unit 9 Digestive Histology Flashcards
What is the inner layer of the alimentary canal’s wall called?
Mucosa
The mucosa comes in direct contact with the lumen where food travels.
What are the three layers of the mucosa?
- Epithelium
- Lamina propria
- Muscularis mucosae
What type of epithelium is found in areas of the digestive tract exposed to abrasive forces?
Stratified squamous epithelium
What type of epithelium is primarily found in the remaining regions of the digestive tract?
Simple columnar epithelium
What is the function of goblet cells within the simple columnar epithelium?
Secrete mucus
What is the connective tissue layer that anchors the epithelium to other tissues in the mucosa?
Lamina propria
What is the muscularis mucosa?
A layer of smooth muscle providing localized movement
What is the layer of loose connective tissue located under the mucosa called?
Submucosa
What nerve network is found within the submucosa?
Submucosal plexus
What are the two layers of smooth muscle in the muscularis externa?
- Inner circular layer
- Outer longitudinal layer
What is the function of the myenteric plexus?
Controls muscle contraction of the muscularis externa
What are the outer layers of the digestive tract wall called?
Serosa
What is the fibrous connective tissue layer found in the esophagus called?
Adventitia
What is the gastroesophageal junction?
The transition where the esophagus meets the stomach
What type of cells make up the stomach’s mucosa?
Mucous cells (simple columnar cells)
What do gastric pits lead into?
Gastric glands
What structures in the small intestine increase surface area for absorption?
- Plicae circulares
- Villi
- Microvilli
What are Brunner’s glands also known as?
Duodenal glands
What do intestinal crypts secrete?
- Enzymes
- Hormones
What type of cells are found in the small intestine to aid in movement of food debris?
Goblet cells
What are Peyer’s patches?
Aggregated lymphoid nodules found in the small intestine
Fill in the blank: The _______ is a network of nerves located in the muscularis externa.
Myenteric plexus
True or False: The esophagus has serosa.
False
What is the primary function of the hepatocytes in the liver?
Metabolism and detoxification
What are the three components of a hepatic triad?
- Portal arteriole
- Portal venule
- Bile duct
What is the primary function of duodenal glands?
Secretion of mucus to aid in neutralizing acidic chyme from the stomach
Where does most absorption occur in the small intestine?
Jejunum
What are Peyer’s patches?
Aggregated lymphoid nodules in the ileum that house leukocytes
What is the main characteristic of the ileum compared to other regions of the small intestine?
Higher concentration of bacteria and pathogens
What is the primary function of goblet cells in the large intestine?
Secretion of mucus
What role does mucus play in the large intestine?
- Aids in the passage of food debris
- Protects the wall of the large intestine from acid
How many different species of microbes are estimated to be in the gut?
About 200
What vitamins do some gut microbes produce?
- Vitamin K
- B vitamins
What distinguishes the large intestine in tissue samples?
Lacks villi or pits but contains a significant number of goblet cells
What is the structural organization of the liver?
Divided into hexagonal lobules
What is the primary cell type found in liver lobules?
Hepatocytes
What are the functions of hepatocytes?
- Produce bile
- Store glucose
- Make important blood proteins
What type of capillaries are found in the liver?
Sinusoids
What is the function of Kupffer cells in the liver?
Digest unwanted bacteria and debris from blood
What are the two important regions of the pancreas?
- Exocrine
- Endocrine
What do acinar cells in the pancreas produce?
Enzymatic bicarbonate-rich pancreatic juice
What hormones do pancreatic islets produce?
- Insulin
- Glucagon
What is the primary characteristic of salivary glands’ epithelium?
Prominent ducts with simple cuboidal and columnar epithelia
What are serous cells responsible for?
Releasing a thin, watery fluid and enzymes for chemical digestion
What do mucous cells produce?
Thick mucus
Fill in the blank: The _______ is the first region of the small intestine.
Duodenum
True or False: The large intestine primarily absorbs nutrients.
False
What structures should be labeled in a histological study of the esophagus?
- Mucosa
- Submucosa
- Muscularis externa
What structures should be identified in the duodenum during histological study?
Duodenal glands
What is the purpose of the mini activity mentioned in the text?
Review the digestive tract regions with their correct epithelium and functions
