When the Ca2+ levels drop:

Myosin LC is dephosphorylated by MLC phosphatase, causing muscle relaxation.

TLS Online TPP Program

#Id: 6567

#Unit 7. System Physiology – Animal

Pancreatic B cells contain GABA, and coincident with the increased insulin secretion produced by hyperglycemia, GABA is released and acts on the A cells by activating GABA A receptors

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#Id: 6568

#Unit 7. System Physiology – Animal

GABA A receptors are Cl– channels, and the resulting Cl– influx hyperpolarizes the A cells to inhibit glucagon secretion 

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#Id: 6569

#Unit 7. System Physiology – Animal

Glucagon secretion is increased by stimulation of the sympathetic nerves to the pancreas, & sympathetic effect is mediated via β-adrenergic receptors and cAMP

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#Id: 6570

#Unit 7. System Physiology – Animal

Somatostatin 14 and its amino terminal-extended form somatostatin 28 are found in the D cells of pancreatic islets

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#Id: 6571

#Unit 7. System Physiology – Animal

SS14 & SS28 both inhibits the secretion of insulin, glucagon, and pancreatic polypeptide and act locally within the pancreatic islets in a paracrine fashion

TLS Online TPP Program

#Id: 6572

#Unit 7. System Physiology – Animal

Human pancreatic polypeptide contains 36 amino acid residues and is produced by F cells in the islets