13. Gut Fluid Balane Flashcards
True/false
Epithelial cells can both secrete and absorb water and electrolytes
True
Which organ absorbs more fluid per day; small intestine/colon?
Small intestine
What is the physiological definition of diarrhoea?
Malabsorption of water
What is the clinical definition of diarrhoea?
Abnormal passage of liquid or loose stools more than 3 times a day and/or volume of stool more than 200g per day
Describe the paracellular route of transport
When substances move across the membrane from lumen to blood through intercellular junctions between cells
Describe the transcellular mechanism of transport
When substances move from lumen to blood through cells. Can be active or passive
In what region in the villi is the stem cell niche?
Crypt
Where are the cells in the villi that have a secretory function?
Crypt
Where are ells in the villi that have an absorptive function?
Villus
What are 5 factors that affect absorption?
Nutrient intake
Gastric motility
Intestinal motility
Number and state of enterocytes
Blood and lymph flows
What are 3 factors that cause increased rates of secretion [so that it may exceed absorption]
Bile
Irritation
Bacterial toxins
Is sodium coupled nutrient absorption energy dependent or independent?
Dependent
Why does intestinal fluid secretion occur?
Dilute hypertonic contents coming from the stomach into the small intestine
Facilitates secretion of enzymes for fine digestion to occur in the intestinal lumen
Where does intestinal secretion occur?
Crypt cells
Describe the process of intestinal secretion ** re do this
Na pumped into blood against conc gradient and brings in K in exchange
K is pumped back put of the cell via basolateral channels
And when the cell is activated these channels are opened up and membrane hyperpolarisation increases driving force for electrogenic transport
Sodium chloride moves into the crypt lumen
