Histology II: Digestive system Flashcards
Another name for the intestinal glands
Crypts of Lieberkühn
What 3 structures increase the absorptive surface area of the small intestine?
Circular folds, villi and microvilli.
Crypts of Lieberkuhn glands are composed of what?
a simple columnar epithelium
What five type of cells are found in intestinal mucosal epithelium?
enterocytes, endocrine cells, goblet cells, M (microfold) cells and paneth cells
What are paneth cells?
highly specialized secretory epithelial cells
located in the crypts of Lieberkühn
secrete antimicrobial substances.
What are M cells?
Microfold cells are modified enterocytes (intestinal epithelial cells) that cover lymphatic nodules.
Enterocytes primary function?
absorption
what are Goblet cells
unicellular mucin-secreting glands
What does Muscularis externa, consist of?
inner circularly and outer longitudinally arranged smooth muscle cells.
What structure is NOT found with the intestinal crypts in the large intestine?
no intestinal villi in large intestine
the mucosa of the large intestine is made up of?
simple columnar epithelium containing numerous goblet cells and few enterocytes.
what are the 4 layers of t. mucosa of the large intestine?
mucosal layer, lamina propria, muscularis mucosae and then by submucosa (after that, we move to the next tunic)
Name 6 functions of the liver
- degrades drugs and toxins
- bile production - is an exocrine function
- endocrine-like functions = its ability to modify the structure of many hormones
- involved in many metabolic pathways
- stores and converts several vitamins and iron
(Vitamin A, D, K) - produces most plasma proteins
From which 2 sources does the liver receive blood?
hepatic artery and hepatic portal vein
Describe liver structure.
parenchymal hexagonal hepatic lobules,
which in turn consist of hepatocytes oriented radially surrounded by connective tissue stroma,
sinusoid structures throughout
where do the sinusoids drain
central vein of hepatic lobule
In addition to endothelial cells, what lines the sinusoids.
Kupffer cells (macrophages)
what structure carries bile to interlobular ducts
Bile canaliculi
the portal triad is what
interlobular bile duct, -artery and -vein located grouped together in the interlobular tissue
what does the pancreatic exocrine process do
produces digestive enzymes and secretes them into the duodenum
what does the pancreatic endocrine process do
synthesizes and secretes the hormones insulin and glucagon into the blood
what do you call groups of pancreatic cells secreting insulin and glucagon?
islets of Langerhans
what divides the pancreas into lobules?
connective tissue septa
Each pancreatic lobule consists of many what
acini (sg. acinus)
what are the secretory cells of the acinus called
the acinar cells
the acinar cells are characterized by?
distinct subnuclear area (ergastoplasm),
and zymogen granules in the apical part of the cytoplasm.
Digestive system divided into what 3 main areas?
Oral cavity, digestive tract and auxiliary gland system.
What is the oral cavity lined by?
Stratified squamous epithelium.
How are papillae divided into 2 main groups (name the groups)?
Based on their function they are grouped as mechanical papillae and gustatory papillae.
Name the 5 main structures of the oral cavity.
Major-, minor salivary glands, tongue, tonsils and teeth.
Name 3 major salivary glands.
the parotid, submandibular, and sublingual gland
Name 5 minor salivary glands located in the submucosa.
the buccal, labial, lingual, molar, and palatine glands
What do the tonsils consist of?
Aggregations of lymphatic nodules.
Two alternate names for the tongue;
lingua or glossa (genioglossus)
What is the cellular composition of the tongue surface?
Stratified squamous epithelium.
On what area of the tongue can you find papillae?
On the anterior part.
Describe mechanic papillae.
Are cornified.
Describe gustatory papillae.
Are covered with taste buds.
Name the 5 types of papillae found in domestic animals.
circumvallate. conical, filiform, foliate, fungiform
Describe filiform papillae
they’re highly keratinized and sharply pointed.
They’re the smallest and most numerous of all papillae.
Describe fungiform papillae
are smooth with a rounded surface, have taste buds on their lateral surfaces