05a: Salivary and Pancreatic Secretion Flashcards by Nuna H

Salivary glands secrete (X) volume of saliva per day. How much fluid does pancreas secrete per day?

X = up to 1 L

Pancreas: 2 L

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List the primary constituents of saliva.

Water/electrolytes
Mucus
Amylase

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Fluid in lumen of salivary acinus is similar in composition to (X) fluid. This fluid came about as a result of (diffusion/filtration/secretion) via (Y) cells.

X = plasma

Active secretion
Y = acinar cells

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Primary salivary secretion is modified as it passes through (X). List the specific modifications that occur.

X = ducts (tubular cells)

Na and Cl reabsorbed
K and HCO3 secreted

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T/F: As primary salivary secretion is modified in ducts, the degrees of ion absorption and secretion are about equal.

False - absorption exceeds secretion

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Saliva produced following modification in ducts is (acidic/neutral/alkaline).
It’s also (hyper/iso/hypo)-tonic. What’s the reason for this tonicity?

Alkaline;
Hypotonic;
Ion absorption exceeds secretion and ducts relatively impermeable to water

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Saliva tends to approach (hyper/iso/hypo)-tonicity at high flow rates. This is because (X) process is incomplete.

Isotonicity;

X = Na and Cl reabsorption in ducts

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Amylase, produced by (X) cells, accounts for about (Y)% of salivary protein.

X = acinar and striated duct 
Y = 30

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Amylase requires (X) ion and (acidic/alkaline/neutral) pH for optimal activity.

X = Cl

Neutral

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Amylase primary function is to (form/cleave) (X) bonds. List the 3 possible products of digestion by amylase.

Cleave;
X = (NON-TERMINAL) alpha-1,4 glycosidic linkages

Maltose
Maltotriose
Dextrins

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Up to (X)% of starch may be broken down by amylase. Where/when does most of this activity take place?

X = 50

After swallowing (within bolus of food, as long as amylase hasn’t been exposed to gastric acid)

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Aside from amylase, salivary protein is predominantly composed of (X), which serve (Y) function.

X = mucins
Y = lubricating

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(X) proteins in (Y) adhere to outer tooth surface and prevent crystallization of super-saturated solutions.

X = proline-rich peptides (PRPs)
Y = saliva

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(X) proteins are rich with (Y) AA. They are found in (Z) and bind to fungal cell surface domains, become internalized, and lead to fungal death.

X = histatins
Y = His
Z = saliva

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Lysozymes in saliva have which function?

Attach bacterial cell wall (oral health)

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Lactoferrins are proteins in (X) that have (Y) function.

X = saliva
Y = chelates iron (oral health)

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(X) is a wound-healing substance found in saliva.

X = epidermal growth factor

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(X) is a salivary digestive enzyme, produced by (serous/mucus) glands in tongue. How does it differ from amylase?

X = lingual lipase
Serous;

Hydrolyzes TAGs (producing DAG and FA), not starch/CHO

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T/F: Both lingual lipase and salivary amylase are found in saliva and can continue to work following exposure to gastric acid.

False - only lingual lipase can work in low pH environment of stomach

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The salivary gland is only under (neural/hormonal) control. Which (hormones/NS) stimulate these glands?

Neural;

Both sympathetic and parasympathetic

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T/F: Profuse secretion of fluid/electrolytes from salivary glands is most effectively produced by stimulation via parasympathetics.

True

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T/F: A proteinaceous secretion from salivary glands is most effectively produced by stimulation via sympathetics.

True

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Parasympathetic activity increases salivary gland secretion by (increasing/decreasing) (X). Which factors are released to allow this?

Increasing;
X = blood flow

VIP
Kallikrein (enzyme)

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Kallikrein is released from (X) and functions to (Y).

X = salivary gland cells (via parasympathetic stimulation)
Y = cleave plasma kininogens

Plasma kininogens are transformed into (X) via (Y). What's the significance of this?

``` X = kallidin Y = kallikrein enzyme ``` Kallidin (vasodil) can be converted to bradykinin (vasodil); increase salivary secretion

T/F: Both sympathetics and parasympathetics activate myoepithelial cells that surround salivary acini and ducts.

True

Unconditioned reflexes in salivary secretion: (X) receptors send afferent signals to (Y).

``` X = mechan- and chemo- (in nose, mouth, pharynx) Y = salivary nucleus in medulla ```

Higher centers (stimulate/inhibit) salivary nuclei of medulla. List some examples when these centers come into play.

Both; Dry mouth/anxious (inhibit salivation via sympathetic NS and vasoconstriction) Vomiting (stimulate salivation)

Pancreatic acinar cells secrete (acidic/neutral/alkaline) fluid that contains numerous (X).

Alkaline | X = digestive enzymes

Pancreatic digestive enzymes are initiated in/on (X). They're transported and eventually enclosed in (Y) at which location?

``` X = rER ribosomes Y = condensing vacuoles ``` In Golgi

Pancreatic digestive enzyme synthesis: as condensing vacuoles move toward (apex/base) of cell, they become visible as (X). Why?

Apex; X = zymogen granules Their density continues to increase during transport

List the four classes of pancreatic enzymes found in each zymogen granule.

1. Proteases 2. Lipolytic enzymes 3. Glycolytic enzymes 4. Nucleic acid hydrolases

(x) is the glycolytic enzyme secreted by the pancreas. What's it's action?

X = pancreatic amylase Same as salivary amylase (cleaves alpha-1,4 glycolytic bonds on interior of starch)

(X) pancreatic enzyme attacks TAGs and produces (MAG/DAG) and FA.

X = lipase | 2 MAGs

Carboxypeptidases are examples of (gastric/pancreatic/liver/intestinal) (X) enzymes with which specific function?

Pancreatic; X = exopeptidases (proteases) Cleave N or C terminal AAs

(X) is the most abundant of the pancreatic enzymes. It's under which class of enzymes? What's its specific function?

X = Trypsin Endopeptidases (protease) Cleaves interior of peptides (C-terminal side of basic AAs)

Which pancreatic enzymes are released as inactive proenzymes?

Proteases and phospholipase A2

Pancreatic enzymes are packaged with (X), which becomes activated by (Y) at which location? This will allow for proenzyme activation.

``` X = trypsinogen Y = enteropeptidase ``` Found on brush border of cells lining duodenum

Pancreatic enzymes: In addition to (X), zymogen granules contain (Y) as a safety mechanism, in case (X) becomes spontaneously activated.

``` X = trypsinogen Y = trypsin inhibitor ```

T/F: pancreatic acinar cells, like salivary glands, secrete fluid similar in ionic composition to plasma.

True

T/F: fluid secreted by pancreatic and salivary acinar cells undergoes identical modification in the respective ducts.

False - salivary is primarily ion secretion/absorption Pancreatic secretion modified via dilution

Pancreatic acinar cells secrete fluid that the ducts modify by (absorbing/secreting):

Secreting (diluting) with large volume of isotonic, alkaline-rich fluid

It's important for pancreatic secretion entering duodenum to be (acidic/neutral/alkaline) for which key reason?

Alkaline; Neutralizes acidic chyme (thus allowing neutral, optimal pH environment for pancreatic enzymes) AND protects small intestine from acidic environment

Pancreatic duct cell secretory process is dependent on (X) enzyme, like which other secretory cells?

X = carbonic anhydrase Parietal cells of stomach

Pancreatic duct cell has (X) (channel/transporter/ATPase) on apical membrane to allow (H/HCO3) into (lumen/cell).

X = HCO3/Cl Antiporter (exchanger); HCO3; lumen (and Cl into cell)

Pancreatic duct cell: The (paracellular/transcellular) movement of Na into (lumen/cell/ISF) is directly dependent on movement of (X) ion(s) through (Y) (channel/transporter/ATPase).

Paracellular; Lumen (to accompany HCO3); X = Cl Y = CFTR (channel)

Pancreatic duct cell: the (positive/negative) luminal potential drives Na paracellularly to (ISF/lumen). What establishes this potential?

Negative; Lumen; Cl exits to lumen via CFTR

Pancreatic secretion is primarily under control of which hormone(s)?

CCK and secretin

CCK hormone directly stimulates (X) cells to (secrete/absorb) (Y).

X = pancreatic acinar cells Secrete Y = enzyme-rich fluid

Secretin hormone directly stimulates (X) cells to (secrete/absorb) (Y).

X = pancreatic acinar cells Secrete Y = HCO3-rich fluid

Vagal stimulation causes (X) to (increase/decrease) pancreatic acinar cell secretion and (Y) to (increase/decrease) duct cell secretion.

``` X = ACh; increase Y = ACh and VIP; increase ```

During gastric phase of pancreatic secretion, it's thought that (X) can stimulate secretion via which mechanism?

X = gastrin Binding CCK receptor

CCK and secretin come into play during which phase of (X) secretion?

X = pancreatic; Intestinal phase

CCK release is instigated by:

Presence of peptides, AA, free FAs in duodenum/jejunum

In addition to CCK's direct effect on (X) cells, it also bind (Y), triggering:

``` X = pancreatic acinar cells Y = vagal afferent nerves ``` Vagal reflex (additional cholinergic stimulation of acinar cells)

Secretin release is instigated by:

Chyme in duodenum with pH under 4.5

(X) is the major agonist for pancreatic duct cell secretion of (H/HCO3). This signal is mediated by which mechanism?

X = secretin HCO3 cAMP (activates PKA, which phosphorylates and opens CFTR)

Pancreatic duct cell, in general, secretes (hyper/hypo/iso)-tonic solution with which ions?

Isotonic; Na and HCO3