Digestive Overview, Upper & Lower GI Histology Flashcards
The mucosa is comprised of an epithelial layer plus the underlying loose, wellvascularized
connective tissue called the ________ .
lamina propria
A thin layer of smooth muscle underlying the lamina propria is referred to as the _________
muscularis mucosae.
Lymphocytes, plasma cells and macrophages will be
scattered throughout the _______
lamina propria.
The submucosa contains connective tissue that is usually more dense than in the mucosa, larger blood vessels, and _________. Lymphoid cells of various types are also scattered throughout
nerve plexes, glands, and lymphatic nodules
The muscularis externa is comprised of an inner circularly and outer longitudinally arranged layers of smooth muscle and nerve plexes. Its main function is _______ & ______
peristalsis,
churning of the lumenal contents.
The serosa is an outer covering of ______ epithelial cells separated from the underlying muscular layers by a relatively thin layer of connective tissue. It is called the _____ in the case of the esophagus above the diaphragm where this outer layer is absent.
squamous,
adventitia
which structure carries out no digestive function but is specialized for passage of food
esophagus
the esophahus is lined with ______
non-cornified (non-keratinized) squamous epithelium
the _______ in the stomach, is a small area of mainly mucus-secreting glands around the entry of the esophagus
cardia
the _____, is the main body of the stomach that secretes acid, peptic digestive products and mucus
fundus
the ______ secretes mainly mucus and has a relative
preponderance of endocrine cells that secrete the stomach hormone gastrin
pyloris
The wall of the stomach has substantial longitudinal folds called rugae or _______ that disappear upon distension
plicae mucosae
Humans have about 3-4 million of these in their stomach
Gastric glands
The gastric epithelium is constantly renewing. Surface cells are replaced every ______ days.
The differentiated cells deep in the glands turn over much more slowly (i.e ________ )
3-5,
6-12 months
Surface mucous cells contain large vesicles full of stomach ______ & ______ that are discharged locally onto the surface to provide a viscous protective layer that shelters the epithelial cells against stomach acid and abrasion from churning chyme.
mucins,
bicarbonate
Directly covering the short microvilli of
surface cells is a more structured layer of cell surface ________, called the _________.
glycoproteins,
glycocalyx
The primary secretory product of Chief (peptic) cells is ______
pepsinogen
________ are unique acid producing cells specialized for pumping H+ ions (using a H+/K+ ATPase) into the lumen of the gastric glands, against a steep (more than a million-fold) gradient.
Parietal cells
The pH of the gastric juice is _____, so production of acid is a vigorous, energy-demanding activity.
1-1.5
Parietal cells are stimulated to produce acid by secretion of the local hormones _____ & _____
gastrin,
histamine
Parietal cells also secrete an important glycoprotein
required for uptake of vitamin B12, _________ ,which, is crucial for the production of red blood cells in bone marrow.
intrinsic factor
_______ cells contain large eosinophilic granules, which contain antibacterial peptides called defensins, in addition to lysozyme and phosopholipase.
Paneth
Brunner’s glands are only found in the _______
and release their contents into the crypts of Lieberkuh. They secrete large quantities of bicarbonate to neutralize the acid arriving through the pyloric sphincter
duodenum
Specialized epithelial cells (_______) function as antigen-uptake cells, and phagocytose luminal contents and present antigens to underlying lymphocytes and macrophages
M-cells
