(F) Lec 2.1: The Digestive System Flashcards
What are the common properties of the wall of the Digestive Tract?
Mucosa
Submucosa
Tunica Muscularis (Muscularis Externa)
Tunica Serosa/Adventitia
Which two structures/organs in the system have glands in the submucosa?
Esophagus and Duodenum
Gastric glands and intestinal glands are seen in which layer?
Lamina propia (in the mucosa)
T or F: Esophageal glands are seen in the tunica muscularis
False (in mucosa and submucosa)
LE of mucosa of esophagus
SSNKE
LP of mucosa of esophagus
Loose CT with lymphocytes and superficial esophageal glands
Glands in the mucosa of esophagus
Superficial esophageal glands
Type of tissue found in the muscularis mucosa of the esophagus
Smooth muscle
Sublayers of mucosa of esophagus
LE
LP
Mucularis Mucosa (MM)
Specific subtype of tissue found in submucosa of esophagus
DICT
Responsible for regulation of mucus secretion in the submucosa of esophagus
Meissner’s plexus
Glands in the submucosa of esophagus
Deep esophageal glands
Responsible for peristalsis in the tunica muscularis of esophagus
Auebach’s plexus / Myenteric
Arrangement of muscles in the tunica muscularis of esophagus
Inner circular and outer longitudinal layer (ICOL)
Muscle of upper 1/3 of esophagus
Skeletal
Muscle of middle 1/3 of esophagus
Smooth and skeletal
Muscle of lower 1/3 of esophagus
Smooth
This layer of esophagus contains LCT, BVs, and LSs
Tunica adventitia
Junction between esophagus and stomach
Squamocolumnar junction
This is where the secretion of the glands exits from the stomach
Gastric pits
Initiates carbohydrates’ digestion
Salivary amylase
Acidic fluid when mixed with food is called?
Chyme
Secretion of ______ begins digestion of triglycerides
Lipase
Begins initial digestion of proteins
Pepsin
Familiarize functions of stomach
Continue digestion of carbohydrates initiated by salivary amylase
Add acidic fluid to ingested food and mix them together to form chyme
Begin digestion of triglycerides by secreted lipase
Promote initial digestion of proteins with pepsin
LE of stomach
Simple columnar epithelium without goblet cells
LP of stomach
Loose CT w/ dense LT and occasional nodules
Part of stomach which separates the mucose from the underlying submucosa
Muscularis mucosa
These are:
Found in the stomach’s body and fundus
Are the characteristic cells of the stomach in general
Gastric glands
Which part of the stomach are gastric glands found?
Body and fundus
Secretion of mucous neck cells
Mucous
Secretion of chief cells
Pepsinogen and gastric lipase
Secretion of parietal cells
HCl and IF
Secretion of endocrine/argentaffin cells
Serotonin, histamine, and gastrin
Cell characteristic of mucous neck cells
Columnar cells
Cell characteristic of chief cells
Low columnar/cuboidal
Cell characteristic of parietal cells
Spheroidal/pyramidal
Cell characteristic of endocrine cells
Pyramidal/flattened
Staining reaction of mucous neck cells
Pale
Staining reaction of chief cells
Basophilic
Staining reaction of parietal cells
Acidophilic
Staining reaction of endocrine/argentaffin cells
Silver and chromium stains affinity
Refer to:
→ rich in bicarbonate ions
→ protects the mucosa from the abrasive effects of intraluminal food and the corrosive effects of stomach acid
→ secretes alkaline fluid containing mucin
Surface mucous cells
Refer to:
→ can be in clusters or single
→ found at the neck of the gastric glands
→ contains round nuclei at the base and apical secretory granules
→ mucous secretions are less alkaline (acidic) than surface epithelial mucous cells
Mucous neck cells
Refer to:
→ the parenchymal cells of gastric glands
→ can be large round or pyramidal cells with 1 or 2 centrally-located round nuclei
→ has eosinophilic cytoplasm
Parietal cells
Refers to:
→ the most numerous in the gland cells
→ predominates at the lower regions of the gland
→ shows abundant rER and secretory granules
Peptic cells
T or F: Chief cells differ in function depending on location
False (enteroendocrine cells)
This is a glycoprotein required for the uptake of Vit. B12 in the S.I
Intrinsic Factor
This initiates the hydrolysis of ingested proteins in the stomach
Pepsin (from Pepsinogen)
Location of entereoendocrine cells that secretes serotonin, inhibits gastric acid secretion, and stimulates the production and release of gastric mucus
Fundus
Location of enteroendocrine cells that produce gastrin and stimulates secretion of acid and pepsinogen
Pylorus
Three glands found in the stomach
Cardiac, Fundic, and Pyloric
Refer to:
The most proximal to the esophagus
Morphology: Simple tubular (some are compound tubular)
The terminal end: Long and coiled
Gastric pits: Short and shallow
Cardiac glands
Refer to:
The most numerous type of gland
Morphology: Simple branched tubular
The terminal end: Slightly coiled
Gastric pit: Occupies ¼ of the thickness of the mucosa
Lumen: Narrow
Fundic glands
Refer to:
Lined by mucous cells
Not much HCl and intrinsic factor secretion
Morphology: Simple branched tubular
The terminal end: Extensively coiled
Gastric pit: Are long and deep extending to about ½ the thickness of the mucosa
Lumen: Wider
Pyloric glands
Cells present in cardiac glands
Mostly mucous secreting cells (mucous neck cells are predominant)
Few parietal and Argentaffin cells
Cells present in fundic glands
All 4 types
Cells present in pyloric glands
No parietal cells except in the pyloric sphincter
Layer of stomach which refer to:
Composed of Loose CT with large BVs and LVs
Has many lymphoid cells, macrophages, and mast cells
Houses the Meissner’s Plexus (for secretion)
Has no glands
Submucosa
The muscularis externa of the stomach is arranged as?
Outer longitudinal
Middle circular
Inner oblique
This is the nerve plexus responsible for peristalsis
Auerbach
T or F: Muscularsi externa of pylorus is arranged as ICOL
True
The circular muscle in the tunica muscularis is thickened to form what?
Pyloric sphincter
LE of smol intestines
Simple columnar epithelium w/ GC
This part of intestinal mucosa refers to:
Have a core of loose CT that extends from the LP
Contains fibroblasts, smooth muscle fibers, lymphocytes, plasma cells, fenestrated capillaries, and a central lymphatic vessel (lacteal)
Found at the lumen of the S.I (not found in the appendix)
Villi
LP of small intestines
Loose CT
This layer of intestinal mucosa refers to thin smooth muscle layer that produces local movement and folding of the mucosa
Muscularis mucosa
Refer to:
→ aka valves of Kerkring; are permanent structures
→ are absent from the first few centimeters of the duodenum and distal ileum but well developed in the jejunum
→ increases the surface area of the mucosa
Plicae Circulares
Plicae circulares are also called what?
Valves of Kerkring
Counterpart of plicae circulares in the large intestines
Plica semilunaris
Refer to:
→ aka intestinal glands/crypts
→ found between the intestinal villi (only in the LP)
→ functions for the secretion of intestinal juice
Crupts of Lieberkuhn
Enumerate the cells in intestinal glands
Enterocytes
GC
Paneth cells
Enteroendocrine cells
Cell in intestinal gland which refers to:
→ are the main absorptive cells; the most numerous
→ the parenchyma of the small intestine
→ are tall columnar in shape with an oval nucleus located at the base
→ its apical ends contain striated brush borders
Enterocytes
Cell in intestinal gland which refers to:
→ are interspersed among the absorptive enterocytes
→ secretes glycoprotein mucin to protect and lubricate the lining of the intestine
→ the apical area is distended with mucin droplets while the base contains secretory materials
→ the cytoplasm is strongly basophilic
Goblet cells
Cell in intestinal gland which refers to:
→ located in the basal portion of the intestinal crypts
→ are exocrine cells with large eosinophilic secretory granules in the apical cytoplasm
→ releases lysozymes, phospholipase A2, and hydrophobic peptides (defensins)
→ has a role in innate immunity and regulates the microenvironment of the intestinal crypts
Paneth cells
Cell in intestinal gland which refers to:
→ concentrated in the lower portion of the intestinal glands
→ produces a lot of peptide hormones
Enteroendocrine cells
Secretion of enteroendocrine cells in the intestinal gland
Cholecystokinin and secretin
Secretion of enteroendocrine cells that stimulates the secretion of digestive enzymes in the pancreas and contraction of the gallbladder
Cholecystokinin
Secretion of enteroendocrine cells that stimulates the pancreas to release “pancreatic juice” which is rich in bicarbonate ions
Secretin
Refer to:
→ specialized epithelial cells in the mucosa of the ileum overlying the lymphoid follicles of the Peyer’s Patches
→ are basal membrane invaginations containing many intraepithelial lymphocytes and are antigen-presenting
→ selectively endocytoses antigens and transports them to the underlying lymphocytes and dendritic cells
M (Microfold) Cells
Three parts of the small intestine
Duodenum
Jejunum
Ileum
T of F: Plicae circulares are more prominent in the duodenum
False (Jejunum)
Cells located at the bottom of the crypts
Paneth cells
Refers to absorptive cells found in the intestinal glands
Enteroendocrine cells
Part of the small intestines which contains Brunner’s gland in the submucosa
Duodenum
Nerve plexus found in the submucosa
Meissner’s plexus
Arrangement of tunica muscularis of small intestines
ICOL
Nerve plexus found in the tunica muscularis of small intestine responsible for presitalsis
Auerbach’s plexus
Characteristic feature of ileum
Peyer’s patches
Characteristic feature of jejunum
Plicae circulares
Characteristic feature of duodenum
Brunner’s gland
Junction between pylorus and duodenum
Gastroduidenal junction
T or F: Goblet cells increase in number as we transition from small intestine to large intestine (GCs are the parenchyma of the colon)
True
T or F: Lymphatic nodules are only seen in the ileum
False
Longest portion of small intestine
Ileum
Widest portion of S.I.
Duodenum
LE of large intestine
Simple columnar w/ GC
LP of large intestine
Loose CT w/ intestinal glands (crypts of Lieberkuhn); rich in lymphoid cells and nodules
T or F: There are no MM in large intestine
False
T or F: Vili are only found in the large intestine, none in L.I.
False (baliktad)
T or F: There are intestinal glands in the submucosa of the large intestine
False
T or F: There are no lymphatic nodules in the large intestine because it is not for defense
False (some solitary LN are present in submucosa)
Arrangement of muscularis externa of the large intestine
ICOL
In the muscularis externa of the large intestine, the outer longitudinal layer forms three flattened strands–the taenia coli that produces the _____ in the colonic wall
CLUE: it refers to housing or sacculations
Haustra
In the tunica serosa of the large intestine, the cecum, appendix, transverse colon, and sigmoid colon have which type of peritoneal covering?
Complete peritoneal covering
In the tunica serosa of the large intestine, the ascending & descending colon, and rectum have which type of peritoneal covering?
Partial peritoneal covering
In the tunica serosa of the large intestine, the anal canal has which type of peritoneal covering?
None (No peritoneal covering)
In the tunica serosa of the large intestine, pouches of adipose tissue have what?
Appendices epiplocae
T or F: The appendix is part of the digestive system
Fase (lymphatic)
Lymphoid tissues can be found in which layer of the appendix?
LP and submucosa
T or F: Like the S.I., the appendix also has intestinal villi
False
LE of appendix
Simple columnar w/ GC
LP of appendix
Dense and nodular lymphatic tissues
T or F: Appendix has MM
True
Layer of appendix which contains lymphatic nodules with BVs and nerves
Submucosa
Arrangement of appendix’s tunica muscularis
ICOL
Layer of appendix which contains peritoneum lined with mesothelium
Tunica serosa
T or F: At the distal end of the rectum, the anal canal, mucosa, and submucosa are highly avascularized
False (vascularized with venous sinuses)
Anal columns are folded a series of longitudinal folds called the _____________ with intervening anal sinuses
anal columns of Morgagni
Junction between anus and rectum
Anorectal junction
Clinical correlation that refers to:
Aka adenocarcinoma
Benign adenomatous polyps in the mucosal epithelium
Common in individuals with low-fiber diets
Prolongs contact of mucosa with toxins of the feces
Colorectal cancer
Clinical correlation that refers to:
Swollen BVs in the mucosa or submucosa of the anal canal
Results from a low-fiber diet, constipation, prolonged sitting, or straining at defecation
Hemorrhoids
Parenchyma of S.I.
Enterocytes / columnar cells
Parenchyma of L.I.
Goblet cells
Parenchyma of stomach
Parietal cells
Why do external hemorrhoids hurt more than the internal ones?
Presence of nerve endings on the skin
