What type of connective tissue surrounds the gastric glands?
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Loose connective tissue
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What type of connective tissue surrounds the gastric glands?
Loose connective tissue
What are the two layers of the muscularis mucosae?
Inner circular and outer longitudinal
What are the cell types found in the gastric glands?
Mucous neck cells, Parietal (oxyntic) cells, Chief cells, Enteroendocrine cells, Stem cells
What are the main components of taste buds?
Taste buds consist of a taste pore, sensory neuroepithelial cells, supporting cells, and basal cells.
What is chyme?
Partially digested food in the stomach.
What type of connective tissue is found in the submucosa?
Dense irregular connective tissue
What is the role of adventitia in relation to structures above the diaphragm?
Adventitia fixes structures to adjacent ones above the diaphragm.
Describe the pyloric glands in the stomach.
They have relatively long pits and short pyloric glands that are branched, coiled, tubular with a wide lumen.
What is the function of the structure indicated by the arrow in image C?
The specific function of the structure indicated by the arrow needs to be identified based on the image.
What should be identified in images D?
The organ and the structures labelled X and Y.
From which region of the gastrointestinal tract is the slide in image E most likely taken?
The specific region of the gastrointestinal tract needs to be identified based on the image.
What is the function of the muscularis externa in the stomach?
To mix stomach contents (chyme) and force the partially digested food into the small intestines.
Does the structure of the alimentary canal remain consistent throughout its length?
Yes, it has the same basic structure throughout, but different parts contain specializations characteristic of that region.
Where are the large mono or binucleated cells concentrated in the gastric glands?
Concentrated in the neck of the gland.
What type of epithelium transitions in the mucosa?
Stratified squamous to simple columnar epithelium.
What replaces the esophageal cardiac glands in the lamina propria?
Cardiac glands of the stomach.
How does the muscularis mucosa change?
It transitions from one layer to two layers of smooth muscles arranged as inner circular and outer longitudinal.
Where do the glands in the gastric mucosa empty?
Into gastric pits
What are the two types of lingual muscles?
Striated muscles: Extrinsic and Intrinsic.
How do mucous neck cells compare in size to surface mucous cells?
Mucous neck cells are smaller than surface mucous cells.
What role do basal cells play in taste buds?
Basal cells serve as stem cells in taste buds.
Describe the structure of the three regions of the stomach.
The stomach consists of the cardia, fundus, and pylorus, each with distinct histological features and specialized functions in digestion.
What is the length of the esophagus?
Approximately 25 cm long.
What type of cells are present in the cardiac glands?
Mucus-secreting cells and enteroendocrine cells.
What are the primary functions of the stomach?
Mixing, partial enzymatic digestion, and minimal absorption of some water and certain drugs.
What type of tissue is found in the submucosa of the stomach?
Dense connective tissue.
What type of cells line the short pits in the gastric mucosa?
Surface mucous cells
What happens to the submucosa in the transition?
Esophageal proper glands are replaced by no glands in the submucosa.
What is the muscularis mucosae composed of?
A single layer of longitudinal muscle.
What types of cells are found in taste buds?
Taste buds contain sensory neuroepithelial cells, supporting cells, and basal cells.
What is the status of taste buds in foliate papillae in adults?
Taste buds in foliate papillae are rudimentary in adults.
What surrounds circumvallate papillae?
Circumvallate papillae are surrounded by a moat-like invagination that receives ducts of serous Von Ebner’s glands.
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What are the distinct four layers characteristic of the alimentary canal?
The four layers are the mucosa, submucosa, muscularis externa, and serosa/adventitia, each serving specific functions in digestion and absorption.
What is the difference in the covering of structures above and below the diaphragm?
Above the diaphragm, structures are covered by adventitia, while below the diaphragm, they are covered by serosa, which is continuous with that of the stomach.
What is the primary function of the esophagus?
To act as a conduit for the bolus of food from the mouth.
Why are the large cells in gastric glands eosinophilic?
Due to the presence of abundant mitochondria for active proton pumps.
What type of epithelium is found in the mucosa of the esophagus?
Stratified squamous non keratinized epithelium.
Where are gastrin secreting cells concentrated?
In the pyloric antrum.
What are the three layers of muscle in the muscularis externa of the stomach?
Innermost oblique, middle circular (which thickens to form the pyloric sphincter), and outer longitudinal.
What additional layer is added to the muscularis externa?
An innermost oblique layer.
What type of cell is located at the base of the gastric gland and is typical for protein secretion?
Chief cell
What gives the chief cells a basophilic appearance?
Abundant rough endoplasmic reticulum (rER)
Which cranial nerves are associated with the synapses of sensory neuroepithelial cells?
The cranial nerves associated are CN VII, IX, and X.
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No alterations to the documents may be made, and the copyright statement must be maintained in all copies.
What is a characteristic feature of surface mucous cells?
Surface mucous cells have an elongated nucleus and a large apical cup of mucinogen granules that takes up most of the cytoplasm.
What is the shape and function of filiform papillae?
Filiform papillae are small and conical, lined by highly keratinized stratified squamous epithelium, distributed over the entire dorsal surface with tips facing backwards, and have a mechanical function with no taste buds.
What type of epithelium lines the excretory duct of the esophageal glands?
Stratified squamous epithelium
What type of epithelium lines the surface and gastric pits of the mucosa?
Simple columnar epithelium
What type of muscle is found in the upper third of the Muscularis Externa?
Skeletal muscle.
What is the function of the lamina propria in the esophagus?
It contains connective tissue with diffuse lymphatic tissue and lymphatic nodules.
How many glands typically empty into one gastric pit?
2 - 4 glands
What can untreated chronic metaplasia lead to?
Irreversible dysplasia and potentially adenocarcinoma.
What do mucous neck cells secrete?
Mucous neck cells secrete soluble mucus that helps transport gastric secretion to the lumen.
What types of lingual papillae are found on the anterior 2/3 of the tongue?
Filiform, Fungiform, Circumvallate, and Foliate.
Where are circumvallate papillae located?
Circumvallate papillae are found anterior to the sulcus terminalis.
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'View only' files are explicitly excluded from download, and creating copies of these recordings is strictly illegal.
What is intrinsic factor and its significance?
Intrinsic factor is a glycoprotein secreted by parietal cells that binds to vitamin B12, essential for its absorption.
How do prostaglandins affect surface mucous cells?
Prostaglandins secreted by the cells of the mucosa stimulate the secretion of bicarbonate and increase the thickness of the mucus.
What are the main components of the digestive system?
The digestive system consists of the alimentary canal and associated organs such as the tongue, teeth, salivary glands, pancreas, liver, and gallbladder.
What is the extensive intracellular system that communicates with the lumen of the gland?
The extensive intracellular canalicular system.
What system contains excess plasma membrane with proton pumps adjacent to the canaliculi?
The tubulovesicular system.
What stimulates the gastric mucosa?
Gastrin and receptors for histamine (H2).
What are the four distinct layers of the alimentary canal?
Mucosa, Submucosa, Muscularis Externa, Serosa/Adventitia.
What major components are found in the submucosa?
Large blood and lymphatic vessels, Submucosal Plexus (Meissner’s plexus)
Where are fungiform papillae located and what is their function?
Fungiform papillae are mushroom-shaped, lined by stratified squamous epithelium, scattered among the filiform papillae, most prominent on the tip of the tongue, and contain taste buds in the epithelium on the dorsal surface.
What do the esophageal glands produce?
Slightly acidic mucus that lubricates the lumen
What does the esophagus connect?
It connects the pharynx to the stomach.
What type of glands are found in the cardiac region of the stomach?
Relatively short pits and short cardiac glands that are tubular with occasional branching.
What do the large mono or binucleated cells in gastric glands secrete?
H +, Cl -, and Intrinsic factor.
From where to where does the alimentary canal extend?
It extends from the proximal esophagus to the anal canal.
How is the serosa related to the stomach?
The serosa below the diaphragm is continuous with that of the stomach.
What type of cells secrete hormones into the lamina propria and are found throughout the gland?
Gastrin secreting cells, which are more prevalent in the base and typically appear clear with H & E stain.
What are the three histological regions of the stomach?
What is the typical state of the lumen of the esophagus?
The lumen is normally collapsed with longitudinal folds.
What are the components to identify in images A and B?
Region of the stomach, extent of mucosa, mucous cells, parietal cells, chief cells, muscularis interna, submucosa.
What are the two general types of cells mentioned in the text?
Closed cells, which do not reach the lumen, and open cells, which are exposed to the lumen.
What are the typical layers of the Muscularis Externa?
Inner circular and outer longitudinal layers.
Where is the cardiac region of the stomach located?
Near the esophageal orifice.
What do the secretory cells in the pyloric glands secrete?
A viscous mucus and they also contain enteroendocrine cells.
What digestive enzymes are secreted by the stomach?
Pepsin and lipase.
What are gastric pits also known as?
Foveolae
What is the primary function of the open cells in the gastric glands?
They serve as primary chemoreceptors.
What type of glands are found in the fundic region of the stomach?
Fundic (gastric) glands.
What are the three parts of the long fundic (gastric) glands?
Isthmus, Neck, Fundus (base)
What type of muscle is found in the middle third of the Muscularis Externa?
Mixed skeletal and smooth muscle.
What type of muscle is found in the lower third of the Muscularis Externa?
Smooth muscle.
What do the esophageal cardiac glands produce?
Neutral mucus that protects from regurgitated gastric contents.
What is the function of extrinsic lingual muscles?
They attach the tongue to outside structures and move the entire tongue.
What is the structure of foliate papillae?
Foliate papillae are arranged in parallel rows separated by deep clefts.
What is the inactive proteolytic enzyme secreted by chief cells?
Pepsinogen
What are the four major components of gastric juice?
Hydrochloric acid (HCl), pepsinogen, mucus, and intrinsic factor.
What is the microscopic structure of lingual papillae?
The microscopic structure of lingual papillae includes various types such as filiform, fungiform, foliate, and circumvallate, each with distinct features and functions.
What is the microscopic structure of the gastric mucosa?
The gastric mucosa features gastric pits and glands, lined with simple columnar epithelium, containing parietal, chief, and mucous cells.
What structures are present in the submucosa?
Lymphatics, blood vessels, and submucosal plexus.
Where are the esophageal cardiac glands primarily located?
In the terminal part of the esophagus.
Should the stomach be covered by serosa or adventitia?
Based on anatomy knowledge, the stomach should be covered by serosa.
What is the role of intrinsic lingual muscles?
They originate and insert within the tongue and alter its shape.
What is the turnover rate for sensory neuroepithelial and supporting cells in taste buds?
The turnover rate for both sensory neuroepithelial and supporting cells is approximately 10 days.
How is pepsinogen converted to its active form?
By low pH in the stomach
Which cells produce hydrochloric acid?
Hydrochloric acid is produced by parietal cells.
Describe the microscopic structure of taste buds.
Taste buds are composed of taste receptor cells, supporting cells, and basal cells, organized in a spherical structure that allows for the detection of taste stimuli.
How do the cells of the gastric mucosa differ based on their histological structures, functions, and localization?
The gastric mucosa contains parietal cells (secreting HCl), chief cells (producing pepsinogen), and mucous cells (providing protection), each with distinct histological characteristics.
What is the shape and location of the pyloric region of the stomach?
It is the distal, funnel-shaped region proximal to the pyloric sphincter.
What type of epithelium is associated with Barrett’s Esophagus?
Metaplastic simple columnar epithelium with mucous cells or sometimes intestinal goblet cells.
Where are stem cells found in the gastric glands?
In the isthmus/neck of the gland
Where are foliate papillae located on the tongue?
Foliate papillae are found on the lateral edges of the tongue.
What triggers the release of mucinogen granules in mucous neck cells?
The release of mucinogen granules is triggered by vagal stimulation.
What weak enzyme is secreted by chief cells along with pepsinogen?
Weak lipase
What is pepsinogen and how is it activated?
Pepsinogen is produced by chief cells and is converted to active pepsin by HCl.
What condition results from a lack of intrinsic factor?
A lack of intrinsic factor results in pernicious anemia and vitamin B12 deficiency.
Where are Meissner’s and Auerbach’s plexuses located and what is their microscopic structure?
Meissner’s plexus is located in the submucosa, while Auerbach’s plexus is found between the layers of the muscularis externa; both are networks of nerve fibers that regulate gastrointestinal motility.
What are rugae of the stomach?
Rugae are folds in the gastric mucosa that allow for expansion of the stomach when filled with food.
What is the main cause of GERD?
A weakened lower esophageal sphincter which causes reflux back into the lower esophagus.
Which substances can be minimally absorbed in the stomach?
Some water and certain drugs such as alcohol, aspirin, and NSAIDs.
What is a frequent symptom of GERD?
Chest pain of a burning nature.
What is the typical protein-secreting cell in the gastric glands characterized by abundant rER?
Chief cell
What type of granules are found in the apical region of chief cells?
Zymogen granules
Where are taste buds located in circumvallate papillae?
Taste buds are located in the epithelium of the lateral surface of circumvallate papillae.
What is the relationship of serosa and adventitia to the GI tract?
Serosa is the outermost layer covering organs within the peritoneal cavity, while adventitia is the connective tissue layer that anchors the GI tract to surrounding structures.
What are the functions of rugae?
Rugae facilitate the expansion of the stomach and increase the surface area for digestion.
What are rugae in the stomach?
Characteristic temporary longitudinal folds of mucosa and submucosa that accommodate expansion and filling of the stomach.
What is the function of the Myenteric plexus (Auerbach’s plexus)?
It innervates the muscularis externa for peristalsis.
What happens to the normal stratified squamous epithelium in Barrett’s Esophagus?
It is replaced by simple columnar epithelium due to chronic acid reflux.
What is the Sulcus Terminalis?
A V-shaped depression that divides the tongue into anterior 2/3 and posterior 1/3, with the foramen cecum at its apex.
Which papillae are associated with taste buds?
Select papillae such as Fungiform, Circumvallate, and Foliate.
What is the daily production of gastric juice by cells?
Cells produce up to 2 L/day of gastric juice.
What do surface mucous cells secrete and what is its function?
Surface mucous cells secrete thick viscous mucus that adheres to the epithelium, protecting it from rough chyme.
How do esophageal cardiac and proper glands differ in their microscopic structures?
Esophageal cardiac glands are located near the esophagogastric junction and have a simple tubular structure, while proper glands are found in the submucosa and have a more complex structure.
What is the function of the muscularis externa of the stomach?
The muscularis externa is responsible for the peristaltic movements that mix and propel food through the stomach.
Where are mucous neck cells located?
Mucous neck cells are located in the neck of the gland.
How do sensory neuroepithelial cells interact with taste stimuli?
They interact with taste receptors on their apical surface and have microvilli that help detect tastants.
How many circumvallate papillae are typically found on the tongue?
There are typically 8 to 12 large and dome-shaped circumvallate papillae.
Who is permitted to make copies of downloadable files for personal and classroom use?
Students enrolled in year 1 of St. George’s University School of Medicine and their faculty are permitted to make copies.
Where are surface mucous cells located?
Surface mucous cells line the gastric pits.
What is the structure of the muscularis externa throughout the length of the esophagus?
The muscularis externa of the esophagus consists of an inner circular layer and an outer longitudinal layer, with the upper third being skeletal muscle and the lower two-thirds being smooth muscle.
Describe the structure of the muscularis externa of the stomach.
The muscularis externa consists of three layers: an inner oblique layer, a middle circular layer, and an outer longitudinal layer, facilitating effective contractions.
What is the characteristic of the nucleus in mucous neck cells?
Mucous neck cells have a spherical nucleus.
Is there any release of mucus in the resting stomach?
There is no release of mucus in the resting stomach.
What is the role of hydrochloric acid (HCl) in gastric juice?
HCl gives gastric juice a low pH, converts pepsinogen into pepsin, and kills most bacteria.
What is the significance of the bicarbonate and potassium content in surface mucous cells?
The high bicarbonate and potassium content in surface mucous cells protects against the acidity of gastric juice.
What changes occur in the epithelium of the lower esophagus due to chronic acid reflux (Barrett’s Esophagus)?
Barrett’s Esophagus involves a change from stratified squamous epithelium to intestinal-type columnar epithelium, which can increase the risk of esophageal adenocarcinoma.
What is the copyright status of year 1 course materials at St. George’s University School of Medicine?
All year 1 course materials, whether in print or online, are protected by copyright and may not be copied, distributed, or published in any form.
What is the function of mucus in the stomach?
Mucus provides a protective coating for the stomach and acts as a physiological barrier.
Describe the microscopic structure of the esophagus.
The esophagus consists of a mucosal layer with stratified squamous epithelium, a submucosal layer with glands, and a muscularis externa with both skeletal and smooth muscle.
Describe the structure of a rugae.
Rugae are formed by folds of the mucosal layer, consisting of the epithelium and underlying connective tissue, allowing for flexibility.
Describe the structure of the esophagogastric junction.
The esophagogastric junction features a transition from stratified squamous epithelium of the esophagus to simple columnar epithelium of the stomach, along with specialized muscular structures.
Differentiate between cardiac, fundic, and pyloric glands based on their microscopic structures.
Cardiac glands are short and branched, fundic glands are long and tubular with specialized cells, and pyloric glands are coiled and contain mucous cells.
