Gastrointestinal tract Flashcards
blood supply of:
- epigastrium region (foregut)
- umbilical region (midgut)
- suprapubic region (hindgut)
coelic trunk T12
superior mesenteric artery L1
inferior mesenteric artery L3
what is rectus abdominalis covered in
rectus sheath made of aponeurosis of external and internal oblique muscles and tranversus abdominis
blood supply abdominal wall (3)
superior and inferior epigastric arteries (anastamose at arcuate line which separates rectus sheath and transversalis fascia)
common iliac artery
bloody supply to posterior abdominal wall (3)
suprarenal arteries
renal arteries
lumbar arteries
venous drainage of posterior abdominal wall (4)
azygos system (hemiazygos)
renal veins
lumbar veins
inferior vena cava
nerves of posterior abdominal wall (4)
subcostal
iliohypogastic iliolingual
lateral cutaneous nerve of thigh
femoral
intraperitoneal organs
organs completely surrounded by peritoneum
e.g. liver, gall bladder, stomach
retroperitoneal organs
organs only attached anteriorly to peritoneum
e.g. SADPUCKER (suprarenal, aorta/IVC, duodenum, pancreas, ureters, colon, kidneys, oesophagus, rectum
acini
exocrine cells of pancreas produce hydrolytic enzymes stored as zymogens in vesicles under apical membrane of acinar cells, released into ductile
basolateral membrane for nutrients into cell, receptors for peptide hormones to regulate zymogen secretion
enzymes secreted by exocrine pancreas
α-amylase, lipase, phospholipase A2, cholesterolase
nuclease
protease e.g. typsinogen, chymotrypsinogen are inactive proenzymes
trysinogen –enteropeptidase–> trypsin
chymotrypsinogen –trypsin–> chymotrypsin
procarboxypeptidase -> carboxypeptidase
procolipase -> colipase
proelastase -> elastase
pancreatic juice contains other than enzymes
sodium bicarbonate (alkali) to neurtralise acidic chyme
endocrine pancreas
alpha cells - glucagon
beta cells - insulin
delta cells - somatostatin
stomach cell secretions:
- mucus cell
- parietal cell
- chief cell
- G cell
mucus, bicarbonate
gastric acid (activates pepsin, denatures protein, kills pathogens) and intrinsic factor (vitamin B12 absorption)
pepsinogen, gastric lipase
gastrin (increase HCl secretion)
control of lipase
bile salt binds to surface to inhibit
colipase displaces bile salt to activate
product of lipid digestion
bile salts -> micelle -> chylomicron in ER and golgi apparatus -> cholesterol
generic structure of layers of GI tract
mucosa (epithelium, lamina propria, muscularis mucosa)
submucosa (glands, lymph)
muscularis externa (smooth muscle, inner circular, outer longitudinal)
serosa (loose connective tissue)
parasympathetic vs sympathetic response with saliva
parasympathetic - volumnous saliva (acetylcholine binds to muscarinic receptors)
sympathetic - viscous saliva
serous saliva
mucous saliva
mixed saliva
main secreted protein is ptyalin (α-amylase)
main secreted protein is mucin
mixed secretion
major salivary glands
parotid gland (serous) submandibular gland (mixed, mostly serous) sublingual gland (mixed, mostly serous)
minor salivary glands
in submucosa of oral cavity e.g. lower lip, tongue, palate, cheek, pharynx
gingiva and central hard palate
mixed, mainly serous
ductal system of salivary glands
acini (serous acinus and mucous alveolus) -> intercalated ducts (add lysosomes and lactotransferrin) -> striated ducts (modification of primary saliva by reasorption and secretion of electrolytes) -> excretory ducts -> main excretory duct
demineralisation-remineralisation of teeth to change of pH of saliva
when pH < 5.5, demineralisation, Ca2+ and PO43- withdrawn from enamel
when pH > 6.5, remineralisation, Ca2+ and PO43- taken into enamel
