PHYS: Salivary Secretion

Question 1

What is the word for a mixture of proteins, water and electrolytes that is secreted by various glands?

Answer 1

saliva

Question 2

What gland secretes a serous secretion of water, ions, and enzymes?

Answer 2

parotid glands

Question 3

Which glands secrete a mixed serous and mucous secretion?

Answer 3

Submandibular and Sublingual glands

Question 4

What secretes mucus for lubrication?

Answer 4

lips and tongue glands

Question 5

What are the 3 major roles of saliva?

Answer 5

Digestion
Lubrication
Protection

Question 6

What are the two enzymes present in saliva?

Answer 6

Salivary amylase

Lingual lipase

Question 7

What is the role of salivary amylase?

Answer 7

responsible for 50-70% of starch digestion (but if absent, not a problem for body)

Question 8

How long will salivary amylase digest food?

Answer 8

until it reaches the stomach (pH optimum of 7, so inactivated by gastric acid)

Question 9

What is the role of lingual lipase?

Answer 9

digests TGs and fat

Question 10

How long will lingual lipase digest food?

Answer 10

into the stomach (not inactivated by acid in stomach, because pH optimum is 4)

Question 11

Why is solubilization important?

Answer 11

allows you to taste food

Question 12

Why is lubrication important?

Answer 12

speech and bolus movement

Question 13

In what ways does saliva serve a protective role?

Answer 13

• Allows you to expel noxious material
• Thermally dilutes things (decrease temperature of hot foods)
• Alkaline to protect from damage and dental caries associated with vomit and acidic foods

Question 14

What causes an increase in saliva in the mouth before vomiting?

Answer 14

vagal reflex

Question 15

What saliva component chelates iron to decrease bacterial growth?

Answer 15

lactoferrin

Question 16

What saliva component destroys bacteria?

Answer 16

lysozyme

binding protein for IgA also helps to kill bacteria

Question 17

What cells make saliva?

Answer 17

acinar cells

Question 18

What are acinar cells?

Answer 18

grape-like cells that elaborate proteins, water and electrolytes when they are squeezed

Question 19

What “squeezes” acinar cells to cause secretion of saliva?

Answer 19

the myoepithelial cells that surround the acinar cells

Question 20

From the acinar cells, where is saliva secreted?

Answer 20

into the intercalated duct→ salivary (striated) duct→ mouth

Question 21

What disease is characterized by the destruction of salivary glands?

Answer 21

Sjogren’s syndrome

Question 22

True or false: saliva is always isotonic.

Answer 22

FALSE: always hypotonic (though less so at high rates of secretion)

Question 23

What are two other characteristics (other than hypotonicity) of saliva?

Answer 23

Alkaline

High K+

Question 24

What ions are secreted into the acinus?

Answer 24

Na+
Cl-
HCO3-

Question 25

Why is the saliva high in K+ and HCO3- and hypotonic?

Answer 25

as the saliva moves from the acinus to the duct opening, K+ and HCO3- are secreted into the lumen and Na+/Cl- are reabsorbed (while water is NOT)

Question 26

What does the saliva resemble with high flow rates? Why?

Answer 26

final saliva closely resembles plasma and initial saliva produced by acinar cells (less time for the ductal cells to modify the saliva).

Question 27

What is another feature of saliva during high flow rate?

Answer 27

HCO3- is high in this saliva because its secretion is selectively stimulated when saliva production is stimulated.

Question 28

What would you give a patient who has high flow rates of saliva?

Answer 28

give back bicarbonate and K+ (no matter what, K+ is always secreted at a 4-5X higher level than plasma

Question 29

What are characteristics of saliva at low flow rates?

Answer 29

saliva is most dissimilar to plasma (lower NaCl and higher K+)

Question 30

True or false: regulation of salivary secretion is totally under nervous control.

Answer 30

TRUE

Question 31

True or false: no hormones are involved in the regulation of salivary secretion.

Answer 31

TRUE

Question 32

True or false: hormones cannot modify salivary secretions.

Answer 32

FALSE- though hormones do NOT regulate salivary secretion, they can modify the secretions

Question 33

What is the major nervous effector of salivary secretion?

Answer 33

parasympathetic innervation

Question 34

What is the name of the parasympathetic response that increases salivation?

Answer 34

Cephalic response

Question 35

What are stimuli that initiate the cephalic response?

Answer 35

smell taste pressure nausea

Question 36

What do the stimuli of the cephalic response do?

Answer 36

stimulate salivary nucleus of the medulla and activate CN IX and X

Question 37

What do CN IX (glossopharyngeal) and X (vagus) do in the cephalic response in response to stimulation?

Answer 37

release Ach molecules that act through M receptors to increase IP3 and Ca2+ in the salivary gland

Question 38

What does increasing levels of Ca2+ do in salivary glands?

Answer 38

increase saliva secretion | Increase blood flow

Question 39

How does increased Ca2+ increase blood flow?

Answer 39

Increases cellular metabolism→ increased kallikrein→ increased bradykinin from plasma proteins→ HUGE blood flow increases

Question 40

What inhibits the salivary nucleus of the medulla?

Answer 40

fatigue sleep fear dehydraiton

Question 41

What are the sympathetic effectors (minor) involved in the regulation of salivary secretion?

Answer 41

T1-T3

Question 42

How do T1-T3 lead to increased salivary secretion?

Answer 42

T1-T3 act on superior cervical ganglion→ release of NE→ beta-adrenergic receptors to increase cAMP and cause saliva secretion