Case 3 - H2O absorption

Question 1

how does H20 move on the osmotic gradient

Answer 1

moves down the osmotic gradient

Question 2

what is the osmotic gradient created by

Answer 2

mainly by absorption of nutrients

Question 3

how much H20 is absorbed in total per day

Answer 3

8.4 litres

Question 4

how much is absorbed by the small intestine

Answer 4

6.5 litres

Question 5

how much is absorbed by the colon

Answer 5

1.9 litres

Question 6

what is the route for H20

Answer 6

via junctional complexes between cells
via SGLT1 and a.a transporters

Question 7

what is absorption not by of H20

Answer 7

aquaporins

Question 8

how much water does saliva secrete a day

Answer 8

1.5 litres

Question 9

how much water is in gastric secretion a day

Answer 9

2 lites per day

Question 10

how much water is in pancreatic secretion a day

Answer 10

1.5 litres

Question 11

how much water is in bile secretion a day

Answer 11

0.5 lires

Question 12

how much water is in the small intestine secretion a day

Answer 12

1 litre a day

Question 13

in total, how much is the inflow a day

Answer 13

8.5 litres

Question 14

what is the total outflow a day

Answer 14

8.4 litres

Question 15

what is the net loss in faeces

Answer 15

100mls

Question 16

where are the Na/glucose and Na/amino acid cotransporters found

Answer 16

found in jejunum and ileum

Question 17

where is the Na-H exchanger found

Answer 17

the duodenum and jejunum

Question 18

where are the parallel Na-H and Cl-HCO3 exchangers found

Answer 18

the ileum and proximal colon

Question 19

where is the epithelial Na+ channel found

Answer 19

distal colon

Question 20

what happens to K+ in the small intestine

Answer 20

paracellular diffusion in ileum

Question 21

what happens to K+ in the large intestine

Answer 21

predominantly secretion

Question 22

what is the normal K+ concentration in faeces

Answer 22

90mM

Question 23

HCO3 absorption in the SI or LI

Answer 23

there is no active absorption in these places

Question 24

what does severe or chronic diarrhoea lead to

Answer 24

hypokalaemia and metabolic acidosis

Question 25

what does increased osmotic load in colon lead to

Answer 25

increased ldiid in faeces

Question 26

what does lack of enzymes or transporters lead to

Answer 26

congenital (neonate) = ‘watery’ Glucose-galactose malabsorption (SGLT1) Lactase deficiency

Question 27

what infections can lead to damage to the mucosa

Answer 27

Bacteria (shigella and campylobacter) lead to destruction of intestinal wall which decreases surface area and leads to blood in faeces (dysentery) Bacteria (salmonella) leads to inflammation Protozoa (giardia, entamoeba)

Question 28

what are toxins produced by and what do they do

Answer 28

they are produced by bacteria which normally hi jacks normal cellular processes

Question 29

what cells normally secrete h20

Answer 29

intestinal cells and about 1 litre a day

Question 30

what does secretion exceed a day in cholera

Answer 30

secretion exceeds 20 litres per day

Question 31

what may toxins also do

Answer 31

may also inhibit Na+ absorption BUT not SGLT1

Question 32

what Is this the basis of

Answer 32

oral rehydration therapy