pancreatic and intestinal secretions

Question 1

what two functions do the pancreas have and what do they secrete

Answer 1

endocrine - glucagon and insulin into the blood

exocrine - lipases, proteases and amylase into ducts that lead directly to the duodenum

Question 2

what secretes pancreatic juice

Answer 2

acini

Question 3

what is the ionic composition of primary pancreatic juice

Answer 3

high in bicarbonate and Na
low in cl
low in K

Question 4

how does pancreatic juice get modified

Answer 4

hco3 is exchanged for cl normally so less hco3 in duodenum

Question 5

what happens to the ionic composition during fast flow rates

Answer 5

less time for modification and higher in HCO3 which is good for neutralisation of stomach acid

Question 6

what happens to the level of Na and K in pancreatic secretions

Answer 6

stay the same

Question 7

what is the ductal pathway for pancreatic juice

Answer 7

acini to pancreatic duct to ampulla to sphincter of oddi to duodenum

Question 8

what are the three reflex causing increase in pancreatic secretion

Answer 8

gastric: food in the stomach causing distension triggers the vaso vagal pathway which increase ACh and more primary secretion
cephalic: sight or smell also triggers vaso-vagal pathway
intestinal (most dominant 80%): high ph and presence of fats stimulates s cells to secrete secretin which increases pancreatic secretion. presence of aa and fats stimulates release of cck to increase secretions.

Question 9

what are the two main roles of the small intestine

Answer 9

absorption and digestion

Question 10

what enzymes does the pancreas release

Answer 10

trypsinogen, chymotrypsinogen and procarboxy-peptidase

Question 11

what regulates activation of enzymes released from the pancreas

Answer 11

enterokinase released from duodenal cells

Question 12

how does activation of enzymes in the duodenum work

Answer 12

enterokinase activates trypsinogen to trypsin which in in turn changes chymotrysinogen and procarboxy-petidase to chymotrypsin and carboxy-peptidase

Question 13

what are the two main secretions from the duodenum

Answer 13

nahco3

nacl

Question 14

what is the role of NaHCO3 in the duodenum and where does it come from

Answer 14

bruner cells in the duodenum mainly and its function are to neutralise acidity and favour conditions for digestive enzymes
act as a lubricant for chyme

Question 15

what are the theories of NaCl release in the duodenum

Answer 15

maintain osmotic balance of fluids

flushing of pathogens: paneth cells at the bottom of crypts release a defensins and lysosomes

Question 16

what is the role of vili

Answer 16

increase surface area and also have micro villi increase sa by 600x

Question 17

what stimulates the release of nacl from the small intestine

Answer 17

release of VIP and adrenergics

Question 18

what effect does VIP and adrenergics have on nacl secretion

Answer 18

increases cAMP and more nacl release

Question 19

describe the process of cl into the lumen from the ecf

Answer 19

2 cl moves into the cell with 1 na and 1 k
3 na out and 2 k in
k leaves basolateral membrane across open channel
cl freely moves into the lumen

Question 20

describe the process of na into the lumen

Answer 20

paracellular

Question 21

what does the cholera toxin do

Answer 21

chronically stimulates cAMP via stimulates of g protein in small intestine
this causes continuous influx of cl into the lumen and water via osmosis follows producing dehydration and diarrhoea

Question 22

how do you relieve symptoms of cholera

Answer 22

treat with ORS containing lots of salt and sugar therefore water moves back from lumen into ecf

Question 23

what ion transport occurs in the colon

Answer 23

na and cl are reabsorbed

k and hco3 are secreted

Question 24

what is colonic ion transport fuelled by

Answer 24

aldosterone causes uptake of Na

Question 25

what is crohns disease, what are the causes and treatment

Answer 25

inflammatory disease of large intestine
abdominal pain, diarrhoea - greater risk to bowel cancer
can be autoimmune or due to pathogens
no cure but treatment include methotrexate, thiopurine or corticosteroids

Question 26

what is chronic pancreatitis, symptoms causes and treatments

Answer 26

inflammation of the pancreases causing reduced enzyme secretions
can be autoimmune, tumour or pathogen induced
surgery or replacement of pancreatic enzyme