GI Secretions (review w/ handout 10/21 11a)

Question 1

Salivary Glands

Answer 1

3 pairs of glands: parotid, submandibular and sublingual

Produce a serous (proteinaceous) or mucus product, or both

Question 2

Water in saliva

Answer 2

facilitates taste and dissolution of nutrients, aids in swallowing/speech

Question 3

bicarb in saliva

Answer 3

neutralizes gastric reflux

Question 4

mucins in saliva

Answer 4

lubrication

Question 5

amylase in saliva

Answer 5

starch digestion

breakdown alpha1-4 bonds

Question 6

lysozyme, lactoferrin, IgA

in saliva

Answer 6

lysozyme: pore forming in bacteria
lactoferrin: sequesters iron (prevent bacteria from obtaining it); great loss w/ IBD
secretory IgA: coats proteins to not internalize bacteria

innate and acquired immune protection

Question 7

epidermal and nerve growth factors in saliva

Answer 7

assumed to contrib to mucosal growth and protection

VEGF, etc

Question 8

Salivary gland structure

Answer 8

myoepithelial cells: contractile cells, facilitate secretion into acinus thru intercalated duct and out thru striated duct

Pancreatic gland doesn’t have myoepi cells

Acinar cells make the saliva and striated duct cells modify its ionic content

Question 9

Salivary secretions

CNS regulation

Answer 9

regulated by cephalic phase of digestion

can be downregulated by sleep (so you don’t aspirate), fatigue, fear

Pressure in mouth can cause increased salivary secretions

Parasymp increases salivary production (vasodilation), secretion from acinus to intercalated, to striated

Octic ganglion and submandibular ganglion, produce ACh, act on parotid and submandibular gland and increased salivary secretion via effects on Acinar secretion and vasodilation

Question 10

Parasymp regulation of salivary secretion

Answer 10

increased acinar cell secretion and vasodilation of blood vessels surrounding the acini (results in protein rich & fluid/ion rich solution)

Question 11

Sympathetic activation of salivary secretion

Answer 11

– increased acinar cell secretion (results in high protein/low fluid solution)

Question 12

how is saliva formed

Answer 12

passive filtration

content and secretion rate dependent on blood flow:
Increased blood flow around the acinus increases the fluid content of saliva by moving ions and water cellularly and paracellularly into the acinar lumen. TJs are leaky in the acinus

99.5% water and 0.5% electrolytes (Na+, Cl-,
K+, HCO3-) and proteins (mucus, enzymes: amylase, lipase, and antibacterial agents: lysozyme & IgA)
Produce 1-2 liters/day

Question 13

Slow flow rate of salivary secretion

Answer 13

At slow flow rate:

Time means more time for reabsorption of Na, Cl, H+ (adjust level of water and solutes) and secretion of K and bicarb

Question 14

High flow rate

Answer 14

salivary secretions
but don’t get time to modify contents in striated ducts

More NaCl present
less K, bicarb

Question 15

Goals of ductal cells

Answer 15

NaCl Reabsorption
K+ secretion
Bicarbonate secretion

Question 16

Bicarb

Answer 16

weak base
CO2 is weak acid
acidic pH–>produce more bicarb
basic pH–> produce less bicarb, more CO2

Question 17

K

Answer 17

very little change in K levels in response to flow rate (don’t want to lose much)

Question 18

Salivary secretion key points

Answer 18

Acinar secretions are close to isotonic. TJs allow movement of ions and water from the blood.
In duct cells, Na+/K+ ATPase establishes a concentration gradient. Carbonic anhydrase uses H2O and CO2 to produce H+ and HCO3-
At a low rate of flow, duct cells absorb Na+ and Cl- and secrete K+ and HCO3-.
The movement of water in the ducts is restricted by TJs, leaving the saliva hypotonic.
Faster flow rate limits the action of duct cells on ionic/water content
Secretion is modified by ANS (parasympathetic and sympathetic) and the changes in blood flow

Question 19

vomit and saliva

Answer 19

going to vomit? more saliva formation

Question 20

acinar cells produce

pancreas

Answer 20

enzymes: proteases, lipases, and amylases

Question 21

ductal cells produce

pancreas

Answer 21

bicarbonate solution to help liquefy and neutralize acidic chyme in the duodenum

Pancreatic secretions are locally and neurally regulated

Question 22

Proteases

Answer 22

trypsinogen
chymotrypsinogen
proleastase
procarboxypeptidase A
procarboxypeptidase B

(stored and secreted in inactive forms)

Question 23

Amylolytic enzyme

Answer 23

amylase

Question 24

lipases

Answer 24

lipase
nonspecific esterase
phospholipase A2 (inactive form)

Question 25

nucleases

Answer 25

deoxyribonucleas | ribonuclease

Question 26

other secretory products of pancrease

Answer 26

procolipase (inactive form) trypsin inhibitors monitor peptide

Question 27

ACh and regulation of pancreatic secretion

Answer 27

released from the vagus and ENS nerves; stimulates the release of digestive enzymes from acinar cells (mostly cephalic stage)

Question 28

Secretin and regulation of pancreatic secretion

Answer 28

– released from endocrine cells in the proximal small intestines in response to acid levels; stimulates the release of a bicarbonate rich solution from pancreatic duct cells

Question 29

CCK and regulation of pancreatic secretion

Answer 29

released from endocrine cells in the proximal small intestines in response to fats & proteins; stimulates the release of digestive enzymes from acinar cells but has other effects in the duodenum

Question 30

Regulation of neutralization in response ot acid

Answer 30

acid in lumen leads to increased secretion from duodenal mucosa secretin carried by blood to pancreatic duct cells leads to increased secretion of aqueous NaHCO3 soln into duodenal luman (neutralized acid in duodenal lumen)

Question 31

CCK regulation

Answer 31

fat/prot in duodenal lumen leads to increased CCL release from duodenal mucoasa CCK acts on panc acinar cells increased secretion of pancreatic dig enzy into duodenal lumen digest fat/prot

Question 32

Exocrine pancreas structure

Answer 32

Acinar cells make the enzymes and duct cells secrete a water/bicarbonate rich solution **** no myoepithelial cells rate of secretion much less variable

Question 33

CCK actions

Answer 33

in GB: contraction pancreas: stim acinar secretion in stomach: reduced emptying (inhibitory) sphincter of Oddi: relaxation Protein, carbohydrate, lipid absorption and digestion Matching of nutrient delivery to digestive and absorptive capacity

Question 34

CCK released from?????? redo this card

Answer 34

I cells trypsin controls releasing and monitoring peptide trypsin prefers to act on prot/aa breakdown Lots of fat? want CCK production to help breakdown fat So shuts off trypsin protein breakdown Monitor peptide monitors level of protein in duodenum turn off CCK

Question 35

cAMP and Ca in acinar cells

Answer 35

in epi/acinar cells, cAMP and Ca do the same thing both stim increased secretion Granules containing zymogens fuse with membrane and secrete contents

Question 36

trypsin

Answer 36

trypsin is inactive from pancrease (trypsinogen) Also released is a trypsin inhibitor. Trypsin becomes activated in the duodenal lumen when trypsinogen is cleaved by enzymes (enterokinases) located on the surface of enterocytes Activated trypsin then autoactivates more trypsinogen along with most of the other pancreatic enzymes

Question 37

secretin?????

Answer 37

acts by increasing cAMP levels in the duct cells. The release of secretin is enhanced by CCK

Question 38

Panc vs salivary differences??????

Answer 38

salivary secretions are susceptible to changes in flow rate, pancreatic secretions are not no myoepithelial cells in panc Panc: neuronal and humorally Salivary: neuironal salivary acinus is very vascular and increased blood flow results in a dilute saliva that is modified by duct cells. Salivary ducts, on the other hand, are fairly impermeable to water. Pancreatic acini are not as vascular and respond to ACh and CCK. Ductal cells actively secrete a water and a bicarbonate rich solution in response to secretin. Saliva is rich in KHCO3 whereas pancreatic juice is rich in NaHCO3.

Question 39

Salivary gland diseases

Answer 39

``` Mumps Cytomegaloviral Sialadenitis Bacterial Sialadenitis Sarcoidosis Sjögren’s Syndrome (autoimmune disease, inflammation) Salivary Lymphoepithelial Lesion Xerostomia or dry mouth Halitosis ```

Question 40

Benign neoplasms

Answer 40

- Mixed Tumor (pleomorphic adenoma) - Monomorphic Adenomas - Ductal papilloma

Question 41

Pleomorphic adenoma

Answer 41

diverse microscopic pattern Islands of cuboidal cells arranged in ductlike structures typically encapsulated Loose chondromyxoid stroma, connective tissue, cartilage (arrows) and even osseous tissue are observed

Question 42

Warthin's Tumor

Answer 42

Warthin's tumor (benign papillary cystadenoma lymphomatosum) the second most common benign tumor of the parotid gland It accounts for 2-10% of all parotid gland tumors Bilateral in 10% of the cases may contain mucoid brown fluid in FNA ID by aspiration epithelial component (papillary fronds), stains pink , shows granularity, can undergo metaplasia but rare and lymphoid component Both lymphoid and oncocytic epithelial elements must be present to diagnose Warthin’s "WHALE"

Question 43

Monomorphic adenoma

Answer 43

rare can be bilateral rare malignant potential multiple types Similar to Pleomorphic Adenoma except no mesenchymal stromal component Predominantly an epithelial component

Question 44

Basal cell adenoma

Answer 44

uniform basaloid epithelial cells with a monomorphous pattern. The arrangement of tumor cells may be trabecular (rod-like), tubular or solid. Histologically, these tumors are distinguished from pleomorphic adenomas by their absence of stroma and the presence of a uniform epithelial pattern.

Question 45

Malignant neoplasms by increasing freq

Answer 45

``` Mucoepidermoid Carcinoma (mucin+) Polymorphous Low-grade Adenocarcinoma Adenoid Cyctic Carcinoma Clear Cell Carcinoma Acinic Cell Carcinoma (no glycogen, fat & mucin, 3% maligant and bilateral) ```

Question 46

Features suggestive of malignancy

Answer 46

``` Induration (hardness) Fixed to Overlying Skin or mucosa Ulceration of skin or mucosa Rapid Growth; Growth Spurt Short Duration Pain, often severe Facial N. Palsy ``` pain and palsy go together often

Question 47

size of T2

Answer 47

T2: 2 cm Tx t0-4

Question 48

Mucoepidermoid carcinoma

Answer 48

MECs contain two major elements: mucin-producing cells and epithelial cells (Epidermoid and Mucinous components). MEC is divided into low-grade (well differentiated) and High-grade (poorly differentiated). Stains that ID mucous musicarmine PAS stain

Question 49

Adeonid cystic carcinoma

Answer 49

Adenoid cystic carcinoma with Swiss cheese pattern. It is the second-most common malignant tumor of the salivary glands. ACC is the most common malignant tumor found in the submandibular, sublingual, and minor salivary glands. against nerve: risk of spread, pain, palsy

Question 50

Rare tumors

Answer 50

``` Carcinoma Ex-mixed Tumor/Malignant Mixed Tumor/Metastasizing Mixed Tumor Epimyoepithelial Carcinoma Salivary Duct Carcinoma Basal cell Adenocarcinoma Squamous Cell Carcinoma ```

Question 51

Pancreatitis

Answer 51

alcohol fatty rich food linked to gallstones acute or chronic Sx: include upper abdominal pain, nausea/vomiting, weight loss and steatorrhea (oily, smelly stool)

Question 52

Panc cancer endocrine

Answer 52

Endocrine: Gastrinoma (Zollinger-Ellison Syndrome) Glucagonoma – usually large, often mets, 70% malignant Insulinoma – the most common pancreatic neuroendocrine tumors Nonfunctional islet cell tumors (NICT) – Usually malignant and hard to detect; don't produce insulin? Somatostatinoma – occur anywhere in the pancreas or doudenum VIP-Releasing Tumor – usually in the body and tail of the pancreas

Question 53

Panc cancer exocrine

Answer 53

Acinar Cell Carcinoma – Rare, leads to overproduction of lipase Adenocarcinoma – 90% of all pancreatic cancer starts in duct Adenosquamous carcinoma - forms glands that flatten as it grows Intraductal Papillary-Mucinous Neoplasm – fingerlike projections into the duct, prelude to malignancy Mucinous Cystadenocarcinoma – rare malignant spongy cystic tumor Pancreatoblastoma – Rare, occurs in kids

Question 54

What usually "gives away" panc cancer?

Answer 54

Pancreatic cancer: mets elsewhere usually gives it away