GI System Flashcards
external of villi
simple columnar epithelium
internal of villi
lamina propria with microvasculature and lymphocytes
celiac disease
loss of villi = malabsorption and abnormal immune response
mucosa of small intestine
simple columnar epithelium
enterocytes
absorptive columnar cells
what creates the brush border in the small intestine?
microvilli
chylomicrons
lipid + protein
goblet cell
produce mucous to protect and lubricate microenvironment
paneth cells
innate immune cells, regulate microenvironment, release lysozyme, defensins to breakdown microorganisms
intestinal crypts
contain the paneth cells, the stem cells are located at the base
secretin
enteroendocine cell that stimulated pancreas and bile duct to secrete HCO3- and H20
CCK
enterendocrine cell that stimulates pancreatic acinar secretion and smooth muscle contraction by gall bladder
GIP
stimulates B-cells pancreas to secrete insulin
what penetrates the core of each villus
lamina propria
the lamina propria contains what?
capillaries, lacteals, and smooth muscle
the mucosa of the small intestine consists of
- Epithelium
- Lamina Propria (capillaries, lacteals, smooth muscle)
- Muscularis Mucosae - local movements of villi and plica circularis
Myenteric Plexus (Auerback’s plexus)
primary regulator of intestinal motility
What glands are present in the duodenum?
Brunner’s glands - secrete mucous and bicarbonate
What produces the local movements of the villi and plica circulae in the small intestine?
muscularis mucosae
peyers patches
lymphatic aggregates
Where do you find more peyer’s patches?
more as you move rectally
Duodenum absorbs what??
triglycerides and iron
Ileum absorbs what?
B12, GIF, and Bile Salts
Where do most digestive enzymes come from?
pancreas
Where are stem cell found in the stomach?
At top of glands
Where are stem cells found in the small intestine?
the bottom of glands
how often do absorptive and columnar cells replace?
5-6 days
how often do paneth cells replace?
30 days
what regulates the muscularis mucosae and DNES cells??
meissner’s plexi (submucosa)
do mucosa of the colon have villi
No villi
type of epithelium of the colon
simple columnar epithelium
colonocytes
absorptive cells, h20 passively absorbed and Na+ actively transported
what makes up the taeniae coli?
3 bands of outer longitudinal layers of the muscularis externa
rectum has what type of epithelium?
stratified squamous non-keratinized epithelium
