Stomach Mucosa and Gastric Glands

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Questions and Answers

What type of epithelium lines the mucosa of the stomach?

Pseudostratified epithelium

Simple cuboidal epithelium

Simple columnar epithelium (correct)

Stratified squamous epithelium

What is the function of chief cells in the gastric fundic glands?

Producing pepsin for protein digestion (correct)

Regenerating damaged cells

Secreting hydrochloric acid

Regulating blood flow and smooth muscle movement

What is the primary function of the mucosa in the stomach?

Producing digestive enzymes

Protecting the stomach wall from acid and enzymes (correct)

Regulating blood flow and smooth muscle movement

Absorbing nutrients from food

What type of cells are responsible for secreting hydrochloric acid in the stomach?

Parietal cells Signup and view all the answers

What is the name of the plexus of nerves found in the submucosa of the stomach?

Meissner's plexus Signup and view all the answers

What is the function of the muscularis mucosa in the stomach?

Coordinating the movement of the mucosa Signup and view all the answers

What type of muscle is found in the muscularis externa of the stomach?

Smooth muscle Signup and view all the answers

What is the outermost layer of the stomach wall?

Serosa Signup and view all the answers

What is the function of the mucosa in the small intestine?

To absorb nutrients from food Signup and view all the answers

What is the function of the pylorus gland?

To secrete intrinsic factor for vitamin B12 absorption Signup and view all the answers

What is the purpose of the villi in the small intestine?

To increase the surface area for absorption Signup and view all the answers

What is the function of the muscularis in the small intestine?

To perform peristaltic contractions Signup and view all the answers

What is the function of the fundic gland?

To secrete hydrochloric acid and pepsin for digestion Signup and view all the answers

What is the function of the Brunner's glands in the small intestine?

To produce alkaline mucus to protect the duodenum Signup and view all the answers

What is the function of the goblet cells in the small intestine?

To secrete mucus for lubrication Signup and view all the answers

What is the length of the small intestine?

6 meters Signup and view all the answers

What is the primary function of the large intestine?

Absorption of water and storage of fecal matter Signup and view all the answers

Which type of cell is responsible for secreting anti-bacterial lysozymes in the small intestine?

Paneth cells Signup and view all the answers

What is the characteristic of the mucosa in the large intestine?

Simple columnar absorptive cells with many goblet cells Signup and view all the answers

What is the location of the intestinal renewal stem cells in the small intestine?

In the base of the crypt Signup and view all the answers

What is the function of the M-cells in the small intestine?

Antigen transport from the gut lumen Signup and view all the answers

What is the characteristic of the muscularis externa in the large intestine?

Three separate longitudinal ribbons of smooth muscle Signup and view all the answers

What is the name of the skeletal voluntary muscles located between the outer and inner lips?

Orbicularis oris Signup and view all the answers

What type of epithelium covers the Red Margin of the lip?

Partially keratinized stratified squamous Signup and view all the answers

What is the function of the tongue during mastication and swallowing?

To mix food with saliva and aid in swallowing Signup and view all the answers

What is the characteristic of the dorsal surface of the tongue?

It is rough and partially keratinized Signup and view all the answers

What is the function of the Labial muco-serous glands found in the inner surface of the lip?

Produce saliva Signup and view all the answers

What is the structure that comes into contact with the Red Margin of the lip?

Tongue Signup and view all the answers

What type of papillae are present on the edge of the tongue?

Fungiform papillae Signup and view all the answers

What is the type of skin found on the outer surface of the lip?

Thin hairy skin Signup and view all the answers

What is the function of Von Ebner glands?

To facilitate taste sensation and wash away food particles Signup and view all the answers

What is the layer of tissue found under the epithelium of the inner surface of the lip?

Connective tissue Signup and view all the answers

What is the characteristic of the ventral surface of the tongue?

It is smooth and non-keratinized Signup and view all the answers

What is the purpose of the lingual papillae?

To facilitate taste sensation Signup and view all the answers

How many vallate papillae are present on the dorsal surface of the tongue?

8-12 Signup and view all the answers

What is the color of the fungiform papillae?

Reddish Signup and view all the answers

What is the shape of the filiform papillae on the tongue?

Conical Signup and view all the answers

What is the function of the supporting cells in the taste buds?

They act as bodyguards for the taste buds. Signup and view all the answers

What is the name of the place where food enters the taste buds?

Taste pore Signup and view all the answers

What type of epithelium is found in the lips and tongue?

Non-keratinizing stratified squamous epithelium Signup and view all the answers

What is the function of the basal cells in the taste buds?

They act as stem cells for renewal of other cells. Signup and view all the answers

What is the shape of the fungiform papillae on the tongue?

Fungiform Signup and view all the answers

What is the function of the cardiac glands in the mucosa of the esophagus?

They produce alkaline secretions to neutralize acid. Signup and view all the answers

How many layers are present in the wall of the esophagus?

4 Signup and view all the answers

Study Notes

Stomach Mucosa

Lined by simple columnar epithelium and contains branched tubular gastric glands.

Gastric Gland Cells

Simple columnar epithelium: mucous surface secreting and protects the stomach wall from HCL (pH 2.5).
Chief cells (zymogen cells): produce pepsin for protein digestion.
Parietal (oxyntic) cells: secrete hydrochloric acid and intrinsic factors.
Gastric enteroendocrin cells: coordinate blood flow and smooth muscle movement.
Stem cells: regenerate damaged cells.

Stomach Layers

Mucosa: consists of three parts - epithelial lining, lamina propria of C.T. with fundic gland, and muscularis mucosa.
Submucosa: contains Meissner's plexus of nerves and lymphatics, and fundic glands.
Muscularis externa: smooth muscle layer with Auerbach's plexus, responsible for peristaltic contractions.
Serosa: peritoneal or C.T. covering.

Function of Stomach

Mixes food with gastric juice (HCL, mucosa protection, pepsin enzyme, and intrinsic factor for vitamin B12 absorption).
Absorbs water and electrolytes.

Pylorus

Muscular sphincter.
Pylorus gland: contains mucus, stem cells, and enteroendocrin cells.
Short, wide gastric pit.

Small Intestine

Function: absorption of food.
Length: 6 meters.
Mucosa: forms villi, crypts, and simple columnar (absorptive) cells with goblet cells that lubricate food.
Submucosa: contains mucous glands (Brunner's glands) and Peyer's patches of lymphatic nodules.
Muscularis: smooth muscles with Auerbach's plexus, performs peristaltic contractions.
Serosa: simple squamous peritoneum.

Small Intestine Mucosal Cells

Surface simple columnar absorptive cells on villi with microvilli.
Goblet cells.
Paneth (exocrinocytes) cells: secrete antibacterial lysozymes and tumor necrosis factor.
Caveolated cells: present in crypt.
M-cells: transporting in crypt.
Intestinal renewal stem cells: in base of crypt.
Entero-endocrine cells: in crypt.

Large Intestine

Function: absorbs water and stores fecal or residual part during defecation.
No villi, only crypts.
Mucosa: simple columnar (absorptive) cells with many goblet cells to soften stool.
Enteroendocrin and stem cells.
Submucosa: Meissner's plexus.
Muscularis externa: teniae coli with three separate longitudinal ribbons.
Serosa: fat cell appendices epiploicae and appendix.

The Digestive System

The digestive system, also known as the gastrointestinal tract or alimentary canal, consists of the oral cavity, digestive tract, and digestive glands.

Oral Cavity

The oral cavity consists of the lips, tongue, palate, and cheeks.
The lips have three histological regions: the outer surface (thin hairy skin), the inner surface (mucous membrane), and the red margin (vermilion).
The color of the lip margin can indicate health conditions: pale red (anemia), blue (cyanosis), or red (healthy).

The Tongue

The tongue is a mass of lingual striated muscle covered by mucosa, which helps mix food during mastication and swallowing.
The tongue has two surfaces: the dorsal surface (rough, covered by partially keratinized stratified squamous epithelium) and the ventral surface (smooth, covered by non-keratinized stratified squamous epithelium).
There are four types of lingual papillae on the tongue:
Filiform papillae (most common, with partially keratinized stratified squamous epithelium)
Fungiform papillae (reddish in color, with few taste buds)
Foliate papillae (on each side of the tongue)
Vallate or circumvallate papillae (rich in taste buds, with Von Ebner glands)

Taste Buds

Taste buds are neuro-epithelial organs found on the tongue, containing three layers: receptor taste cells (with microvilli), supporting cells, and basal cells.
Taste buds have a taste pore where food enters to be tasted.

The Esophagus

The esophagus is a 25 cm long muscular tube that connects the oral cavity and stomach, conducting food without digesting it.
The esophageal wall consists of four layers: mucosa, submucosa, musculosa, and adventitia.
The mucosa layer has three sublayers: non-keratinizing stratified squamous epithelium, lamina propria with cardiac glands, and muscularis mucosa.
The submucosa layer contains esophageal glands that secrete mucus.
The musculosa layer is composed of skeletal muscle in the upper 1/3, mixed in the middle 1/3, and smooth muscle in the lower 1/3.
The adventitia layer is connective tissue covering the esophagus with blood vessels and lymphatic vessels.

The Stomach

The stomach is a sac-like, muscular, and extended organ, acting as the first station for digestion.

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Description

Learn about the structure and functions of the stomach mucosa and gastric glands, including the types of cells and their roles in digestion.