Gastric Hormones And Regulators

Front 1

Stimulatory Neurotransmitters

and their role in intrinsic neuronal motility control

Back 1

Ach

Substance P

*Released by Excitatory Motor Neurons to depol. smooth mm for stronger contractions

Front 2

Inhibitory Neurotransmitters

and their role in intrinsic neuronal motility control

Back 2

VIP

NO

*Released by Inhibitory Motor Neurons to hyperpol. smooth mm for weaker contractions or prevent reaching threshold w/ ICC stimulation

Front 3

NE

(in extrinsinc neural motility control)

Back 3

Released by symp. to inhibit ENS and thus prevent motility

Front 4

Incretin Effect

Back 4

Larger release of insulin w/ oral administration vs IV due to release of GIP release from K-cells in duodenum

Front 5

3 secretions from Surface and Neck Mucus Cells

and

2 means of stimulation

Back 5

Mucus

HCO3-

Trefoil Peptides (heal damaged tissue)

Stimulated : Ach from Vagus and chyme rubbing surface

Front 6

2 Secretions from Parietal Cells

and

3 means of stimulation, 2 means of inhibition

Back 6

H+

Intrinsic Factor (binds cobalamin - aka B12)

Stimulated : Ach from Vagus, Gastrin, Histamine

Inhibited: Somatostatin, Prostaglandin

Front 7

2 secretions from Chief Cells

and 2 means of stimulation

Back 7

Pepsinogen

Gastric Lipase

Stimulation: Ach from Vagus and low pH

Front 8

Gastrin

Back 8

Secreting Cell: G-cell in stomach antrum

Stimulants: GRP from Vagal efferent, Oligopeptides, stomach distention, rise in pH

Fxn: mainly stimulate ECL-cell to release Histamine, some direct stim of parietal cell via increase in IP/Ca2+

Front 9

Histamine

Back 9

Secreting Cell: Enterochromaffin-like Cells (ECL)

Stimulants: Gastrin

Fxn: Paracrine stimulation of parietal cells via increase in cAMP

Front 10

Somatostatin

Back 10

Secreting Cell: D-cell in stomach antrum

Stimulants: pH < 3.5

Fxn: Inhibits G-cell from releasing Gastrin and directly inhibits parietal via decrease in cAMP

Front 11

Enterokinase

Back 11

Location: Membrane of brush border of duod.

Fxn: Activates Trypsinogen released from pancreas. Active Trypsin activates rest of zymogens

Front 12

Trypsin Inhibitor

Back 12

Location: Secretory granules of acinar cells of pancreas

Fxn: prevents activation of proteases to prevent autodigestion

Front 13

What do the ductal cells of the pancreas secrete?

Back 13

HCO3- to neutralize duodenal pH (protects mucosa, optimize brush border enzymes, and increase solubility of bile acids and FA's)

Monitor Peptide to stimulate CCK release

Front 14

Secretin

Back 14

Secreting Cell: S-Cells in duodenum

Stimulants: pH < 4.5 in SI lumen

Fxn: increase HCO3- release from pancreatic ductal cells (potentiated by Ach & CCK) and from Bile ductule, increase bile secretion

Front 15

Cholecystokinin (CCK)

Back 15

Secreting Cell: I cells in duodenum and Jejunum

Stimulants: digestive products, Monitor peptide & CCK-RP (both degraded by trypsin in fasting state to inhibit CCK release)

Fxn: Increases pancreatic secretion by binding CCK-1 receptor and activating Vagal reflex to increase Ach/VIP/CRP, Contracts GB, slows gastric emptying, relaxes sphincter of Oddi

Front 16

Alpha-Amylase

Back 16

Source: Pancreatic Acini and Salivary Glands

Fxn: Endoglycosidase for α-1,4 bonds in starch (ie can't break bonds at ends or adjacent to α-1,6 bonds).

Product: Di- and Oligosaccharides (can't make monosaccharides)

Front 17

Glucoamylase,

Isomaltase,

Sucrase,

Lactase

Back 17

Location: Brush border enzymes in duodenum

Fxn: Glucoamylase splits α-1,4 in maltose/maltotriose

Isomaltase splits α-1,6 and α-1,4

Sucrase splits sucrose, Lactase splits lactose

Front 18

3 means of digesting protein

Back 18

1) Gastric pepsin and pancreatic proteases

2) Brushborder Aminooligopeptidases (hydrolize tri-/tetra-peptides adjacent to Leu)

3) Cytoplasmic Peptidases (hydrolyze Di-/Tri-peptides absorbed in enterocyte)

Front 19

Gastric Lipase

Back 19

Source: Cheif cells

Fxn: Cleave TG into DG + 1FA

Front 20

Pancreatic Lipase,

Phospholipase,

Carboxy Esterase

Back 20

Source: Acinar cells

Fxn: Lipase cleaves TG into MG + 2FA

Phospholipase cleaves phospholipid into FA +Lysophospholipid

Carboxy esterase cleaves CH, esters, Lysophospholipids

*Newborns have little lipase -- compensated by milk lipase

Front 21

Colipase

Back 21

Coenzyme of pancreatic lipase that brings lipase to fat droplet surface of micelles

*w/out, no TG get release from micelle

Front 22

Hepcidin

Back 22

Source: Liver

Stimulation: Increase in Fe stores in liver

Fxn: Causes endocytosis of Feroportin on Duodenal Enterocytes to decrease Fe2+ reabsorption

Front 23

3 hormones that increase motility and 1 hormone that inhibits it

Back 23

Stimulants = Gastrin, CCK, Motilin

Inhibitor = PYY

Front 24

3 hormones that slow Gastric Emptying and 1 hormone that speeds it up

Back 24

Slows emptying: CCK, PYY, Neurotensin

Speeds emptying: Motilin