Proteoglycan solutions, viscosity

Viscosity with stational flow. As is usual for solutions of high polymeric compounds, the apparent viscosity of proteoglycan solutions depended strongly on the rate of shear the higher viscosity was observed at the lower rate of shear (Figure 3). 

Whole saliva (spit) is a dilute, viscous solution of proteins and shed epithelial cells. The major electrolytes are sodium, chloride, and bicarbonate. Calcium and phosphate are present at a supersaturated concentration. Viscosity is due to mucins, proteoglycans with numerous short glycan chains that lubricate the oral cavity, hold a bolus of chewed food together, and reduce bacterial adherence to teeth. Besides mucins, the major proteins secreted in saliva are amylase and proline-rich proteins. The major electrolytes, sodium chloride and sodium bicarbonate, increase with stimulation of salivary flow, but the protein content decreases. All proteins in whole saliva adhere to some extent to... 

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