PSC1002/L27 Gut Function Flashcards
Give the 3 key stages of regulation of gut function.
Cephalic
Gastric
Intestinal
In what 3 ways is gut function regulated?
Neural
Hormonal
Local
Give 3 functions of saliva.
Lubrication
Digestion
Solution
Moistness
Protection
Give the 3 pairs of salivary glands.
Parotid glands
Sublingual
Submandibular
Describe the structure of the salivary glands. (3)
Acinus - primary secretion, isotonic, plasma-like
Duct - secondary modification, low H2O permeability
Final saliva - hypotonic, HCO3–rich
Describe the salivary fluid secretion pathway. (2)
Primary fluid from acinar epithelial cells
Secondary ductal modification - Na+ and Cl- reabsorption, K+ and HCO3- secretion, duct impermeable to water
Describe cephalic control of salivation. (2)
Sight, smell, taste and thought of food
Vagal efferent nerves
Describe parasympathetic control of salivation. (2)
Cranial nerves VII and IX
Large volume
Describe sympathetic control of salivation.
Smaller volume, but rich in enzymes, mucus
Give 3 gastric functions.
Reservoir
Mixing food with gastric secretions
Digestion
Controlled gastric emptying
Protection
Describe the composition of gastric juice. (2)
HCl pH<1
Pepsinogen -> pepsin
Mucus & bicarbonate
Intrinsic factor
What is produced by parietal cells?
HCl
What is the role of carbonic anhydrase?
Catalyses generation of H+
What structures are within the apical membrane? (3)
H+,K+ ATPase
K+ channels
Cl- channels
What structures are within the basal membrane? (2)
Na+/K+-ATPase
Cl-/HCO3- exchange
