GI Physiology: Secretions Flashcards
What proteins are found in saliva?
Alpha amylase
lingual lipase
IgA
Kallikrinin
What are the electrolyte components of saliva?
High K+
High HCO3-
Low Na+,
Low Cl-
What is the net electrolyte movement in salivary ductal cells?
Absorption of Na+/Cl-»_space;» Secretion of K+/HCO3- + H2O impermeability (this creates a hypotonic solution)
What happens to the osmolarity of saliva with changes in flow rate?
High flow rate = isotonic
Low flow rate = More hypotonic
This is because there less or more time to absorb Na+/Cl-
Why doesn’t HCO3- in saliva decrease with increased flow rate despite being secreted?
Because HCO3- secretion is only stimulated when salivation is stimulated.
How is salivation stimulated?
Parasympathetic
CN VII, IX –> Ach –> M3 –> IP3/Ca –> Salivation
Sympathetic
T1-T3 (superior cervical ganglion) –> NE –> beta receptors –> cAMP –> Salivation
What are the antibacterial factors found in saliva?
Cl-
Lysozyme
lactoferrin
Binding protein IgA
What is the effect of Addison’s disease on saliva?
increased Na+
decreased K+
What is the effect of Cushing’s disease on saliva?
Decreased Na+
increased K+
What is the function of Kallikrinin in saliva?
Kalikrinin –> Bradykinin –> Vasodilation (increased blood flow)
What stimuli negatively regulate salivation?
Fatigue
sleep
Fear
Dehydration
What stimuli positively regulate salivation?
Smell
Taste
Pressure
Nausea
