Histology Flashcards
What are the three layers of the mucosa?
Surface epithelium
Lamina propria
Muscularis mucosae (smooth muscle)
In what layers are the nerves?
Submucosal nerve plexus is in submucosa layer
Myenteric plexus is between the two smooth muscle layers
What are four other layers of hollow visceral organs?
Submucosa–>Inner circular muscle layer–>outer longitudinal muscle layer–>adventitia
Is there any absorption or secretion in the esophagus?
No absorption, little secretion
What is special about the muscle in the esophagus
It’s super thick
What types of glands are in the esophagus? How common are they
There are salivary-type glands, but they are rare
What are the three different regions of the stomach?
cardia, corpus, antrum
Describe the components of a fovea:
surface epithelium with gastric pits leading to gastric gland
In the gland, there are mucous neck cells, gastric glands, chief cells and enteroendocrine cells
What are the pink cells? What are the blue cells?
Pink: parietal cells producing acid (think pH)
Blue: chief cells producing pepsinogen
How is acid production stimulated in the corpus of the stomach?
Histamine and gastrin stimulate acid production by parietal cells
How is gastrin secreted?
Gastrin is secreted by antral neuroendocrine cells into the blood steam and acts directly on parietal cells
How is histamine secreted?
Gastrin from antral neuoendocrine cells stimulates enterchromaffin-like cells in the corpus to secrete histamine
What are the various levels of increased surface area in the SI?
Plica (folds)–>Villi–>microvilli
At what point do we start seeing mucosa-associated lymphoid tissue?
Small intestine
What are lacteals?
lymph vessels in lamina propr. that absorb dietary lipids into the lymphatic system
What are paneth cells?
Cells that provide phagocytosis and intracellular digestion of intestinal microorganisms
What are the slight pink glands in the small intestine? What are their function?
Brunner glands produce a mucus-rich alkaline secretion
Protection from gastric acid, alkalization to allow digestive enzymes to work
What substances are absorbed and secreted by the colon?
Absorption: water, sodium, chloride
Secretion: bicarbonate and mucus
How is mucus secreted in the colon? What is its function?
Globlet cells secrete mucus in response to tactile stimuli from luminal contents–
Mucus protects the epithelium and binds ingested material to form feces
Where are the lymphatic vessels in the colon?
In the submucosa layer– rarely metastasize
Are there villi in the colon?
No, but there are crypts
Rectum: does it have villi or crypts?
Crypts
What are hemorrhoids?
Anal vein prolapse due to raised intra-abdominal pressure
Enlarging uterus increases pressure
Poor venous drainage
Straining at stool
