Small Intestine to Anus Flashcards
Small intestine mucosa
simple columnar epithelium - with microvilli
Number of microvilli per enterocyte increasing absorptive function by 20-fold
3000
Small intestine villi is composed of
Lining epithelium + lamina propria
Small intestine plicae circulares is composed of
mucosa + submucosa
(1) Absorptive cells of the small intestine
(2) Mucous-secreting cells of the small intestine
(1) Enterocytes
(2) Goblet cells
Cypts of Lieberkuhn morphology
Simple tubular gland
Cells of the crypt of lieberkuhn
- enterocytes
- goblet cells
- paneth cells
- microfold cells
- enteroendocrine cells
enteroendocrine cells are scattered along the crypts and secrete specific hormones for digestion
Paneth Cell secretions
*phospholipase
*defensins
*lysozymes
Present in the lamina propria of small intestine
Lacteals
Specialized submucosal structure of duodenum
Brunner’s/Duodenal gland
Specialized submucosal structure of ileum
Peyer’s patches
can also be found in the lamina propria
Specialized submucosal structure of jejunum
None
Microfold cells
antigen presenting cells
Taenia coli in the large intestine is formed by
narrowed thickenings of the outer longitudinal muscle layer
(Present/Absent)
Villi in the large intestine
Absent
(small intestine/large intestine)
More abundant goblet cells
large intestine
Absorptive cells in the large intestine
colonocytes
(small intestine/large intestine)
Larger and longer crypts of lieberkuhn
large intestine
(Present/Absent)
Microvilli in large intestine
Present
Length of Appendix
6 to 7cm
Distinguishing structure in appendix
Lymphoid nodules
(Present/Absent)
Taenia coli in the appendix
Absent
(Present/Absent)
Villi in Appendix
Absent
Distinguishing factor in Rectum
Transverse rectal folds or Houston’s valves
Histologically, rectal features are similar to large intestinal features
3 histological zones of the anal canal
- colorectal
- transitional
- squamous
Small intestine equivalent to stomach rugae
Plicae circularis or valves of kerckring
Enteroendocrine cells (#3)
(1) s cells - secretin
(2) Mo cells - motilin for peristalsis
(3) I cells - cholecystokinin
Secretin action
Causes pancreas to release bicarbonate to neutralize acidic chyme
Causes gallbladder to contract and release bile
Is triggered by fat
CCK - cholecystokinin
Shortest portion of the small intestine
Duodenum
Location of the small intestine’s gut-associated lyphoid tissue
Lamina propria
has abundant B-cells, plasma cells, & microfold cells where the loose CT of the lamina propria will appear darker than the dense irregular CT of the submucosa
Blind ending capillary for the absorption of dietary fat
Fat absorbed in the form of chylomicrons
Lacteals
(True/False)
Similar to the ileum, the appendix has lymphoid nodules at the antimesenteric border
antimesenteric - the border that is not protected by the mesentery
False
Lymph nodes in the appendix are dispersed throughout the organ
Abundant cells in the Peyer’s patches
Microfold cells
Conspicous accummulations of adipose or fatty tissues on the external surface of the large intestine
Epiploic/Omental Appendages
Large sacculations on the wall of the colon
Haustra
What are the secretions of the Brunner’s glands?
aka duodenal glands
Alkaline mucous & Bicarbonate
neutralizes acid from incoming chyme
