4 - Pancreatic Secretions PPT

Question 1

Where on earth is the pancreas located?

Answer 1

Epigastric region behind the stomach

Question 2

(TRUE/FALSE): The pancreas only produces endocrine hormones.

Answer 2

(FALSE): The pancreas produces both endocrine and exocrine hormones.

Question 3

The pancreas has ________ and ________ cells that produce endocrine hormones like ________ and ________ that are secreted into the bloodstream to regulate blood sugar levels.

Answer 3

1. alpha, beta
2. insulin, glucagon

Question 4

What type of hormone is secreted the most from the pancreas (around 90%)?

Answer 4

Exocrine hormones

Question 5

What are the goals of exocrine secretions from the pancreas?

Answer 5

To help neutralize acid and digest food within the intestines

Question 6

What are the divisions of the pancreas called?

Answer 6

Lobules

Question 7

What are pancreatic units called?

Answer 7

Acinus/acini

Question 8

What do the ductal cells secrete to help neutralize the acidic stomach contents as they enter the intestines?

Answer 8

Bicarbonate (HCO3-)

Question 9

Reminder- what should we always think when we see the word “bicarbonate”?

Answer 9

Question 10

Intercalated ducts merge together, forming an ________ duct which joins together with other ________ ducts to finally drain into the main ________ duct.

Answer 10

1. intralobular
2. intralobular
3. pancreatic

Question 11

What travels through the length of the pancreas and drains into the duodenum?

Answer 11

The main pancreatic duct

Question 12

What are some enzymes produced by acinar cells?

Answer 12

1. Pancreatic amylase
2. Trypsin/Chymotrypsin
3. Lipases

Question 13

What’s the function of pancreatic amylase?

Answer 13

It breaks down carbs

Idea: “Pancreatic amylase c̲r̲u̲s̲h̲e̲s̲ carbs”

Question 14

What’s the function of trypsin/chymotrypsin?

Answer 14

They break down proteins

Idea: “Trypsins pu̲l̲v̲e̲r̲i̲z̲e̲ proteins”

Question 15

What’s the function of the lipases?

Answer 15

They break down lipids

Idea: Triple L- “Lipases Liquify Lipids”

Question 16

An inactive enzyme will have the ending…

Answer 16

… -ogen!

Question 17

What inactive enzymes can be synthesized from acinar cells?

Answer 17

Proenzymes and zymogens

Question 18

Why are these enzymes kept in an inactive state?

Answer 18

To prevent self-destruction (essentially preventing them from eating you alive)

Question 19

What failsafe did our Creator implement to prevent enzymes from doing damage should they become prematurely active?

Answer 19

The enzymes are to be stored in vesicles alongside a protease inhibitor to shut the enzyme down. So cool.

Question 20

What is trypsinogen?

Answer 20

A zymogen (inactive enzyme) that is released into the pancreatic duct to make its way to the small intestine- it is activated by protease enteropeptidase.

Question 21

Ductal cell secretions are filled with various ions, including…

Answer 21

1. Sodium (Na+)
2. Potassium (K+)
3. Chloride (Cl-)
4. Bicarbonate (HCO3-)

Question 22

During 𝐡𝐢𝐠𝐡 𝐟𝐥𝐨𝐰 𝐫𝐚𝐭𝐞, which is when food contents are present in the intestines, what are the respective concentrations of HCO3- and Cl-?

Answer 22

𝐇𝐢𝐠𝐡 HCO3- & 𝐥𝐨𝐰 Cl-

Question 23

During 𝐥𝐨𝐰 𝐟𝐥𝐨𝐰 𝐫𝐚𝐭𝐞, which is when food contents are NOT present in the intestines, what are the respective concentrations of HCO3- and Cl-?

Answer 23

𝐇𝐢𝐠𝐡 Cl- & 𝐥𝐨𝐰 HCO3-

Question 24

What’re the three phases of pancreatic secretions?

Answer 24

1. Cephalic phase
2. Gastric phase
3. Intestinal phase

Question 25

What happens during the Cephalic phase?

Answer 25

- Sensory inputs (sight/smell) stimulate the brain - Brain sends efferent signals via Vagus (CN X) to pancreas - Vagus releases acetylcholine that causes acinar cells to secrete enzymatic fluid

Question 26

What happens during the Gastric phase?

Answer 26

- Distention of stomach is sensed by mechanoreceptors - The afferent info travels via Vagus (CN X) to the brain - Brain sends efferent signals back to the pancreas to cause acinar cells to produce slightly more fluid

Question 27

What happens during the Intestinal phase?

Answer 27

Chyme gets sent out; this phase is responsible for over 80% of pancreatic secretions

Question 28

What is chyme?

Answer 28

Partially digested food and stomach acid. - Check out this absolutely cursed picture I found

Question 29

Where does chyme go during the intestinal phase?

Answer 29

The duodenum

Question 30

What happens to the proteins and lipids within the chyme?

Answer 30

They are broken down into their monomers (make sens rye) by pancreatic enzymes that were produced in the earlier phases

Question 31

The presence of fatty acids and amino acids (monomers) stimulates what cells in the lining of the duodenum and jejunum?

Answer 31

𝐼 Cells

Question 32

Once stimulated, these 𝐼 Cells secrete ___________ to act on acinar cells to begin the secretion of digestive enzymes.

Answer 32

Cholecystokinin (CCK)

Question 33

What else is CCK responsible for?

Answer 33

Gallbladder contraction

Question 34

(TRUE/FALSE): Chemoreceptors send afferent information via Vagus (CN X) to increase secretions during the intestinal phase.

Answer 34

(TRUE): This does in fact happen- Chemoreceptors DO send afferent information via Vagus (CN X) to increase secretions during the intestinal phase!

Question 35

What other hormone is secreted during the intestinal phase? Is it: A - Secretin B - Ghrelin C - Testosterone D - Gooba-gabba

Answer 35

A - Secretin Good job 👍

Question 36

What signals to the S cells within the duodenum to release secretin?

Answer 36

The acidity detected

Question 37

Why do the S cells want to release secretin when high acidity is detected?

Answer 37

Because then the aqueous portion of the pancreatic fluid massively increases, and it just so happens that this aqueous portion contains a crap-ton of bicarbonate (HCO3-) to neutralize that acidic chyme!

Question 38

When the chyme finally leaves the duodenum and enters the ileum and colon, what peptide inhibits the pancreatic secretions?

Answer 38

Peptide YY from neuroendocrine cells

Question 39

What, oh what is made by the liver and stored in the gallbladder?

Answer 39

𝓑𝓲𝓵𝓮 <3

Question 40

What are the functions of bile?

Answer 40

Digestion, absorption of lipids, excretion of various molecules, emulsification

Question 41

Lipids are hydrophobic, so what does bile need to do?

Answer 41

Bile MUST emulsify and solubilize the fats.

Question 42

What is bile made up of?

Answer 42

- Bile salts - Phospholipids - Cholesterol - Bilirubin (a bile pigment)

Question 43

What are the steps to create bilirubin?

Answer 43

1. Hemoglobin from RBC is taken up by macrophages 2. Macrophages convert heme into biliverdin 3. Biliverdin converts to bilirubin via biliverdin reductase

Question 44

What is bilirubin's classification once it completes these first three steps?

Answer 44

Unconjugated/indirect

Question 45

What binds to unconjugated/indirect bilirubin within the blood?

Answer 45

Albumin

Question 46

What happens after albumin binds to the unconjugated/indirect bilirubin?

Answer 46

Unconjugated/indirect bilirubin is taken up into hepatocytes, where it turns into conjugated/direct bilirubin!

Question 47

Bilirubin's conjugation makes it more soluble, which means it can be secreted into...

Answer 47

... BILE!

Question 48

In the intestines, bacteria hydrolyze the conjugated/direct bilirubin, reducing it to a colorless compound called what?

Answer 48

Urobilinogen

Question 49

What form of bilirubin gives doodoo its signature brown color?

Answer 49

Stercobilin

Question 50

What form of bilirubin gives urine its signature yellah color?

Answer 50

Urobilin

Question 51

How much of bile acids are recycled and how much of them are lost in feces?

Answer 51

- 95% recycled - 5% lost

Question 52

What are carbs referred to as?

Answer 52

Saccharides

Question 53

List our three monosaccharides we can find in our foods.

Answer 53

- Glucose - Fructose - Galactose