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43 Cards in this Set
- Front
- Back
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Four layers of the wall of the GI tract |
Mucosa Submucosa Muscularis Externa Adventitia or Serosa |
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Layers of Musoca |
Epithelia Lamina Propria Muscularis Mucosa |
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Lymphocytes are usually found in this layer; what is the name of these, collectively? |
Lamina propria of the mucosa; Gut Associated Lymphoid Tissue |
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Cells in the epithelium are connected by these |
Tight junctions |
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ENS portion in the submucosa |
Meissner's Plexus (submucous plexus) |
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Muscularis externa contains this part of the ENS |
Auerbach's Plexus (myenteric plexus) |
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Possible gland locations |
Mucosal, submucosal, accessory (liver and pancreas) |
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Functions of enteric nervous system |
-controls muscle contraction and gut motility -controls secretion and microcirculation (arterioles) |
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ENS is influenced by this division of the ANS |
BOTH parasympathetic and sympathetic influences |
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Specialization for reuptake of water and electrolytes (and location in the GI tract) |
Taenia coli (colon) |
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Specialization for initial breakdown of proteins (and location in the GI tract) |
secretion of acids, enzymes; additional muscle (stomach)
Muscle: oblique (extra layer is added) |
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Starch and fat breakdown begins here |
oral cavity (lysozyme also acts as antibacterial agent) |
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Specialization for increased absorption of nutrients (and where this is located) |
Villi, Microvilli (small intestine) |
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Type of epithelium in the esophagus |
Stratified squamous |
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Submucosal glands' function |
Secrete mucous for lubrication
Mucins=glycoproteins |
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How mucins work |
Mucins are glycoproteins that have a number of O-linked sugar chains
The sugar chains are polar and attract a layer of water to form around the mucin; mucins then can slide easily past each other and provide lubrication |
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Why do mucins work and not get degraded by acidity? |
Sugar chains resistant to HCl and protect the polypeptide backbone from digestion by proteases. |
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Muscle type of the esophagus |
Striated skeletal muscle to start (vagus somatic input)
Transitions to alternating striated and skeletal muscle |
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Around junction of the esophagus and stomach |
cardia region |
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Gastroesophageal junction has these cell characteristics |
Transition from stratified squamous to simple columnar epithelium |
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Regions of the stomach and what differentiates them |
Cardia, fundus and pyloric region
Characterized by differences in glands of the different regions |
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Allow for expansion of the stomach to accommodate a large meal |
Rugae |
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Cardia region epithelium- what is it like? |
Simple columnar epithelium and mucuous cells |
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Gastric gland cells |
Parietal cells, chief cells, enteroendocrine cells |
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Cells in the stomach that secrete digestive enzymes |
Chief cells -Secrete proteases, particularly -Packed with zymogen granules -Will have large amount of golgi apparatus and rough ER |
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Cells that secrete HCl into the lumen of the stomach and complex absorbing vitamin B12 |
Parietal Cell -Need a lot of energy to pump the H+ out (also have K+ pumps, Na++ pumps, channels) -Increased membrane surface area to maximize pumping capacity -Intracellular canaliculus -Prominent amounts of mitochondria |
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Enteroendocrine cells: function and characteristics |
Secrete hormones- on the side of basolateral surface Don't have to contact lumen directly Prominent basolateral surface next to capillary |
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Cholecystokinine functions |
Secreted by the gall bladder to tell the stomach to contract (in response to fatty meal) AND Smooth muscle sphincter of Oddi to open |
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Other examples of hormones in GI tract |
Motilin (Duodenum to Stomach Gastric inhibitory polypeptide (Duodenum to stomach) Secretin (Duodenum to pancreas) Gastrin |
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Digestive upsets with chemotherapy due to this |
Normally, constant regeneration of cells in the digestive tract because of harsh environment but chemo puts a hold on cell division |
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Gastric pits: what are they and where do you find them? |
Where mucous-secreting cells used to be before H&E staining Found in cardia region, walls of pylorus |
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Surface area-increasing structures |
Plica (need more at the start and less at the end) Villi Microvilli |
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Structure of villi |
Epithelial cells (simple columnar), lamina propria containing blood vessels and lacteal (lymphatic vessel) |
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Where are enterocytes located? |
Both on villi and in glands -These are specialized for absorption -Use specific transporter proteins to take up amino acids and oligopeptides of 2-3 amino acids, as well as glucose, fructose and galactose. |
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Small droplets for fat in the basolateral intercellular space of enterocytes |
Chylomicrons |
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How does cholera bacteria affect enterocytes? |
Acts to decrease the "tightness" of a junction, thus allowing an increased amount of water to enter the lumen and cause diarrhea. |
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Gastric bypass surgery: what is it? |
Make a new stomach pouch and a tract which bypasses most of the stomach and goes directly into the small intestine |
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When food reaches the small intestine, what happens to give the sensation that you're full? |
Triggering of release of hormones to indicate satiety |
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Important for regulatory cells |
Enteroendocrine cells |
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What are the Brunner's glands? Where are they located? |
Located in the duodenum, Brunner's glands will change the pH from acidic (stomach) back to more basic as the materal courses into the small intestines |
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Plicae circulares: what is the pattern as your move more distally from the stomach? |
Very notable to non existent |
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Where are Peyer's patches located? |
Distal ileum |
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What are Peyer's patches? |
the numerous areas of lymphoid tissue in the wall of the small intestine that are involved in the development of immunity to antigens present there. |
