Salivary Secretion & Function

Question 1

What are the 3 Major salivary glands?

Answer 1

1. Parotid
2. Submandibular
3. Sublingual

Question 2

What is the functional unit of salivary glands?

Answer 2

Salivon

Question 3

What is the rough structure of the salivary glands?

Answer 3

Broccoli shaped

• external capsule
• Septae: separating lobes and lobules
• lobules: contain salivon, functional unit

Question 4

What 3 things are found in the Salivon?

Answer 4

• secretory acinus
• intercalated duct
• striated duct

Question 5

What cells form the central lumen around the secretory Acinus?

Answer 5

1. Serous cells

2. Mucous cells

Question 6

What kind of secretion do serous cells produce?

Answer 6

Watery secretion rich in A-amylase

Question 7

What kind of secretion do mucous cells produce?

Answer 7

Thick mucous rich saliva

Question 8

What are the main functions of saliva?

Answer 8

1. Lubrication
2. Protection
3. Digestion
4. Others

Question 9

What are the effects of lubrication? what contents of saliva make this possible?

Answer 9

Water and mucus contents

Aids food movement. Facilitates speech & swallowing.

Question 10

What protection does saliva offer?

Answer 10

Against bacteria + their metabolic products.

Protects teeth.

Question 11

How does saliva help with digestion?

Answer 11

• A-amylase stimulates complex carb digestion

- lingual lipase= fat digestion

Question 12

What are the main electrolyte constituents of saliva?

Answer 12

Na,K,Ca,Cl,P04,HCO3,I

Question 13

Concentration of these electrolytes except _ and _ are lower in saliva than the rest of the body?

Answer 13

K & HC03

Question 14

Parotid gland produces what type of secretion?

Answer 14

watery A-amylase rich

Question 15

Submandibular gland produces what type of secretion?

Answer 15

Thicker than parotid secretion

Question 16

Sublingual gland produces what type of secretion?

Answer 16

Thick mucus based

Question 17

How is HC03 concentration affected by salivary flow rate?

Answer 17

Increases with rate

Question 18

How is K concentration affected by salivary flow rate?

Answer 18

Decreases with rate

Question 19

What are the two stages in saliva formation?

Answer 19

1. Primary secretion (acinar cells)

2. Secondary modification (duct cells)

Question 20

What happens in secondary modification?

Answer 20

Na & Cl Influx
K & HC03 Efflux

Influx exceeds efflux–> Overall diluting effect.

Question 21

What two types of reflexes control saliva secretion?

Answer 21

1. Simple- stimulated by presence of food in mouth

2. Acquired- brought on by sight, smell, thought of food

Question 22

Which one (para/symp) of the autonomic nervous system is dominant in saliva secretion under resting conditions?

Answer 22

Parasympathetic.

Sympathetic- stimulated in stressful situation

Question 23

Which nerves are used in parasympathetic salivary secretion?

Answer 23

1. Glossopharyngeal (CN9)

2. Facial (CN7)

Question 24

Effect of parasympathetic stimulation on type of saliva produced and blood flow?

Answer 24

Large volume, watery, enzyme rich.
Mediated by- M3/M1 AcH receptors

Blood flow- increases

Question 25

How does sympathetic stimulation reach the mouth to cause salivary secretion?

Answer 25

1. Post ganglionic fibres from superior cervical ganglia | 2. Adrenaline from adrenal medulla

Question 26

Effect of sympathetic stimulation on type of saliva produced and blood flow?

Answer 26

Small volume, mucus thick saliva Blood flow reduced. Mediated by (A & b1 receptors)

Question 27

Which Cranial nerve controls relaxation of the stomach?

Answer 27

CN 10- Vagus nerve

Question 28

What food group is digested in the stomach? by what?

Answer 28

Proteins. By pepsin and HCL

Question 29

What is chyme

Answer 29

food + gastric secretion

Question 30

Is the pyloric sphincter open or closed when food is mixed in the stomach?

Answer 30

Closed

Question 31

When does the pyloric sphincter open?

Answer 31

When food passes from stomach to duodenum. | Opens sufficiently to allow semi liquid chyme to pass.

Question 32

What drives this movement of food from stomach to duodenum?

Answer 32

Peristalsis

Question 33

What two factors does rate of stomach emptying depend on?

Answer 33

1. Gastric factors | 2. Duodenal factors

Question 34

What are the gastric factors that affect rate of emptying? (2)

Answer 34

Consistency & volume of chyme. Affected by: - Gastric motility - intrinsic nerve activity - Vagus nerve activity - gastrin release

Question 35

In what two ways can the duodenum delay gastric emptying?

Answer 35

1. Neuronal response | 2. Hormonal response

Question 36

What is the neuronal response known as? what happens in it?

Answer 36

Enterogastric reflex- intrinsic nerve plexus & ANS= decreases Peristaltic activity

Question 37

What is the hormonal response known as and what happens?

Answer 37

Enterogastrone release- e.g. CCK release from duodenum inhibits stomach contraction

Question 38

What are the two areas of gastric gland secretions?

Answer 38

1. Pyloric gland area | 2. Oxyntic mucosa

Question 39

What are the secretions of the Oxyntic mucosa and each of their functions? (5)

Answer 39

1. HCL: Pepsinogen--> pepsin 2. Pepsinogen- inactive precursor 3. Intrinsic factor- binding of Vitamin B12 for absorption 4. Histamine- HCL secretion 5. Mucus- protective

Question 40

What are the secretions of the Pyloric gland area and each of their functions?

Answer 40

1. Gastrin- HCL secretion 2. Somatostatin- Inhibits HCL secretion 3. Mucus- protective

Question 41

What are the 3 phases of Gastric secretion?

Answer 41

1. Cephalic- before food reaches stomach 2. Gastric- in stomach 3. Intestinal- left the stomach

Question 42

What happens in the Cephalic phase?

Answer 42

Prepares stomach for food Increased Secretions of - Gastrin - Histamine - AcH Reduced secretion of - Somatostatin

Question 43

What happens in the Gastric phase?

Answer 43

1. Distension (promotes peristalsis) | 2. Protein digestion products released

Question 44

What happens in the Intestinal phase?

Answer 44

Gastric secretions switched off. Same factors also reduce gastric motility. Somatostatin increased

Question 45

How is the mucosa protected from attack by HCL and pepsin?

Answer 45

Release of Prostaglandin E2 and I2 (PGE2, PGI2)

Question 46

How do the prostaglandins protect the mucosa?

Answer 46

- Increase mucus + bicarb production - Reduce acid secretion - Increase mucosal blood flow

Question 47

How does a peptic ulcer develop?

Answer 47

Damage to the mucosa by HCL and pepsin.

Question 48

What main type of drug can cause Peptic ulcers?

Answer 48

NSAID's like Aspirin

Question 49

What bacteria can cause infection in peptic ulcers?

Answer 49

H.Pylori- helicobacter pylori

Question 50

What are the 4 main mechanisms of action that reduce acid section?

Answer 50

1. Inhibition of proton pump 2. Competeive antagonism of histamine receptors 3. Competitive antagonism of M1,M3 receptors 4. Antagonism of gastrin receptors

Question 51

Example of a proton pump inhibitor? How does it work?

Answer 51

Omeprazole. Inhibits Active H/K dependent ATPase proton pump. Note- only works on active proton pumps, and in a strong acidic environment

Question 52

Example of Histamine agonist? Mechanism?

Answer 52

Ranitidine, Cimetidine Competitive inhibitor of H2 histamine receptors Block histamine mediated acid secretion

Question 53

What are two examples of mucosal strengtheners?

Answer 53

1. Sucralfate- binds with mucosa to improve barrier function. Increases mucosal blood flow, HC03, PGE production 2. Bismuth Chealate- eradicates H.pylori.