Physiology introduction
4 layers:
Mucosa
Submucosa
Muscularis externa
Serosa
Circular or spiral folds – first layer of SA amplification
Vectorial transport is only possible because cells are polarised having apical and
basolateral membranes
Paracellular pathway – Passing through the intercellular space between the cells.
Transcellular pathway - substances travel through the cell, passing through both
the apical membrane and basolateral membrane.
Transcellular transport of Cl- drives paracellular movement of water and Na+
ions. Sodium ions move to neutralise charge across the epithelium.
NKCC1 is the main mechanism to bring in Cl- into the cell to drive secretion.
GI tract secretes 8-9 litres per day
4 layers:
Mucosa
Submucosa
Muscularis externa
Serosa
Circular or spiral folds – first layer of SA amplification
Vectorial transport is only possible because cells are polarised having apical and
basolateral membranes
Paracellular pathway – Passing through the intercellular space between the cells.
Transcellular pathway - substances travel through the cell, passing through both
the apical membrane and basolateral membrane.
Transcellular transport of Cl- drives paracellular movement of water and Na+
ions. Sodium ions move to neutralise charge across the epithelium.
NKCC1 is the main mechanism to bring in Cl- into the cell to drive secretion.
GI tract secretes 8-9 litres per day
