GI - Pt 3 Secretions Flashcards
Serous (acinar) cells secrete [] & []
Mucus acinar cell secrete []
Serous (acinar) cells secrete water & bicarb
Mucus acinar cell secrete mucus
Salivary Secretions:
- Almost totally under [] NS control
- Primarily []
- Secondarily []
- What are the ~4 main secretions we covered?
- Almost totally under Autonomic NS control
- Primarily parasympathetic
- Secondarily sympathetic
- What are the ~4 main secretions we covered?
- Salivary Amylase
- Lingual lipase
- Haptocorrin
- Intrinsic Factor
Salivary Amylase:
- Indentical to [] amylase
- Its optimum resides around pH - []
- Cleaves the interal [] [] [] []
- Indentical to pancreatic amylase
- Its optimum resides around pH - 7
- Cleaves the interal alpha 1-4 glycosidic bonds
Lingual Lipase
- secreted by the glands of the []
- Begins digestion of []
- Optimal pH resides around - [] []
- secreted by the glands of the tongue
- Begins digestion of triglycerides
- Optimal pH resides around - acidic conditions
Haptocorrin
- It is a []
- Binds vitamin [] in the []/duodenum
- so it protects B12 in [] environments.
- VERY similar to [] []
- This protects B12 in the []
Haptocorrin
- It is a glycoprotein
- Binds vitamin B12 in the stomach/duodenum
- so it protects B12 in acidic environments.
- VERY similar to Instrinsic Factor
- This protects B12 in the intestines
Lubrication & protection salivary secretions:
- [] - protect stomach from initial [] stress
- [] aspect (bacteriocidal)
- [] (IgA) - optimizing an immunological response against bacteria and virus
- [] - chelates Iron
- Mucus - protect stomach from initial food stress
- Lyzozymal aspect (bacteriocidal)
- Immunoglobin A (IgA) - optimizing an immunological response against bacteria and virus
- Lactoferrin - chelates Iron
Dry Mouth
- [] refers to chronic infectins of the buccal mucosa
- Dissolution of [] components by [] acids produced by enzymatic actions of masses of []
-
Xerostomia refers to chronic infectins of the buccal mucosa
- Dissolution of inorganic components by organic acids produced by enzymatic actions of masses of microorganism
Parotid Gland
- Largest [] gland
- Made of serous cells with produce []/[] and []
- At rest, produce [] of saliva volume
- Active, produces [] of saliva volume
- Largest salivary gland
- Made of serous cells with produce H2O/HCO3- and enzymes
- At rest, produce 25% of saliva volume
- Active, produces 80% of saliva volume
Submandibular Gland
- Unstimulated, accounts for [] of overall saliva volume
- It is a [] salivary gland
- [] is the major component
- Also has a [] component.
- Unstimulated, accounts for 70% of overall saliva volume
- It is a mixed salivary gland
- mucus is the major component
- Also has a serous component.
Sublingual Gland
- Mainly a [] gland
- contains a very minor [] portion
- Mainly a mucus gland
- contains a very minor serous portion
T/F
Saliva secreted by serous/mucus acinus is modified in the intercalated duct and not the striated duct?
FALSE
The modification of saliva happens in the stiated duct
- Salivary glands receive a high blood flow which results in the production of a large volume of []
fluid
- Salivary glands receive both [] and [] innervation
- Parasympathetic is the [] component and is done by 2 nerves:
- [] Nerve (VII)
- [] (IX)
- Sympathetic is the []component done through the [] spinal cord via the superior [] ganglion
- Parasympathetic is the [] component and is done by 2 nerves:
- Salivary glands receive both parasympathetic and sympathetic innervation
- Parasympathetic is the major component and is done by 2 nerves:
- Facial Nerve (VII)
- Glossopharyngeal Nerve (IX)
- Sympathetic is the minor component done through the thoracic spinal cord via the superior cervical ganglion
- Parasympathetic is the major component and is done by 2 nerves:
For salivary glands, even though they receive Para/Symp innervation, [] innervation is more important because they are somehow [] to the salivary glands. So, if this innervation is cut off…the glands would []
For salivary glands, even though they receive Para/Symp innervation, parasympathetic innervation is more important because they are somehow nutritive to the salivary glands. So, if this innervation is cut off…the glands would “die”
Salivary glands, Autonomics regulate…
- secretions by acting on [] cells
- Blood flow by acting on [] networks
- Growth by acting directly on [] cells
- secretions by acting on myoepithelial cells
- Blood flow by acting on arteriolar networks
- Growth by acting directly on acinar cells
Parasympathetic flow of Salivary glands
- Receptors - [] and []
- [] of transport process
- Contraction of [] cells
- [] the blood vessels
- [] the cellular activity resulting in [] of the cell.
- Receptors - muscarinic and cholinergic
- Activation of transport process
- Contraction of myoepithelial cells
- Vasodilate the blood vessels
- Increase the cellular activity resulting in growth of the cell.
Sympathetic (w/ Para)
- Uses [] receptors
- Increases secretion, metabolism, and growht
- With [] parasympathetic stimulation..
- produces a more[] secretion
- increases []
- Causes [] - reduced [] secretions.
- Uses B2 adrenergic receptors
- Increases secretion, metabolism, and growth
- With reduced parasympathetic stimulation..
- produces a more viscous secretion (thicker), = nervous
- increases mucus
- Causes vasoconstriction - reduced serous secretions.
Salivary Flow
- [] [] [] (VIP), a [], is released at the [] end and mediates []
Vasoactive intestinal peptide (VIP), a neurocrine, is released at the postganglionic end and mediates vasodilation
- Conditioned reflex like smell/taste –>
- stimuli in the Nucleii Salvatorii in the medulla Oblongata –>
- Parasymp Nerves: Facial (VII) & Glossopharyngeal (IX) –> releases ACh & VIP –>
- Vasodilation and Salivary gland stimulation –>
- In salivary gland: Increase in IP3 = Increase in Ca2+ –> Increase in metabolism, secretion, growth, myoepithelial contraction.
- Conditioned reflex like smell/taste –>
- Sympathetic nerves T1/T2/T3 - release [] –>
- Superior [] ganglion–> postgonglionic axons release [] at salivary gland that bind to [] [] receptors –> increase in [] = increase in [] –> increaes metabolism, cell contraction, secretion, growth.
- Conditioned reflex like smell/taste –>
- Sympathetic nerves T1/T2/T3 - release ACh –>
- Superior Cervical ganglion–> postgonglionic axons release norepinephrine at salivary gland that bind to B2 adrenergic receptors –> increase in cAMP = increase in Ca2+ –> increaes metabolism, cell contraction, secretion, growth.
Saliva Compostion:
- High [] concentration
- Low []
- Inorganic Composition:
- K+ is always [] than plasma
- Na+ is [] than plasma
- CL- is [] than plasma
- HCO3- is [] than plama (except at [] [])
- High K+ concentration
- Low Osmolarity
- Inorganic Composition:
- K+ is always greater than plasma
- Na+ is less than plasma
- CL- is less than plasma
- HCO3- is greater than plama (except at low flow)
All ions in salivary acinus = the plasma [] of ions
concentration
T/F - all ion in the acinus are in equal concentration to the ionic concentration of the plasma
True
Striated Ductal Function
- Reabsorb [] and []
- Secrete [] and []
- [] dependent
- More [] and [] leaves than [] and [] enter
- Epithelium is relatively [] to H2O
- As saliva leaves the duct, it is []
- Reabsorb Na+ and Cl-
- Secrete K+ and HCO3-
- Time dependent
- More Na+ and Cl- leaves than K+ and HCO3- enter
- Epithelium is relatively impermeable ot H2O
- As saliva leaves the duct, it is hypotonic
As flow past the salivary duct cells increase, the time for resorptive and secretory processes []; saliva moves toward []
As flow past the salivary duct cells increase, the time for resorptive and secretory processes decreases; saliva moves toward isotonicity
As salivary flow rate increase:
- Na+ and Cl- concentrations in the lumen []
- [K+] in the lumen [] slightly
- [HCO3-] in the lumen [] because its secretion is increased by the same [] that increase flow rate.
- Na+ and Cl- concentrations in the lumen increase
- [K+] in the lumen decreases slightly
- [HCO3-] in the lumen increases because its secretion is increased by the same stimuli that increase flow rate.
Even when salivary flow rate increase, Na+ and Cl- will [] reach their concentrations in the plasma.
Even when salivary flow rate increase, Na+ and Cl- will never reach their concentrations in the plasma.
- Increased Flow rate –> Increased metabolism and Increased[] and [] production —> H+ and [] production
- The H+ gets [], but the HCO3- does not…so pH of saliva will [].
- Increased Flow rate –> Increased metabolism and Increased CO2 and H2O production —> H+ and HCO3- production
- The H+ gets buffered, but the HCO3- does not…so pH of saliva will increase.