Gastrointestinal system 2 Flashcards
pancreas
lumpy lobular organ
duct delivers pancreatic secretions to duodenum
islet releases insulin and glucagon
pancreatic acini
simple cuboidal epithelium
primary lipase production and release of pancreatic juice into the duct
what happens when chyme reaches the duodenum
secretin and CCK are released triggering pancreatic secretion
pancreatic juice
amylase
lipase
nucleases
inactivated proteolytic enzyme for activation in small intestine
(trypsinogen, chymotrypsinogen, procarboxpeptidase, proelastase)
liver
4 lobes, regenerative if blood supply not affected
falciform ligament
porta hepatis - blood vessel to to live - hepatic artery and hepatic portal vein to inferior vena cava
histology of the liver
sinusoids lining - endothelial cells, stellate macrophages (Kupffer cells)
adjacent veins
liver lobules - 6 portal triads
bile canaliculi (duct)
liver functions
metabolic function
haematological function - largest blood reservoir, plasma proteins, removes old blood cells
bile production
what regulates bile secretion
CCK
what is bile made of
cholesterol, lipids, bilirubin, water, ions
role of the gall bladder
concentration of bile for when needed for high lipid content
gallbladder stones
(gallstones)
cholecystitis
when bile is too concentrated
high fat diet
small intestine
90% of absorption
mesentery proper (blood and lymphatic vessels, nerves)
circular folds
purpose of fold in small intestine
increased surface area for absorption not expansion
histology of small intestine
villi lined simple columnar epithelium with microvilli
brush border
lamina propria capillaries
lacteals
duodenum
Connection from stomach, curves into C shape
Less circular folds
Mixing bowl for chyme, pancreatic juice and bile
Main function is receiving chyme and neutralising acid
duodenum secretions
Gastrin, CCK, secretin
Mucous (pH) and urogastrone (inhibits gastric acid)
duodenal submucosa glands
Brunner’s patches
mucous and urogastrone
jejunum
bulk of chemical digestion and absorption
circular folds prominent at middle part before decreasing
ileum
ends with ileocecal valve, sphincter controlling entry to coecum
distal part lacks circular folds
contains payers patches
payers patches of ileum
lymphoid nodules that gatekeep bacteria of large intestine
close to large intestine entrance
rich in macrophages
functions of large intestine
water absorption
excretion
vitamin absorption (K, B5, biotin) from microbiome
coecum
pouch where entry is controlled by ileocecal valve
appendix and vermiform appendix
what mesentery supplies the appendix and vermiform appendix
meso-appendix mesentery
colon
ascending, transverse, descending, sigmoid
haustra allow expansion and elongation
attached to omental appendices (pouches of fat)
what create haustra of large intestine
taeniae coli
smooth muscle
ascending colon
from coecum
bends right at hepatic flexure
transverse colon
bends left at splenic flexure
descending colon
reaches iliac fossa
firmly attaches to abdominal wall
sigmoid colon
S shaped
empties into rectum
blood supplies of the colon
superior and inferior mesentery arteries and veins
histology of colon
large lymphoid nodules at lamina propria
muscular layer - taeniae coli
lacks villi
goblet cells (mucous)
rectum
epithelium
faeces storage
anal canal contains longitudinal folds
transitions from columnar epithelium to stratified squamous epithelium
anus is keratinised
anal sphincters
internal: involuntary
external: voluntary
what can occur due to the lamina propria of the rectum being highly vascularised with veins
haemorrhoids
