Physiology Flashcards
where is gastrin produced from ?
G cells in antrum of stomach and duodenum
where is somatostatin produced from?
D cells in pancreas
where is cholecytokinin produced from?
I cells from duodenum, jejunum
where is secretin produced from?
S cells in duodenum
where is glucose-dependant insulotropic peptide produced from?
K cells in duodenum, jejunum
where is motilin produced from?
small intestine
where is vasoactive intestinal polypeptide produced from?
parasympathetic ganglion in sphincters, gallbladder and small intestine
where is grehlin produced from?
stomach
what substance is responsible for pancreatic HC03 production and what is the purpose of this
produced by secretin as it allows pancreatic enzymes to function
what substance increases gallbladder contraction?
cholecystokinin (CKK)
action of VIP
vasoactive intestinal peptide
- increases water and electrolyte secretion
- increases relaxation of smooth muscle and sphincter
what substance increases bile secretion
secretin
what is the action of intrinsic factor and what cells does it act on
acts on parietal cells - binding protein for uptake of vitamin 12
what is the action of pepsin and what cells does it act on
acts on the chief cells for protein digestion
what is the role of gastrin
increases acid secretion primarily through its efects on enterochromaffn-like cells (ECL)
also has a direct effect on parietal cells
role of alpha-amylase
starch digestion
role of trypsinogen
converted to active enzyme - trypsin by enterokinase / enteropeptidase - activates other protoenzymes
how are monossaccharides (glucose, galactose and fructose) absorbed?
monossacharides are absorbed by enterocytes
glucose + galactose are taken up by GLUT 1
fructose is taken up by fascilitated diffusion by GLUT5
all are transported to blood by GLUT2
where is iron, vitamin B12 and folate absorbed?
iron - duodenum
vitamin B12 - terminal ileum
folate - small intestine
what are peyers patched?
unencapsulated lymphoid tissue found in lamina propria and submucosa of ileum
(microfold) M cells present angients to immune cells
B cells differentiate into IgA cells which transport into the gut
what enzyme catalyses the rate-limiting step in bile acid synthesis
cholesterol 7-alpha hydroxylase
What are brunner’s glands and where are they located?
Located in the submucosa of duodenum
Secrete bicarbonate
Acts a protective mechanism for peptic ulcers
Pathophysiology of wernicke’s encaphalopathy
Small vessel haemorrhage and necrosis in mammillary bodies of the hypothalamus
Atrophy of caudate and putamen
Huntingtons disease
Widespread atrophy of cerebral cortex
Alzheimers
does neuropeptide Y increase in the fasted or fed state
increases in starved state as it increases appetite
where is neuropeptide Y released from
produced by neurones of the arcuate nucleus then secreted from lateral hypothalamus
causative organism - hepatic abscess, bloody diarrhoea, abdo pain. recent travel.
E.histolytica
E.histolytica on microscopy
trophozoites containing phagocytosed RBCs in the stool
