Exocrine pancrease and salivary gland - Collins Flashcards
List the constituents of saliva (8).
Water
Bicarb
Mucins
Amylase (alpha 1,4 bonds in starch. Hence, alpha-amylase)
Lysozyme (pore forming antibacterial - pops them)
lactoferrin (sequesters iron from bacteria)
IgA (opsonizes)
Epidermal and nerve growth factors (dogs licking wounds - healing facilitation)
Acinar cells make the saliva and _____cells modify its ionic content
striated duct
Pressure in the mouth (increases or decreases) salivary secretion?
increases
Three things that decrease salivary secretions?
Sleep, fear, fatigue
Release of this neurotransmitter from the octic ganglion or the submandibular ganglion onto the parotid/submandibular glands will increase salivation.
Ach
Type I secretions. Describe
Plenty of water, parasympathetic.
Type II secretions. Describe.
Thick, crusty secretion driven by sympathetic nervous system. Vasoconstriction, less water into the secretions, more proteinaceous, etc.
Saliva content and secretion is dependent on ____?
At a low rate of flow, duct cells absorb _____ and secrete _____.
blood flow rate.
absorb Na+ and Cl- and secrete K+ and HCO3-.
Faster flow rate limits the action of duct cells on ionic/water content
What do the salivary acinar cells do? What path do secretions take?
Acinar cells make the saliva and secrete it into the acinus. It then proceeds into the intercalated duct and then the striated duct.
What are the secretory products of the exocrine pancreas? (many)
Trypsinogen
Chrmotrypsinogen
Proleastase
Procarboxypeptidase A and B
Amylase Lipase Deoxyribonuclease/Ribonuclease Procolipase Monitor peptide Trypsin inhibitor
WHat three compounds regulate pancreatic secretion?
Ach, Secretin, CCK
How does Ach regulate pancreatic secretions?
released from the vagus and ENS nerves; stimulates the release of digestive enzymes from acinar cells (mostly cephalic stage)
How does Secretin regulate pancreatic secretions?
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
How does CCK regulate pancreatic secretions?
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
What is one difference in the secretion of HCO3 between the salivary and pancreatic glands?
Salivary - kHCO3
Pancreatic/duodenal - NaHCO3
What is a key structural difference between the salivary and pancreatic acinus?
Pancreatic acini lack myoepithelial cells
What is the effect of CCK in the duodenum on: Gallbladder Pancreas Stomach Sphincter of Oddi
Gallbladder - contraction
Pancreas - Acinar secretion
Stomach - REduced emptying
Sphincter of Oddi - relaxation, facilitation and release
**Balance between buffering acid and having the necessary enzymes present to digest
In the duodenum, CCK is released from the ___ cells.
I cells.
Which are more sensitive to changes in flow rate between the pancreas and salivary glands?
Salivary glands more susceptible to changes in flow rate.
What are 4 differences between salivary and pancreatic acini?
Myoepithelium–> salivary only
Rate of secretion–> affected more in salivary
K/Na–> K salivary Na pancreatic
Neuronal vs hormonal–> salivary is neuronal pancreatic is hormonal.
At high flow rates, saliva is slightly (hypotonic OR hypertonic) and rich in bicarbonate, while at low flow rates it becomes quite (hypotonic OR hypertonic).
High flow rate–> Hypotonic
Low flow rate–> hypertonic
_____ activates trypsinogen.
Enterokinase
The presence of chyme in the duodenum stimulates the release of ____ which is the primary stimulator of enzymatic release from acinar cells.
Acidity in the lumen triggers release of ____, which increases NaHCO3 to raise the pH.
CCK; secretin
CCK and secretin are inhibitory to gastric acid production and delay gastric emptying until the chyme has been processed and the intestine is ready for more.
Additionally, CCK potentiates release of secretin.
____ cells in the pancreas secrete digestive enzymes.
____ cells secrete aqueous component
Acinar
Duct
