Lecture #28 - Secretion

Question 1

Endocrine secretions:
-Secretion across ____-____ surface into _____ ____ and into blood and goes to body e.g. gastrin

Exocrine secretions:
-Most are out on body surface and since GI is ‘surface’ - these secretions are exocrine

What are the 4 functions of exocrine secretion?

1. D____ food = key role in what?
2. D_____ food = regulate what of food?
3. Optimal ___ = want to do this because?
4. P___ and l____ = yeah, seems logical

What are the three major components of exocrine secretion?

Answer 1

-

Question 2

Production of saliva:

1. 3 pairs of salivary glands - what are they?
2. Two-stage model for this production - what is it?
3. How much saliva per day? What is the basal vs the stimulated rate in ml/min?
4. 5. Why have a basal rate? (2)
5. What three things does it comprise of what do each of them do? (two points each)
6. Regulation of secretion - through what two things? Can you regulate it by hormones? What two things send signals to CNS to increase salivary secretion? And what can you say about the combined effect of parasymp and symp?
7. What’re the three main functions of saliva and yeah, explain them

Answer 2

-1. Parotid, submandibular and sublingual

Question 3

Gastric secretion: Volume and composition

1. How much volume per day?
2. Between meals - slow rate; what is it and mainly?
3. When eating/have food in stomach - superimposed on basal rate. What rate and secrete mainly what? (4)
4. What do each of these three things do? (well, more on that in the next flash card)

Answer 3

-

Question 4

Functions of the 4 gastric secretions:

1. Mucous
   - protection from what?
2. I_____ _____
   - absorption of what in SI? Explain
3. P____
   - secreted as what?
   - converted to what and how?
   - Starts what?
4. G____ ____
   - ___ proteins
   - activates what to what?
   - optimum pH for what?
   - protection - how?
   - dilutes food - how?

Answer 4

-

Question 5

Gastric secretion: cells - three of them mentioned here - what do they secrete?

Answer 5

-

Question 6

Gastric secretion: regulation

1. Coordinated with ____ and ____ of food
2. Three phases and what are their one-word things?

Answer 6

-

Question 7

Gastric secretion: Cephalic phase

1. What percentage of secretion associated with a meal?
2. P____
3. What’re the two main stimuli for this secretion?
4. Parasympathetic NS - to increase secretion, use this to signal from brain down to stomach via ____ nerve. This nerve innervates ____ first (which then stimulates ____ cells directly). The parietal cells then produce ____ ___ and ____ ____. The PNS also innervates ENS and targets G-cells (endocrine cells) in gastric mucosa to produce ____ and this ALSO stimulates parietal cells (so both ENS/gastrin stimulate parietal)…….The gastrin produced by G-cells diffuses into blood through capillaries and makes its way to parietal cells so have both the nervous and hormonal mechanism to increase gastric secretion [remember from last lecture that gastrin is also used for stomach contractility)

Answer 7

–

Question 8

Gastric secretion: Gastric phase

1. How percentage of secretion associated with a meal?
2. Ensures sufficient secretion to handle what?
3. What are its two stimuli?
4. Two kinda of responses - what are they? Explain them
5. Stimulates what two things>

Answer 8

-

Question 9

Gastric secretion: intestinal phase:

1. What percentage?
2. Control amount of acid delivered to where?
3. Two kinds of responses - what are they?

Answer 9

-

Question 10

Pancreatic secretion: volume and composition:

1. Two components contained in how many L per day?
2. What are the two components and what are they produced by?

Answer 10

-

Question 11

Pancreatic secretion: Enzymes from acinar cells

1. Act on ___ classes of food
2. What are three examples of the range of enzymes?
3. What’s their function?

Activation of proteolytic enzymes:

1. Proteolytic secreted as ____ precursors
   e. g. trypsin and chymotripsyn secreted as?
2. In SI, what is trypsinogen converted to trypsin by? What does trypsin then do?

Bicarbonate (ducts)

1. ____ chyme
2. Create what for pancreatic and intestinal enzymes?

Answer 11

-

Question 12

Regulation of pancreatic secretion

1. Slow basal rate during ____
2. Hormonal regulation during meal: CCK
   - produced by what? In response to what? E.g.
   - Stimulates what?
3. Hormonal: secretin
   - produced by what in response to what?
   - stimulates what secretion by duct cells?

Answer 12

-

Question 13

Biliary secretions
1. What’s the volume per day?

2. Consists of: E____ products
   - ____ pigments - waste products
   - c____ - excreted by liver
3. Consists of: products associated with digestion
   - bile salts and _____
   - Bicarb rich fluid secreted by duct cells
4. Functions of bile - bile salts + lecithin, bicarb rich fluid, bile pigments - their functions

5. Control of biliary secretion 
=Bile secreted \_\_\_\_ and stored in \_\_\_\_\_
-delivered to SI when?
=Delivery of bile under hormonal control
-CCK: stimulated by products of digestion in duodenum and leads to contraction + relaxation of what?

Answer 13

-

Question 14

Intestinal secretions:

1. SI
   - how much per day?
   - What two things and their purpose?
2. LI:
   - what secreted and why?
3. So, what three places does bicarbonate come from?

Answer 14

-