Physiology of exocrine pancreas and slivary glands Flashcards
List the 6 main constituents of saliva and their function.
WATER
-fascilitates taste and dissolution of nutrients, aids in swallowing and speech
BICARBONATE
-which helps to maintain an optimal pH for enzyme activity and also to reduce Ca2+ solubility. When the pH > 7.0, teeth do not lose Ca2+ to oral fluids;
MUCINS
-large glycoproteins that lubricate food and facilitate swallowing
alpha-AMYLASE
-begin the digestion of starches and fats breaks alpha 1,4 bonds;
LYSOZYME, LACTOFERRIN, IgA
-The antibacterial agents immunoglobulin A (lgA), lysozyme which destroys bacterial cell walls, and Iactoferrln which chelates iron thus preventing the growth of bacteria that require iron.
EPIDERMAL and NERVE GROWTH FACTORS
-mucosal growth and protection
Mechansism of salivary secretion
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
List the major ionic and peptide/protein components secreted by the pancreas.
PROTEASES Trypsinogen* Chymotrypsinogen Proleastase Procarboxypeptidase A Procarboxypeptidase B
Amylase
Lipase
Nonspecific esterase
Prophospholipase A2
Deoxyribonuclease
Ribonuclease
Procolipase
Trypsin inhibitors
monitor peptide
State three types of stimuli that increase pancreatic secretion.
parasympathetic
chyme-CCK
acid-Secretin
Explain the function of CCK, where it is released from, what cells it works on and what the outcome of its actions are.
CCK released from I cells CCK acts on -gallbladder--> contraction -pancreas-->acinar secretion -stomach-->reduced emptying -sphincter of Oddi-->relaxation
Protein, carbohydrate, lipid absorption and digestion
Matching of nutrient delivery to digestive and absorptive capacity
when there isnt much protein to break down, trypsin will act on monitor peptide and CCK RP (inhibiting both). causing less release of CCK from I cells
List the eight different infection/immunological salivary gland diseases
Mumps- Cytomegaloviral Sialadenitis Bacterial Sialadenitis Sarcoidosis Sjögren’s Syndrome Salivary Lymphoepithelial Lesion Xerostomia or dry mouth Halitosis
Discuss characteristics of benign and malignant salivary neoplasia and be able to describe examples of both.
benign Mixed Tumor (pleomorphic adenoma) -Warthin’s Tumor- epithelial component, lymphoid components Monomorphic Adenomas -Basal cell adenoma Ductal papilloma
malignant Mucoepidermoid Carcinoma (mucin+) Polymorphous Low-grade Adenocarcinoma Adenoid Cyctic Carcinoma Clear Cell Carcinoma Acinic Cell Carcinoma (no glycogen, fat & mucin, 3% maligant and bilateral)
Induration (hardness)--more risk Fixed to Overlying Skin or mucosa--less risk Ulceration of skin or mucosa--more risk Rapid Growth; Growth Spurt---more risk Short Duration--more risk Pain, often severe--more risk Facial N. Palsy-more risk
T2 is two centimeters
List eight forms of endocrine and eight exocrine pancreatic cancers, identify their key features and how the TNM method of staging is used to grade them
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
Somatostatinoma – occur anywhere in the pancreas or duodenum
VIP-Releasing Tumor – usually in the body and tail of the pancreas
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
Explain the structure and function of the salivary gland
proteinaceous and mucus type secretion
acinar cells-make the saliva (hypertonic)
striated duct cells modify its ionic content
Myoepithelial cell- facilitate secretion in the Acinus and propel secretions through intercaleted duct into striated duct (Pancrease doesn’t have these)
low flow saliva rate Na Cl reabsorbtion
high flow rate na cl reabsoption
high
low
before you vomit, you…
increase ur saliva
Contrast the plasma and salivary concentrations of Na+, CI-, and HCO3 - at low secretion rates and at high secretion rates and the principal cell types involved in each secretion rate.
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regulation of pancreatic secretion
Acetylcholine (ACh) – released from the vagus and ENS nerves; stimulates the release of digestive enzymes from acinar cells (mostly cephalic stage)
Secretin – released from endocrine cells in the proximal small intestines in response to acid; stimulates the release of a bicarbonate rich solution from pancreatic duct cells
Cholecystokinin (CCK) – 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
are there myoepithelial cells in pancreatic secretions?
no
Ca2+ and cAMP increase acinar secretion
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