Physiology: Saliva

Question 1

what are the components of saliva?

Answer 1

water
mucus (high Ca)
lysozyme
lactoferrin
IgA
a-amylase (ptyalin)
lingual lipase

Question 2

what’s the function of water and mucus in saliva?

Answer 2

lubrication (aids movement, speech, swallowing)

Question 3

what’s the function of bicarbonate, phosphate and mucus in saliva?

Answer 3

to buffer bacterial metabolic acids

Question 4

what’s the function of the high Ca content of saliva?

Answer 4

to prevent demineralisation of teeth

Question 5

what’s the function of lysozyme in saliva?

Answer 5

to attack bacterial cell walls

Question 6

what’s the function of lactoferrin in saliva?

Answer 6

it chelates iron, limiting the availability of iron to bacteria requiring iron for growth

Question 7

what’s the function of IgA in saliva?

Answer 7

contributes to immunity against bacteria and viruses

Question 8

which of the 3 pairs of salivary glands secretes a watery a-amylase rich solution which is 25% total secretions?

Answer 8

parotids

Question 9

which of the 3 pairs of salivary glands secretes a mixture of serous and mucus cells - giving a more viscous solution than the parotids, and makes up 70% total secretions?

Answer 9

the submandibular

Question 10

which of the 3 pairs of salivary glands secretes the thickest (mucus rich) solution, comprising 5% total secretion?

Answer 10

sublinguals

Question 11

what is involved in the first stage (primary secretion) of saliva by acinar cells?

Answer 11

• saliva is isotonic and similar composition to plasma

- Cl, K, H20, and Cl enter the lumen (Na and H20 via paracellular route)

Question 12

what is involved in the second stage (secondary modification) of saliva secretion?

Answer 12

• secondary modification is by striated, intercalated, and excretory ducts
• it removes Na and Cl from saliva, and adds K and HCO3 (Na and Cl influx is more than K and HCO3 efflux - so the overall effect is diluting)

Question 13

which CN nerves control salivary secretion of each of the pairs of salivary glands?

Answer 13

• parotid glands = CNIX

- sublingual and submandibular glands = CNVII

Question 14

what are the features of saliva produced under parasympathetic stimulation?

Answer 14

large volume
watery
enzyme rich

Question 15

what are the features of saliva produced under sympathetic conditions?

Answer 15

small volume
thick
mucus rich