Histology Of SI And LI Flashcards
Transverse folds of the SI
PLICAE CIRCULARES
within the submucosa
Not that visible in Ileum, very visible in Jejunum
Increase SA (and even more with the villi) and dilation
Intestinal Villi
On the plicae circulares
Project into lumen of SI
Simple columnar + goblet cells + enterocytes
Vascularized and CT and LACTEAL inside the villi
Lacteals
Inside the SI villi and absorb lipids from the lymph vessels that go through it and carry lipids from lumen
Microvilli
Every cell on the villi, except Goblet cells, have microvilli
EVEN MORE INCREASED SA
Enterocytes
Decrease enzymes for digestion and absorption
Goblet cells
Make mucus coating for protection from abrasion or bacteria
Mucosa Layer of SI
Simple columnar (tubular SI glands) Lamina Propria + Muscularis mucosae
Submucosa Layer of the SI
Dense irr CT
Nerves, Vascularized, L, Glands (in some parts)
Muscularis Externa of SI
Inner + outer layer
Serosa Layer of SI
loose CT covered by visceral peritoneaum (mesothelium)
Innervation to SI and LI
ENS from the Gangionic cells
in connection with the ANS
1. Meissenteric plexus = move plicae circulares and mucosa
2. Myenteric plexus = peristalsis and mixing
(Para: vagus and pelvic N,,,, Sympa: postganglionic)
SI glands are called
Crypts of Lieberkuhn’s
Intestinal Glands 4 types
CRYPRS, Lined by simple columnar
- Paneth cells
- M (Microfold) cells
- Intestinal Stem cells
- ENTEROENDOCRINE cells
Opens to lumen at the base of the villi
Paneth Cells
Pyramidal, at the base of the glands BIG EOSINOPHILIC (Dr. andersons favorite)
= innate immunity - secrete anti microbial substances (Lysosome, a-Defensins)
= Regulate normal bacteria flora by antibacterial and phagocytic activity
Intestinal Stem Cells
At the base of the crypt near paneth cells
Regenerate the epithelium
ISC—-> Goblet cell + Enterocytes + ENTEROENDOCRINE cells
M (Microfold) Cells
epithelial cells
= transepithelial transport of particles and microorganisms
In ILEUM mucosa, over Peter Pateches
= invaginate membrane and hold macrophages and lymphocytes there
= APICAL: receptors bind to gram - (E-coli), internalize it and transfer to the immune cells
*highly specialized Ag- transporting cells
Which part of the SI has submucosal glands
Duodenum
Acinar mucous glands = alkaline for neutralization
Which parts of the SI has villi with a lacteal
Jejunum
Which part of the SI has intestinal glands (crypts)
in mucosal layer
Jejunum distinct
Only also Ileum and Duodenum
Which part of the SI has lymph in lamina Propria
Jejunum
Which part of the SI has villi with no lacteal
Ileum, Duodenum ?
Which part of the SI has Peyer’s patches and what are they
Lymphoid nodules (MALT) Ileum
Which part of the SI has Panath Cells
At the base of Crypts
Ileum
Gastroduodenal Junction is by Pyloris and Duodenum
Pyloris - thick wall with sphincter
- gastric pits with pyloric glands
Duodenum - Many duodenal glands in submucosa
-ecreatory mucosa with villi
Function of the LI
Absorb H2O, NA, VIT, Minerals, anesthesia, steroids, sedatives
NO VILLI
GOBLET CELLS
Tubular intestinal crypts (glands)
Mucosa Layer of the LI
Glands, Simple columnar COLONOCYTES GC SC enteroendocrine cells GALT
Submucosa Layer of the LI
Dense irr CT VASCULARIZED
Muscularis Externa Layer of the LI
Outer layer has TAENIAE COLI that for HAUSTRA *most prominent on transverse colon
Inner layer is normal SM
Hirschprung’s Disease
Reason
Aganglionosis in the distal colon Mutations of the RET gene : X migration and differentiation of NCC = no NCC in plexuses and Bowel Rectosigmoid (85%) Rectosigmoid—> Splenic flexure (10%)
Hirschprung’s Disease
Sx:
Dx:
Tx:
Constipation, poor feeding, ABD dissension progressive
Delayed Bowel Movement (48hr after birth), Rectal biopsy, Barium Enema
Surgical removal, and pull through ganglionic colon segment and reattaching
Rectum Proper
Upper Part of Rectum
Transverse rectal folds, glands, mucosa
Anal Canal
Lower Part of Rectum
- Anal Columns: mucosal folds
- Anal sinus : Depression between columns
- Anal Gland : in submucosa and Muscularis Externa
Which glands surround the anal Orifice
Circumanal Glands, Large Apical Glands
Anal Canal 3 sections
PECTINATE LINE
COLORECTAL ZONE 1/3
-simple columnar epithelium
ANAL TRANSITION ZONE ATZ 1/3
-simple columnar +non-kerit. stratified squamous of perineal skin
SQUAMOUS ZONE 1/3
-stratified squamous continuous with perineal skin (upper is non-ker. And then becomes Ker. By skin
What makes the inner Anal Sphincter
The inner layer of Muscularis Externa
Bruners Glands are
Submucosal glands
