Flashcards in Exam 4: Review Questions Small Intestine Deck (20):
Compare the lengths of the Duodenum, Illeum , and the jejunum
Dudodenum smallest at 25 cm, Jejunum Second smallest at 2.5 m, Illeum longest at 3.5 m.
Describe the layers of the small intestines going from outside to the inner luminal layer
1) Tunica Serosa 2) Tunica Muscularis ( Outer longitudinal layer, myenteric plexus, inner circular layer) 3) Tunica Submucosa 4) Lamina Muscularis Mucosa Lamina propria, Lamina epithelialis (Tunica Mucosa)
Dudodenum Tunica Mucosa (Lamina Epithelialis) Composition
1) Villi to increase surface area 2) Enterocytes (simple columnar epithelium, which contain microvilli which increase absorption capability, replaced every 4-6 days) 3) Goblet Cells (secretes mucous to protect the lining of the G.I tract) replaced every 4-6 days) 4) Neuroendocrine Cells 5) M Cells
Secrete gastrin motilin, VIP etc.
modified epithelial cells who cover peyer's patches endocytose and transport macromolecules and gram-positive bacteria to intraepithelial lymphocytes and other immune cells.
Duodenum Tunica Mucosa (Lamina Propria) Composition
1) Reticular, elastic, and loose collagenous elastic fibers. Also have lacteals, blood vessels (absorb small chain fatty acids) , and smooth muscle 2) Lymph follicles (Peyer's Patches) 3) Cypts of Lieberkuhn 4) Simple columnar epithelium, goblet cells, neuroendocrine cells, and paneth cells
located at the base of the crypts of Lieberkuhn ; eosinophilic granules, secrete antimicrobial substances such as lysozyme.
Dudodenum Tunica mucosa (Lamina Muscularis) Composition
Thin layer of both inner circular and outer longtitudinal smooth muscle
Crypts of Lieberkun
Glands located at the base of villi that are exposed to the lumen of the duodenum
Duodenum Tunica Submucosal arrangement
1) Make of the core of Plica Circulares 2) DCT in humans LCT in domestic animals 3) Contain Brunner's Glands, Peyer's patches, adipose cells, blood vessels and Meissner's plexus 4) Distinct of the duodenum
1) Tubuloalveolar glands 2) Serous and mucous secreting in humans and cats 3) simple columnar epithelium w/goblet cells interspersed
Dudodenum Tunica Muscularis
1) Thicker inner circular smooth muscle layer Thinner longitudinal smooth muscle layer 2) Auebach's or myenteric plexus (parasympathetic ganglia between muscle layers)
Duodenum vs. Jejunum
Similar anatomically and histologically with the exception of the presence of Brunner's glands in the duodenum.
Larger peyer's patches
First section of the large intestine in humans, diverticulum of ascending colon in domestic animals
Worm like appendage of cecum in humans. Plays an immune function: large numbers of lymphatic nodules that protrude into the submucosa
same as the duodenum except w/o veriform appendix and doesn't have lacteals. has smaller versions of peyer's patches.
Similar to the colon, which is similar to the ileum. The rectum has a thicker tunica muscularis.
Similar morphology to the colon 1) Subdivided into colorectal, transitional, and squamous zones in humans 2) 4cm in length 3) The lamina muscularis disappears at the level of anal transitional/intermediate zones 3) Thicker inner circular layer of tunica muscularis forms anal sphincter. 4) Technically has a tunica adventitia