntary control over defecation. It can relax to allow feces to pass or contract to prevent it.

The junctional zone marks the transition between the simple columnar epithelium of the rectum and the stratified squamous epithelium of the anal canal. A line called the pectinate line defines this junction.

The anal columns are longitudinal folds in the lining of the anal canal. They contain blood vessels, which can become enlarged, leading to hemorrhoids.

The submucosa of the anal canal is a layer of dense connective tissue that contains the internal anal sphincter. It also holds blood vessels and nerves.