Production of saliva

Question 1

Parotid gland secretes?

Answer 1

Serous

Question 2

Submandibular gland secretes?

Answer 2

Mixed

Question 3

Sublingual gland secretes?

Answer 3

Mixed

Question 4

Von Ebner’s glands secretes?

Answer 4

Serous

Question 5

Other minor salivary glands secrete?

Answer 5

Mucous

Question 6

Describe components of saliva

Answer 6

• Water (most important component)
• Electrolytes (e.g. Bicarbonate and fluoride)
• Proteins: mucin, glycoproteins, immunoglobulin (IgA), Enzymes, phosphoproteins

Question 7

Describe the saliva secretory unit:

Answer 7

Salivon -> basic unit of salivary gland

Acinus -> Berry-shaped cluster of cells; initial site of secretory process.

Intercalated duct -> Initial part of duct; contains secretory granules.

Striated duct -> Modifies secretory product.

Excretory duct -> Modify the saliva composition.

Question 8

Describe primary secretion

Answer 8

Isotonic saliva secreted by acinus and intercalated ducts.

• Ions pumped into acinus cells (KNOW PUMPS): NaK-ATPase, NaKCl-symporter
• Channels on apical surface diffuse ions out
• Na passively passes between cells
• Water follows Na

Question 9

Describe secondary secretion

Answer 9

Hypotonic saliva after modifications from striated and excretory ducts.

• Na and Cl absorbed from lumen
• K and HCO3 secreted into lumen
• Water impermeability

Question 10

Describe flow rate:

Answer 10

High flow rate = saliva is 70% the composition of plasma

Low flow rate = very hypotonic; high K+

Question 11

Describe control of the secretion

Answer 11

Dual innervation: parasympathetic and sympathetic control. Acts simultaneously.
Hormones affect composition.

Question 12

List factors in saliva stimulation

Answer 12

• Taste, temperature and smell
• Physical stimulation
• Mastication and chewing
• Nausea
• Stimulated Flow: rate = 1.0 - 2.0mL/min, source = mostly submandibular -> mostly mucous
• Unstimulated flow: rate = 0.3-0.5 mL/min, source = mostly parotid -> mostly serous

Question 13

Describe parasympathetic nervous control of production of saliva

Answer 13

• Primary instigator
• CN IX (glossopharyngeal) - otic ganglion to parotid
• CN VII (facial nerve) - Submandibular ganglion to submandibular and sublingual glands
• Acetylcholine to muscarinic receptor
• Watery saliva

Question 14

Describe sympathetic nervous control of production of saliva

Answer 14

• Superior cervical ganglion of sympathetic trunk to external carotid, lingual and facial arteries
• Noradrenaline to adrenergic receptors
• Short increase in salivary secretion
• Viscous saliva

Question 15

List factors in saliva inhibition

Answer 15

• Medication
• Autoimmune (e.g. Sjogrens)
• Infection or obstruction of gland